Linus Pauling May Have Been Vindicated - Vitamin C May Treat Cancer

haidut

Member
Joined
Mar 18, 2013
Messages
17,943
Location
USA / Europe
I am posting this only because Linus Pauling is so vilified and mocked by mainstream medicine. In fact, his proposal to use high doses vitamin C for cancer treatment is listed on QuackWatch as one of the greatest medical hoaxes of the 20th century.
The Dark Side of Linus Pauling's Legacy
Well, it looks like Linus may have the last laugh. This recent study found that very high doses vitamin C, achievable only through injection of IV infusion increase hydrogen peroxide inside the tumor cells and the resulting excessive oxidative stress kills the tumor cells. Pauling repeatedly said that only very high doses of vitamin C are likely to have an effect because lower doses act as an anti-oxidant while higher ones as oxidant, and this is what the study found. Tumor cells surround themlseves with antioxidants like NAC and do everything possible to avoid oxidative stress and ROS like H2O2.

http://www.sciencedirect.com/science/article/pii/S2213231716302634

"...The data presented here quantitatively establish a central role for H2O2, generated upon the oxidation of P-AscH−, in the cytotoxic effects of P-AscH− to cancer cells in vitro. Our data quantitatively support the many observations that indicate that the cytotoxicity of P-AscH− to cancer cells observed in vitro is largely due to its generation of H2O2 in the medium (Supplementary Fig. S1) [1], [2], [3], [4], [5] and [9]. Ascorbate delivered at pharmacological concentrations has shown selective toxicity to several different tumor cell types. While this selective cytotoxicity has been observed to be dependent on the generation of H2O2, the mechanism by which this occurs is still under investigation. Several mechanisms for how the H2O2 generated by P-AscH− elicits its cytotoxicity to tumor cells have been hypothesized and examined, for example: DNA damage [3], [13], [52], [55], [56] and [57]; and the depletion of ATP leading to tumor cell death [1], [3], [10], [58] and [59]. H2O2 plays an integral role in the mechanism. However, many other factors can modulate the toxicity of P-AscH−, e.g. KRAS status [3], the level of catalytic metals[60] and [61], the redox status of the intracellular GSSG,2 H+/2GSH redox couple[45] and [62], and the status of NAD [58]. Yun et al. recently extended the observations that ascorbate selectively kills KRAS and BRAF mutant cells [59]; they suggest that P-AscH− has as a target the redox state of GAPDH. However, the mechanism the authors propose does not consider important published data that clearly demonstrate that P-AscH− induces selective oxidative stress and cytotoxicity in cancer cells vs. normal cells by a mechanism involving the production of H2O2. Some of the biochemical reagents used to probe possible mechanism react directly with H2O2, thereby removing it and protecting the cells; see Supplementary Discussion."
 

encerent

Member
Joined
Sep 16, 2014
Messages
595
@haidut Ray talks about the old-school vitamin C which was expensive and came in very small doses. It was, though, very effective and didn't harm you like modern mass produced vitamin C contaminated with heavy metals.

You should come out with an "original C" like you did for E.
 
Last edited:

paymanz

Member
Joined
Jan 6, 2015
Messages
2,693
Interesting,

Once I read an article by Linus Pauling , he mentioned vitamin c is important to produce body's natural hyaluronidase inhibitor.

And by that also vitamin c may prevent cancer..;
Hyaluronidase causes tissue enlargement ,and fragments of hyaluronic acid in blood causing inflammation in the body.according to peat.
 

haidut

Member
Thread starter
Joined
Mar 18, 2013
Messages
17,943
Location
USA / Europe
@haidut Ray talks about the old-school vitamin C which was expensive and came in very small doses. It was, though, very effective and didn't harm you like modern mass produced vitamin C contaminated with heavy metals.

You should come out with an "original C" like you did for E.

Interesting, thanks! Do you have a link to his article/interview where he discusses the different vitamin C types and how the old one was better?
 

haidut

Member
Thread starter
Joined
Mar 18, 2013
Messages
17,943
Location
USA / Europe
Interesting,

Once I read an article by Linus Pauling , he mentioned vitamin c is important to produce body's natural hyaluronidase inhibitor.

And by that also vitamin c may prevent cancer..;
Hyaluronidase causes tissue enlargement ,and fragments of hyaluronic acid in blood causing inflammation in the body.according to peat.

Makes sense. I'd imagine all of these people injecting themselves with hyaluronic acid for cosmetic purposes are really not doing themselves any favors, right?
 

sugarbabe

Member
Joined
Sep 13, 2012
Messages
3,565
Location
USA
I use ascorbic acid with < 3 ppm heavy metals. I imagine most supps are contaminated to some degree. Not to mention if you drink soda!

Thanks for sharing Haidut :)
 
L

lollipop

Guest
@haidut a doctor in Britain has been pulling people out of late late stage cancer and curing it with high dose Vit C injections and iv for years now. Crazy that Pauling was so vilified.
 

encerent

Member
Joined
Sep 16, 2014
Messages
595
Interesting, thanks! Do you have a link to his article/interview where he discusses the different vitamin C types and how the old one was better?

I just have this fragment from the search engine.

Herb Doctors: The Ten Most Toxic Things In Our Foodnew
At that time, it was very expensive to make. And the pills on sale were only 50 mg. Several years later they developed new ways of manufacturing it. One of the processes Linus Pauling described as the lead room for making sulfuric acid which is then – the sulfuric acid is slightly contaminated with lead and other heavy metals.


cornstarch is processed, oxidized with this industrial sulfuric acid and ends up as ascorbic acid containing quite a bit of heavy metal. And with these new methods, I found that when people were taking 500 or 1,000 mg, they would often develop cold symptoms when they took it rather than when they didn't take it. And it apparently is irritating enough to the intestines that it causes endotoxin
 

Mjhl85

Member
Joined
Mar 30, 2016
Messages
119
I use ascorbic acid with < 3 ppm heavy metals. I imagine most supps are contaminated to some degree. Not to mention if you drink soda!

Thanks for sharing Haidut :)
Janelle could you elaborate on the soda comment?
 

Koveras

Member
Joined
Dec 17, 2015
Messages
719
Interesting, thanks! Do you have a link to his article/interview where he discusses the different vitamin C types and how the old one was better?

14:07


Also this from somewhere...

"Yes, more than 20 years ago, I pointed out the amount of heavy metal
contamination, and the frequent reactions I had seen, to Pauling, and he
just said I should use Bronson's C, as if that would have been made with
anything except Hoffman-LaRoche's stuff. (It was Pauling's own
description of the manufacturing process for sulfuric acid, using a
"lead room," that got me thinking about the dangers of things
manufactured with it.) I guess ADM is making a large fraction of
ascorbic acid now, so I wouldn't be surprised if some of it was worse
than when the heavy metal studies were published several years ago.

Ray Peat's experiences and work with C:
The alteration of production processes in vitamin E manufacture when the
evil soybean monopoly bought the industry from Eastman Chemical is
analogous to what happened earlier in the vitamin C industry, as profits
were maximized. The dramatic vitamin C studies in the 1930s often used
only 15 or 25 milligrams per day. In 1953, my first experience with it
(which was still sold as "cevitamic acid")involved 50 mg per day, and
over a period of just 2 or 3 days, my chronic awful poison oak allergy
disappeared. Up until this time, it was still too expensive to sell in
large doses. Around 1955 or '56, new manufacturing methods made it cheap
(and, for some reason, the name changed from cevitamic to ascorbic) and
the average tablet went up to 500 mg. The first time I tried the new
form, around 1956, I developed allergy symptoms within a couple of days.
Over the next 20 years, my own increased sensitivity to synthetic
ascorbate led me to look for such reactions in others. The same
people who reacted to it often reacted similarly to riboflavin and
rutin, which were also made from cornstarch by oxidation. I ascribed the
reaction to some industrial contaminant that they had in common,
possibly the heavy metals introduced with the sulfuric acid. The heavy
metal contamination of synthetic ascorbate is so great that one 500 mg
tablet dissolved in a liter of water produces free radicals at a rate
that would require a killing dose of x-rays to equal. The only clean and
safe vitamin C now available is that in fresh fruits, meats, etc. The
commercial stuff is seriously dangerous.

http://designserver.mae.cornell.edu/rea ... ocess.html
..

Process conditions for ascorbic acid manufacture
1. Hydrogenation Typical conditions are: Equal amounts of glucose, water
and methanol, with pH adjusted to slightly above neutral with calcium
hydoxide. Abour 3% by vol. of Raney nickel catalyst. Temp 140-150 C and
pressure 80-125 atm!!
After 2 hours get about 95% yield . Filter while hot to remove nickel
catalyst. Must treat with ion exchange resins to remove essentially all
nickel that may have dissolved from the catalyst (see next step). Cool
down and filter the white crystalline mass

2. Oxidation of sorbitol to sorbose with Gluconobacter suboxydans
Ni ions are a problem--tank materials --since the bacteria are
sensitive. Only 10 ppm may be toxic, although now some strains can
tolerate 25 ppm.

About a 20% solution of sorbitol--also add mineral salts and 0.0.2 -
0.4% of corn steep liquor or yeast extract as accessory nutrients. Must
sterilize medium. Use 10% or even more inocu;lum if batchwise. Highly
aerobic-use oxygen-enriched air and ca, 2 atm backpressure. Temp 30 C
and pH of 5-6 is now possible. After 24 hr. centrifuge to remove the
bacteria De-ionize and vacuum concentrate ( at not more than 50º C )
Drop to pH 3.0 crystallize; then filter and dry. Yield: 90%

3. Acetonation
Dissolve in dry acetone + conc. sulfuric acid ( e.g. 100 gm in 2 liters
acetone plus 80 ml acid) May take 3 hrs to dissolve--forms mono-
derivative first as it dissolve. Stir at room temp for another 20 hours!
Neutralize with CaCO3 , filter off the Ca SO4 and distill off the
acetone. Residue is taken up in ether and dried with anhydrous sodium
sulfate. Ether is distilled off and finally the product is purified by
vacuum distillation at 135º C and 3 mm Hg (Somemonosubstituted sorbose
is recycled back to the process). Yield: 85%

4. Oxidation to di-acetone 2-ketogulonic acid
Originally permanganate was used to accomplish this oxidation, but now
the acetonated sorbose is dissolved in dilute NaOH and aerated with
palladium-oncarbon catalyst for 3-5 hrs at slightly elevated
temperature. The solution is acidified to give the free acetone complex
of ketogulonic acid which precipitates. It is wahed with acetone and
dried. Ca. 90% yield

5. Hydrolysis, rearrangement, & final purification
The product from Step 4 is treated with methanol/HCl at pH around 2 in
an inert chlorinated -hydrocarbon solvent. The temp is held at around
100ºC for 2 hrs. Acetone is released and the molecule forms a ring
structure (inner ester) known as a "lactone". Mother liquors of acetone
and methanol are recovered by distillation, Further acid treatment may
be used to accomplish full enolization. The crude product is
re-crystallized from dilute ethanol. (This and all subsequent steps must
be done under notrogen/CO2 atmosphere to prevent the oxidation of
ascorbic acid) Vacuum evaporation and seeding with pure crystals of the
vitamin are used in the final stage. Yield, overall, for Step 5 is about 85%
=======================================================================
Biochemistry 1995 Feb 28;34(8):2653-61
Differential dependence on chromatin structure for copper and iron ion
induction of DNA double-strand breaks. Chiu SM, Xue LY, Friedman LR,
Oleinick NL. Department of Radiology, Case Western Reserve University
School of Medicine, Cleveland, Ohio 44106.
The induction of DNA DSB (double-strand breaks) in isolated nuclear
chromatin by Cu(II) or Fe(II)-EDTA in the presence of H2O2 and ascorbate
has been compared to DSB induction by gamma-radiation. V79 nuclei
embedded in agarose plugs were treated with each agent on ice, and the
resultant DNA fragments were analyzed by pulsed-field gel
electrophoresis. In the absence of low molecular weight radical
scavengers, both irradiation and treatment with iron ion induced random
DSB, as judged by the size distribution of DNA fragments, and the yield
of DSB in each case was enhanced by either the expansion of chromatin
(approximately 5-fold) or the removal of histones (21-25-fold) before
treatment. In contrast, treatment with Cu(II) produced small DNA
fragments of uniform size (approximately 100-200 kbp), independent of
the yield of DSB. In addition, neither the DNA fragment
size nor the yield of DSB produced by Cu(II) was affected by the prior
removal of histones from chromatin. Deproteinized DNA was degraded
randomly by Cu(II) but at a slower rate than observed for chromatin. In
the presence of ascorbate, H2O2 was found to be essential for DSB
induction by Fe(II)-EDTA but not by Cu(II), possibly because H2O2 can be
produced from ascorbate and Cu(II)in the presence of oxygen. Despite the
above differences between the production of DSB by the two metal ions,
DSB induction in native chromatin by either metal ion was
blocked by 0.1 M EDTA or 0.25 M thiourea but was resistant to the
hydroxyl radical scavengers 0.25 M DMSO and 0.25 M mannitol.(ABSTRACT
TRUNCATED AT 250 WORDS)

Radiat Res 1996 May;145(5):532-41
Catalytic metals, ascorbate and free radicals: combinations to avoid.
Buettner GR, Jurkiewicz BA. ESR Facility and Radiation Research
Laboratory, University of Iowa, Iowa City, 52242-1101, USA.

