Estudo fitoquímico de Virola sebifera associado ao controle de formigas cortadeiras

• Autor(a) principal: Bicalho, Keylla Utherdyany
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFSCAR
• Texto Completo: https://repositorio.ufscar.br/handle/ufscar/6502
• topic: Produtos naturais; Virola sebifera; Formigas cortadeiras; Cromatografia contracorrente; CIENCIAS EXATAS E DA TERRA::QUIMICA

Leaf-cutting ants are considered one of the main pests that affect Brazilian agriculture. To control this pest are employed, most often, halogenated, sulfurous and phosphorus compounds. However, the continued use of these compounds leads to problems such as the emergence of resistance by insects, soil and underwater contamination e most of them affect many non-target species, may cause environmental imbalance and thus raising the needed of search for new compounds that are more selective and less damaging to the environment. From this perspective, the present work presents a phytochemical study of the specie Virola sebifera and evaluation of the insecticide and/or fungicide potential of the crude extracts, fractions and isolated compounds against the leaf-cutting ants, Atta sexdens rubropilosa, and its symbiotic fungus, Leucoagaricus gongylophorus. One of the techniques employed to the phytochemical study was the high-speed counter-current chromatography and it was confirmed the efficiency of this technique and the importance of choosing a suitable biphasic solvent system for the desired separation. In this work were isolated and/or identified three acylresorcinols, four lignans and five flavonoids, being all the flavonoids the first time reported for this specie. From the biological tests with leaf-cutting ants, it was found that the methanol extract of leaves of Virola sebifera and theirs fractions showed insecticidal activity as a result of the synergistic effect of their chemical composition. The bioassay with the symbiotic fungus, Leucoagaricus gongylophorus, revealed great fungicide potential of the isolated lignans, mainly the lignan (-)-kusunokinin, which exhibited 100% of inhibition of mycelial growth.