Atividade biológica dos extratos aquosos de Solanum lycocarpum St. Hil. (Solanaceae) procedente de regiões fitogeográficas distintas sobre Biomphalaria glabrata (Say, 1818) (Planorbidae)

Abstract

There is urgent need for selective and effective molluscicidal for control of Biomphalaria glabrata the intermediate host of Schistosoma mansoni. This study aimed to evaluate the acute effects of aqueous extract of Solanum lycocarpum founded the Estação Ecológica de Pirapitinga, Três Marias, MG and Campus Seropédica of Universidade Federal Rural do Rio de Janeiro on B. glabrata using different methods of extraction; identify saponin in all extracts used; determine the chronic effects of extracts on the survivors and F1 generation by analyzing the mortality and reproduction and also analyses the influence of extracts on the levels of glucose, urea and uric acid. Leaves of S. lycocarpum after dried at room temperature, perforated, heavy, maintaining a ratio of 10.0% w/v, stock solution, were submitted to the infusion, "hot", where the plant material remained in contact with hot distilled water for 15 minutes reached a temperature of 90º C. And the method of static maceration, "cold", where the leaves remain in contact with distilled water at room temperature for 24 hours. From the stock solution were obtained from the other concentrations, 7.0 and 4.0%. Were used snails 9- 13 mm diameter shell. The snails’ observations submitted to the bioassays were made in 24, 48 and 72h. The survivors’ snails were observed for 60 days and the generation F1 over 90 days. This hemolymph of survivors was collected in periods of 4, 30 and 60 days. High rates were observed with concentrations of 10.0% and 7.0% in the first 24 hours of observation in both localities of collection, regardless of the method of extraction. However, the concentration of 4.0% only showed a high percentage of mortality in the cold extraction, in Três Marias. The static maceration was equivalent to the infusion method, but influenced the determination of the LC90 the location Três Marias. Infusion in the LC90 was 7.0% and the method "cold" was 4.0%. It was verified the presence of saponins in all aqueous extracts S. lycocarpum’s leaves used. Biochemical analysis showed increased levels of glucose in some treated groups, as well as high levels of urea in the hemolymph of survivors snails exposed to plant extract originating from Três Marias. There was no significant difference in the levels of glucose, urea and uric acid of the snails survivors submitted to extract the plant collected in the Campus Seropédica UFRRJ. There was no significant difference in the mortality’s percentage of the survivors during 60 days observation. However, there was no statistical difference in the mortality rate of the F1 generation. It was the influence of extracts on reproduction: number of eggs/snail, eggs/egg masses and snail hatched/number of eggs, the same was observed in the F1 generation, including the number of egg masses/snail. The molluscicidal activity of aqueous extracts of S. lycocarpum was influenced by origin of the plant, but also by the method of extraction. These aspects also affected the reproduction of live survivors, reproduction and mortality of the F1 generation.