Trace levels of transition metals can participate in the metal-catalyzed
Haber-Weiss reaction (superoxide-driven Fenton reaction) as well as
catalyze the oxidation of ascorbate. Generally ascorbate is thought of
as an excellent reducing agent; it is able to serve as a donor
antioxidant in free radical-mediated oxidation processes. However, as a
reducing agent it is also able to reduce redox-active metals such as
copper and iron, thereby increasing the pro-oxidant chemistry of these
metals. Thus ascorbate can serve as both a pro-oxidant and an
antioxidant. In general, at low ascorbate concentrations, ascorbate is
prone to be a pro-oxidant, and at high concentrations, it will tend
to be an antioxidant. Hence there is a crossover effect. We propose that
the "position" of this crossover effect is a function of the catalytic
metal concentration. In this presentation, we discuss: (1) the role of
catalytic metals in free radical-mediated oxidations; (2) ascorbate as
both a pro-oxidant and an antioxidant; (3) catalytic metal catalysis of
ascorbate oxidation; (4) use of ascorbate to determine adventitious
catalytic metal concentrations; (5) use of ascorbate radical as a marker
of oxidative stress; and (6) use of ascorbate and iron as free radical
pro-oxidants in photodynamic therapy of cancer.

Photochem Photobiol 1996 May;63(5):649-55
Quantitation of the reactive oxygen species generated by the UVA
irradiation of ascorbic acid-glycated lens proteins.
Linetsky M, Ortwerth BJ. Mason Institute of Ophthalmology, University of
Missouri, Columbia 65212, USA.

The oxidation products of ascorbic acid rapidly glycate proteins and
produce protein-bound, advanced glycation endproducts. These endproducts
can absorb UVA light and cause the photolytic oxidation of proteins
(Ortwerth, Linetsky and Olesen, Photochem. Photobiol. 62, 454-463,
1995), which is mediated by the formation of reactive oxygen species. A
dialyzed preparation of calf lens proteins, which had been incubated for
4 weeks with 20 mM ascorbic acid in air, was irradiated for 1 h with 200
mW/cm2 of absorbed UVA light (gamma >338nm), and the concentration of
individual oxygen free radicals was measured.Superoxide anion attained a
level of 76 microM as determined by the superoxide
dismutase (SOD)-dependent increase in hydrogen peroxide formation and of
52 microM by the SOD-inhibitable reduction of cytochrome c. Hydrogen
peroxide formation increased linearly to 81 microM after 1 h. Neither
superoxide anion nor hydrogen peroxide, however, could account for the
UVA photolysis of Trp and His seen in this system. Singlet oxygen levels
approached 1.0 mM as measured by the oxidation of histidine, which was
consistent with singlet oxygen measurements by the bleaching of
N,N-dimethyl-4-nitrosoaniline. High concentrations of sodium azide, a
known singlet oxygen quencher, inhibited the photolytic destruction of
both His and Trp. Little or no protein damage could be ascribed to
hydroxyl radical based upon quenching experiments with added mannitol.
Therefore, superoxide anion and H2O2 were generated by the UVA
irradiation of ascorbate advanced glycation endproducts, however, the
major reactive oxygen species formed was singlet oxygen.

Graefes Arch Clin Exp Ophthalmol 1999 Oct;237(10):855-60
Failure of ascorbate to protect against broadband blue light-induced
retinal damage in rat. Wu J, Chen E, Soderberg PG.
Research Laboratory, St. Erik's Eye Hospital, Karolinska Institutet,
S-112 82 Stockholm, Sweden. mei@...
BACKGROUND: Excessive generation of free radicals due to light
absorption is proposed as the most likely mechanism for photochemical
retinal damage.The observed reduction of green light-induced retinal
injury after ascorbate treatment is believed to be an antioxidative
effect. The aim of the present study was to evaluate the possible
protection of ascorbate against blue light-induced photoreceptor damage.
METHODS: Cyclic light-reared albino rats were injected
intraperitoneally with either ascorbate (1 mg/g body weight)
or,as placebo, physiological saline 24 h before and just prior to
exposure to blue light. After 20-22 h of dark adaptation, two groups of
the rats were exposed in pairs to the blue light (400-480 nm) for 6 h at
an average irradiance of 0.7 W/m(2) in the cage. Six days after light
exposure, all rats were killed and retinal samples were analyzed.
RESULTS: Diffuse blue light irradiation resulted in an uneven
distribution of damage in the retina. As judged from the pathological
changes in the retina irradiated, no microscopic difference was
observed between the two groups. The preserved thickness of the outer
nuclear layer was on average 61.3% in the ascorbate-treated and 66.4% in
the placebo-treated group. The photoreceptor loss was not significantly
different between the two groups. CONCLUSION: The ascorbate did not
protect the retina from blue-light induced damage. This favors the
assumption that the mechanisms for blue light-induced retinal damage
might differ from that for green light.

Photochem Photobiol 1987 Aug;46(2):161-4
ESR detection of endogenous ascorbate free radical in mouse skin:
enhancement of radical production during UV irradiation following
application of chlorpromazine.
Buettner GR, Motten AG, Hall RD, Chignell CF.

Photochem Photobiol 1988 May;47(5):635-45
Porphyrin-sensitized photoreactions in the presence of ascorbate:
oxidation of cell membrane lipids and hydroxyl radical traps.
Bachowski GJ, Morehouse KM, Girotti AW.

Free Radic Biol Med 1988;5(1):3-6
Light-stimulated formation of hydrogen peroxide and hydroxyl radical in
the presence of uroporphyrin and ascorbate. Bachowski GJ, Girotti AW.
Department of Biochemistry, Medical College of Wisconsin, Milwaukee
53226.
Blue light irradiation of 2-deoxyribose (DOR) in the presence of
uroporphyrin I (UP), ascorbate (AH-), trace iron, and phosphate buffer
resulted in a strong stimulation of hydroxyl radical (OH.)-dependent
oxidation of DOR. Photostimulated generation of H2O2 was monitored after
removal of residual AH- (i) by ascorbate oxidase treatment, or (ii) by
anion exchange on mini-columns of DEAE-Sephadex. Irradiation of the
above mixture produced a strong burst of H2O2 which was intensified by
desferrioxamine and suppressed by catalase or EDTA. The mechanism
suggested by these observations is one in which photoreduction
of UP to the radical anion initiates the formation of H2O2, which gives
rise to OH. via Fenton chemistry. This is the first known investigation
of H2O2 fluxes in a Type I (free radical) photoreaction involving AH- as
the electron donor.

Proc Natl Acad Sci U S A 1985 Nov;82(21):7193-6
The role of ascorbic acid in senile cataract.
Bensch KG, Fleming JE, Lohmann W.
The reductone ascorbic acid, present in the crystalline lens in
concentrations higher than those of glucose, is capable of undergoing
nonenzymatic "browning" in the presence of lenticular proteins. We
studied the nonenzymatic browning with ascorbate in model systems
employing bovine serum albumin and lens crystallins. When bovine serum
albumin, alpha-crystallin, or gamma-crystallin was incubated with
[14C]ascorbic acid, the formation of yellow and then brown condensation
products appeared to correlate with increasing protein-associated
radioactivity. The fluorescence spectrum of these products was similar
to that of homogenates of human cataractous lenses. We suggest that the
nonenzymatic reaction of lens crystallins with ascorbic acid may
contribute, at least in part, to the color changes of aging lenses and
to the physical lenticular deterioration leading to senile cataract.
High dietary intake of ascorbic acid did not affect the fluorescence
spectrum of murine lenses; thus, we assume that the speed and extent of
the lenticular browning reactions must depend on a deterioration of
other factors of the multicomponent antioxidant system of the eye.

Int J Radiat Biol Relat Stud Phys Chem Med 1981 Jul;40(1):47-61
A study of the peroxidation of fatty acid micelles promoted by ionizing
radiation, hydrogen peroxide and ascorbate.
Yau TM, Mencl J. The kinetics of peroxidation of fatty acid micelles
promoted by ionizing radiation, hydrogen peroxide and ascorbate were
compared. At the dose-rate range of ionizing radiation studied, the
higher the dose-rate, the greater the total dose required to produce the
same effect. With ascorbate, the rate of lipid peroxidation was
dependent on the concentration of the promoter only up to 1 X 10(-4) M,
beyond which a decreasing rate of peroxidation induction was observed.
Higher concentration of ascorbate also suppressed the promoting effect
of ionizing radiation. Formate, a hydroxyl radical scavenger, inhibited
the peroxidation process promoted by these three agents. Caesium was
found to be slightly inhibitory. EDTA and deoxycholate were also
inhibitory, which may be attributed to iron-chelating and
micelle-disrupting capacity, respectively.
Addition of iron (Fe2+ or Fe3+) to EDTA-chelated fatty acid micelles
re-initiated the peroxidation process. The ease of fatty acid oxidation
at pH 7.5 was arochidonic (20:4) greater than linolenic (18:3) greater
than linoleic (18:2). This order was reversed at pH 11.5. Similarities
in the kinetics of peroxidation obtained suggest that certain biological
sequelae encountered in cells treated with these seemingly dissimilar
agents might arise through some common mechanism(s).

30: Int J Radiat Biol 1994 Jan;65(1):27-33
Free radicals in biology: oxidative stress and the effects of ionizing
radiation. Riley PA.
Department of Molecular Pathology, UCL Medical School, London, UK.
The most important electron acceptor in the biosphere is molecular
oxygen which, by virtue of its bi-radical nature, readily accepts
unpaired electrons to give rise to a series of partially reduced species
collectively known as reduced (or 'reactive') oxygen species (ROS).
These include superoxide (O.2-),hydrogen peroxide (H2O2), hydroxyl
radical (HO.) and peroxyl (ROO.) and alkoxyl (RO.) radicals which may be
involved in the initiation and propagation of free radical chain
reactions and which are potentially highly damaging to cells.
Mechanisms have evolved to restrict and control such processes, partly
by compartmentation, and partly by antioxidant defences such as
chain-breaking antioxidant compounds capable forming stable free
radicals (e.g. ascorbate, alpha-tocopherol) and the evolution of enzyme
systems (e.g. superoxide dismutase, catalase, peroxidases) that diminish
the intracellular concentration of the ROS. Although some ROS perform
useful functions, the production of ROS exceeding the ability of the
organism to mount an antioxidant defence results in oxidative stress and
the ensuing tissue damage may be involved in certain disease processes.
Evidence that ROS are involved in primary pathological mechanisms is a
feature mainly of extraneous physical or chemical perturbations of which
radiation is perhaps the major contributor. One of the important
radiation-induced free-radical species is the hydroxyl radical which
indiscriminately attacks neighbouring molecules often at near
diffusion-controlled rates. Hydroxyl radicals are generated by
ionizing radiation either directly by oxidation of water, or indirectly
by the formation of secondary partially ROS. These may be subsequently
converted to hydroxyl radicals by further reduction ('activation') by
metabolic processes in the cell. Secondary radiation injury is therefore
influenced by the cellular antioxidant status and the amount and
availability of activating mechanisms. The biological response to
radiation may be modulated by alterations in factors affecting these
secondary mechanisms of cellular injury.

