Fungitoxic effect of natural extracts on mycelial growth, spore germination and aflatoxin B1 production of Aspergillus flavus

Abstract

The methanolic extracts of leaves from Tamarix aphylla, Tamarix pauciovulata, T. hirsuta, D. gnidium, C. procera, aerial parts from H. scoparium, A. schmittianum, P. argentea and M. canescens were investigated for their antifungal and antiaflatoxigenic activities against the aflatoxigenic fungus A. flavus. The results of antifungal activity evaluated by two methods indicate that three plant species (H. scoparium, A. schmittianun and D. gnidium) among the nine investigated showed significant (p<0.05) mycelium growth inhibition which is of 65.33%, 83.56% and 100% respectively. Moreover five plant species showed significant (p<0.05) spore germination inhibition. These are extracts of C. procera (81.53%), T. pauciovulata (83.81%), T. aphylla (92.33%), M. canescens (97.73%) and D. gnidium (100%). Extracts from D. gnidium exhibited complete inhibitory effect on mycelium growth and spore germination, while H. scoparium exhibited complete inhibitory effect only on spore germination. In addition, all extracts from different plant species were found efficacious in checking aflatoxin B1 production and extract of D. gnidium was the more potent inhibitor of aflatoxin B1 biosythesis by the fungitoxic strain A. flavus at the concentration of 10µg/ml. The findings obtained reveals that the natural extract of D. gnidium is an important source of potentially useful molecules for the development of new antifungal agents and the possible exploitation of D. gnidium extract to protect the spoilage grains and food stuffs against the aflatoxigenic fungus A. flavus.