Atividades antioxidante e fungitóxica do óleo essencial de capim-limão e do citral

• Autor(a) principal: Guimarães, Luiz Gustavo de Lima
• Data de Publicação: 2011
• Outros Autores: Cardoso, Maria das Graças, Sousa, Paulo Estevão de, Andrade, Juliana de, Vieira, Sara Silveira
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Repositório Institucional da UFLA
• Texto Completo: http://repositorio.ufla.br/jspui/handle/1/41893
• topic: Cymbopogon citratus; Fitopatógenos; Atividade biológica; Metabólitos secundários; Phytopathogens; Biological activity; Secondary metabolites

Given the importance of essential oils, this study evaluated the antioxidant activity and fungitoxic effects of lemongrass essential oil and its main constituent citral on mycelial inhibition of phytopathogens Fusarium oxysporum cubense, Colletotrichum gloeosporioides, Bipolaris sp. and Alternaria alternata. The antioxidant activity was evaluated by employing the DPPH free radical reduction method and oxidation tests of the system β-carotene/linoleic acid. For each method, a completely randomized design in a 4 x 5 factorial arrangement was used with four compounds (essential oil, citral, thymol and α-tocopherol) and five concentrations (5; 10; 25; 50 and 100 Mg L-1), with three replicates. The tests to determine fungitoxic activities were performed by applying the in vitro fumigation test on mycelial inhibition of studied phytopathogens. The treatments were arranged in a completely randomized design with three replicates and a factorial arrangement. The essential oil and citral showed little antioxidant activity by the methodology that measures the reduction of the stable radical DPPH; however, by the methodology that employs the emulsified β-carotene/linoleic acid system, these compounds showed significant antioxidant activities. At fungitoxic activities, the essential oil and citral showed greater activity against the phytopathogen Alternaria alternata. When compared to the values of IC50, the lowest values presented by the essential (75.83 µg mL-1) and citral (58.24 µg mL-1) oils were found for Bipolaris sp. Citral caused the greatest mycelial inhibition on all phytopathogens.