Fungitoxic action of the essential oil of Tanaecium nocturnum (Barb. Rodr.) Bur. and K. Shum on Aspergillus flavus isolated from the Brazil nut (Bertholletia excelsa)

• Published in: Acta amazonica Vol. 40; no. 1; pp. 213 - 220
• Main Authors: Pimentel, F A, das Gracas Cardoso, M, Batista, L R, de Lima Guimaraes, LG, Silva, D M
• Format: Journal Article
• Language: Portuguese
• Published: 01.03.2010
• Subjects: Antiviral activity; Aspergillus flavus
• ISSN: 0044-5967

The present work sought to evaluate the fungitoxic activity of the essential oil from fresh Tanaecium nocturnum fresh leaves on Aspergillus flavus isolated from Brazil nuts, using contact and fumigation techniques. The results of bioassays performed up to 10 days of incubation demonstrated that total inhibition of mycelial growth occurred when using the essential oil at concentrations of 782 ppm (contact technique) and 1000 ppm (fumigation technique). In both techniques, the essential oil inhibited the formation of spores at the concentration of 500 ppm. No significant difference in the results presented by the two techniques was observed in the first five days of incubation. After this period, the essential oil showed a reduction in activity at concentrations lower than 1000 ppm in the fumigation test. The fungitoxic activity of the essential oil on the organism studied can be attributed to the presence of benzaldehyde (major component of the essential oil), in combination with other compounds also present in this oil, such as, benzyl alcohol, benzyl benzoate and mandelonitrila.Original Abstract: Neste trabalho, avaliou-se a capacidade fungitoxica do oleo essencial de folhas frescas de Tanaecium nocturnum sobre o Aspergillus flavus isolado da castanha-do-brasil, por meio das tecnicas de contato e fumigacao. Pelos resultados dos bioensaios realizados ate 10 dias de incubacao, verificou-se que a inibicao total do crescimento micelial ocorreu quando se utilizou o oleo essencial nas concentracoes de 782 ppm (tecnica de contato) e 1000 ppm (tecnica de fumigacao). Em ambas as tecnicas, o oleo essencial inibiu a esporulacao a partir da concentracao de 500 ppm. Observou-se que nos cinco primeiros dias de incubacao nao houve diferenca significativa nos resultados apresentados pelas duas tecnicas estudadas, havendo a partir dai uma reducao da atividade do oleo essencial nas concentracoes inferiores a 1000 ppm pelo teste de fumigacSo. A acjio fungitoxica do 6leo essencial sobre o microrganismo estudado pode ser atribuida a presenca do benzaldefdo (composto majoritario do oleo essencial estudado), em associacao com outros compostos tambem presentes nesse oleo essencial, tais como; alcool benzilico, benzoato de benzila e mandelonitrila.