Molluscicidal activity against Bulinus truncatus of Croton campestris

The bark of Croton campestris provided three furano-clerodane named, respectively, velamone, velamolone acetate and velamolone. Fractions containing these diterpenoids were investigated for their molluscicidal activity against Bulinus truncatus, one of the aquatic snail vectors of schistosomiasis. A dichloromethanic extract of root barks, rich in furano-clerodane and molluscicidal at 20ppm was promising as natural molluscicide. Enriched fraction with velamone gave 80% mortality from 25ppm, while its LD(100) was at 50ppm. The LD(80) was ca. at 45ppm, while LD(100) was at 60ppm for the enriched fraction containing velamolone acetate. The velamolone-enriched fraction was less efficient and gave a mortality of 90% at 90ppm. The pure compounds, velamone and velamolone acetate were active at 100% at 3 and 6ppm, respectively. Velamolone showed a molluscicidal activity at 20ppm.