Biotransformation of Glycyrrhizin to 18.BETA.-Glycyrrhetinic Acid-3-O-.BETA.-D-glucuronide by Streptococcus LJ-22, a Human Intestinal Bacterium.

Abstract

By human intestinal bacteria, glycyrrhizin (18beta-glycyrrhetinic acid-3-O-[beta-D-glucuronopyranosyl-(1-->2)-betaD-glucuro nopyranoside], GL) was metabolized to 18beta-glycyrrhetinic acid (GA): the main pathway metabolized GL to GA by glucuronidases of Bacteroides J-37 and Eubacterium sp. GLH and the minor pathway metabolized GL to 18beta-glycyrrhetinic acid-3-O-beta-D-glucuronide (GAMG) by beta-glucuronidase of Streptococcus LJ-22. Beta-Glucuronidase from Streptococcus LJ-22 hydrolyzed GL to GAMG (not GA). The molecular weight and optimal pH of the enzyme were 240 kDa and 5-6.