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

초록

The probiotic properties of ten lactic acid bacteria and antioxidant and alpha-glucosidase inhibitory activities of the exopolysaccharide (EPS) of the selected strain were investigated in this study. Levilactobacillus brevis 1010 was one of the most active strains across all the in vitro tests. The cellfree supernatant (50 g/l) of L. brevis 1010 showed high levels of both alpha-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 L. brevis 1010 showed 2,2'-azino-bis (3ethylbenzothiazoline-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 alpha-glucosidase at different substrate concentrations. Kinetic analysis suggests that the mode of inhibition was competitive, with a kinetic constant of K-m = 2.87 +/- 0.88 mM and V-max= 0.39 +/- 0.06 mu mole/min. It was concluded that the EPS might be one of the plausible candidates for possible antioxidant and alpha-glucosidase activities of the L. brevis 1010 strain.

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