Insecticidal and antifungal potentials of a proteinaceous extract of Cassia occidentalis (Linn.) seeds

Abstract

Proteinaceous extract obtained from Cassia occidentalis seeds with purification fold of 3.91 and 82.7% of bovine trypsin inhibitory activity was assessed at different concentrations (25, 50, 100, 200, 400 and 800 μg/ml) against Spodoptera litura. Assay of larval feeding suggested proteinaceous extract to be toxic as prepupal (80.16%) and pupal mortalities (100%) along with growth deterrent effect with only 16.71% pupation was observed at 800 μg/ml. Fifty per cent mortality (LC50) was observed at 132.91 μg/ml. Also the inhibitor affected fecundity, longevity and percentage of egg hatching. Nutritional indices were adversely affected as both efficiency of conversion of ingested and digested food decreased while approximate digestibility and metabolic cost increased. In vitro studies on proteolytic enzymes of S. litura revealed inhibition of trypsin and chymotrypsin in lumen and faecal matter at all tested concentrations. Also proteinaceous extract inhibited mycelial growth in Fusarium oxysporum, Alternaria brassicicola and Alternaria alternata at 100 μg/ml.