Bacteroides J-37, a human intestinal bacterium, produces alpha-glucuronidase

beta-Glucuronidases of mammalian tissues metabolized glycyrrhizin (18 beta-glycyrrhetinic acid, beta-D-glucuronyl alpha-D-glucuronic acid, GL) to glycyrrhetinic acid (GA) via 18 beta-glycyrrhetinic acid alpha-D-glucuronic acid (GAMG); they hydrolyzed beta-glucuronic acid conjugates better than alpha-glucuronic acid conjugates. However, human intestinal bacteria directly metabolized GL to GA, and minorly to GA via GAMG. Bacteroides J-37, isolated from human intestinal bacteria, transformed GL or GAMG to GA, but not baicalin; it produced alpha-glucuroniase, which hydrolyzed the alpha-linkage of glucuronic acid conjugates. alpha-Glucuronidase of Bacteroides J-37 hydrolyzed alpha-glucuronic acid conjugates better than beta-glucuronic acid conjugates. beta-Glucuronidase from E. coli, a human intestinal bacterium, hydrolyzed baicalin to baicalein, but did not transform GL.