Novel saponins hainaneosides A and B isolated from Marsdenia hainanensis

Novel saponins possessing fertility-regulating activity, hainaneosides A (1) and B (2), have been isolated from the twigs and stems of Marsdenia hainanensis, and their structures have been elucidated unambiguously as 12-nicotinoyl sarcostin-3-O-beta-D-glucopyranosyl-(1-->4)-3-O-methyl-6-deoxy-bet a-D- allopyranosyl-(1-->4)-beta-D-oleandropyranosyl-(1-->4)-beta-D- cymaropyranosyl-(1-->4)-beta-D-cymaropyranoside and 12-nicotinoyl-20-cinnamoyl sarcostin-3-O-beta-D-glucopyranosyl-(1-->4)-3-O-methyl-6-deoxy-bet a-D- allopyranosyl-(1-->4)-beta-D-oleandropyranosyl-(1-->4)-beta-D-c ymaropyranoside using NMR spectroscopic techniques and chemical transformations.