Cat's Claw Binds Estradiol By 47.2%

RealNeat

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Is this a supplement worth taking in the Peat world!?

I'm taking this for viral reasons but ran into this during my research:

"Cat's Claw appears to have anti-estrogenic properties, as in a concentration dependent manner in vitro between 10-20mcg Cat's Claw noncompetitively inhibits the estrogen receptor (possibly by preventing formation of estrogen receptor complexes required for genomic signalling) with the higher concentration (20mcg) reducing binding of estradiol by 47.2%. [44] This was lesser than the active control of 20mcg Tamoxifen, a direct antagonist inhibiting 69.3% of signalling. [44]"

Depletion of specific binding sites for estrogen receptor by Uncaria tomentosa. - PubMed - NCBI

Depletion of specific binding sites for estrogen receptor by Uncaria tomentosa. - PubMed - NCBI

I remember Haidut mentioning that Tamoxifen wasn't very safe.
 

Lejeboca

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Is this a supplement worth taking in the Peat world!?

I'm taking this for viral reasons but ran into this during my research:

"Cat's Claw appears to have anti-estrogenic properties, as in a concentration dependent manner in vitro between 10-20mcg Cat's Claw noncompetitively inhibits the estrogen receptor (possibly by preventing formation of estrogen receptor complexes required for genomic signalling) with the higher concentration (20mcg) reducing binding of estradiol by 47.2%. [44] This was lesser than the active control of 20mcg Tamoxifen, a direct antagonist inhibiting 69.3% of signalling. [44]"

Depletion of specific binding sites for estrogen receptor by Uncaria tomentosa. - PubMed - NCBI

Depletion of specific binding sites for estrogen receptor by Uncaria tomentosa. - PubMed - NCBI

I remember Haidut mentioning that Tamoxifen wasn't very safe.

Couldn't get the paper test you've pointed to: Only titles (and no DOI) on the pubmed site. Ony quotes from this paper everywhere on the web.
I was surprised to learn that Cat's Claw is one of the most consumed herb for various ailments in the EU and US, to such an extent that EU has publish a voluminous report of it

Assessment report on Uncaria tomentosa (Willd. ex Schult.) DC., cortex EMA/HMPC/259598/2014

in which there is a curious paragraph (page 40):

" It was reported that in human granulosa cells obtained from patients undergoing in vitro fertilization, Uncaria tomentosa extracts (part not specified) at amounts equivalent to dietary doses, dose-dependently (100 pg/ml to 10 μg/ml) caused statistically significant inhibition of progesterone production. Administered orally to sexually mature female rats for eight weeks, a low dose of cat’s claw extract (2 mg/day), equivalent to the manufacturer’s suggested daily dosage, produced no significant changes in profiles of electrolytes, kidney, liver or glucose. For six weeks no changes were noticed in circulating hormone levels compared to the untreated controls. By the eighth week however, serum progesterone and oestradiol levels were reduced by 68% and 71%, respectively, in both the high dose group (20 mg/day) and a low dose group (2 mg/day) (McKenna et al. 2002)"

Since other studies, as you pointed out, show a decrease the estrogen binding/receptor activity, I imagine, that estrogen was excreted eventually rather than being stuck in the cells. And I guess progesterone is not being produced either...
 
OP
RealNeat

RealNeat

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Couldn't get the paper test you've pointed to: Only titles (and no DOI) on the pubmed site. Ony quotes from this paper everywhere on the web.
I was surprised to learn that Cat's Claw is one of the most consumed herb for various ailments in the EU and US, to such an extent that EU has publish a voluminous report of it

Assessment report on Uncaria tomentosa (Willd. ex Schult.) DC., cortex EMA/HMPC/259598/2014

in which there is a curious paragraph (page 40):

" It was reported that in human granulosa cells obtained from patients undergoing in vitro fertilization, Uncaria tomentosa extracts (part not specified) at amounts equivalent to dietary doses, dose-dependently (100 pg/ml to 10 μg/ml) caused statistically significant inhibition of progesterone production. Administered orally to sexually mature female rats for eight weeks, a low dose of cat’s claw extract (2 mg/day), equivalent to the manufacturer’s suggested daily dosage, produced no significant changes in profiles of electrolytes, kidney, liver or glucose. For six weeks no changes were noticed in circulating hormone levels compared to the untreated controls. By the eighth week however, serum progesterone and oestradiol levels were reduced by 68% and 71%, respectively, in both the high dose group (20 mg/day) and a low dose group (2 mg/day) (McKenna et al. 2002)"

Since other studies, as you pointed out, show a decrease the estrogen binding/receptor activity, I imagine, that estrogen was excreted eventually rather than being stuck in the cells. And I guess progesterone is not being produced either...

Excuse my incorrect title on this thread btw, just noticed it.

Very interesting report. I found the initial passage from (www.examine.com) as I was interested in it's validity with the quoted studies as referenced, I can't seem to pull them up to view details either.

It's strange that progesterone is also inhibited, doesn't sound like so much of a plus then.

Here's an interesting video on it.

