Steroidal oligoglycosides from Solanum nigrum

Abstract

Two new steroidal saponins, named nigrumnins I and II, together with two known saponins were obtained from the whole plant of Solanum nigrum L. On the basis of spectroscopic analysis (1H-NMR, 13C-NMR, 1H-1H COSY, TOCSY, HMQC, HMBC and FAB-MS), nigrumnin I was established as (25R)-5α-spirostan-3β-ol 3-O-β- D-xylopyranosyl-(1→3)-[α-L-arabinopyranosyl-(1→2)]-β-D- glucopyranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-β-D- galactopyranoside (1), and nigrumnin II was elucidated as (25R)- 3β,17α-dihydroxy-5α-spirostan-12-one 3-O-β-D-xylopyranosyl- (1→3)-[α-L-arabinopyranosyl-(1→2)]-β-D-glucopyranosyl-(1→4)- [α-L-rhamnopyranosyl-(1→2)]-β-D-galactopyranoside (2).