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Four labdanes with a 8alpha,15-epoxy ring (8alpha,15-epoxylabdan-16beta-oic acid; 8alpha,15-epoxy-16-norlabdan-13-one; 8alpha,15-epoxy-16-norlabdane; and 16-acetoxy-8alpha,15-epoxylabdane) and the known compound ambreinolide were isolated from the hexane extract of the aerial parts of the grass Eragrostis viscosa. The structures of all compounds were established based on spectroscopic data and the X-ray analysis of 8alpha,15-epoxy-16-norlabdan-13-one. The hexane extract presented moderate activity against the snail Biomphalaria glabrata. 8alpha,15-Epoxylabdan-16beta-oic acid showed no mutagenic activity for doses up to 1000 microg/plate and no significant clastogenic activity for doses up to 100 microg/ml., (Copyright 2010 Elsevier Ltd. All rights reserved.)

Abstract: Leaf extracts of Euphorbia conspicua (Euphorbiaceae), together with the latex and fractions derived therefrom, were evaluated for their molluscicidal and cercaricidal activities and their toxicities to brine shrimps. Whilst the leaf extracts were inactive against Biomphalaria glabrata, the latex, its triterpenic fraction and irritant fractions I and II exhibited high activities against adult snails with LC90 values of 4.87, 10.55, 0.64 and 0.10μg/mL, respectively. The latex and its derived fractions were considered lethal to the cercaria of Schistosoma mansoni at concentrations of 100μg/mL. The toxicities of the latex and the irritant fractions, but not of the triterpenic fraction, against Artemia salina were high with LC50 values<10μg/mL. The possible application of the latex of E. conspicua as an alternative natural molluscicide is considered. [Copyright &y& Elsevier]