Separation and identification of triterpenoid saponins having molluscicidal activity from pittosporum tobira

ABSTRACT

In this work, the molluscicidal properties of Pittosporum tobira were studied. The dry powder suspension showed LC90 80, 60 and 52 ppm against Biomphalaria alexandrina, B. truncatus and L. Caillaudi, respectively. The chemical screening of the different fractionated extracts of the powdered plant showed the presence of some sterols, saponins, glycosides and a flavonoid. Using different chromatographic techniques, two components were separated from the methanol extract; the first was identified as 22-0-[2-methyl butyryl]-Al-barrigenol linked at C-3 to a linear pentasaccharide composed of rhamnose-xylose- xylose through an ether linkage. The second compound was identified as Al- barrigenol-22-0-angeloyl linked at C-3 to a linear pentasaccharide composed of glucose-xylose-glucuronic acid- xylose- glucose through an ether linkage. The structures of the separated compounds were identified by spectroscopic methods such as UV, 1H- NMR, IR and mass spectra