Inhibitory effects of Thyme oils on growth and aflatoxin production by Aspergillus parasiticus

Inhibition of Aspergillus parasiticus growth and its aflatoxin production exposed to the essential oils extracted from two varieties of Thyme i.e. Thymus eriocalyx and Thymus x-porlock were studied. The disc diffusion method was used to evaluate the zone of fungal growth inhibition at various concentrations of the oils. Minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of the oils were determined and compared with each other. The oils from the above plants were found to be strongly fungicidal and inhibitory to aflatoxin production. The oils analyzed by GC and GC/MS lead to identification of 18 and 19 components in T. eriocalyx and T. x-porlock oils respectively. The profile of the oil components from T. eriocalyx was similar to that of T. x-porlock in almost all the compounds but at different concentrations. The major components of T. eriocalyx and T. x-porlock oils were Thymol (64.3, 30.7%), β-phellandrene (13.2, 39.4%) and cis-sabinene hydroxide (8.4, 9.7%) respectively. Substitution of currently used antifungal and aflatoxin inhibiting chemicals by natural compounds such as thyme is recommended.