Screening of antioxidant strains and its protective effect on oxidative stress damage of HepG2 cells

Abstract:

[Background] The oxidative damage of the body can cause a variety of diseases and body aging. It had been found that probiotics can improve the metabolic level and the antioxidant capacity of the host. This provided a new direction for the development of antioxidant products. [Objective] To screen the strains with good antioxidant effects and provide strain materials for the development and research of antioxidant drugs and nutraceuticals. [Methods] The strains isolated from the feces of healthy people in Changshou Village, Wentang Town, Yichun City, Jiangxi Province were identified by 16S rRNA gene sequencing. We selected six strains of probiotics and then determined the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity of the culture supernatants of the strains. One strain with the best antioxidant capacity was selected for subsequent cellular experiments. A model of oxidative stress damage in HepG2 cells was established, and the protective effect of the culture supernatant of the selected strain on the cell model was evaluated by the CCK-8 method. The protective effect of the culture supernatant on SOD in the cells was determined by the enzyme assay kit, and the antioxidant effect of the culture supernatant was further verified. [Results] Among the six strains of probiotics, strain H0661 had the best antioxidant capacity with GSH-Px activity of 586.11 U/mL (P<0.01), SOD activity of 1 278.00 U/mL (P<0.01), and DPPH radical scavenging capacity of 40.5%. The strain was identified based on the 16S rRNA gene sequencing results and named Staphylococcus xylosus TG022. The culture supernatant of this strain at the concentration of 15% (volume fraction) showed the best protective effect against oxidative stress in HepG2 cells (P<0.01). In addition, the culture supernatant of S. xylosus TG022 was effective in protecting the SOD activity of the HepG2 cells exposed to oxidative stress (P<0.01). Moreover, the antioxidant activity of HepG2 cells was increased after treatment with the culture supernatant of S. xylosus TG022 (P<0.05). [Conclusion] S. xylosus TG022 was screened out, and its culture supernatant had strong antioxidant effects. This study provided a candidate strain for the development of antioxidant drugs and nutraceuticals.