In-vitro Antioxidant and Antibacterial Potential of Mannose/Glucose-binding Pterocarpus osun Craib. Seeds Lectin

Abstract

Objective: This study was carried out to purify and characterize a carbohydrate-binding and cell-agglutinating protein, lectin, from Pterocarpus osun seeds and also to evaluate its antioxidant and antibacterial potential. Methods: Isolation and purification of the lectin were done by ammonium sulphate precipitation and size exclusion chromatography on Sephadex G-100. Physicochemical properties of the lectin were determined and antioxidant activity was evaluated by DPPH radical scavenging, lipid peroxidation inhibition and ferric reducing antioxidant potential assay. A disc diffusion method was used for antibacterial effect. Results: Lectin was detected in the seeds and was able to agglutinate native and enzyme-treated rabbit erythrocytes but only enzyme-treated erythrocytes of human blood were agglutinated. Mannose, Maltose and α-methylmannoside inhibited the divalent cation-independent hemagglutinating activity, which was stable up to 60°C and at pH range of 3-13. It showed antioxidant activity with IC50 of 1.17 ± 0.08, 0.58 ± 0.03, and 2.51 ± 0.03 mg/ml for those methods respectively. No antibacterial activity was observed. Conclusion: Pterocarpus osun seeds lectin possess properties similar to other lectins from Dalbergieae tribe and its ability to scavenge free radical and inhibit lipid peroxidation show the presence of a valuable health promoting agent in the seeds.