Molluscicidal constituents of Calophyllum from Madagascar: activity of some natural and synthetic neoflavonoids and khellactones.

Crude extracts of seeds, leaves and barks of four Madagascan Calophyllum species: C. inophyllum, C. recedens, C. chapelieri, and C. verticullatum, have been tested for molluscicidal activity against Biomphalaria glabrata. All seed extracts showed significant activity. The major constituents of the most active Calophyllum species were examined. Some related coumarinic derivatives were synthesized in order to improve the biological activity. Among the compounds prepared, 5,7-dihydroxy-6-(2-methylbutyryl)-4-phenyl-coumarin presented an interesting molluscicidal activity.