Isolation of a Potential Probiotic and Evaluation of Its Exopolysaccharide for Antioxidant and α-Glucosidase Inhibitory Activities.

The probiotic properties of ten lactic acid bacteria and antioxidant and α-glucosidase inhibitory activities of the exopolysaccharide (EPS) of the selected strain were investigated in this study. L010 was one of the most active strains across all the in tests. The cell-free supernatant (50 g/l) of L010 showed high levels of both α-glucosidase inhibitory activity (98.73 ± 1.32%) and 2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity (32.29 ± 3.86%). The EPS isolated from cell-free supernatant of L010 showed 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical-scavenging activity (80.27 ± 2.51%) at 80 g/l, DPPH radical-scavenging activity (38.19 ± 9.61%) at 40 g/l, and ferric reducing antioxidant power (17.35 ± 0.20 mg/l) at 80 g/l. Further, EPS exhibited inhibitory activities against α-glucosidase at different substrate concentrations. Kinetic analysis suggests that the mode of inhibition was competitive, with a kinetic constant of = 2.87 ± 0.88 mM and = 0.39 ± 0.06 μmole/min. It was concluded that the EPS might be one of the plausible candidates for possible antioxidant and α-glucosidase activities of the L010 strain.