Steroidal Sapogenins in Dioscorea collettii

Ten Steroidal compounds were isolated from the acid-treated rhizome of wild DIOSCOREA COLLETTII collected from Sichuan province, China. Five of them were identified as diosgenin ( 1), yamogenin ( 2), beta-sitosterol ( 3), Delta (3,5)-deoxytigogenin ( 5) and isonarthogenin ( 9). The other four compounds have not been reported previously in the literature and their structures have been elucidated by spectroscopic data and chemical transformation. They are Delta (3,5)-deoxyneotigogenin ( 6), diosgenin palmitate ( 7), yamogenin palmitate ( 8) and yamogenin-beta-D-glucoside ( 10). It is of interest to note that three pairs of C (25) isomers were isolated: 1 and 2,5 and 6,7 and 8, apparently as artefacts due to the acid treatment. The structure of dihydroxysterol ( 4) is still to be determined.