Molluscicidal steroidal saponins from Yucca elephantipes

ABSTRACT

Three spirostanol and two furostanol saponins have been isolated from the methanol extract of the leaves of Yucca elephantipes. The structures of these saponins were established as 3-O-beta-D-xylopyranosyl [1->2] [-beta-D-glucopyranosyl- [1->3]]- beta-D-glucopyranoside yamogenin [I], 3-O-beta-D-xylopyranosyl- [1->2] [beta-D-glucopyranosyl- [1->3]], 26-beta-D- glncopyranoside [25 S]- furost-5-ene-3,22,26-triol [II], 3-O-alpha-L- rhamnopyranosyl [1->2]- [beta-D-xylopyranosyl- [1->3]]- beta-D-glucopyranosyl- [1->4]-beta-D-galactopyranoside gitogenin [III], 3-O-beta-D-xylopyranosyl- [1-> 3]-[beta-D-glucopyranosyl- [1->2]- beta-D-glucopyranosyl- [1->4]- beta-D-galactopyranoside gitogenin [IV], and 26-O-beta-D-glucopyranosyl-22-O-methyl [25R]-5-furostan- 2,3,26-tetrol-3-O- [alpha-L-rhamnopyranosyl- [1->3]]- beta-D-glucopyranosyl- [1->2]- beta-D-glucopyranosyl [1->4]- beta-D-galactopyranoside [V]. Saponins I, III and IV showed high molluscicidal activities against Biomphalaria alexandrina snails after 24 hours exposure [LC90 = 4,9 and 7 ppm] whereas saponins II and V were inactive up to 50 ppm