POTENCIAL DE PRODUTOS VEGETAIS DE Tagetes erecta L. NO CONTROLE DA ESQUISTOSSOMOSE: atividade moluscicida e cercaricida.

Abstract

Schistosomiasis mansoni is a parasitic disease caused by the helminth Schistosoma mansoni Sambon (1907), with high occurrence in Brazil and endemic areas in Maranhão. For the transmission of the disease, the parasite needs an intermediate host that are snails of the genus Biomphalaria responsible for the release of the cercariae that are the infective larvae to the man. The World Health Organization determines that one of the ways to prevent transmission of the disease is to control the intermediate host and to block the forms of helminth dissemination through the use of molluscicidal and cercaricidal. Since the use of molluscicidal substances and synthetic cercaricidal presents disadvantages such as low selectivity and high financial cost, the use of natural products represents a promising alternative. The species Tagetes erecta L. (Asteraceae), popularly known as Marigold, has ample and diversified use in popular practice with rich chemical composition and easy cultivation. Considering the problematic of schistosomiasis, the high incidence of vectors, the low selectivity of the products currently used, as well as the resistance already presented to niclosamide, this work aims to perform the chemical characterization of hydroethanolic extract of the essential oil of the leaves and the essential oil of the flowers of Tagetes erecta; to investigate the activity of the essential oil hydroethanolic extract of the leaves and the essential oil of the Tagetes erecta flowers against Biomphalaria glabrata and cercaria fronts of Schistosoma mansoni, to evaluate parameters of toxicity of the vegetal products against non-target organisms.The extract of Tagetes erecta was obtained by the percolation method in the drug: solvent ratio of 1/12 m / v with yield of 26%. The chemical analysis showed phenolic compounds with highlight the class of flavonoids from which they presented three glycosylated flavones. The essential oil of the leaves and the essential oil of the flowers were extracted by steam distillation in a clevenger apparatus. The yield of the essential oils was 1.6% for the essential oil of the leaves and 1.2% for the essential oil of the flowers. The comparison of the chemical composition of the oils showed a difference in the composition profile, monoterpenes prevailed in the essential oil of the leaves with the major compound piperitone and in the essential oil of the flowers prevailed the sesquiterpenos emphasizing the compound caryophyllene. The bioassays were performed with the molluscs of the species Biomphalaria glabrata (Say, 1818) and with the cercariae of the helminth Schistosoma mansoni according to methodologies described in the literature. Already in the toxicity tests against non - target organisms the microcrustacean Artemia salina Leach and the fish Danio rerio Hamilton-Buchanan. The hydroethanolic extract presented cercaricidal action front infective larvae of the helminth Schistosoma mansoni and demonstrated safety for use in non - target organisms toxicity tests. Leaf essential oil demonstrated promising cercaricidal activity and safety in toxicity tests against non - target organisms. However, the essential oil of the flowers showed activity against the molluscs and cercariae of Schistosoma mansoni, but presented as an insecure product of use against Artemia salina and Danio rerio. These results indicate that essential oils and the hydroethanolic extract of Tagetes erecta have potential for product development for the control of schistosomiasis demonstrating greater safety than the product recommended by the World Health Organization.