31: FEBS Lett 1993 Oct 4;331(3):281-4
Bilirubin attenuates radical-mediated damage to serum albumin.
Neuzil J, Stocker R.
Biochemistry Group, Heart Research Institute, Sydney, NSW, Australia.
Oxidative damage to biological macromolecules has been implicated in a
number of diseases. Much interest has focused on how non-proteinaceous,
low-molecular weight antioxidants prevent oxidative damage to lipids,
while comparatively little is known about protein antioxidation. Here we
show that bilirubin (BR), the end-product of heme catabolism, when bound
to bovine serum albumin (BSA), is oxidised by hydroxyl (.OH),
hydroperoxyl (HO2.), and superoxide anion (O2-.) radicals to so far
mostly uncharacterised products. The initial oxidation rates of
BSA-bound BR decreased in the order OH > HO2. > O2-.. BR protected
its carrier protein from oxidative damage inflicted by .OH radicals.
This protective action included a reduction in the .OH-mediated cleavage
of BSA, conversion of Trp into kynurenine and formation of
bityrosine-specific' fluorescence. BR also strongly inhibited
.OH-mediated formation of protein carbonyls, whereas ascorbate and
Trolox (a water-soluble analogue of vitamin E) were much less effective.
These results support an antioxidant-protective function of BR and
point towards significant differences in the efficacies of various
antioxidants in the prevention of oxidative damage to lipids and proteins.

32: Photochem Photobiol 1993 May;57(5):777-84
Photosensitized formation of ascorbate radicals by riboflavin: an ESR
study. Kim H, Kirschenbaum LJ, Rosenthal I, Riesz P.
Radiation Oncology Branch, National Cancer Institute, NIH, Bethesda, MD
20892.
The riboflavin-sensitized photooxidation of ascorbate ion (HA-) to
ascorbate radical (A.-) was followed by electron spin resonance (ESR)
spectroscopy in conjunction with oxygen depletion measurements. In
air-saturated aqueous media,steady-state amounts of A.- are rapidly
established upon irradiation. The ESR signal disappears within a few
seconds after the light is extinguished--more slowly under constant
irradiation as oxygen is depleted. No photooxidation was observed in
deaerated media. Similar results were obtained with other flavins
and when ascorbyl palmitate was substituted for HA-. The effect of added
superoxide dismutase, catalase, desferrioxamine, and singlet oxygen
scavengers (NaN3 and tryptophan) was studied, as was replacement of
water by D2O and saturation with O2. The results are indicative of
ascorbate free radical production via direct reaction between ascorbate
ion and triplet riboflavin in the presence of O2. While the presence of
superoxide ion tends to reduce the steady-state concentration of A.-,
competition from the reaction of HA- with singlet oxygen is less
apparent in this system (at HA- > or = 1 mM) than in the previously
studied aluminum phthalocyanine tetrasulfonate-photosensitized
reaction.

34: Chem Biol Interact 1992 Dec;85(2-3):243-54
Oxidative damage to bovine serum albumin induced by hydroxyl radical
generating systems of xanthine oxidase + EDTA-Fe3+ and ascorbate +
EDTA-Fe3+.
Miura T, Muraoka S, Ogiso T.
Department of Biochemistry, Hokkaido Institute of Pharmaceutical
Sciences, Otaru, Japan.
Oxidative damage to bovine serum albumin (BSA) was induced by hydroxyl
radical (HO.) generating systems of xanthine oxidase (XO) + EDTA-Fe3+
and ascorbate + EDTA-Fe3+. Formation of bityrosine and loss of
tryptophan were observed in the ascorbate + EDTA-Fe3+ system and
carbonyl formation was induced by both systems.
Mannitol and ethanol very strongly inhibited the carbonyl and/or
bityrosine formation, indicating that the oxidative damage to BSA was
due to HO(.). The sulfhydryl (SH) groups of BSA were very sensitive to
the XO + EDTA-Fe3+ but not to the ascorbate + EDTA-Fe3+ system. Catalase
but not hydroxyl radical scavengers or superoxide dismutase strongly
inhibited the loss of SH groups, indicating that H2O2 is involved in
their oxidation. Fragmentation of BSA was observed during exposure to
the XO + EDTA-Fe3+ and ascorbate + EDTA-Fe3+ systems and the products
presented a broad band on sodium dodecyl sulfate polyacrylamide
gel electrophoresis. Little formation of amine groups was observed in
these systems, indicating that little peptide bond cleavage occurred.
BSA exposed to the ascorbate + EDTA-Fe3+ system was more readily
degraded by trypsin than that exposed to the XO + EDTA-Fe3+ system.
Elastase degraded BSA exposed to the ascorbate + EDTA-Fe3+ system but
not to the XO + EDTA-Fe3+ system.

36: Photochem Photobiol 1992 Feb;55(2):191-6
Oxidation of ascorbic acid as an indicator of photooxidative stress in
the eye. Glickman RD, Lam KW.
Department of Ophthalmology, University of Texas Health Science Center,
San Antonio 78284-6230.
When whole retinal pigmented epithelium (RPE) cells isolated from bovine
eyes are incubated with 14C-labeled ascorbic acid and exposed to a
visible laser, the ascorbic acid is oxidized to dehydro-L-ascorbic acid
(DHA). The amount of ascorbic acid which is oxidized is proportional to
the radiant exposure of the sample (i.e. the total amount of radiation
per unit area delivered over the exposure time). Blue light is more
effective than red light in driving the reaction. The amount of label
appearing in the DHA fraction is increased if unlabeled DHA is present
in the reaction mixture, indicating that some redox cycling of ascorbate
is occurring in the RPE cells. The ascorbic acid oxidizing activity does
not depend on intact cells, is not inactivated by heating the
cells to 80 degrees C, and appears to reside mainly in the subcellular
fraction which contains melanin pigment granules. The ascorbic acid
oxidation may be caused by free radicals formed when melanin is
illuminated with light. This reaction appears to be a useful method for
quantifying the production of free radicals during photooxidative stress.

37: Free Radic Biol Med 1992;13(2):121-6
8-Hydroxydeoxyguanosine in vitro: effects of glutathione, ascorbate, and
5-aminosalicylic acid. Fischer-Nielsen A, Poulsen HE, Loft S.
Department of Pharmacology, University of Copenhagen, Denmark.
Oxidative DNA damage, as expressed by 8-hydroxydeoxyguanosine (8-OHdG),
was investigated in calf thymus DNA exposed to either ultraviolet
radiation or to FeCl2/H2O2 in a Fenton-like reaction. The influence of
iron (absent in the UV system and present in the FeCl2/H2O2 system) and
pH (7.4 and 4.0) on the effect of glutathione (GSH), ascorbate, and
5-aminosalicylic acid (5-ASA, a drug used in the treatment of chronic
inflammatory bowel diseases) was examined in these systems. Without
iron, all three compounds considerably reduced 8-OHdG formation
(i.e., acted as scavengers), while in the presence of iron salts, 8-OHdG
formation was accelerated (except for GSH at pH 7.4), i.e., the
compounds acted as prooxidants. This effect was augmented at low pH. The
prooxidant property of 5-ASA may have implications for its clinical use.
Maximum scavenging effect for all the compounds investigated was
obtained at much lower doses than the maximum enhancing effect. This
demonstrates that to the end of oxy-radical scavenging, the
concentration of the GSH, ascorbate, and 5-ASA, respectively, should
be chosen to obtain maximum antioxidant effect and minimum prooxidant
effects. The significance of this finding for the selection of
antioxidant dose is important but remains to be investigated further.

39: Photochem Photobiol 1991 Apr;53(4):481-91
Photosensitized lipid peroxidation and enzyme inactivation by
membrane-bound merocyanine 540: reaction mechanisms in the absence and
presence of ascorbate. Bachowski GJ, Pintar TJ, Girotti AW.
Department of Biochemistry, Medical College of Wisconsin, Milwaukee
53226.
The lipophilic photosensitizing dye merocyanine 540 (MC540) is being
studied intensively as an antitumor and antiviral agent. Since plasma
membranes are believed to be the principal cellular targets of
MC540-mediated photodamage, we have studied membrane damage in a well
characterized test system, the human erythrocyte ghost. When irradiated
with white light, MC540-sensitized ghosts accumulated lipid
hydroperoxides (LOOHs derived from phospholipids and cholesterol) at a
rate dependent on initial dye concentration. Neither desferrioxamine nor
butylated hydroxytoluene inhibited LOOH formation, suggesting that Type
I (iron-mediated free radical) chemistry is not important.
By contrast, azide inhibited the reaction in a dose-dependent fashion,
implicating a Type II (singlet oxygen, 1O2) mechanism. Stern-Volmer
analysis of the data gave a 1O2 quenching constant approximately 50
times lower than that determined for an extramembranous target, lactate
dehydrogenase (the latter value agreeing with literature values). This
suggests that 1O2 reacts primarily at its membrane sites of origin and
that azide has limited access to these sites. Using
{14C}cholesterol-labeled membranes and HPLC with
radiodetection, we identified 3 beta-hydroxy-5
alpha-cholest-6-ene-5-hydroperoxide as the major cholesterol
photoproduct, thereby confirming 1O2 intermediacy. Irradiation of
MC540-sensitized membranes in the presence of added iron and ascorbate
resulted in a large burst of lipid peroxidation, as shown by
thiobarbituric acid reactivity and appearance of
7-hydroperoxycholesterol and 7-hydroxycholesterol
as major oxidation products. Amplification of MC540-initiated lipid
peroxidation by iron/ascorbate (attributed to light-independent
reduction of nascent photoperoxides, with ensuing free radical chain
reactions) could prove useful in augmenting MC540's phototherapeutic
effects.
 
Joined
Nov 26, 2013
Messages
7,367
You should come out with an "original C" like you did for E.

:+1

14:07


Also this from somewhere...

"Yes, more than 20 years ago, I pointed out the amount of heavy metal
contamination, and the frequent reactions I had seen, to Pauling, and he
just said I should use Bronson's C, as if that would have been made with
anything except Hoffman-LaRoche's stuff. (It was Pauling's own
description of the manufacturing process for sulfuric acid, using a
"lead room," that got me thinking about the dangers of things
manufactured with it.) I guess ADM is making a large fraction of
ascorbic acid now, so I wouldn't be surprised if some of it was worse
than when the heavy metal studies were published several years ago.

Ray Peat's experiences and work with C:
The alteration of production processes in vitamin E manufacture when the
evil soybean monopoly bought the industry from Eastman Chemical is
analogous to what happened earlier in the vitamin C industry, as profits
were maximized. The dramatic vitamin C studies in the 1930s often used
only 15 or 25 milligrams per day. In 1953, my first experience with it
(which was still sold as "cevitamic acid")involved 50 mg per day, and
over a period of just 2 or 3 days, my chronic awful poison oak allergy
disappeared. Up until this time, it was still too expensive to sell in
large doses. Around 1955 or '56, new manufacturing methods made it cheap
(and, for some reason, the name changed from cevitamic to ascorbic) and
the average tablet went up to 500 mg. The first time I tried the new
form, around 1956, I developed allergy symptoms within a couple of days.
Over the next 20 years, my own increased sensitivity to synthetic
ascorbate led me to look for such reactions in others. The same
people who reacted to it often reacted similarly to riboflavin and
rutin, which were also made from cornstarch by oxidation. I ascribed the
reaction to some industrial contaminant that they had in common,
possibly the heavy metals introduced with the sulfuric acid. The heavy
metal contamination of synthetic ascorbate is so great that one 500 mg
tablet dissolved in a liter of water produces free radicals at a rate
that would require a killing dose of x-rays to equal. The only clean and
safe vitamin C now available is that in fresh fruits, meats, etc. The
commercial stuff is seriously dangerous.

http://designserver.mae.cornell.edu/rea ... ocess.html
..

Process conditions for ascorbic acid manufacture
1. Hydrogenation Typical conditions are: Equal amounts of glucose, water
and methanol, with pH adjusted to slightly above neutral with calcium
hydoxide. Abour 3% by vol. of Raney nickel catalyst. Temp 140-150 C and
pressure 80-125 atm!!
After 2 hours get about 95% yield . Filter while hot to remove nickel
catalyst. Must treat with ion exchange resins to remove essentially all
nickel that may have dissolved from the catalyst (see next step). Cool
down and filter the white crystalline mass

2. Oxidation of sorbitol to sorbose with Gluconobacter suboxydans
Ni ions are a problem--tank materials --since the bacteria are
sensitive. Only 10 ppm may be toxic, although now some strains can
tolerate 25 ppm.

