Abstract
Osteospermum vaillantii (Decne) T. Norl., collected from southern Saudi Arabia, yielded two new saponins characterised as 3-O--D-glucopyranosyl-(2' 1'')--D-glucopyranosyl-(3' 1''')-O--D-galactopyranosyl-oleanolic acid, designated as osteosaponin (1), and 3-O--D-glucopyranosyl-(2' 1'')--D-glucopyranosyl-(2''-1''')--D-glucopyranosyl-(3' 1''')-O--(-D-galactopyranosyl-oleanolic-acid-28-C(O)-O--D-(1''')-glucopyranosyl ester, designated as osteosaponin (2). The sugar attachments and configurations were confirmed by spectroscopic methods, that is, 1H, 13C-NMR, COSY, HSQC and HMBC-NMR experiments.