Effect of Extracts of Capparis spinosa, Withania somnifera and Peganum harmala on Aspergillus flavus Growth and Expression of Major Genes in Aflatoxin Biosynthetic Pathway

[Background]Aflatoxins, a polyketide group derived from furanocoumarins, are highly toxic carcinogens produced by Aspergillus flavus and other closely related species.[Objectives]In this research, the effects of Capparis spinosa, Withania somnifera, and Peganum harmala extracts on A. flavus growth and the expression of some major genes in aflatoxin biosynthetic pathway were investigated.[Methods]Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were measured and the expression of aflQ, aflO, aflS, and aflR genes was evaluated by using quantitative real-time polymerase chain reaction (qRT-PCR) technique.[Results]Capparis spinosa extract had the lowest MIC value (200 mg/mL) and the extracts of W. somnifera and P. harmala had the highest MIC value (400 mg/mL). The extracts of W. somnifera and P. harmala had no fungicidal activity, and the C. spinosa extract had the lowest MFC value (400 mg/mL) and had the highest fungicidal effect on A. flavus. The expression of aflQ, aflO, aflS, and aflR genes was significantly decreased by the C. spinosa extract.[Conclusions]In general, the C. spinosa extract could have fungicidal and inhibitory effects on A. flavus and reduce expression of major genes in the aflatoxin biosynthetic pathway.