Antifungal activity of Azadirachta indica (Neem), Tephrosia vogelii (Utupa) and Diospyros shimbaensis extracts against Aspergillus flavus and Aspergillus parasiticus

Abstract Aflatoxins are harmful contaminants of nuts and grains caused by food-borne fungi mainly, Aspergillus flavus and Aspergillus parasiticus . The present study focused on investigating the antifungal activity of the leaves of Azadirachta indica (Neem), Tephrosia vogelii (Utupa), and Diospyros shimbaensis against A. flavus and A. parasiticus . Leaf samples of A. indica , T. vogelii , and D. shimbaensis were extracted by Soxhlet and maceration methods, using methanol. The final methanolic extracts at the concentrations of 125, 250, and 500 μg/ml were used in antifungal bioassays against A. flavus and A. parasiticus using the poisoned food method. Antiaflatoxigenic activities of the extracts of A. indica , T. vogelii , and D. shimbaensis were analysed by using high-performance liquid chromatography (HPLC) with a fluorescence detector. All the extracts showed to have stronger anti-aflatoxigenic than their growth inhibition activities against A. flavus and A. parasiticus . Furthermore, the leaf extracts of T. vogelii could control aflatoxin production in A. flavus by 97.8 ± 0.03% just as it reduced aflatoxin levels in A. parasiticus by 97.3 ± 0.22% at the lowest concentration of 125 μg/ml. Nevertheless, the leaf extracts of D. shimbaensis were found as the most effective at controlling both growth (by 59.00%)) and aflatoxin production (by >98%) against A. flavus at the lowest concentration of 125 μg/ml. Therefore, further investigation of these plant extracts to combat the problem of aflatoxin contamination is needed.