Estudo da atividade antifúngica dos fitoconstituintes carvacrol e timol contra cepas de aspergillus spp.: aplicabilidade em grãos de milho.

Abstract

Fungi are organisms that play an important ecological and economic role, also participating in processes of food decomposition. The genus Aspergillus is one of the main responsible for contamination of foods, such as maize, being able to reduce the quality and nutritional value of the grains and to produce mycotoxins harmful to health. Thus, new strategies are sought to control these microorganisms, mainly by the use of natural products, such as carvacrol and thymol phytoconstituents. The present study investigated the antifungal potential of carvacrol and thymol against strains of A. flavus, A. fumigatus and A. niger. The minimum inhibitory concentration (MIC) was determined by the microdilution technique and the minimum fungicidal concentration (MFC) was also performed. The effect of the constituents on fungal mycelial growth was also evaluated as its possible preservative activity on the maize grain contamination model. Carvacrol inhibited the growth of all strains of the assay, with MICs ranging from 64- 256 μg/mL, whereas thymol, at the concentrations tested, only did not present MIC for the A. flavus strain. The minimum fungicidal concentration determined for the A. niger strain was equivalent to the value of its MIC for both phytochemicals, whereas for A. flavus and A. fumigatus strains the MFC determined for carvacrol was equivalent to four times the value of its CIM. The phytochemicals were able to slow the fungal mycelial growth at the concentrations tested. Carvacrol showed to be more effective than thymol in the maize grain contamination model, presenting no fungal growth in the tubes with MIC and 2xMIC concentrations for strains of A. flavus and A. fumigatus, making it a good choice for future studies over food conservation.