About a 20% solution of sorbitol--also add mineral salts and 0.0.2 -
0.4% of corn steep liquor or yeast extract as accessory nutrients. Must
sterilize medium. Use 10% or even more inocu;lum if batchwise. Highly
aerobic-use oxygen-enriched air and ca, 2 atm backpressure. Temp 30 C
and pH of 5-6 is now possible. After 24 hr. centrifuge to remove the
bacteria De-ionize and vacuum concentrate ( at not more than 50º C )
Drop to pH 3.0 crystallize; then filter and dry. Yield: 90%

3. Acetonation
Dissolve in dry acetone + conc. sulfuric acid ( e.g. 100 gm in 2 liters
acetone plus 80 ml acid) May take 3 hrs to dissolve--forms mono-
derivative first as it dissolve. Stir at room temp for another 20 hours!
Neutralize with CaCO3 , filter off the Ca SO4 and distill off the
acetone. Residue is taken up in ether and dried with anhydrous sodium
sulfate. Ether is distilled off and finally the product is purified by
vacuum distillation at 135º C and 3 mm Hg (Somemonosubstituted sorbose
is recycled back to the process). Yield: 85%

4. Oxidation to di-acetone 2-ketogulonic acid
Originally permanganate was used to accomplish this oxidation, but now
the acetonated sorbose is dissolved in dilute NaOH and aerated with
palladium-oncarbon catalyst for 3-5 hrs at slightly elevated
temperature. The solution is acidified to give the free acetone complex
of ketogulonic acid which precipitates. It is wahed with acetone and
dried. Ca. 90% yield

5. Hydrolysis, rearrangement, & final purification
The product from Step 4 is treated with methanol/HCl at pH around 2 in
an inert chlorinated -hydrocarbon solvent. The temp is held at around
100ºC for 2 hrs. Acetone is released and the molecule forms a ring
structure (inner ester) known as a "lactone". Mother liquors of acetone
and methanol are recovered by distillation, Further acid treatment may
be used to accomplish full enolization. The crude product is
re-crystallized from dilute ethanol. (This and all subsequent steps must
be done under notrogen/CO2 atmosphere to prevent the oxidation of
ascorbic acid) Vacuum evaporation and seeding with pure crystals of the
vitamin are used in the final stage. Yield, overall, for Step 5 is about 85%
=======================================================================
Biochemistry 1995 Feb 28;34(8):2653-61
Differential dependence on chromatin structure for copper and iron ion
induction of DNA double-strand breaks. Chiu SM, Xue LY, Friedman LR,
Oleinick NL. Department of Radiology, Case Western Reserve University
School of Medicine, Cleveland, Ohio 44106.
The induction of DNA DSB (double-strand breaks) in isolated nuclear
chromatin by Cu(II) or Fe(II)-EDTA in the presence of H2O2 and ascorbate
has been compared to DSB induction by gamma-radiation. V79 nuclei
embedded in agarose plugs were treated with each agent on ice, and the
resultant DNA fragments were analyzed by pulsed-field gel
electrophoresis. In the absence of low molecular weight radical
scavengers, both irradiation and treatment with iron ion induced random
DSB, as judged by the size distribution of DNA fragments, and the yield
of DSB in each case was enhanced by either the expansion of chromatin
(approximately 5-fold) or the removal of histones (21-25-fold) before
treatment. In contrast, treatment with Cu(II) produced small DNA
fragments of uniform size (approximately 100-200 kbp), independent of
the yield of DSB. In addition, neither the DNA fragment
size nor the yield of DSB produced by Cu(II) was affected by the prior
removal of histones from chromatin. Deproteinized DNA was degraded
randomly by Cu(II) but at a slower rate than observed for chromatin. In
the presence of ascorbate, H2O2 was found to be essential for DSB
induction by Fe(II)-EDTA but not by Cu(II), possibly because H2O2 can be
produced from ascorbate and Cu(II)in the presence of oxygen. Despite the
above differences between the production of DSB by the two metal ions,
DSB induction in native chromatin by either metal ion was
blocked by 0.1 M EDTA or 0.25 M thiourea but was resistant to the
hydroxyl radical scavengers 0.25 M DMSO and 0.25 M mannitol.(ABSTRACT
TRUNCATED AT 250 WORDS)

Radiat Res 1996 May;145(5):532-41
Catalytic metals, ascorbate and free radicals: combinations to avoid.
Buettner GR, Jurkiewicz BA. ESR Facility and Radiation Research
Laboratory, University of Iowa, Iowa City, 52242-1101, USA.

Trace levels of transition metals can participate in the metal-catalyzed
Haber-Weiss reaction (superoxide-driven Fenton reaction) as well as
catalyze the oxidation of ascorbate. Generally ascorbate is thought of
as an excellent reducing agent; it is able to serve as a donor
antioxidant in free radical-mediated oxidation processes. However, as a
reducing agent it is also able to reduce redox-active metals such as
copper and iron, thereby increasing the pro-oxidant chemistry of these
metals. Thus ascorbate can serve as both a pro-oxidant and an
antioxidant. In general, at low ascorbate concentrations, ascorbate is
prone to be a pro-oxidant, and at high concentrations, it will tend
to be an antioxidant. Hence there is a crossover effect. We propose that
the "position" of this crossover effect is a function of the catalytic
metal concentration. In this presentation, we discuss: (1) the role of
catalytic metals in free radical-mediated oxidations; (2) ascorbate as
both a pro-oxidant and an antioxidant; (3) catalytic metal catalysis of
ascorbate oxidation; (4) use of ascorbate to determine adventitious
catalytic metal concentrations; (5) use of ascorbate radical as a marker
of oxidative stress; and (6) use of ascorbate and iron as free radical
pro-oxidants in photodynamic therapy of cancer.

Photochem Photobiol 1996 May;63(5):649-55
Quantitation of the reactive oxygen species generated by the UVA
irradiation of ascorbic acid-glycated lens proteins.
Linetsky M, Ortwerth BJ. Mason Institute of Ophthalmology, University of
Missouri, Columbia 65212, USA.

The oxidation products of ascorbic acid rapidly glycate proteins and
produce protein-bound, advanced glycation endproducts. These endproducts
can absorb UVA light and cause the photolytic oxidation of proteins
(Ortwerth, Linetsky and Olesen, Photochem. Photobiol. 62, 454-463,
1995), which is mediated by the formation of reactive oxygen species. A
dialyzed preparation of calf lens proteins, which had been incubated for
4 weeks with 20 mM ascorbic acid in air, was irradiated for 1 h with 200
mW/cm2 of absorbed UVA light (gamma >338nm), and the concentration of
individual oxygen free radicals was measured.Superoxide anion attained a
level of 76 microM as determined by the superoxide
dismutase (SOD)-dependent increase in hydrogen peroxide formation and of
52 microM by the SOD-inhibitable reduction of cytochrome c. Hydrogen
peroxide formation increased linearly to 81 microM after 1 h. Neither
superoxide anion nor hydrogen peroxide, however, could account for the
UVA photolysis of Trp and His seen in this system. Singlet oxygen levels
approached 1.0 mM as measured by the oxidation of histidine, which was
consistent with singlet oxygen measurements by the bleaching of
N,N-dimethyl-4-nitrosoaniline. High concentrations of sodium azide, a
known singlet oxygen quencher, inhibited the photolytic destruction of
both His and Trp. Little or no protein damage could be ascribed to
hydroxyl radical based upon quenching experiments with added mannitol.
Therefore, superoxide anion and H2O2 were generated by the UVA
irradiation of ascorbate advanced glycation endproducts, however, the
major reactive oxygen species formed was singlet oxygen.

Graefes Arch Clin Exp Ophthalmol 1999 Oct;237(10):855-60
Failure of ascorbate to protect against broadband blue light-induced
retinal damage in rat. Wu J, Chen E, Soderberg PG.
Research Laboratory, St. Erik's Eye Hospital, Karolinska Institutet,
S-112 82 Stockholm, Sweden. mei@...
BACKGROUND: Excessive generation of free radicals due to light
absorption is proposed as the most likely mechanism for photochemical
retinal damage.The observed reduction of green light-induced retinal
injury after ascorbate treatment is believed to be an antioxidative
effect. The aim of the present study was to evaluate the possible
protection of ascorbate against blue light-induced photoreceptor damage.
METHODS: Cyclic light-reared albino rats were injected
intraperitoneally with either ascorbate (1 mg/g body weight)
or,as placebo, physiological saline 24 h before and just prior to
exposure to blue light. After 20-22 h of dark adaptation, two groups of
the rats were exposed in pairs to the blue light (400-480 nm) for 6 h at
an average irradiance of 0.7 W/m(2) in the cage. Six days after light
exposure, all rats were killed and retinal samples were analyzed.
RESULTS: Diffuse blue light irradiation resulted in an uneven
distribution of damage in the retina. As judged from the pathological
changes in the retina irradiated, no microscopic difference was
observed between the two groups. The preserved thickness of the outer
nuclear layer was on average 61.3% in the ascorbate-treated and 66.4% in
the placebo-treated group. The photoreceptor loss was not significantly
different between the two groups. CONCLUSION: The ascorbate did not
protect the retina from blue-light induced damage. This favors the
assumption that the mechanisms for blue light-induced retinal damage
might differ from that for green light.

Photochem Photobiol 1987 Aug;46(2):161-4
ESR detection of endogenous ascorbate free radical in mouse skin:
enhancement of radical production during UV irradiation following
application of chlorpromazine.
Buettner GR, Motten AG, Hall RD, Chignell CF.

Photochem Photobiol 1988 May;47(5):635-45
Porphyrin-sensitized photoreactions in the presence of ascorbate:
oxidation of cell membrane lipids and hydroxyl radical traps.
Bachowski GJ, Morehouse KM, Girotti AW.

Free Radic Biol Med 1988;5(1):3-6
Light-stimulated formation of hydrogen peroxide and hydroxyl radical in
the presence of uroporphyrin and ascorbate. Bachowski GJ, Girotti AW.
Department of Biochemistry, Medical College of Wisconsin, Milwaukee
53226.
Blue light irradiation of 2-deoxyribose (DOR) in the presence of
uroporphyrin I (UP), ascorbate (AH-), trace iron, and phosphate buffer
resulted in a strong stimulation of hydroxyl radical (OH.)-dependent
oxidation of DOR. Photostimulated generation of H2O2 was monitored after
removal of residual AH- (i) by ascorbate oxidase treatment, or (ii) by
anion exchange on mini-columns of DEAE-Sephadex. Irradiation of the
above mixture produced a strong burst of H2O2 which was intensified by
desferrioxamine and suppressed by catalase or EDTA. The mechanism
suggested by these observations is one in which photoreduction
of UP to the radical anion initiates the formation of H2O2, which gives
rise to OH. via Fenton chemistry. This is the first known investigation
of H2O2 fluxes in a Type I (free radical) photoreaction involving AH- as
the electron donor.

Proc Natl Acad Sci U S A 1985 Nov;82(21):7193-6
The role of ascorbic acid in senile cataract.
Bensch KG, Fleming JE, Lohmann W.
The reductone ascorbic acid, present in the crystalline lens in
concentrations higher than those of glucose, is capable of undergoing
nonenzymatic "browning" in the presence of lenticular proteins. We
studied the nonenzymatic browning with ascorbate in model systems
employing bovine serum albumin and lens crystallins. When bovine serum
albumin, alpha-crystallin, or gamma-crystallin was incubated with
[14C]ascorbic acid, the formation of yellow and then brown condensation
products appeared to correlate with increasing protein-associated
radioactivity. The fluorescence spectrum of these products was similar
to that of homogenates of human cataractous lenses. We suggest that the
nonenzymatic reaction of lens crystallins with ascorbic acid may
contribute, at least in part, to the color changes of aging lenses and
to the physical lenticular deterioration leading to senile cataract.
High dietary intake of ascorbic acid did not affect the fluorescence
spectrum of murine lenses; thus, we assume that the speed and extent of
the lenticular browning reactions must depend on a deterioration of
other factors of the multicomponent antioxidant system of the eye.

