Inhibitory Effects of Essential Oils and Extracts of Nettle (Urtica Dioica L.) and Mentha Piperita on Growth and Aflatoxin B1 Production by Aspergillus Flavus

The use of essential oils and extracts of medicinal plants for thefood, feed, and pharmaceutical industries is growing in response to their medicinal, antifungal, antibacterial, and antioxidant properties.The inhibitory effect of nettle and Mentha piperita on the growth of Aspergillus flavus and decrease in aflatoxin B1level was studied. Essential oils (62.5, 125, 250, 500 and 1000 mg/l) and aqueous, ethanol, and 70% ethanolextracts (500, 1000, 2000, 4000 and 6000 mg/l) of the plants were testingfor reducing A. flavus growth and AFB1content in a liquid culture. The AFB1 content was evaluated using high-performance thin-layer chromatography. Essential oil of M. piperita and nettle at the 1000 mg/l concentration decreasedthe dried mycelia weight 79.40% and 53.30% and decreased AFB1production 88.25% and 57.3%,respectively. The extracts of M. piperita were stronger thannettle for reducing AFB1 content and mycelial growth; the ethanol extract of M. piperita at 6000mg/l decreasedmycelial growth 95.25% and FB1 production 89.58%. Essential oils, ethanol and 70% ethanolextracts of both plants did notsignificantly decrease AFB1 content, whereas aqueous extracts of nettle and M. piperita at the 4000 mg/l concentration decreased AFB1 content 78.15% and 56.1%, respectively. In general, essential oil and extracts of M. piperita were stronger than those from nettlefor reducing AFB1 content and mycelial growth. Aqueous extracts of nettle showed strong AFB1degradation activity andshould be considereda promising new candidate for decreasing AFB1 content.Keywords: