Comparative cytotoxicity of the possibly occurring mycotoxins in wheat on the basis of a mycological analysis

A mycological survey was carried out at the Northern part of Tunisia on freshly harvested durum wheat in 2007, as wheat is the basic staple food for the Tunisianpopulation. A total of 65 samples was analysed for their contamination with pathogenic andsaprophytic fungal species and isolation frequencies and relative densities of the fungalspecies were recorded. Our results showed that Alternaria species were observed in all theprospected samples and Fusarium spp. were present in about 70% of fields whereas theincidence of the genus Penicillium was low. In the light of the mycological analysis, weevaluated the cytotoxicity of the possible occurring mycotoxins in such crops using the MTTbioassay. For this purpose, four mycotoxins - Deoxynivalenol (DON), Alternariol (AOH),Ochratoxin A (OTA) and Citrinin (CTN) - were screened for their toxicity in human coloncarcinoma cell line HT 29. The viability assay showed significant variation in IQoconcentrations between the tested mycotoxins.