Antifungal properties and inhibitory effects upon aflatoxin production of Thymus vulgaris L. by Aspergillus flavus Link

The antifungal and antiaflatoxigenic properties of Thymus vulgaris essential oil (TEO) were evaluated upon Aspergillus litmus in vitro. Suspension containing 10(6) of A. flavus were cultivated with TEO in concentrations ranging from 50 to 500 mu g/mL. TEO reached minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) at 250 mu g/mL. Inhibition of ergosterol biosynthesis was detected at a concentration of 100 mu g/mL of TEO. Morphological evaluation performed by both light microscopy and scanning electron microscopy showed that antifungal activity of TEO could be detected starting at a concentration of 50 mu g/mL and the fungicide effect at a concentration of 250 mu g/mL. TEO completely inhibited production of both B-1 and B-2 aflatoxins (AFB(1) and AFB(2)) at a concentration of 150 mu g/mL. This way, fungal biomass development and aflatoxin production were dependent on TEO concentration. Therefore, TEO was capable of controlling the growth of A. flavus and its production of aflatoxins. (C) 2014 Elsevier Ltd. All rights reserved.