STEROIDAL GLYCOSIDES FROM THE FRESH STEM OF STEPHANOTIS-LUTCHUENSIS VAR JAPONICA (ASCLEPIADACEAE) - CHEMICAL STRUCTURES OF STEPHANOSIDES-K-Q

The structural elucidation of seven related oxypregnane-oligoglycoside s stephanosides K (1), L (2), M (3), N (4), O (5), P (6), and Q (7) fr om the fresh stem of Stephanotis lutchuensis var. japonica (Asclepiada ceae) was achieved through on a detailed study of their high-field H-1 - and C-13-NMR spectra. The results show that ail the sugars are beta (1 --> 4)-linked. The aglycones of stephanosides K, M, and O, and step hanosides L, N, and P were identified as 12-O-cinnamoyl-20-O-(E)-2-met hyl-2-butenoyl, and 12-O-cinnamoyl-20-O-nicotinoyl derivatives of (20S )-pregn-6-ene-3 beta,5 alpha,8 beta,12 beta,14 beta,17 beta,20-heptaol , respectively. The aglycone of stephanoside Q was 12-O-cinnamoyldeace tylmetaplexigenin (kidjoranin).