Evaluation of temporal, seasonal and geographic stability of the molluscicidal property of Euphorbia splendens latex

• Autor(a) principal: Schall, Virginia Torres
• Data de Publicação: 1992
• Outros Autores: Vasconcellos, Mauricio Carvalho de, Villaça-Coelho, Ana Luiza, Ferreira-Lopes, Fátima Eliana, Silva, Ivonise Paz da
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Revista do Instituto de Medicina Tropical de São Paulo
• Texto Completo: https://www.revistas.usp.br/rimtsp/article/view/28917
• topic: Molluscicidal Plants; Biomphalaria sp.; Schistosomiasis

Laboratory tests with aqueous solutions of Euphorbia splendens var. hislopii latex have demonstrated seasonal stability of the molluscicidal principle, with LD90 values of 1.14 ppm (spring), 1.02 ppm (fall), 1.09 ppm (winter), and 1.07 ppm (summer) that have been determined against Biomphalaria tenagophila in the field. Assays on latex collected in Belo Horizonte and Recife yielded LD90 values similar to those obtained with the reference substance collected in Rio de Janeiro (Ilha do Governador), demonstrating geographic stability of the molluscicidal effect. The molluscicidal action of aqueous dilutions of the latex in natura, centrifuged (precipitate) and lyophilized, was stable for up to 124 days at room temperature (in natura) and for up to 736 days in a common refrigerator at 10 to 12ºC (lyophilized product). A 5.0 ppm solution is 100% lethal for snails up to 13 days after preparation, the effect being gradually lost to almost total inactivity by the 30th day. This observation indicated that the active principle is instable. These properties together with the wide distribution of the plant, its resistance and adaptation to the tropical climate, its easy cultivation and the easy obtention of latex and preparation of the molluscicidal solution, make this a promising material for large-scale use in the control of schistosomiasis