Preliminary Screening of Brazilian Plant Extracts for Molluscicidal Activity; Part II¹

Abstract

Schistosomiasis is one of the major health problems in Brazil and other tropical and sub-tropical countries. Chemoprophylactic control of the disease should be possible using molluscicidal formulations. Molluscicides obtained from plants which can be grown in endemic areas of schistosomiasis transmission could provide a relatively low cost method for controlling Biomphalaria glabrata snails, the intermediate host (1). We wish to report the results of the screening for molluscicidal activity of 48 extracts from 23 Brazilian plants against B. glabrata. Most of these were Asteraceae, representatives of which have previously been shown to exhibit molluscicidal activity (2-5). The tests were carried out both on snails and snails eggs, and only the plants extracts that showed activity against both are presented in Table 1.Plants were collected in the States of São Paulo and Minas Gerais. Taxonomic identification was carried out by Dr. Hermógenes Freitas Leitão Filho of the Institute of Biology of the University of Campinas; herbarium samples were deposited in that Department's herbarium. Crude extracts used for the screening tests were prepared from dried plants by extraction with hexane, chloroform, hexane/ethyl acetate (3: 1), and ethanol, Bioassays were made with snails and with eggs of B. glabrata as previously described (6).Ethanol extracts were generally more toxic than extracts using less polar solvents. This suggests that the activity is associated with the presence of more polar substances. The ethanolic extract of the stems of A. populnea was toxic (100%) at 10 ppm, while the other extracts were active at lOOppm.Further studies are being carried out with these crude extracts, including fractionation and purification in the hope of isolating the biologically active substances. It should be stressed that the plants tested are widely encountered in Brazil and thus could afford suitable sources for extracts and/or pure compounds usable as molluscicides.

Morfologia floral de Aspidosperma Mart. & Zucc. (Apocynaceae)

“…Aspidosperma é um gênero de cerca de 43 espécies de distribuição neotropical (Marcondes-Ferreira & Kinoshita 1996), cujas espécies apresentam importância como fornecedoras de madeira nobre e como detentoras de alcalóides (Raffauf 1964;Gilbert 1966;INPA 1976;Robert et al 1983;Lopes et al 1989), grupo de substâncias com notórias aplicações antimicrobianas. Destaca-se o potencial dos alcalóides provenientes de espécies de Aspidosperma no tratamento de cânceres (Kansal & Potier 1986;Oliveira & Alencar-Filho 1994).…”