Steroidal Sapogenins in Dioscorea collettii

Abstract

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), β-sitosterol (3), Δ^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 Δ^3,5-deoxyneotigogenin (6), diosgenin palmitate (7), yamogenin palmitate (8) and yamogenin-β-D-glucoside (10). It is of interest to note that three pairs of C₂₅ 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.

Key Word Index

Dioscorea collettii - Dioscoreaceae - Steroidal Sapogenins - Δ^3,5-Deoxyneotigogenin - Diosgenin palmitate - Yamogenin palmitate - Yamognenin-β-D-glucoside