Most orally administered polyphenols are metabolized, with very little absorbed\nas aglycones and/or unchanged forms. Metabolic and pharmacokinetic studies are therefore\nnecessary to understand the pharmacological mechanisms of polyphenols. Jumihaidokuto\n(JHT), a traditional Japanese medicine, has been used for treatment of skin diseases including\ninflammatory acne. Because JHT contains various types of bioactive polyphenols, our aim was\nto clarify the metabolism and pharmacokinetics of the polyphenols in JHT and identify active\nmetabolites contributing to its anti dermatitis effects. Orally administered JHT inhibited the\nincrease in ear thickness in rats induced by intradermal injection of Propionibacterium acnes.\nQuantification by LC-MS/MS indicated that JHT contains various types of flavonoids and is\nalso rich in hydrolysable tannins, such as 1,2,3,4,6-penta-O-galloyl glucose. Pharmacokinetic\nand antioxidant analyses showed that some flavonoid conjugates, such as genistein 7-O-glucuronide and liquiritigenin 7-O-glucuronide, appeared in rat plasma and had an\nactivity to inhibit hydrogen peroxide-dependent oxidation. Furthermore, 4-O-methylgallic\nacid, a metabolite of Gallic acid, appeared in rat plasma and inhibited the nitric oxide\nreaction. JHT has numerous polyphenols; it inhibited dermatitis probably via the antioxidant\neffect of its metabolites. Our study is beneficial for understanding in vivo actions of orally\nadministered polyphenol drugs.
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