Two new pregnane glycosides from Dioscorea futschauensis R. KUNTH

Two new pregnane glycosides (1, 2) together with two known saponins were isolated from the rhizomes of Dioscorea futschauensis R. KUNTH. The structures of 1 and 2 were established as 16alpha-methoxyl-3beta-[(O-alpha-L-rhamnopyranosyl-(1-->2)-O-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-D-glucopyranosyl)oxy]pregn-5-en-20-one and 21-methoxyl-3beta-[(O-alpha-L-rhamnopyranosyl-(1-->2)-O-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-D-glucopyranosyl)oxy]pregn-5,16-en-20-one, respectively, on the basis of two-dimension NMR (2D NMR) and other spectral analysis. Their in vitro bioactivity against plant pathogenic fungus Pyricularia oryzae and osteoblastic proliferation stimulatory activity in the UMR106 cell line were evaluated.