Cellular model to assess the antioxidant activity of lactobacilli

Lactobacilli are associated with multiple health-protective effects. One beneficial effect is their antioxidant activity, which needs to be measured using efficient biologically relevant assays. In this study, a cellular antioxidant assay (CAA) was used to determine the cellular anti-oxidative properties of 10 Lactobacillus strains from 5 species (L. rhamnosus, L. plantarum, L. acidophilus, L. casei, L. fermenti) in hepatocellular carcinoma (HepG2) cells and the results were compared with those obtained with the traditional 2,2-diphenylpicrylhydrazyl (DPPH) radical scavenging assay. The results from these two methods showed no obvious correlation at three concentrations (10(7)-10(9) colony-forming units per mL). A further study was performed to evaluate the protective effects of the strains against H2O2-induced oxidative stress in HepG2 cells and the results showed greater consistency in the data obtained with CAA assay than in those from the DPPH radical scavenging assay. The findings indicate that CAA may be a better choice for the detection of the antioxidant activity of Lactobacillus strains.