 
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RealNeat

RealNeat

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Couldn't get the paper test you've pointed to: Only titles (and no DOI) on the pubmed site. Ony quotes from this paper everywhere on the web.
I was surprised to learn that Cat's Claw is one of the most consumed herb for various ailments in the EU and US, to such an extent that EU has publish a voluminous report of it

Assessment report on Uncaria tomentosa (Willd. ex Schult.) DC., cortex EMA/HMPC/259598/2014

in which there is a curious paragraph (page 40):

" It was reported that in human granulosa cells obtained from patients undergoing in vitro fertilization, Uncaria tomentosa extracts (part not specified) at amounts equivalent to dietary doses, dose-dependently (100 pg/ml to 10 μg/ml) caused statistically significant inhibition of progesterone production. Administered orally to sexually mature female rats for eight weeks, a low dose of cat’s claw extract (2 mg/day), equivalent to the manufacturer’s suggested daily dosage, produced no significant changes in profiles of electrolytes, kidney, liver or glucose. For six weeks no changes were noticed in circulating hormone levels compared to the untreated controls. By the eighth week however, serum progesterone and oestradiol levels were reduced by 68% and 71%, respectively, in both the high dose group (20 mg/day) and a low dose group (2 mg/day) (McKenna et al. 2002)"

Since other studies, as you pointed out, show a decrease the estrogen binding/receptor activity, I imagine, that estrogen was excreted eventually rather than being stuck in the cells. And I guess progesterone is not being produced either...

Do you think Cats Claw would be beneficial for men but not women then? I don't see many positive accounts of men using progesterone on this forum so maybe it's inhibition is of lesser importance to men and they could benefit from its estrogen receptor decrease?
 

Kingpinguin

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Is this a supplement worth taking in the Peat world!?

I'm taking this for viral reasons but ran into this during my research:

"Cat's Claw appears to have anti-estrogenic properties, as in a concentration dependent manner in vitro between 10-20mcg Cat's Claw noncompetitively inhibits the estrogen receptor (possibly by preventing formation of estrogen receptor complexes required for genomic signalling) with the higher concentration (20mcg) reducing binding of estradiol by 47.2%. [44] This was lesser than the active control of 20mcg Tamoxifen, a direct antagonist inhibiting 69.3% of signalling. [44]"

Depletion of specific binding sites for estrogen receptor by Uncaria tomentosa. - PubMed - NCBI

Depletion of specific binding sites for estrogen receptor by Uncaria tomentosa. - PubMed - NCBI

I remember Haidut mentioning that Tamoxifen wasn't very safe.

I believe the opposite that it might have estrogenic activity. Many drugs that are promoted to be anti estrogens that act on the estrogen receptors are estrogenic. Like the study mentions Tamoxifen a serm. Selective estrogen receptor modulator. The effect on estrogen receptors are unclear but it antagonize on some receptors and agonize on some. Same goes with many so called anti estrogenic herbs like resveratol for an example. If you look around the forum you find information that these anti estrogens are actually estrogenic. Vitamin E in my opinion is a much better and more potent way to reduce the systemic estrogen load. i would not mess too much with drugs/herbs that affect estrogen to much rather than trying to lower inflammation, stress etc thus lowering estrogenic/serotonogenic effects. Another way to lower estrogen is aromataze inhibitors which blocks the enzyme that makes estrogen instead of the estrogen receptor. But from my experience most people dont tend to benefit from going that route unless you have very high estrogen on paper as these drugs are extremly potent.
 
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RealNeat

RealNeat

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I believe the opposite that it might have estrogenic activity. Many drugs that are promoted to be anti estrogens that act on the estrogen receptors are estrogenic. Like the study mentions Tamoxifen a serm. Selective estrogen receptor modulator. The effect on estrogen receptors are unclear but it antagonize on some receptors and agonize on some. Same goes with many so called anti estrogenic herbs like resveratol for an example. If you look around the forum you find information that these anti estrogens are actually estrogenic. Vitamin E in my opinion is a much better and more potent way to reduce the systemic estrogen load. i would not mess too much with drugs/herbs that affect estrogen to much rather than trying to lower inflammation, stress etc thus lowering estrogenic/serotonogenic effects. Another way to lower estrogen is aromataze inhibitors which blocks the enzyme that makes estrogen instead of the estrogen receptor. But from my experience most people dont tend to benefit from going that route unless you have very high estrogen on paper as these drugs are extremly potent.

I see what you mean, kind of like the actions of cruciferous compounds. Vitamin E is interesting, I feel its necessary for individuals who are new to PUFA avoidance but saturated fat intake also seems to accomplish a lot of the same things (stability). Ive never been too comfortable messing around with isolated fat soluble nutrients, they seem to have a very complex interplay with themselves and minerals. Plus, it seems that after a while of avoiding PUFA, hence not really needing E, it would only add more obstacles in the way of properly balancing, arguably more important nutrients, like A, D and K.

The only one Ive ever considered is the one by Jarrow Toco-Sorb for those times when one eats "mystery fats."
Jarrow Formulas : Toco-Sorb
 

Vinny

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