Enzymatic Characterization, Antioxidant and Antimicrobial Activities of Protease from Chickpea (Cicer arietinum L.) Seed and Leaf Extracts

Abstract

Chickpea (Cicer arietinum L.)  proteins are appreciated due to their high biological values, well balanced amino acid content and low content of anti-nutritional factors. The present study was undertaken to investigate enzymatic characterization, antioxidant and antimicrobial activities of protease extract from chickpea (Cicer arietinum L.). The chickpea seed and leaf samples collected from farmer’s field were used for protease enzyme extraction. The protein concentration was determined by Lowry method. Protease activity was assayed by using casein as a substrate. Optimization of the enzyme activity was made based on pH and temperature. The antioxidant activity was tested based on hydrogen peroxide, and DPPH free radical scavenging activities. The antimicrobial experiment was conducted based on disc diffusion and broth dilution methods. The result of crude protein extracts and protease activity has demonstrated that significantly the highest protein concentration (74.53%) and protease activity (22. 20U/ml) in seed supernatant solution. The effect pH on protease activity demonstrated the optimum pH for the protease extract was > pH6. The effect of temperature on protease activity demonstrated that the optimum temperature for protease activity was around 40^oC. Significantly the highest free radical scavenging activity of diphenyl-1-picrylhydrazyl DPPH (40.65%) and HPSA (57.95%) were recorded for seed supernatant enzyme extract. The the strongest antibacterial activity with maximum zone of inhibition (22.35mm), minimum inhibitory concentration MIC (1.5µg/ml) and corresponding minimum bactericidal concentration MBC (2.5µg/ml) against S. aureus were recorded for leaf supernatant enzyme extract against  Staphylococcus aureus. The highest dose of the enzyme extract (30µg/ml) revealed maximum antifungal activity with the highest zone of inhibition (18.25mm), MIC (1.5µg/ml) and corresponding minimum fungicidal concentration MFC (2µg/ml) was recorded for leaf supernatant against Candida albicans. The finding of the present study demonstrated that the supernatant enzyme extract has got higher biological activities including antioxidant and antimicrobial potentials.