Evaluation of temporal, seasonal and geographic stability of the molluscicidal property of Euphorbia splendens latex Avaliação da estabilidade temporal, estacional e geográfica da ação moluscicida do latex da Euphorbia splendens

• Published in: Revista do Instituto de Medicina Tropical de São Paulo
• Main Authors: Virginia Torres Schall, Mauricio Carvalho de Vasconcellos, Ana Luiza Villaça-Coelho, Fátima Eliana Ferreira-Lopes, Ivonise Paz da Silva
• Format: Article in Journal/Newspaper
• Language: English
• Published: Universidade de São Paulo (USP) 1992
• Subjects: Molluscicidal Plants; Biomphalaria sp; Schistosomiasis; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1590/S0036-46651992000300001; https://doaj.org/article/01c330c08dc344afb1e90d951c570c6f

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 Testes de laboratório com soluções aquosas do látex da Euphorbia splendens var. hislopii demonstraram uma estabilidade estacional da atividade moluscicida do produto coletado na Ilha do Governador - RJ, encontrando-se as seguintes DL90: 1,14 ppm (primavera); 1,02 ppm (outono); 1,09 ppm (inverno) e 1,07 ppm (verão) sobre Biomphalaria tenagophila de campo. Ensaios com o látex da planta coletado em Belo Horizonte e Recife, identificaram DL90 semelhantes aos da substância de referência coletada no Rio, demonstrando uma estabilidade geográfica do efeito moluscicida. Usando diluições aquosas do latex in natura, centrifugado (precipitado) e liofilizado, observou-se a estabilidade da ação ...