Metabolism of Sennosides by Human Intestinal Bacteria

During the course of studies on the metabolism of sennosides by human intestinal bacteria, an enzyme which takes part in the reduction of sennosides and sennidins was originally isolated from Peptostreptococcus intermedius. This enzyme catalyzed the electron transfer from NADH to FAD, FMN or benzyl viologen, which reduced nonenzymatically sennosides and sennidins to 8-glucosyl-rhein anthrone and rhein anthrone, respectively.