Constituents of a Fern, Diplazium subsinuatum. II. Structure Elucidation of Five New Hopane-Triterpene Glycosides.

From whole fern, Diplazium subsinuatum (Wall. ex Hook. et Grev.) Tagawa, two new hopane-triterpene glycosides named diplaziosides III and IV were isolated, together with three new hopane glycosides with acetylated sugars. The structures of diplaziosides III and IV were established as (22S)-24-O-alpha-L-arabinofuranosyl-(1 --> 2)- [beta-D-glucopyranosyl-(1 --> 6)]-beta-D-glucopyranosyl-20 alpha-O-beta-D-glucopyranosyl-30-hydroxyhopan-28-oic acid (1) and (22R)-24-O-alpha-L-arabinofuranosyl-(1-->2)-[beta-D-glucopyranosyl-(1--> 6)]-beta-D-glucopyranosyl-30-carboxy-17-hydroxy-hopano-28,22-lacto ne (2), respectively, on the basis of spectral evidence. Diplazioside III (1) is novel not only in its glycoside structure, but also in its triterpene structure and moreover, 1 provides the first instance of a naturally occurring bisdesmoside with a hopane aglycone. The structures (3a, 3b, and 4a) of the acetylated glycosides were also elucidated, and this is the first report of naturally occurring acetates of hopane glycosides.

Hali tarjima qilinmagan