Effects of botanicals on growth and aflatoxin production by aspergillus flavus infecting maize

Abstract

Finding a cost-effective measure to prevent fungal deterioration of grains in the global world has become imperative. Effects of selected botanicals on growth and aflatoxin (AF) production by Aspergillus flavus (A. flavus) in maize were investigated. A. flavus isolated from field samples and stored samples of maize, collected in 18 batches of five varieties, were cultured with various edible plant: methanol extracts (Annona muricata and Moringa oleifera) and essential oils (Cymbopogon citrates and Ocimum gratissimum) onto mycological media using standard microbiological methods. Aflatoxins levels in all the maize batches were assayed using competitive enzyme immunoassay. The total natural aflatoxin was reduced to various levels by all the botanicals, with percentage reduction ranging from 0 to 91.8% for Cymbopogon citratus,7.1 to 88.3% for Ocimum gratissimum, 0 to 77.9% for Moringa oleifera and 23.3 to 90% for Annona muricata, which had the highest effect; the difference in percentage reduction was statistically significant (p<0.05). Similarly, in in-vitro studies using plate experiments, the various plant extracts showed significant reductions in counts/mean clearance zone diameter according to the extract concentration on the fungus. The botanicals studied significantly inhibited the growth of A. flavus; hence reduction in aflatoxin production.