Stimulato-Inhibitory Response to Cumin Oil in Aflatoxin B1 Production of Aspergillus Species

Abstract

Background: Aspergillus species produce the highly toxic and carcinogenic metabolite, Aflatoxin B1 (AFB1), on food and agricultural commodities. Some natural products are known to inhibit aflatoxin production. Objectives: With the aim of controlling aflatoxin production, the essential oils of Cuminum cyminum L. from the best known regions of Iran i.e. Alborz Mountain and Kerman region, were obtained by hydrodistillation. Materials and Methods: Antifungal activities of the oils to inhibit growth and aflatoxin productivity of A. flavus PICC-AF39, A. flavus PICC-AF24, and A. parasiticus NRRL-2999 were studied. Minimal inhibitory (MIC) and minimal fungicidal (MFC) concentrations of the oil were determined. Sub-MIC was selected for the measurement of aflatoxins B and G concentration. Samples were analyzed either using a high performance liquid chromatography (HPLC) method with some minor modifications. Aflatoxins (AFs) were determined by reverse-phase HPLC and fluorescence detector with post column derivatization (PCD) involving bromination. Results: A significant reduction in Aflatoxin production was noted which was not due to the inhibitory effect but because of antifungal property of the oil. Interestingly, the oil promoted toxin production for the reasons yet to be investigated. The extent of aflatoxin production was dependent on the concentration of essential oil used. All toxin-producing fungi in this study produced higher amount of aflatoxin at low concentrations of the oil. 400 ppm concentration of C. cyminum L. from Alborz Mountain increased aflatoxin production to over fourfold. Aflatoxin productivity was declined at high concentration of the oil. Conclusions: Antimicrobial and antitoxigenic properties of natural products need a firmly established criterion before they could be offered to application.