A new glucoside, sennoside G, was isolated from the leaves of Cassia angustifolia (Senna) in crystalline form and shown by chemical and physical means to be the optical antipode of sennoside A with respect to the sennidin moiety. The optical rotatory dispersion spectrum of sennidin G showed a pattern exactly opposite to that of sennidin A. Sennosides A, B and G were isomerized to each other reversibly, and were oxidized to give 8-glucosylrhein.
