Aflatoxigenic Fungi Associated with Some Medicinal Plants

Aim: A total of one hundred and forty four samples belonging to 48 kinds of dried medicinal plants collected from different markets in Mansoura city, Dakahlia governorate were examined for the natural occurrence of molds and aflatoxins.

Methods: All the samples were analyzed for aflatoxin contamination using TLC and HPLC techniques.

Results: There is a high occurrence of the various fungal population of the analyzed samples and their counts ranged between 5-100 colonies/g. Thirty six species and 1 variety belonging to 11 genera were isolated using standard potato dextrose agar plate method. The most heavily contaminated samples were observed in anise and linseeds in order of magnitude of 95 and 100 colony/g, while sumac, clove and cinnamon revealed no fungal contamination indicating their antifungal properties. The genus Aspergillus(91.7%) was encountered as the most frequent fungal genus recorded, followed by Penicillium (68.8%). The most frequent fungal species were Aspergillus niger, Penicillium chrysogenum, Aspergillus flavus var columnaris and Aspergillus flavus comprising 75%, 56.3%, 41.7% and 33.3% in their frequency of occurrence. Out of 151 isolates of Aspergillus flavus group isolated from various samples, 67 isolates (44.4%) were found to be toxigenic and their potential to produce aflatoxins was in the range of 0.1 to 818.2 ng/ml of culture filtrate. Of 30 medicinal plant samples screened, 19 samples (63.3%) were found contaminated with aflatoxins in the range of 1.5 to 724.6 ng/g.

Conclusion: These results revealed that the selected medicinal plants are heavily contaminated with fungal strains and more strict measures must be taken to prevent mold contamination and hence aflatoxins production in medicinal plants.