RESUMO
ABSTRACT Plants represent a huge source of substances, with pharmacological potential. Brazil has a diversity of agricultural insect pests and an urgent need for safer methods of insect control. Dysdercus peruvianus (Guerin-Meneville, 1831), Pyrrhocoridae, is an economically important species of the Order Hemiptera and a pest of cotton (Gossypium hirsutum L., Malvaceae). Secondary metabolites in stems of Clusia hilariana Schltdl., Clusiaceae, such as terpenes and benzophenones, have been reported to be insecticidal. The present study investigated the effects of semi-purified fractions of hexane crude extracts from male C. hilariana stems on development of D. peruvianus. Biological parameters at different stages of development including body malformations, range of molting period and toxicity were evaluated. Most insects died and failed to develop due to attachment of their exuviae to the abdomen. Deformations of wings and defective tarsi also occurred. The secondary metabolites from semi-purified fractions of C. hilariana caused mortality, interference in molting and metamorphosis, and body deformations, probably by interacting with the neuroendocrine system. The results demonstrate the potential of C. hilariana extracts as an alternative for the control of the phytophagous insect D. peruvianus and for the development of environmentally safe and biodegradable bio insecticides.
RESUMO
Resumen Los mares ocupan aproximadamente tres cuartas partes de la tierra constituyendo el hábitat de una gran cantidad de especies de flora y fauna. Como parte de los organismos marinos, los phylum bioquímicamente más estudiados son Porífera, Cnidaria y más recientemente Ascomycota, de todos ellos se han aislado e identificado un gran número de compuestos químicos, los cuales han mostrado diferentes tipos de actividades biológicas, principalmente citotóxica, bactericida y antioxidante, entre otras. En esta investigación se estudió la esponja marina Iotrochota birotulata recolectada en Punta Bello-Córdoba en el Caribe colombiano lográndose determinar su perfil lipídico a partir del análisis de los correspondientes espectros de masas de sus compuestos constituyentes, fueron identificados 19 ácidos grasos, los cuales son reportados por primera vez para esta especie. Además fueron identificados 10 esteroles. Se encontraron ácidos grasos con cadenas carbonadas entre C15 y C27, mostrando una amplia diversidad estructural lo cual es característico del phylum porífera. En cuanto a los esteroles se encontraron estructuras principalmente con núcleos Δ5 y Δ7 que son los más abundantes en las esponjas. Se encontró moderada actividad antioxidante en la estabilización del catión radical ABTS+• y baja actividad en la estabilización del radical DPPH•, el mayor valor de inhibición se encontró en el extracto acuoso con un valor de IC50 de 43.9 µg/ml frente al catión radical ABTS+•, mostrando que I. birotulata puede producir compuestos con moderada actividad antioxidante. En el ensayo de actividad insecticida, se encontró afectación larval en los extractos metanólico y acuoso en todas las concentraciones y en todos los tiempos de exposición evaluados frente a Spodoptera frugiperda, también se determinó que estos extractos inducen un efecto antialimentario en las larvas como parte del mecanismo insecticida. Se determinaron las condiciones y los tiempos de exposición óptimos para la mejor eficiencia del ensayo, las cuales fueron de 3 000 µg/ml y 48 h para el extracto metanólico y 2 000 µg/ml y 24 h para el extracto acuoso, respectivamente. En conclusión, los extractos evaluados de I. birotulata mostraron moderada actividad antioxidante y buenas e interesantes actividades insecticida y antialimentaria.(AU)
Abstract It is estimated that three quarters of earth´s surface is occupied by the oceans. This constitutes the habitat of a large number of species of flora and fauna. As part of the marine organisms, the most studied biochemical phylum are Porifera, Cnidaria and more recently Ascomycota, from which a large number of chemical compounds have been isolated and identified. These have shown different types of biological activities, mainly cytotoxic, bactericidal and antioxidant. In this research the marine sponge Iotrochota birotulata collected in Punta Bello-Córdoba in the Colombian Caribbean was studied, and its lipid profile from the analysis of the corresponding mass spectra of its constituent compounds was determined, 19 fatty acids were identified, which are reported for the first time for this specie, besides 10 sterols were identified. Fatty acids with carbon chains between C15 and C27 were found, showing a wide structural diversity, which is characteristic of the porifera phylum. The sterols showed structures mainly with nucleus Δ5 and Δ7, which are the most abundant in sponges. Moderate antioxidant activity was found in the stabilization of the radical cation ABTS+• and low activity in the stabilization of the radical DPPH•, the highest inhibition value was found in the aqueous extract with an IC50 de 43.9 µg/ml against the radical cation ABTS+•, showing that I. birotulata can produce compounds with moderate antioxidant activity. In the insecticidal activity test, larval affectation was found in methanolic and aqueous extracts at all concentrations and at all times of exposure evaluated against Spodoptera frugiperda, it was also determined that these extracts induce an antifeedant effect on the larvae as part of the mechanism insecticide. The optimal conditions and exposure times were determined for the best efficiency of the assay, which were 3 000 µg/ml and 48 h for the methanolic extract and 2 000 µg/ml and 24 h for the aqueous extract, respectively. In conclusion, the evaluated extracts of the I. birotulata showed moderate antioxidant activity and good and interesting insecticidal and antifeedant activities.(AU)
Assuntos
Fauna Marinha/análise , Spodoptera , Metabolismo dos Lipídeos , Ácidos Graxos , Elementos de Resposta Antioxidante , ColômbiaRESUMO
O objetivo do presente experimento foi selecionar extratos com atividade antialimentar sobre Diabrotica speciosa (Germar, 1824). O consumo foliar de insetos adultos foi determinado, em laboratório, sob condições de livre escolha. Folhas de feijoeiro (Phaseolus vulgaris) foram cortadas em formato circular e tratadas com extratos aquosos de folíolos e de pecíolos com caule de: Cedrela fissilis Vell., Cabralea canjerana (Vell.) Mart, Melia azedarach L. var. azedarach, Trichilia claussenii C. DC., Trichilia catigua A. Juss. e Trichilia elegans A. Juss., dispostos em placas de Petri, e um inseto liberado e mantido no interior da placa por 24 horas. A área foliar consumida foi determinada após este período. O extrato de folíolos de M. azedarach var. azedarach apresentou maior efeito antialimentar que o extrato de pecíolos com caule. Entretanto, a área foliar consumida nas folhas tratadas com o extrato de pecíolos com caule foi menor do que nas tratadas com extratos de folíolos, indicando maior efeito antialimentar. O índice KOGAN & GOEDEN (1970) mostrou efeito fagodeterrente para todos os extratos, mas não mostrou diferenças significativas entre eles.
The aim of this research was to select extracts with insect antifeedant activity. Leaf consumption by adults of Diabrotica speciosa was determined under laboratory conditions with free choice. Bean leaf had been cut in circular format and treated with aqueous extracts of leaflets, petioles with stems of Cedrela fissilis Vell., Cabralea canjerana (Vell.) Mart, Melia azedarach L. var. azedarach, Trichilia claussenii C. DC., Trichilia catigua A. Juss. e Trichilia elegans A. Juss, arranged in Petri plates, and an insect released and kept within the plate for 24 hours. The consumed leaf area was determined after this period. The leaflet extract of M. azedarach var. azedarach showed greater antifeedant activity tham the extract of petiole with stems. However, the consumed leaf area in the leaves treated with the extract of petioles with stem was lower than in treated with extracts of leaves, giving greater antifeedant effect. The KOGAN & GOEDEN index (1970) showed antifeedant activity for all the extracts, but did not show significant differences between them.