Herbal remedies for the management of seed-borne fungal pathogens by an edible plant Decalepis hamiltonii (Wight & Arn)

Abstract

Antifungal activity-guided assay of solvent extracts of Decalepis hamiltonii (Wight & Arn) (Asclepiadaceae) against important phytopathogenic fungi, known to cause diseases in sorghum, maize and paddy proved to be highly significant. Among the five solvent extracts tested, Petroleum ether extract showed highly significant antifungal activity. Phytochemical analysis revealed that the antifungal active principle is a phenolic compound. TLC separation of the phenolic fraction using chloroform as an eluting solvent revealed the presence of seven bands but the antifungal activity was observed only in band five with Rf value 0.77. The antifungal active compound is identified as 2-hydroxy-4-methoxybenzaldehyde based on Nuclear Magnetic Resonance (NMR) and mass spectral analysis. The Minimal inhibitory concentration (MIC) varied between 200 μg ml−1 and 700 μg ml−1 depending on the fungal species. Seed treatment of the active principle significantly increased seed germination and seed vigour with a corresponding decrease in seed mycoflora. The antifungal active compound was effective against all the 24 fungal species tested suggesting broad-spectrum antifungal activity. Comparative evaluation of the active principle with the synthetic fungicides revealed that the antifungal activity of the active principle obtained from the plant is better than that of synthetic fungicide. This plant being an edible one can be exploited in the management of seed-borne pathogenic fungi and the prevention of biodeterioration of grains and mycotoxin elaboration during storage.