Int J Radiat Biol Relat Stud Phys Chem Med 1981 Jul;40(1):47-61
A study of the peroxidation of fatty acid micelles promoted by ionizing
radiation, hydrogen peroxide and ascorbate.
Yau TM, Mencl J. The kinetics of peroxidation of fatty acid micelles
promoted by ionizing radiation, hydrogen peroxide and ascorbate were
compared. At the dose-rate range of ionizing radiation studied, the
higher the dose-rate, the greater the total dose required to produce the
same effect. With ascorbate, the rate of lipid peroxidation was
dependent on the concentration of the promoter only up to 1 X 10(-4) M,
beyond which a decreasing rate of peroxidation induction was observed.
Higher concentration of ascorbate also suppressed the promoting effect
of ionizing radiation. Formate, a hydroxyl radical scavenger, inhibited
the peroxidation process promoted by these three agents. Caesium was
found to be slightly inhibitory. EDTA and deoxycholate were also
inhibitory, which may be attributed to iron-chelating and
micelle-disrupting capacity, respectively.
Addition of iron (Fe2+ or Fe3+) to EDTA-chelated fatty acid micelles
re-initiated the peroxidation process. The ease of fatty acid oxidation
at pH 7.5 was arochidonic (20:4) greater than linolenic (18:3) greater
than linoleic (18:2). This order was reversed at pH 11.5. Similarities
in the kinetics of peroxidation obtained suggest that certain biological
sequelae encountered in cells treated with these seemingly dissimilar
agents might arise through some common mechanism(s).

30: Int J Radiat Biol 1994 Jan;65(1):27-33
Free radicals in biology: oxidative stress and the effects of ionizing
radiation. Riley PA.
Department of Molecular Pathology, UCL Medical School, London, UK.
The most important electron acceptor in the biosphere is molecular
oxygen which, by virtue of its bi-radical nature, readily accepts
unpaired electrons to give rise to a series of partially reduced species
collectively known as reduced (or 'reactive') oxygen species (ROS).
These include superoxide (O.2-),hydrogen peroxide (H2O2), hydroxyl
radical (HO.) and peroxyl (ROO.) and alkoxyl (RO.) radicals which may be
involved in the initiation and propagation of free radical chain
reactions and which are potentially highly damaging to cells.
Mechanisms have evolved to restrict and control such processes, partly
by compartmentation, and partly by antioxidant defences such as
chain-breaking antioxidant compounds capable forming stable free
radicals (e.g. ascorbate, alpha-tocopherol) and the evolution of enzyme
systems (e.g. superoxide dismutase, catalase, peroxidases) that diminish
the intracellular concentration of the ROS. Although some ROS perform
useful functions, the production of ROS exceeding the ability of the
organism to mount an antioxidant defence results in oxidative stress and
the ensuing tissue damage may be involved in certain disease processes.
Evidence that ROS are involved in primary pathological mechanisms is a
feature mainly of extraneous physical or chemical perturbations of which
radiation is perhaps the major contributor. One of the important
radiation-induced free-radical species is the hydroxyl radical which
indiscriminately attacks neighbouring molecules often at near
diffusion-controlled rates. Hydroxyl radicals are generated by
ionizing radiation either directly by oxidation of water, or indirectly
by the formation of secondary partially ROS. These may be subsequently
converted to hydroxyl radicals by further reduction ('activation') by
metabolic processes in the cell. Secondary radiation injury is therefore
influenced by the cellular antioxidant status and the amount and
availability of activating mechanisms. The biological response to
radiation may be modulated by alterations in factors affecting these
secondary mechanisms of cellular injury.

31: FEBS Lett 1993 Oct 4;331(3):281-4
Bilirubin attenuates radical-mediated damage to serum albumin.
Neuzil J, Stocker R.
Biochemistry Group, Heart Research Institute, Sydney, NSW, Australia.
Oxidative damage to biological macromolecules has been implicated in a
number of diseases. Much interest has focused on how non-proteinaceous,
low-molecular weight antioxidants prevent oxidative damage to lipids,
while comparatively little is known about protein antioxidation. Here we
show that bilirubin (BR), the end-product of heme catabolism, when bound
to bovine serum albumin (BSA), is oxidised by hydroxyl (.OH),
hydroperoxyl (HO2.), and superoxide anion (O2-.) radicals to so far
mostly uncharacterised products. The initial oxidation rates of
BSA-bound BR decreased in the order OH > HO2. > O2-.. BR protected
its carrier protein from oxidative damage inflicted by .OH radicals.
This protective action included a reduction in the .OH-mediated cleavage
of BSA, conversion of Trp into kynurenine and formation of
bityrosine-specific' fluorescence. BR also strongly inhibited
.OH-mediated formation of protein carbonyls, whereas ascorbate and
Trolox (a water-soluble analogue of vitamin E) were much less effective.
These results support an antioxidant-protective function of BR and
point towards significant differences in the efficacies of various
antioxidants in the prevention of oxidative damage to lipids and proteins.

32: Photochem Photobiol 1993 May;57(5):777-84
Photosensitized formation of ascorbate radicals by riboflavin: an ESR
study. Kim H, Kirschenbaum LJ, Rosenthal I, Riesz P.
Radiation Oncology Branch, National Cancer Institute, NIH, Bethesda, MD
20892.
The riboflavin-sensitized photooxidation of ascorbate ion (HA-) to
ascorbate radical (A.-) was followed by electron spin resonance (ESR)
spectroscopy in conjunction with oxygen depletion measurements. In
air-saturated aqueous media,steady-state amounts of A.- are rapidly
established upon irradiation. The ESR signal disappears within a few
seconds after the light is extinguished--more slowly under constant
irradiation as oxygen is depleted. No photooxidation was observed in
deaerated media. Similar results were obtained with other flavins
and when ascorbyl palmitate was substituted for HA-. The effect of added
superoxide dismutase, catalase, desferrioxamine, and singlet oxygen
scavengers (NaN3 and tryptophan) was studied, as was replacement of
water by D2O and saturation with O2. The results are indicative of
ascorbate free radical production via direct reaction between ascorbate
ion and triplet riboflavin in the presence of O2. While the presence of
superoxide ion tends to reduce the steady-state concentration of A.-,
competition from the reaction of HA- with singlet oxygen is less
apparent in this system (at HA- > or = 1 mM) than in the previously
studied aluminum phthalocyanine tetrasulfonate-photosensitized
reaction.

34: Chem Biol Interact 1992 Dec;85(2-3):243-54
Oxidative damage to bovine serum albumin induced by hydroxyl radical
generating systems of xanthine oxidase + EDTA-Fe3+ and ascorbate +
EDTA-Fe3+.
Miura T, Muraoka S, Ogiso T.
Department of Biochemistry, Hokkaido Institute of Pharmaceutical
Sciences, Otaru, Japan.
Oxidative damage to bovine serum albumin (BSA) was induced by hydroxyl
radical (HO.) generating systems of xanthine oxidase (XO) + EDTA-Fe3+
and ascorbate + EDTA-Fe3+. Formation of bityrosine and loss of
tryptophan were observed in the ascorbate + EDTA-Fe3+ system and
carbonyl formation was induced by both systems.
Mannitol and ethanol very strongly inhibited the carbonyl and/or
bityrosine formation, indicating that the oxidative damage to BSA was
due to HO(.). The sulfhydryl (SH) groups of BSA were very sensitive to
the XO + EDTA-Fe3+ but not to the ascorbate + EDTA-Fe3+ system. Catalase
but not hydroxyl radical scavengers or superoxide dismutase strongly
inhibited the loss of SH groups, indicating that H2O2 is involved in
their oxidation. Fragmentation of BSA was observed during exposure to
the XO + EDTA-Fe3+ and ascorbate + EDTA-Fe3+ systems and the products
presented a broad band on sodium dodecyl sulfate polyacrylamide
gel electrophoresis. Little formation of amine groups was observed in
these systems, indicating that little peptide bond cleavage occurred.
BSA exposed to the ascorbate + EDTA-Fe3+ system was more readily
degraded by trypsin than that exposed to the XO + EDTA-Fe3+ system.
Elastase degraded BSA exposed to the ascorbate + EDTA-Fe3+ system but
not to the XO + EDTA-Fe3+ system.

36: Photochem Photobiol 1992 Feb;55(2):191-6
Oxidation of ascorbic acid as an indicator of photooxidative stress in
the eye. Glickman RD, Lam KW.
Department of Ophthalmology, University of Texas Health Science Center,
San Antonio 78284-6230.
When whole retinal pigmented epithelium (RPE) cells isolated from bovine
eyes are incubated with 14C-labeled ascorbic acid and exposed to a
visible laser, the ascorbic acid is oxidized to dehydro-L-ascorbic acid
(DHA). The amount of ascorbic acid which is oxidized is proportional to
the radiant exposure of the sample (i.e. the total amount of radiation
per unit area delivered over the exposure time). Blue light is more
effective than red light in driving the reaction. The amount of label
appearing in the DHA fraction is increased if unlabeled DHA is present
in the reaction mixture, indicating that some redox cycling of ascorbate
is occurring in the RPE cells. The ascorbic acid oxidizing activity does
not depend on intact cells, is not inactivated by heating the
cells to 80 degrees C, and appears to reside mainly in the subcellular
fraction which contains melanin pigment granules. The ascorbic acid
oxidation may be caused by free radicals formed when melanin is
illuminated with light. This reaction appears to be a useful method for
quantifying the production of free radicals during photooxidative stress.

37: Free Radic Biol Med 1992;13(2):121-6
8-Hydroxydeoxyguanosine in vitro: effects of glutathione, ascorbate, and
5-aminosalicylic acid. Fischer-Nielsen A, Poulsen HE, Loft S.
Department of Pharmacology, University of Copenhagen, Denmark.
Oxidative DNA damage, as expressed by 8-hydroxydeoxyguanosine (8-OHdG),
was investigated in calf thymus DNA exposed to either ultraviolet
radiation or to FeCl2/H2O2 in a Fenton-like reaction. The influence of
iron (absent in the UV system and present in the FeCl2/H2O2 system) and
pH (7.4 and 4.0) on the effect of glutathione (GSH), ascorbate, and
5-aminosalicylic acid (5-ASA, a drug used in the treatment of chronic
inflammatory bowel diseases) was examined in these systems. Without
iron, all three compounds considerably reduced 8-OHdG formation
(i.e., acted as scavengers), while in the presence of iron salts, 8-OHdG
formation was accelerated (except for GSH at pH 7.4), i.e., the
compounds acted as prooxidants. This effect was augmented at low pH. The
prooxidant property of 5-ASA may have implications for its clinical use.
Maximum scavenging effect for all the compounds investigated was
obtained at much lower doses than the maximum enhancing effect. This
demonstrates that to the end of oxy-radical scavenging, the
concentration of the GSH, ascorbate, and 5-ASA, respectively, should
be chosen to obtain maximum antioxidant effect and minimum prooxidant
effects. The significance of this finding for the selection of
antioxidant dose is important but remains to be investigated further.

39: Photochem Photobiol 1991 Apr;53(4):481-91
Photosensitized lipid peroxidation and enzyme inactivation by
membrane-bound merocyanine 540: reaction mechanisms in the absence and
presence of ascorbate. Bachowski GJ, Pintar TJ, Girotti AW.
Department of Biochemistry, Medical College of Wisconsin, Milwaukee
53226.
The lipophilic photosensitizing dye merocyanine 540 (MC540) is being
studied intensively as an antitumor and antiviral agent. Since plasma
membranes are believed to be the principal cellular targets of
MC540-mediated photodamage, we have studied membrane damage in a well
characterized test system, the human erythrocyte ghost. When irradiated
with white light, MC540-sensitized ghosts accumulated lipid
hydroperoxides (LOOHs derived from phospholipids and cholesterol) at a
rate dependent on initial dye concentration. Neither desferrioxamine nor
butylated hydroxytoluene inhibited LOOH formation, suggesting that Type
I (iron-mediated free radical) chemistry is not important.
By contrast, azide inhibited the reaction in a dose-dependent fashion,
implicating a Type II (singlet oxygen, 1O2) mechanism. Stern-Volmer
analysis of the data gave a 1O2 quenching constant approximately 50
times lower than that determined for an extramembranous target, lactate
dehydrogenase (the latter value agreeing with literature values). This
suggests that 1O2 reacts primarily at its membrane sites of origin and
that azide has limited access to these sites. Using
{14C}cholesterol-labeled membranes and HPLC with
radiodetection, we identified 3 beta-hydroxy-5
alpha-cholest-6-ene-5-hydroperoxide as the major cholesterol
photoproduct, thereby confirming 1O2 intermediacy. Irradiation of
MC540-sensitized membranes in the presence of added iron and ascorbate
resulted in a large burst of lipid peroxidation, as shown by
thiobarbituric acid reactivity and appearance of
7-hydroperoxycholesterol and 7-hydroxycholesterol
as major oxidation products. Amplification of MC540-initiated lipid
peroxidation by iron/ascorbate (attributed to light-independent
reduction of nascent photoperoxides, with ensuing free radical chain
reactions) could prove useful in augmenting MC540's phototherapeutic
effects.

