LABORATORY AND FIELD ASSESSMENT OF MOLLUSCICIDAL ACTIVITY OF GOGO (ENTADA-PHASEOLOIDES) AGAINST AMPHIBIOUS SNAIL INTERMEDIATE HOST OF SCHISTOSOMA-JAPONICUM

Abstract

A molluscicidal fraction occurs naturally in the bark of a vine (gogo in Tagalog), E. phaseoloides, which grows indigeneously and abundantly in the Philippines. Butanol fraction of the methanol extracts of the bark was most toxic against Oncomelania quadrasi with the LC50 [median lethal concentration] of 3.6-5.8 ppm. Analytical work on the butanol fraction by TLC indicated that the active molluscicidal agents contained at least 2 kinds of saponins. The potency of E. phaseoloides remained rather stable over a wide range of pH values, in the presence of minerals and yeast cells and after UV irradiation of solutions. Preliminary field trials, however, showed that doses higher than 40 g/m2 are needed to produce a satisfactory molluscicidal effect.