Glucan exopolysaccharide from Enterococcus hirae OL616073 alleviates oxidative stress and extends lifespan in different model systems

Abstract

Objective This study aims to evaluate the oxidative stress alleviating potential of glucan exopolysaccharide (EPS) using in vitro (biochemical and cell culture) and in vivo Caenorhabditis elegans model systems. Methods The in vitro antioxidant potential of EPS from Enterococcus hirae OL616073 of food origin was evaluated using reducing power, ferric-reducing antioxidant power (FRAP) assay, and 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical-scavenging activity assays. The antioxidant effect of EPS was also evaluated in C. elegans (wild type Bristol N2), a simple multi-cellular eukaryotic model via survival assay, gene expression, DCF-DA staining, reproduction, and pharyngeal pumping assay. Finally, the ROS scavenging activity of EPS was investigated in human colon cancer cells (Caco-2 cell line) by DCF-DA staining and flow cytometry. Results and discussion The in vitro assays showed the significant antioxidant activity of EPS as evidenced by reducing power, FRAP, and ABTS radical-scavenging activity. In C. elegans , EPS treatment (150 and 300 μg/mL) significantly extended the lifespan of wild-type (Bristol N2) C. elegans (∼1.21% and ∼0.83%) compared to control. EPS treatment (150 μg/mL) resulted in increased egg-laying capacity and little change in the pharyngeal pumping rate of C. elegans over five consecutive days. In addition, pre-, post-, and co-treatment of EPS (150 μg/mL) in the presence or absence of H 2 O 2 (1 mM) showed a reduction in ROS generation. Similarly, in the colorectal cancer cell line (Caco-2), high basal intracellular ROS levels were reduced with increasing concentration of EPS via an increase in intracellular antioxidant enzymes. Conclusion EPS from E. hirae OL616073 of food origin exhibited significant antioxidant potential across diverse model systems. These findings highlight its potential as a natural antioxidant ingredient for applications in functional foods, nutraceuticals, and pharmaceutical formulations.