Alkaloid extracts of Prosopis juliflora (Sw.) DC. (Mimosaceae) against Alternaria alternata

The antifungal activity of aqueous, petroleum ether, benzene, chloroform, methanol and ethanol extracts and alkaloid extract of Prosopis juliflora (Sw.) DC. leaves (Mimosaceae) was evaluated for antifungal activity by poisoned food technique against Alternaria alternata a causal organism of brown spot of tobacco. Aqueous extract recorded highly significant antifungal activity at 24% concentration. Among different solvent extracts tested, methanol and ethanol extract recorded highly significant antifungal activity. Methanol extract was further subjected to fractionation guided by antifungal activity leading to the isolation of alkaloid extract, which was also recorded highly significant antifungal activity against the test fungus and the minimum inhibitory activity was recorded at 1000 ppm. The antifungal activity of alkaloid extract was compared with synthetic fungicides viz., blitox, captan, dithane M-45 and thiram at their recommended dosage of 2000 ppm indicating that the alkaloid extract was highly effective even at the dosage lesser than the synthetic fungicides.