Antifungal evaluation of plant essential oils and their major components against toxigenic fungi

Contamination of toxigenic fungi in foods, agricultural commodities and Chinese herbal medicines has posed serious threaten to human and animals' health and safety. Natural antifungal agents from plant essential oils (PEOs) and their active components have been candidates of interest. In this study, the antifungal activities of PEOs from 11 natural plants against three kinds of toxigenic fungi including Aspergillus flavus, Penicillium viridicatum and Aspergillus carbonarius were evaluated and compared through the determination of fungi zone diameter. Results showed that 4 PEOs of Cinnamomum cassia Presl, Litsea cubeba, Cymbopogon martini and Thymus mongolicus Ronn expressed stronger inhibitory effects and lower minimal inhibitory concentrations (MICs) against the three kinds of fungi, which would be the ideal antifungal candidates. Then, the chemical compositions of them were analyzed by an optimized gas chromatography-mass spectrometry method with trans-cinnamaldehyde and d-limonene, citral and citronellal, trans-geraniol, and carvacrol as their main active components, respectively. The six compounds with strong antifungal activity and small MICs on the three kinds of fungi might contribute largely to the inhibitory effects of the 4 selected PEOs containing them. The 4 selected PEOs and their 6 main active components exhibited wide application prospect as the novel natural antifungal alternatives for preventing fungal contamination in different matrices to assure their quality and safety. The use of PEOs with highly-volatile components is environment-friendly, convenient and highly-effective with minimal residues and low cost will get more interest in practice.