Cleavages of the O- and C-glucosyl bonds of anthrone and 10,10'-bianthrone derivatives by human intestinal bacteria.

A strictly anaerobic bacterium, Bifidobacterium sp. SEN, capable of hydrolyzing the O-glucosyl of sennosides was isolated from human feces. The bacterium stepwisely hydrolyzed sennoside B to sennidin B through sennidin-8-monoglucoside in PYF medium but not in GAM broth. Addition of D-glucose to PYF medium resulted in loss of the hydrolyzing activity in culture but addition of D-fructose did not affect the activity. Coculture of this bacterium with Peptostreptococcus intermedius led to rapid accumulation of rhein anthrone in the medium. Similarly, a bacterium, Eubacterium sp. BAR, capable of cleaving the C-glucosyl of barbaloin was isolated from human feces. This bacterium grew in PYF medium containing barbaloin and produced enzyme(s) that cleave(s) the C-glucosyl. The induction of the enzymes was completely inhibited in the presence of D-glucose. Nojirimycin inhibited the enzyme activity induced by barbaloin but it did not inhibit the bacterial growth in the presence of D-glucose.