In vitro Efficacy of Aqueous Extracts of Neem, Garlic, Moringa, and Vinca against Aspergillus flavus Growth in Groundnut

Abstract

This study addresses an important post-harvest challenge in groundnut production in Sudan: aflatoxin contamination caused by Aspergillus flavus. It evaluates locally available plant extracts (neem, garlic, moringa, vinca) as potential antifungal agents, which aligns with the growing interest in plant-based alternatives to synthetic fungicides. Groundnut quality and safety can be compromised by Aspergillus flavus, a major aflatoxin-producing fungus. The present study evaluated the in vitro inhibitory activity of selected plant extracts: neem (Azadirachta indica), garlic (Allium sativum), moringa (Moringa oleifera) and vinca (Vinca rosea) against fungal growth. Laboratory work was conducted using plant extracts at 100, 50, 25 and 12.5% concentrations, with an untreated control. Inhibition zones were measured on culture media. The results showed clear differences among the plant treatments. Neem produced the greatest overall inhibition zone (mean 12.3), followed by garlic (8.3), moringa (7.7) and vinca (1.3). Across concentrations, the largest mean inhibition zone was recorded at 50% (11.50), followed by 100% (10.92), 25% (10.67) and 12.5% (3.92), while the untreated control recorded zero inhibition. For neem, the 50% concentration produced the highest inhibition zone (16.0), followed by 25% (15.66), 12.5% (15.0) and 100% (14.33). Garlic and moringa also showed measurable inhibition, whereas vinca showed weak activity. The findings contribute to the knowledge base on indigenous plant materials for mycotoxin management and may support the development of environmentally friendly, low-cost interventions for smallholder farmers in semi-arid regions. However, the study is limited to in vitro testing and requires further validation.