ABSTRACT
Hydrolyzable tannins, including ellagitannins, occur in foods such as berries and nuts. Various biological activities, including antioxidant, antiviral, and antitumor activities, have been noted and reported for ellagitannins, but the absorption and metabolism of purified ellagitannins are poorly understood. We describe herein the characterization of urinary and intestinal microbial metabolites in rats after the ingestion of ellagitannins. Urine samples were collected after oral administration of ellagitannins such as geraniin ( 1), corilagin ( 2), and their related polyphenols. The suspension of rat intestinal microflora was anaerobically incubated with ellagitannins. Each sample was separated by column chromatography and/or preparative HPLC to give seven metabolites, M1- M7. The structures of these metabolites were determined on the basis of spectroscopic data and chemical evidence. These compounds, except for M1, were characterized as ellagitannin metabolites for the first time. Furthermore, among four major metabolites ( M1- M4) in urine, M2 showed an antioxidant activity comparable to intact geraniin and related polyphenols.
Subject(s)
Bacteria/metabolism , Glucosides/metabolism , Glucosides/urine , Hydrolyzable Tannins/metabolism , Hydrolyzable Tannins/urine , Intestines/microbiology , Animals , Antioxidants/pharmacology , Feces/chemistry , Glucosides/pharmacology , Hydrolyzable Tannins/pharmacokinetics , Hydrolyzable Tannins/pharmacology , Male , RatsABSTRACT
Chlorogenic acid possessed a weak caffeine-like psychostimulant property when assessed for its effect on spontaneous locomotor activity in mice. In the evaluation of the effects for the major metabolites of chlorogenic acid which were detected upon incubation with rat feces and/or excreted in urine after oral administration to rats, caffeic and m-coumaric acids were found to be the principal active metabolites, while the others contributed little to this caffeine-like psychostimulant activity.