Molluscicidal hydroxynaphthoquinones and derivatives: Correlation between their redox potentials and activity against Biomphalaria glabrata

Abstract

Several 2-hydroxy-3-alkyl-1,4-naphthoquinones have been submitted to molluscicidal bioassays against the snail Biomphalaria glabrata, intermediate host of Schistosoma mansoni. Cyclic voltammetric studies in aprotic medium (N,N-dimethylformamide plus tetrabutylammonium perchlorate) on Hg and glassy carbon electrodes have been performed on these compounds in order to obtain information about their biological mechanism of action. Several of the quinones assayed showed significant molluscicidal activities, and correlation of their activities and electrochemical parameters showed that the first wave reduction potential is an important parameter. The easily reduced quinones (>Eplc) were more active against adult snails and against their egg masses, whilst the 3-methylamino-2-hydroxy derivatives presented higher negative reduction potentials and were not active as molluscicides.