Molluscicidal and Trypanocidal Activity of Lapachol and Some Derivatives

Abstract

In search for new molluscicidal natural products, we have tested the activity of lapachol, its potassium salt and acetyl derivative against the snail Biomphalaria glabrata and its egg masses. The LD50 values for the salt (2.70 ppm and 1.43 ppm, respectively) and for lapachol (2.57 ppm and 0.190 ppm, respectively) are indicative of a strong activity. The methyl derivative is less active against adult snails (LD50 7.72 ppm) and egg masses (LD50 38.26 ppm) Lapachol derivatives were also assayed against infective trypomastigote blood forms of T. cruzi and the triacetoxy derivative of reduced lapachol showed relevant trypanocidal activity, killing 95.7% of the parasites at the concentration of 42 µg/mL. As lapachol is easily extracted and its derivatives synthesized without any difficulty, field tests can be conducted, with a perspective of application in large-scale molluscicidal programs.