Antifungal and antiaflatoxigenic activities of 1,8-Cineole and t-Cinnamaldehyde on Aspergillus flavus

Aspergillus flavus and A. parsiticus produce aflatoxins that are highly toxic to mammals and birds. In this study, the inhibitory effects of 1,8-cineole and t-cinnamaldehyde were examined on the growth of Aspergillus flavus ATCC 22546 and aflatoxin production. 1,8-Cineole showed 50% inhibition of fungal growth at a concentration of 250 ppm, while t-cinnamaldehyde almost completely inhibited fungal growth at a concentration of 50 ppm. Furthermore, no fungal growth was observed when the growth medium was treated with 100 ppm t-cinnamaldehyde. 1,8-Cineole also exhibited 50% inhibition on the production of aflatoxin B₁ and aflatoxin B₂ at a concentration of 100 ppm, while the addition of 100 ppm t-cinnamaldehyde completely inhibited aflatoxin production. These antiaflatoxigenic activities were related to a dramatic downregulation of the expression of aflE and aflL by 1,8-cineole, but the mode of action for t-cinnamaldehyde was unclear. Collectively, our results suggest that both of the compounds are promising alternatives to the currently used disinfectant, propionic acid, for food and feedstuff preservation.