:goodpost
 

TubZy

Member
Joined
Sep 30, 2016
Messages
1,649
Location
USA
@haidut Ray talks about the old-school vitamin C which was expensive and came in very small doses. It was, though, very effective and didn't harm you like modern mass produced vitamin C contaminated with heavy metals.

You should come out with an "original C" like you did for E.

Yeah, I agree. I don't even know any legit vit C brands anymore just stick with OJ, but would be willing to buy original C :D
 

Regina

Member
Joined
Aug 17, 2016
Messages
3,678
Location
Chicago
My Gourmia EPJ100 10qt 160 watt citrus press juicer arrived today. Yay. What a welcome addition during Chicago winter.
 

paymanz

Member
Joined
Jan 6, 2015
Messages
2,693
Makes sense. I'd imagine all of these people injecting themselves with hyaluronic acid for cosmetic purposes are really not doing themselves any favors, right?
Hyaluronic acid seems to be the good guy!
I don't know how different is exogenous vs indigenous hyaluronic acid, but it for sure works for cosmetic purposes, and I read many places that it can prevent cancer by inhibiting growth.

Blood levels of hyaluronic acid increases in cancer or pre cancer stage due to degradation by enzyme "hyaluronidase".from peat view that is a sign of cancer, while some of other researchers think it can cause cancer(most probably they are wrong!).
 

paymanz

Member
Joined
Jan 6, 2015
Messages
2,693
Hey it made me to do a search on hyaluronic acid and cancer,
http://www.cancertreatmentsresearch.com/?p=1489
Here they mentioned our friend name naked mole rat!
One of the only known mammals that has never contracted cancer (when not genetically modified to lack hyaluronic acid) is the naked mole rat. The naked mole rat produces large amounts of hyaluronic acid. http://www.nature.com/nature/journal/v499/n7458/full/nature12234.html
Update 22-June-2016: It seems other mechanism may be behind the cancer resistance in naked mole rat: Tumour resistance in induced pluripotent stem cells derived from naked mole-rats : Nature Communications
 

burtlancast

Member
Joined
Jan 1, 2013
Messages
2,889
What i understood from Ray's explanations and past experiences with Vit C contamination is that the chemical production stages remains basically the same ( the original 1935 patented Hoffman LaRoche process) but dirty equipment causes metal contamination in some of the steps.

It should theoretically be possible to produce the original, metal-free "cevitamic acid" by executing each production step with non-leaching metal equipment.

Ray pointed out the problem, but just getting Vit c from food does very little in offering an alternative.
 
Last edited:

haidut

Member
Thread starter
Joined
Mar 18, 2013
Messages
17,943
Location
USA / Europe
Hey it made me to do a search on hyaluronic acid and cancer,
Hyaluronic Acid Modulation: Preventing Recurrence or Supporting Other Therapies – Otherwise Better Not – Mihaela Catalina Stanciu Foundation for Life
Here they mentioned our friend name naked mole rat!

In a few of his articles Ray says that the free-floating hyaluronic acid is inflammatory. So, I think inhibiting hyaluronidase is a valid approach but injecting hyaluronic acid is probably dangerous.
 

haidut

Member
Thread starter
Joined
Mar 18, 2013
Messages
17,943
Location
USA / Europe
14:07


Also this from somewhere...

"Yes, more than 20 years ago, I pointed out the amount of heavy metal
contamination, and the frequent reactions I had seen, to Pauling, and he
just said I should use Bronson's C, as if that would have been made with
anything except Hoffman-LaRoche's stuff. (It was Pauling's own
description of the manufacturing process for sulfuric acid, using a
"lead room," that got me thinking about the dangers of things
manufactured with it.) I guess ADM is making a large fraction of
ascorbic acid now, so I wouldn't be surprised if some of it was worse
than when the heavy metal studies were published several years ago.

Ray Peat's experiences and work with C:
The alteration of production processes in vitamin E manufacture when the
evil soybean monopoly bought the industry from Eastman Chemical is
analogous to what happened earlier in the vitamin C industry, as profits
were maximized. The dramatic vitamin C studies in the 1930s often used
only 15 or 25 milligrams per day. In 1953, my first experience with it
(which was still sold as "cevitamic acid")involved 50 mg per day, and
over a period of just 2 or 3 days, my chronic awful poison oak allergy
disappeared. Up until this time, it was still too expensive to sell in
large doses. Around 1955 or '56, new manufacturing methods made it cheap
(and, for some reason, the name changed from cevitamic to ascorbic) and
the average tablet went up to 500 mg. The first time I tried the new
form, around 1956, I developed allergy symptoms within a couple of days.
Over the next 20 years, my own increased sensitivity to synthetic
ascorbate led me to look for such reactions in others. The same
people who reacted to it often reacted similarly to riboflavin and
rutin, which were also made from cornstarch by oxidation. I ascribed the
reaction to some industrial contaminant that they had in common,
possibly the heavy metals introduced with the sulfuric acid. The heavy
metal contamination of synthetic ascorbate is so great that one 500 mg
tablet dissolved in a liter of water produces free radicals at a rate
that would require a killing dose of x-rays to equal. The only clean and
safe vitamin C now available is that in fresh fruits, meats, etc. The
commercial stuff is seriously dangerous.

http://designserver.mae.cornell.edu/rea ... ocess.html
..

Process conditions for ascorbic acid manufacture
1. Hydrogenation Typical conditions are: Equal amounts of glucose, water
and methanol, with pH adjusted to slightly above neutral with calcium
hydoxide. Abour 3% by vol. of Raney nickel catalyst. Temp 140-150 C and
pressure 80-125 atm!!
After 2 hours get about 95% yield . Filter while hot to remove nickel
catalyst. Must treat with ion exchange resins to remove essentially all
nickel that may have dissolved from the catalyst (see next step). Cool
down and filter the white crystalline mass

2. Oxidation of sorbitol to sorbose with Gluconobacter suboxydans
Ni ions are a problem--tank materials --since the bacteria are
sensitive. Only 10 ppm may be toxic, although now some strains can
tolerate 25 ppm.

About a 20% solution of sorbitol--also add mineral salts and 0.0.2 -
0.4% of corn steep liquor or yeast extract as accessory nutrients. Must
sterilize medium. Use 10% or even more inocu;lum if batchwise. Highly
aerobic-use oxygen-enriched air and ca, 2 atm backpressure. Temp 30 C
and pH of 5-6 is now possible. After 24 hr. centrifuge to remove the
bacteria De-ionize and vacuum concentrate ( at not more than 50º C )
Drop to pH 3.0 crystallize; then filter and dry. Yield: 90%

3. Acetonation
Dissolve in dry acetone + conc. sulfuric acid ( e.g. 100 gm in 2 liters
acetone plus 80 ml acid) May take 3 hrs to dissolve--forms mono-
derivative first as it dissolve. Stir at room temp for another 20 hours!
Neutralize with CaCO3 , filter off the Ca SO4 and distill off the
acetone. Residue is taken up in ether and dried with anhydrous sodium
sulfate. Ether is distilled off and finally the product is purified by
vacuum distillation at 135º C and 3 mm Hg (Somemonosubstituted sorbose
is recycled back to the process). Yield: 85%

4. Oxidation to di-acetone 2-ketogulonic acid
Originally permanganate was used to accomplish this oxidation, but now
the acetonated sorbose is dissolved in dilute NaOH and aerated with
palladium-oncarbon catalyst for 3-5 hrs at slightly elevated
temperature. The solution is acidified to give the free acetone complex
of ketogulonic acid which precipitates. It is wahed with acetone and
dried. Ca. 90% yield

5. Hydrolysis, rearrangement, & final purification
The product from Step 4 is treated with methanol/HCl at pH around 2 in
an inert chlorinated -hydrocarbon solvent. The temp is held at around
100ºC for 2 hrs. Acetone is released and the molecule forms a ring
structure (inner ester) known as a "lactone". Mother liquors of acetone
and methanol are recovered by distillation, Further acid treatment may
be used to accomplish full enolization. The crude product is
re-crystallized from dilute ethanol. (This and all subsequent steps must
be done under notrogen/CO2 atmosphere to prevent the oxidation of
ascorbic acid) Vacuum evaporation and seeding with pure crystals of the
vitamin are used in the final stage. Yield, overall, for Step 5 is about 85%
=======================================================================
Biochemistry 1995 Feb 28;34(8):2653-61
Differential dependence on chromatin structure for copper and iron ion
induction of DNA double-strand breaks. Chiu SM, Xue LY, Friedman LR,
Oleinick NL. Department of Radiology, Case Western Reserve University
School of Medicine, Cleveland, Ohio 44106.
The induction of DNA DSB (double-strand breaks) in isolated nuclear
chromatin by Cu(II) or Fe(II)-EDTA in the presence of H2O2 and ascorbate
has been compared to DSB induction by gamma-radiation. V79 nuclei
embedded in agarose plugs were treated with each agent on ice, and the
resultant DNA fragments were analyzed by pulsed-field gel
electrophoresis. In the absence of low molecular weight radical
scavengers, both irradiation and treatment with iron ion induced random
DSB, as judged by the size distribution of DNA fragments, and the yield
of DSB in each case was enhanced by either the expansion of chromatin
(approximately 5-fold) or the removal of histones (21-25-fold) before
treatment. In contrast, treatment with Cu(II) produced small DNA
fragments of uniform size (approximately 100-200 kbp), independent of
the yield of DSB. In addition, neither the DNA fragment
size nor the yield of DSB produced by Cu(II) was affected by the prior
removal of histones from chromatin. Deproteinized DNA was degraded
randomly by Cu(II) but at a slower rate than observed for chromatin. In
the presence of ascorbate, H2O2 was found to be essential for DSB
induction by Fe(II)-EDTA but not by Cu(II), possibly because H2O2 can be
produced from ascorbate and Cu(II)in the presence of oxygen. Despite the
above differences between the production of DSB by the two metal ions,
DSB induction in native chromatin by either metal ion was
blocked by 0.1 M EDTA or 0.25 M thiourea but was resistant to the
hydroxyl radical scavengers 0.25 M DMSO and 0.25 M mannitol.(ABSTRACT
TRUNCATED AT 250 WORDS)

Radiat Res 1996 May;145(5):532-41
Catalytic metals, ascorbate and free radicals: combinations to avoid.
Buettner GR, Jurkiewicz BA. ESR Facility and Radiation Research
Laboratory, University of Iowa, Iowa City, 52242-1101, USA.

Trace levels of transition metals can participate in the metal-catalyzed
Haber-Weiss reaction (superoxide-driven Fenton reaction) as well as
catalyze the oxidation of ascorbate. Generally ascorbate is thought of
as an excellent reducing agent; it is able to serve as a donor
antioxidant in free radical-mediated oxidation processes. However, as a
reducing agent it is also able to reduce redox-active metals such as
copper and iron, thereby increasing the pro-oxidant chemistry of these
metals. Thus ascorbate can serve as both a pro-oxidant and an
antioxidant. In general, at low ascorbate concentrations, ascorbate is
prone to be a pro-oxidant, and at high concentrations, it will tend
to be an antioxidant. Hence there is a crossover effect. We propose that
the "position" of this crossover effect is a function of the catalytic
metal concentration. In this presentation, we discuss: (1) the role of
catalytic metals in free radical-mediated oxidations; (2) ascorbate as
both a pro-oxidant and an antioxidant; (3) catalytic metal catalysis of
ascorbate oxidation; (4) use of ascorbate to determine adventitious
catalytic metal concentrations; (5) use of ascorbate radical as a marker
of oxidative stress; and (6) use of ascorbate and iron as free radical
pro-oxidants in photodynamic therapy of cancer.

