This study was performed to investigate the in vitro antioxidant and cytoprotective effects of fermented sesame sauce (FSeS) against hydrogen peroxide (H₂O₂)-induced oxidative damage in renal proximal tubule LLC-PK1 cells.

1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical (^•OH), and H₂O₂ scavenging assay was used to evaluate the in vitro antioxidant activity of FSeS. To investigate the cytoprotective effect of FSeS against H₂O₂-induced oxidative damage in LLC-PK1 cells, the cellular levels of reactive oxygen species (ROS), lipid peroxidation, and endogenous antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-px) were measured.

The ability of FSeS to scavenge DPPH, ^•OH and H₂O₂ was greater than that of FSS and AHSS. FSeS also significantly inhibited H₂O₂-induced (500 µM) oxidative damage in the LLC-PK1 cells compared to FSS and AHSS ( P < 0.05). Following treatment with 100 µg/mL of FSeS and FSS to prevent H₂O₂-induced oxidation, cell viability increased from 56.7% (control) to 83.7% and 75.6%, respectively. However, AHSS was not able to reduce H₂O₂-induced cell damage (viability of the AHSS-treated cells was 54.6%). FSeS more effectively suppressed H₂O₂-induced ROS generation and lipid peroxidation compared to FSS and AHSS ( P < 0.05). Compared to the other sauces, FSeS also significantly increased cellular CAT, SOD, and GSH-px activities and mRNA expression ( P < 0.05).

These results from the present study suggest that FSeS is an effective radical scavenger and protects against H₂O₂-induced oxidative damage in LLC-PK1 cells by reducing ROS levels, inhibiting lipid peroxidation, and stimulating antioxidant enzyme activity.