Antimycotic, Antibiodeteriorative and Antiaflatoxigenic Potency of 2-hydroxy-4-methoxybenzaldehyde Isolated from Decalepis hamiltonii on Fungi Causing Biodeterioration of Maize and Sorghum Grains

摘要

We characterized the antimycotic, antibiodeteriorative and antiaflatoxigenic efficacy of the compound, 2-hydroxy-4-methoxybenzaldehyde isolated from Decalepis hamiltonii Wight & Am, against different species of fungi that cause biodeterioration of maize (Zea mays L.) and sorghum (Sorghum bicolor L.) grains during storage. Fungal species that cause biodeterioration were isolated from maize and sorghum grains by agar plating method and standard blotter method (SBM). Poisoned food technique was adopted to assess fungitoxicity of the compound against fungal isolates. For different fungal species, the inhibitory concentration (IC50), minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of 2-hydroxy-4-methoxybenzaldehyde varied between 80 to 350 mu g/ml, 350 to 800 mu g/ml and 450 to 850 mu g/ml, respectively. Among the 14 fungal species tested, Aspergillus niger, A. columnaris and A. tamari were completely inhibited at higher concentrations, while Fusarium oxysporum; F. proliferatum, Drechslera tetramera and Aspergillus ochraceus were completely inhibited at low concentrations. The inhibitory effect of the compound was of broad-spectrum in activity and was concentration-dependent. Comparative evaluation of the active compound with the synthetic fungicides, Blitox and Thiram, at recommended dosages revealed that the antimycotic activity of 2-hydroxy-4-methoxybenzaldehyde was superior than that of synthetic fungicides. In vivo evaluation of the compound, 2-hydroxy-4-methoxybenzaldehyde at 0.5 g/kg as seed treatment on maize and sorghum revealed that carbohydrates, water soluble proteins, lipids, aflatoxin B-1 production and dry matter losses (DML) were significantly conserved in treated compared with control untreated grains up to 120 days storage. D. hamiltonii being an edible plant can be exploited in the management of seed-borne pathogenic fungi and in the prevention of biodeterioration of grains and mycotoxin production during storage in an eco-friendly way.