Revised structures of avenacosides A and B and a new sulfated saponin from Avena sativa L.

Abstract

The revised structures of avenacosides A and B and a new sulfated steroidal saponin isolated from grains of Avena sativa L. were elucidated. Their structures and complete NMR assignments are based on 1D and 2D NMR studies and identified as nuatigenin 3-O-{α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-β-D-glucopyranoside}-26-O-β-D-glucopyranoside (1), nuatigenin 3-O-{α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→3)-β-D-glucopyranosyl-(1→4)]-β-D-glucopyranoside}-26-O-β-D-glucopyranoside (2), and nuatigenin 3-O-{α-L-rhamnopyranosyl-(1→2)-[β-D-6-O-sulfoglucopyranosyl-(1→4)]-β-D-glucopyranoside}-26-O-β-D-glucopyranoside (3).