Mycotoxin-producing potential of fungi associated with qat (Catha edulis) leaves in Yemen.

Forty-four fungal species belonging to 20 genera were isolated from 30 samples of qat leaves. The most frequent genera were Aspergillus, Alternaria, Penicillium, and Cladosporium followed by Fusarium, Drechslera, Chaetomium, and Mucor. The most prevalent species in above genera were Aspergillus niger, A. flavus, A fumigatus, Alternaria alternata, Penicillium chrysogenum, P. citrinum, Cladosporium cladosporioides, and Fusarium verticillioides. From these fungi, 17 species (39%) related to 7 genera (35%) proved to be true endophytes. Eleven out of 75 isolates were mycotoxigenic. A. alternata produced alternariol and alternariol monomethyl ether whereas A. flavus produced aflatoxins B1 and B2. Ochratoxin A, sterigmatocystin, citrinin and T-2 toxin were produced by A. ochraceus, A. versicolor, P. citrinum and F. oxysporum, respectively. The presence of such toxigenic fungi associated with qat leaves is considered to be a threat to public health.