Steroidal saponins from the leaves of Agave macroacantha.

A new monodesmosidic spirostanol saponin, along with three known saponins was isolated from Agave macroacantha Zucc leaves. The structure of the new saponin was established as hecogenin-3-O-alpha-L-rhamnopyranosyl (1-->4) beta-D-xylopyranosyl (1-->3)[beta-D-glucopyranosyl (1-->2)] beta-D-glucopyranosyl (1-->4) beta-D-galactopyranoside. The (1)H and (13)C resonances of the four compounds were assigned using a combination of 1D and 2D NMR techniques including (1)H, (13)C, COSY, TOCSY, ROESY, HSQC and HMBC NMR and confirmed by mass spectrometry.