New steroidal saponins from Agave lophantha Schiede and their pharmacological evaluation

The structures of one new monodesmosidic spirostanoside and one new bisdesmosidic furanostanol glycoside isolated from leaves of Agave lophantha Schiede have been determined by means of spectroscopic and chemical methods as (25R)-5 beta-spirostan-3 beta-ol-3-O-(beta-D-apiofuranosyl(1-->4)beta-D -glucopyranosyl(1-->3)[beta-D-glucopyranosyl(1-->2)]beta-D -galactopyranoside) and 26-O-beta-D-glucopyranosyl(25R)-5 beta-furost-20(22)-ene-3 beta, 26-diol-3-O-(beta-D-xylopyranosyl(1-->3)-[beta-D-glucopyranosyl(1--2)] beta-D-galactopyranoside), respectively. The 1H and 13C NMR resonances of the two compounds were assigned by NMR (1H, 13C, HOHAHA, 1H-1H COSY, HMQC, HMBC, NOE difference) studies. The pharmacological activities of the saponin containing fraction are discussed.