M.G. Lima, et al., /Journal of Natural Products, Vol. 5(2012): 222- 232 Copyright © 2012, Journal of Natural Products, INDIA, Dr. Sudhanshu Tiwari, All rights reserved 222 ISSN 0974 – 5211 Metabolic changes in Biomphalaria glabrata infected with Schistosoma mansoni exposed to latex of Euphorbia milii solution versus times of preparation M.G. Lima 1 , R. de C. Augusto 2 , M. C. de Vasconcellos 3 , C.C. Mello-Silva 2 , J. Pinheiro 4 1 Curso de Pós-Graduação em Ciências Veterinárias, Departamento de Parasitologia Animal, Instituto de Veterinária, UFRRJ, Seropédica, RJ, Brazil. 2 Laboratório de Esquistossomose Experimental, IOC/FIOCRUZ-RJ, Brazil. 3 Laboratório de Avaliação e Promoção da Saúde Ambiental - LAPSA, IOC, FIOCRUZ, RJ, Brazil. 4 Laboratório de Biofísica, Departamento de Ciências Fisiológicas, Instituto de Biologia,UFRRJ, Seropédica, RJ, Brazil. * Corresponding Author (Received 02 August 2012; Revised 10 August-10 October 2012; Accepted 15 October 2012) ABSTRACT In order to establish how long after the first application of the latex of Euphorbia milii it remains with activity on the metabolic pathways of molluscs host, this study aimed to screen the effects of latex exposure from 24 hours until 35 days after exposure to the latex solution to check how long the solution exhibits harmful effects on the carbohydrate metabolism and on the nitrogen excretion products of molluscs. Snails exposed to the solution presented a reduction of the glycogen levels in the tissues analyzed and changes in the ways of excreting nitrogen and the concentration of total proteins in the hemolymph, an effect that was strongest in the groups exposed up to 14 days after preparation of the solution. In both cases, the glycogen concentrations and the nitrogen excretions products in the treated groups only returned near the levels in the control groups from the 21 days onwards, but there were still statistically significant differences. These results contribute to the optimization of the use of this product as a molluscicide of natural origin and the development of protocols for control of schistosomiasis. Keywords: Biomphalaria glabrata; Schistosoma mansoni; Euphorbia milii; Metabolism. INTRODUCTION Studies on vegetable materials with molluscicidal activity have been carried out since 1930s aiming to control Schistosoma mansoni intermediate hosts. The molluscicidal activities of Euphorbia milii were firstly studied by Vasconcellos and Schall (1986) who showed lethal action on Biomphalaria glabrata under laboratory conditions. The snail B. glabrata is the main intermediate host of S. mansoni and is closely associated with the occurrence of mansonic schistosomiasis in Brazil. The use of molluscicides is a complementary action of the program for global control of schistosomiasis (WHO Research Journal of Natural Products Volume 5 (2012) www.JournalofNaturalProducts.Com