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 20 ppm was promising as natural molluscicide.Enriched fraction with velamone gave 80% mortality from 25 ppm, while its LD100 was at 50 ppm. The LD80 was ca. at 45 ppm, while LD100 was at 60 ppm for the enriched fraction containing velamolone acetate. The velamolone-enriched fraction was less efficient and gave a mortality of 90% at 90 ppm.The pure compounds, velamone and velamolone acetate were active at 100% at 3 and 6 ppm, respectively. Velamolone showed a molluscicidal activity at 20 ppm.