yes, i use cascara to reduce swollen colon, only below levels that create diarrhea.emodin (one active component in Cascara and Chinese rhubarb) and if used in doses lower than what's causing a laxative effect, can be systemically beneficial
but if constipation is bad you may need more temporarily, but it will irritate the mucosa. that's why i explained how to empty the colon without cascara, and use cascara after the colon has been flush to increase the lumen volume.
if you cannot do it like that, I'm not sure witch one is safer, laxative cascara or doing a colon cleanse with water. sometimes too much cascara can irritate the mucosa more than a colon flush with water.
I've never did colon cleanse to help with constipation, only did it when i felt my poo was burning or irritating, so i can't tell how well it works for constipation.