Photochem Photobiol 1996 May;63(5):649-55
Quantitation of the reactive oxygen species generated by the UVA
irradiation of ascorbic acid-glycated lens proteins.
Linetsky M, Ortwerth BJ. Mason Institute of Ophthalmology, University of
Missouri, Columbia 65212, USA.

The oxidation products of ascorbic acid rapidly glycate proteins and
produce protein-bound, advanced glycation endproducts. These endproducts
can absorb UVA light and cause the photolytic oxidation of proteins
(Ortwerth, Linetsky and Olesen, Photochem. Photobiol. 62, 454-463,
1995), which is mediated by the formation of reactive oxygen species. A
dialyzed preparation of calf lens proteins, which had been incubated for
4 weeks with 20 mM ascorbic acid in air, was irradiated for 1 h with 200
mW/cm2 of absorbed UVA light (gamma >338nm), and the concentration of
individual oxygen free radicals was measured.Superoxide anion attained a
level of 76 microM as determined by the superoxide
dismutase (SOD)-dependent increase in hydrogen peroxide formation and of
52 microM by the SOD-inhibitable reduction of cytochrome c. Hydrogen
peroxide formation increased linearly to 81 microM after 1 h. Neither
superoxide anion nor hydrogen peroxide, however, could account for the
UVA photolysis of Trp and His seen in this system. Singlet oxygen levels
approached 1.0 mM as measured by the oxidation of histidine, which was
consistent with singlet oxygen measurements by the bleaching of
N,N-dimethyl-4-nitrosoaniline. High concentrations of sodium azide, a
known singlet oxygen quencher, inhibited the photolytic destruction of
both His and Trp. Little or no protein damage could be ascribed to
hydroxyl radical based upon quenching experiments with added mannitol.
Therefore, superoxide anion and H2O2 were generated by the UVA
irradiation of ascorbate advanced glycation endproducts, however, the
major reactive oxygen species formed was singlet oxygen.

Graefes Arch Clin Exp Ophthalmol 1999 Oct;237(10):855-60
Failure of ascorbate to protect against broadband blue light-induced
retinal damage in rat. Wu J, Chen E, Soderberg PG.
Research Laboratory, St. Erik's Eye Hospital, Karolinska Institutet,
S-112 82 Stockholm, Sweden. mei@...
BACKGROUND: Excessive generation of free radicals due to light
absorption is proposed as the most likely mechanism for photochemical
retinal damage.The observed reduction of green light-induced retinal
injury after ascorbate treatment is believed to be an antioxidative
effect. The aim of the present study was to evaluate the possible
protection of ascorbate against blue light-induced photoreceptor damage.
METHODS: Cyclic light-reared albino rats were injected
intraperitoneally with either ascorbate (1 mg/g body weight)
or,as placebo, physiological saline 24 h before and just prior to
exposure to blue light. After 20-22 h of dark adaptation, two groups of
the rats were exposed in pairs to the blue light (400-480 nm) for 6 h at
an average irradiance of 0.7 W/m(2) in the cage. Six days after light
exposure, all rats were killed and retinal samples were analyzed.
RESULTS: Diffuse blue light irradiation resulted in an uneven
distribution of damage in the retina. As judged from the pathological
changes in the retina irradiated, no microscopic difference was
observed between the two groups. The preserved thickness of the outer
nuclear layer was on average 61.3% in the ascorbate-treated and 66.4% in
the placebo-treated group. The photoreceptor loss was not significantly
different between the two groups. CONCLUSION: The ascorbate did not
protect the retina from blue-light induced damage. This favors the
assumption that the mechanisms for blue light-induced retinal damage
might differ from that for green light.

Photochem Photobiol 1987 Aug;46(2):161-4
ESR detection of endogenous ascorbate free radical in mouse skin:
enhancement of radical production during UV irradiation following
application of chlorpromazine.
Buettner GR, Motten AG, Hall RD, Chignell CF.

Photochem Photobiol 1988 May;47(5):635-45
Porphyrin-sensitized photoreactions in the presence of ascorbate:
oxidation of cell membrane lipids and hydroxyl radical traps.
Bachowski GJ, Morehouse KM, Girotti AW.

Free Radic Biol Med 1988;5(1):3-6
Light-stimulated formation of hydrogen peroxide and hydroxyl radical in
the presence of uroporphyrin and ascorbate. Bachowski GJ, Girotti AW.
Department of Biochemistry, Medical College of Wisconsin, Milwaukee
53226.
Blue light irradiation of 2-deoxyribose (DOR) in the presence of
uroporphyrin I (UP), ascorbate (AH-), trace iron, and phosphate buffer
resulted in a strong stimulation of hydroxyl radical (OH.)-dependent
oxidation of DOR. Photostimulated generation of H2O2 was monitored after
removal of residual AH- (i) by ascorbate oxidase treatment, or (ii) by
anion exchange on mini-columns of DEAE-Sephadex. Irradiation of the
above mixture produced a strong burst of H2O2 which was intensified by
desferrioxamine and suppressed by catalase or EDTA. The mechanism
suggested by these observations is one in which photoreduction
of UP to the radical anion initiates the formation of H2O2, which gives
rise to OH. via Fenton chemistry. This is the first known investigation
of H2O2 fluxes in a Type I (free radical) photoreaction involving AH- as
the electron donor.

Proc Natl Acad Sci U S A 1985 Nov;82(21):7193-6
The role of ascorbic acid in senile cataract.
Bensch KG, Fleming JE, Lohmann W.
The reductone ascorbic acid, present in the crystalline lens in
concentrations higher than those of glucose, is capable of undergoing
nonenzymatic "browning" in the presence of lenticular proteins. We
studied the nonenzymatic browning with ascorbate in model systems
employing bovine serum albumin and lens crystallins. When bovine serum
albumin, alpha-crystallin, or gamma-crystallin was incubated with
[14C]ascorbic acid, the formation of yellow and then brown condensation
products appeared to correlate with increasing protein-associated
radioactivity. The fluorescence spectrum of these products was similar
to that of homogenates of human cataractous lenses. We suggest that the
nonenzymatic reaction of lens crystallins with ascorbic acid may
contribute, at least in part, to the color changes of aging lenses and
to the physical lenticular deterioration leading to senile cataract.
High dietary intake of ascorbic acid did not affect the fluorescence
spectrum of murine lenses; thus, we assume that the speed and extent of
the lenticular browning reactions must depend on a deterioration of
other factors of the multicomponent antioxidant system of the eye.

Int J Radiat Biol Relat Stud Phys Chem Med 1981 Jul;40(1):47-61
A study of the peroxidation of fatty acid micelles promoted by ionizing
radiation, hydrogen peroxide and ascorbate.
Yau TM, Mencl J. The kinetics of peroxidation of fatty acid micelles
promoted by ionizing radiation, hydrogen peroxide and ascorbate were
compared. At the dose-rate range of ionizing radiation studied, the
higher the dose-rate, the greater the total dose required to produce the
same effect. With ascorbate, the rate of lipid peroxidation was
dependent on the concentration of the promoter only up to 1 X 10(-4) M,
beyond which a decreasing rate of peroxidation induction was observed.
Higher concentration of ascorbate also suppressed the promoting effect
of ionizing radiation. Formate, a hydroxyl radical scavenger, inhibited
the peroxidation process promoted by these three agents. Caesium was
found to be slightly inhibitory. EDTA and deoxycholate were also
inhibitory, which may be attributed to iron-chelating and
micelle-disrupting capacity, respectively.
Addition of iron (Fe2+ or Fe3+) to EDTA-chelated fatty acid micelles
re-initiated the peroxidation process. The ease of fatty acid oxidation
at pH 7.5 was arochidonic (20:4) greater than linolenic (18:3) greater
than linoleic (18:2). This order was reversed at pH 11.5. Similarities
in the kinetics of peroxidation obtained suggest that certain biological
sequelae encountered in cells treated with these seemingly dissimilar
agents might arise through some common mechanism(s).

30: Int J Radiat Biol 1994 Jan;65(1):27-33
Free radicals in biology: oxidative stress and the effects of ionizing
radiation. Riley PA.
Department of Molecular Pathology, UCL Medical School, London, UK.
The most important electron acceptor in the biosphere is molecular
oxygen which, by virtue of its bi-radical nature, readily accepts
unpaired electrons to give rise to a series of partially reduced species
collectively known as reduced (or 'reactive') oxygen species (ROS).
These include superoxide (O.2-),hydrogen peroxide (H2O2), hydroxyl
radical (HO.) and peroxyl (ROO.) and alkoxyl (RO.) radicals which may be
involved in the initiation and propagation of free radical chain
reactions and which are potentially highly damaging to cells.
Mechanisms have evolved to restrict and control such processes, partly
by compartmentation, and partly by antioxidant defences such as
chain-breaking antioxidant compounds capable forming stable free
radicals (e.g. ascorbate, alpha-tocopherol) and the evolution of enzyme
systems (e.g. superoxide dismutase, catalase, peroxidases) that diminish
the intracellular concentration of the ROS. Although some ROS perform
useful functions, the production of ROS exceeding the ability of the
organism to mount an antioxidant defence results in oxidative stress and
the ensuing tissue damage may be involved in certain disease processes.
Evidence that ROS are involved in primary pathological mechanisms is a
feature mainly of extraneous physical or chemical perturbations of which
radiation is perhaps the major contributor. One of the important
radiation-induced free-radical species is the hydroxyl radical which
indiscriminately attacks neighbouring molecules often at near
diffusion-controlled rates. Hydroxyl radicals are generated by
ionizing radiation either directly by oxidation of water, or indirectly
by the formation of secondary partially ROS. These may be subsequently
converted to hydroxyl radicals by further reduction ('activation') by
metabolic processes in the cell. Secondary radiation injury is therefore
influenced by the cellular antioxidant status and the amount and
availability of activating mechanisms. The biological response to
radiation may be modulated by alterations in factors affecting these
secondary mechanisms of cellular injury.

31: FEBS Lett 1993 Oct 4;331(3):281-4
Bilirubin attenuates radical-mediated damage to serum albumin.
Neuzil J, Stocker R.
Biochemistry Group, Heart Research Institute, Sydney, NSW, Australia.
Oxidative damage to biological macromolecules has been implicated in a
number of diseases. Much interest has focused on how non-proteinaceous,
low-molecular weight antioxidants prevent oxidative damage to lipids,
while comparatively little is known about protein antioxidation. Here we
show that bilirubin (BR), the end-product of heme catabolism, when bound
to bovine serum albumin (BSA), is oxidised by hydroxyl (.OH),
hydroperoxyl (HO2.), and superoxide anion (O2-.) radicals to so far
mostly uncharacterised products. The initial oxidation rates of
BSA-bound BR decreased in the order OH > HO2. > O2-.. BR protected
its carrier protein from oxidative damage inflicted by .OH radicals.
This protective action included a reduction in the .OH-mediated cleavage
of BSA, conversion of Trp into kynurenine and formation of
bityrosine-specific' fluorescence. BR also strongly inhibited
.OH-mediated formation of protein carbonyls, whereas ascorbate and
Trolox (a water-soluble analogue of vitamin E) were much less effective.
These results support an antioxidant-protective function of BR and
point towards significant differences in the efficacies of various
antioxidants in the prevention of oxidative damage to lipids and proteins.

32: Photochem Photobiol 1993 May;57(5):777-84
Photosensitized formation of ascorbate radicals by riboflavin: an ESR
study. Kim H, Kirschenbaum LJ, Rosenthal I, Riesz P.
Radiation Oncology Branch, National Cancer Institute, NIH, Bethesda, MD
20892.
The riboflavin-sensitized photooxidation of ascorbate ion (HA-) to
ascorbate radical (A.-) was followed by electron spin resonance (ESR)
spectroscopy in conjunction with oxygen depletion measurements. In
air-saturated aqueous media,steady-state amounts of A.- are rapidly
established upon irradiation. The ESR signal disappears within a few
seconds after the light is extinguished--more slowly under constant
irradiation as oxygen is depleted. No photooxidation was observed in
deaerated media. Similar results were obtained with other flavins
and when ascorbyl palmitate was substituted for HA-. The effect of added
superoxide dismutase, catalase, desferrioxamine, and singlet oxygen
scavengers (NaN3 and tryptophan) was studied, as was replacement of
water by D2O and saturation with O2. The results are indicative of
ascorbate free radical production via direct reaction between ascorbate
ion and triplet riboflavin in the presence of O2. While the presence of
superoxide ion tends to reduce the steady-state concentration of A.-,
competition from the reaction of HA- with singlet oxygen is less
apparent in this system (at HA- > or = 1 mM) than in the previously
studied aluminum phthalocyanine tetrasulfonate-photosensitized
reaction.

