ABSTRACT
ABSTRACT The constant use of chemical insecticides for Aedes aegypti control has caused resistance in the mosquito populations. Thus, the objective of this study was to analyze the larvicidal potential of extracts and fractions of plants on A. aegypti larvae. The analysis included sixty one extracts and twenty five fractions of fifty botanical species at concentrations of 0.25; 0.12; 0.06 to 0.03 mg mL-1; 4 replications and one negative control of dechlorinate water and 1% DMSO; and a positive control with rotenone. The toxicity index in descending order with LC50 for the most active of the extracts selected were ethanol extract of Ormosea arborea (0.111 mg mL-1) seeds and ethanol extracts of leaves such as Piper hispidum (0.169 mg mL-1), Solanum variabile (0.188 mg mL-1), O. arborea (0.238 mg mL-1), Turnera umifolia (0.242 mg mL-1) and Piper hispidum (0.567 mg mL-1). For plant fractions, the most active were chloroform (0.192 mg mL-1) and hexane (0.342 mg mL-1) P. aduncum leaves, hexane fraction (0.415 mg mL-1) and methanol extract (0.625 mg mL-1) of Spermacocea latifolia leaves. Regarding the extract of T. umifolia single species, there is no bibliographic report on their degree of efficiency as an insecticide.
Subject(s)
Animals , Plant Extracts , Aedes , Biological Control Agents , Insecticides , Larva , Reference Values , Biological Assay , Brazil , Reproducibility of Results , Toxicity Tests , Plant Leaves/chemistry , Ethanol/chemistryABSTRACT
A total of twenty different extracts from six Brazilian Bromeliaceae species was screened for antioxidant activity by assessment of their capacity to scavenge the DPPH radical. In a general way, the polar rhizome extracts from Bromeliaceae representatives showed better antioxidant results than the extracts from leaves and fruits of the same species. The best results were found for the rhizome extracts of Vriesea procera (Mart. ex Schult.f.) Wittm. and Neoregelia cruenta (Graham) L.B. Sm. Crude methanol extract of Ananas bracteatus (Lindl.) Schult. & Schult. f. leaf had a significant antiradical activity among the leaves extracts assessed its purification afforded four metabolites: 2-O-feruloyl glyceride, 2-O-p-coumaroyl glyceride, 5,7,4'-trihydroxy-3,3',5'-trimethoxyflavone and 3-O-β-D-glucopyranosyl sitosterol.
Um total de vinte extratos de seis espécies de Bromeliaceae brasileiras foram avaliadas quanto a atividade antioxidante, usando-se o método colorimétrico de redução do radical DPPH. De maneira geral, os extratos polares dos rizomas das espécies de Bromeliaceae testadas revelaram melhor perfil antioxidante do que os extratos das folhas e dos frutos das mesmas espécies. Os melhores resultados foram encontrados para os rizomas de Vriesea procera (Mart. ex Schult.f.) Wittm. e Neoregelia cruenta (Graham) L.B. Sm. O extrato bruto metanólico das folhas de Ananas bracteatus (Lindl.) Schult. & Schult. f. apresentou uma atividade significativa, em relação aos extratos de folhas testados, e o processo de purificação desse extrato resultou na identificação de quatro metabólitos: ferulato de 2-glicerila, p-cumarato de 2-glicerila, 5,7,4'-triidroxi-3,3',5'-trimetoxiflavona e 3-O-β-D-glicopiranosil sitosterol.