Molluscicidal activity of 2-hydroxy-3-alkyl-1,4-naphthoquinones and derivatives

In the search for new molluscicidal agents we tested the activity of lapach ol and other 2-hydroxy-3-alkylnaphthoquinones possessing nitrogenated alkyl chains, against the snail Biomphalaria glabrata. Lapachol, isolapachol and nor-lapachol showed strong molluscicidal activity against the adult snail (LD90 < 10 ppm) and significant toxicity against snail egg masses (LD90 < 0 .2 ppm). As lapachol is easily extracted, and the derivatives can be synthe sised without any difficulty, large-scale synthesis and field tests can be conducted, with a view to large-scale molluscicidal programs. (C) 2000 Aust ralian Society for Parasitology Inc. Published by Elsevier Science Ltd. All rights reserved.