34: Chem Biol Interact 1992 Dec;85(2-3):243-54
Oxidative damage to bovine serum albumin induced by hydroxyl radical
generating systems of xanthine oxidase + EDTA-Fe3+ and ascorbate +
EDTA-Fe3+.
Miura T, Muraoka S, Ogiso T.
Department of Biochemistry, Hokkaido Institute of Pharmaceutical
Sciences, Otaru, Japan.
Oxidative damage to bovine serum albumin (BSA) was induced by hydroxyl
radical (HO.) generating systems of xanthine oxidase (XO) + EDTA-Fe3+
and ascorbate + EDTA-Fe3+. Formation of bityrosine and loss of
tryptophan were observed in the ascorbate + EDTA-Fe3+ system and
carbonyl formation was induced by both systems.
Mannitol and ethanol very strongly inhibited the carbonyl and/or
bityrosine formation, indicating that the oxidative damage to BSA was
due to HO(.). The sulfhydryl (SH) groups of BSA were very sensitive to
the XO + EDTA-Fe3+ but not to the ascorbate + EDTA-Fe3+ system. Catalase
but not hydroxyl radical scavengers or superoxide dismutase strongly
inhibited the loss of SH groups, indicating that H2O2 is involved in
their oxidation. Fragmentation of BSA was observed during exposure to
the XO + EDTA-Fe3+ and ascorbate + EDTA-Fe3+ systems and the products
presented a broad band on sodium dodecyl sulfate polyacrylamide
gel electrophoresis. Little formation of amine groups was observed in
these systems, indicating that little peptide bond cleavage occurred.
BSA exposed to the ascorbate + EDTA-Fe3+ system was more readily
degraded by trypsin than that exposed to the XO + EDTA-Fe3+ system.
Elastase degraded BSA exposed to the ascorbate + EDTA-Fe3+ system but
not to the XO + EDTA-Fe3+ system.

36: Photochem Photobiol 1992 Feb;55(2):191-6
Oxidation of ascorbic acid as an indicator of photooxidative stress in
the eye. Glickman RD, Lam KW.
Department of Ophthalmology, University of Texas Health Science Center,
San Antonio 78284-6230.
When whole retinal pigmented epithelium (RPE) cells isolated from bovine
eyes are incubated with 14C-labeled ascorbic acid and exposed to a
visible laser, the ascorbic acid is oxidized to dehydro-L-ascorbic acid
(DHA). The amount of ascorbic acid which is oxidized is proportional to
the radiant exposure of the sample (i.e. the total amount of radiation
per unit area delivered over the exposure time). Blue light is more
effective than red light in driving the reaction. The amount of label
appearing in the DHA fraction is increased if unlabeled DHA is present
in the reaction mixture, indicating that some redox cycling of ascorbate
is occurring in the RPE cells. The ascorbic acid oxidizing activity does
not depend on intact cells, is not inactivated by heating the
cells to 80 degrees C, and appears to reside mainly in the subcellular
fraction which contains melanin pigment granules. The ascorbic acid
oxidation may be caused by free radicals formed when melanin is
illuminated with light. This reaction appears to be a useful method for
quantifying the production of free radicals during photooxidative stress.

37: Free Radic Biol Med 1992;13(2):121-6
8-Hydroxydeoxyguanosine in vitro: effects of glutathione, ascorbate, and
5-aminosalicylic acid. Fischer-Nielsen A, Poulsen HE, Loft S.
Department of Pharmacology, University of Copenhagen, Denmark.
Oxidative DNA damage, as expressed by 8-hydroxydeoxyguanosine (8-OHdG),
was investigated in calf thymus DNA exposed to either ultraviolet
radiation or to FeCl2/H2O2 in a Fenton-like reaction. The influence of
iron (absent in the UV system and present in the FeCl2/H2O2 system) and
pH (7.4 and 4.0) on the effect of glutathione (GSH), ascorbate, and
5-aminosalicylic acid (5-ASA, a drug used in the treatment of chronic
inflammatory bowel diseases) was examined in these systems. Without
iron, all three compounds considerably reduced 8-OHdG formation
(i.e., acted as scavengers), while in the presence of iron salts, 8-OHdG
formation was accelerated (except for GSH at pH 7.4), i.e., the
compounds acted as prooxidants. This effect was augmented at low pH. The
prooxidant property of 5-ASA may have implications for its clinical use.
Maximum scavenging effect for all the compounds investigated was
obtained at much lower doses than the maximum enhancing effect. This
demonstrates that to the end of oxy-radical scavenging, the
concentration of the GSH, ascorbate, and 5-ASA, respectively, should
be chosen to obtain maximum antioxidant effect and minimum prooxidant
effects. The significance of this finding for the selection of
antioxidant dose is important but remains to be investigated further.

39: Photochem Photobiol 1991 Apr;53(4):481-91
Photosensitized lipid peroxidation and enzyme inactivation by
membrane-bound merocyanine 540: reaction mechanisms in the absence and
presence of ascorbate. Bachowski GJ, Pintar TJ, Girotti AW.
Department of Biochemistry, Medical College of Wisconsin, Milwaukee
53226.
The lipophilic photosensitizing dye merocyanine 540 (MC540) is being
studied intensively as an antitumor and antiviral agent. Since plasma
membranes are believed to be the principal cellular targets of
MC540-mediated photodamage, we have studied membrane damage in a well
characterized test system, the human erythrocyte ghost. When irradiated
with white light, MC540-sensitized ghosts accumulated lipid
hydroperoxides (LOOHs derived from phospholipids and cholesterol) at a
rate dependent on initial dye concentration. Neither desferrioxamine nor
butylated hydroxytoluene inhibited LOOH formation, suggesting that Type
I (iron-mediated free radical) chemistry is not important.
By contrast, azide inhibited the reaction in a dose-dependent fashion,
implicating a Type II (singlet oxygen, 1O2) mechanism. Stern-Volmer
analysis of the data gave a 1O2 quenching constant approximately 50
times lower than that determined for an extramembranous target, lactate
dehydrogenase (the latter value agreeing with literature values). This
suggests that 1O2 reacts primarily at its membrane sites of origin and
that azide has limited access to these sites. Using
{14C}cholesterol-labeled membranes and HPLC with
radiodetection, we identified 3 beta-hydroxy-5
alpha-cholest-6-ene-5-hydroperoxide as the major cholesterol
photoproduct, thereby confirming 1O2 intermediacy. Irradiation of
MC540-sensitized membranes in the presence of added iron and ascorbate
resulted in a large burst of lipid peroxidation, as shown by
thiobarbituric acid reactivity and appearance of
7-hydroperoxycholesterol and 7-hydroxycholesterol
as major oxidation products. Amplification of MC540-initiated lipid
peroxidation by iron/ascorbate (attributed to light-independent
reduction of nascent photoperoxides, with ensuing free radical chain
reactions) could prove useful in augmenting MC540's phototherapeutic
effects.

Awesome, thanks!
 
Similar threads
Thread starter Title Forum Replies Date
pauljacob Linus Pauling Institute article implicates Saturated Fats as Unhealthy Diet 10
johnwester130 The Linus Pauling Collagen Drink That Tastes Good Recipes 22
Steven Bussinger Linus Pauling Institute: Uncovering The Secrets Of The Naked Mole Rat CO2, Bag Breathing 3
M The Pauling Therapy For Cardiovascular Disease Miscellaneous Health Discussions 20
haidut PUFA required for periodontal disease, aspirin may help Scientific Studies 0
ecstatichamster Yes, Nick Minaj may be right: swollen balls are entirely possible after the "vaccine" Vaccines 19
ImprovingDaily Almost fully recovered from Covid pneumonia, here are some tips for anyone who may need them. Viruses, Parasites, Fungus, Vaccines 13
A Is lactose free milk safe ? (galactose may be toxic) Dairy 20
haidut Having SARS-CoV-2 confers MUCH stronger immunity than vaccines, and it may last a lifetime Scientific Studies 33
haidut Vitamin D, reducing fat oxidation may treat lung fibrosis, COVID-19 Scientific Studies 5
haidut How lipolysis may damage organs such as the heart Scientific Studies 0
OccamzRazer Income idea for anyone who's lost or may lose their job Miscellaneous 38
A Https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7250771/ Mortality From Coronavirus Disease 2019 Increases With Unsaturated Fat and May Be Reduced by Metabolism 1
J Think I may have vitamin D toxicity Skin 15
RenaissanceMan Omega-3 EPA and DHA may be the solution to "male pattern baldness" / hair loss in men Polyunsaturated Fats, Seed Oils 29
G CDC may be preparing internment camps Ask For Help or Advice 52
G The COVID Vaccine May Induce COVID Sensitivity Vaccines 0
D New article frames SIBO as a gender specific disease; anabolic steroids may be useful treatment Articles & Scientific Studies 3
haidut COVID-19 vaccines may cause 82%+ miscarriage rate Scientific Studies 79
haidut Iron supplementation may not cure anemia, unless nutrition is also improved Scientific Studies 1
haidut Damaged mitochondria may cause 90%+ of Parkinson Disease (PD) cases Scientific Studies 4
haidut Aging is an energy deficiency problem, taking cardiolipin may reverse it Scientific Studies 8
haidut It's official: COVID-19 vaccination may be stemming evolution of “fitter” SARS-CoV-2 variants Scientific Studies 15
A How teen marijuana use may alter the shape of the brain Scientific Studies 0
D Theory, which may explain copper toxicity/deficiency/low cerruloplasmin Minerals 86
charlie Like night and day: Animal studies may not translate to humans if time of day is disregarded Scientific Studies 2
P Progesterone Suppresses GAD enzyme MRNA (If progesterone excites you, it may be glutamate) Progesterone 2
haidut Mitochondrial dysfunction may be the cause of anemia Scientific Studies 0
haidut Blocking the endotoxin receptor (TLR4) may prevent / treat hearing loss Scientific Studies 3
haidut Upregulated serotonin synthesis may be a biomarker for breast cancer Scientific Studies 0
haidut Vitamin B6, lowering stress, may treat schizophrenia Scientific Studies 3
haidut Many people may suffer from chronic serotonin syndrome Scientific Studies 65
haidut Endocrine disruptors in cosmetics may cause postpartum depression, premature births Scientific Studies 1
haidut Endotoxin (LPS) may be the cause of fatal lung damage in COVID-19 Scientific Studies 0
L UK Freedom Rally on May 29 2021 Society 1
P Ray Peat Interview Friday May 28th Ray w/ Danny Interviews 29
Lejeboca Ray Peat Interview KMUD - 10pm ET, May 21 2021 KMUD Radio-The Herb Doctors 6
Sam321 Chinese rocket to crash back to earth May 8th - unknown landing location Breaking News 0
GorillaHead Vitamin B5 supplementation may cause adrenal over activity? Ask For Help or Advice 12
Zpol 'SARS-CoV-2 Spike Protein Alone May Cause COVID-19 Lung Damage – Even Without the Presence of Intact Virus' Scientific Studies 15
bzmazu Transmissible Viral Vaccines... how the shots are affecting those who haven't taken it. They may be designed to do exactly that Viruses, Parasites, Fungus, Vaccines 492
Mito Anti-inflammatory activity of ivermectin in late-stage COVID-19 may reflect activation of systemic glycine receptors Miscellaneous Health Discussions 7
Zsazsa Hormone drugs that reduce androgen levels may help disarm the coronavirus spike protein Scientific Studies 0
haidut Blocking cortisol may treat terminal pancreatic cancer Scientific Studies 6
haidut Oral testosterone + vitamin E may treat NAFLD, NASH, cirrhosis in humans Scientific Studies 6
haidut Metabolic (energy) deficiency may be the cause of Parkinson Disease (PD) Scientific Studies 6
haidut Aspirin may prevent and treat COVID-19 Scientific Studies 1
haidut PUFA metabolites may drive bacterial infections and their resistance to antibiotics Scientific Studies 0
haidut Fasting ineffective for shrinking belly fat, may actually increase it Scientific Studies 4
haidut Mitochondrial debris leaking in bloodstream may cause autoimmune disease Scientific Studies 2

Similar threads

Top