Evaluation of antifungal activity of aqueous extracts of some medicinal plants against Aspergillus flavus, pistachio aflatoxin producing fungus in vitro

Background: Contamination with aflatoxin, by Aspergillus flavus, is one the major challenges in agriculture and food industry. Preparation of organic products using natural components is widely considered these days. Aims: In this study, effects of aqueous extracts of five medicinal herbs, including thyme, senna, mentha, basil, and safflower on the growth of the A. flavus were investigated. Mterials and Methods: The extracts with different concentrations (200-800 µg/mL) and polyethylene glycol with the equal osmotic potential of plant extracts were added to the potato dextrose agar medium to evaluate fungus growth after 7 days using agar dilution method. Benomyl, a fungicide, was used as a positive standard. The tests were performed in triplicate, and the mean diameters of fungus growth were calculated as well. Results and Conclusion: All concentrations of the plants extracts significantly inhibited the fungus growth in comparison with each other and control treatments, while the extracts of thyme and safflower manifested the most effective prohibition compared to benomyl with minimum inhibitory concentration of 200 and 400 µg/mL, respectively.