In vitro antioxidant activities of Rhodobacter sphaeroides and protective effect on Caco-2 cell line model

The present study aimed to evaluate the in vitro antioxidant activities and the protective effect of Rhodobacter sphaeroides on H 2 O 2 -induced oxidative stress in Caco-2 cells. The results showed that the antioxidant action of R. sphaeroides varied with different cell concentrations and treatments. Also, the intact cells and intracellular cell-free extracts showed better antioxidant activities. Caco-2 cell–based oxidative stress model was developed by optimizing H 2 O 2 concentration and culture time with the half lethal dose and methyl thiazolyl tetrazolium. By increasing the activity of endogenous antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase, upregulating the antioxidant ability of the anti-superoxide anion and anti-hydroxyl radical, R. sphaeroides , especially the mutant strain R. sphaeroides (CGMCC No. 8513), exhibited significant protective activity against H 2 O 2 -induced oxidative stress in Caco-2 cells. Taken together, R. sphaeroides (CGMCC No. 8513) exhibits strong antioxidant activities and is a candidate to be investigated as a potential probiotic in the future.