Antioxidative and aldose reductase-inhibitory effects of a fermentation filtrate of Rubus coreanus

Antioxidative and aldose reductase (AR)-inhibitory effects of a fermentation filtrate of Rubus coreanus (FRC) were investigated using corneal/retinal homogenate and lens cytosol, respectively. Rat corneal/retinal homogenate was treated with 50 µM FeCl(3) in the presence of FRC (3.2-100 µg/mL) for 30 min at 37℃, and thiobarbituric acid-reactive substances (TBARS) was quantified as a lipid peroxidation parameter. FRC markedly suppressed the TBARS production in a concentration-dependent manner, leading to 50% (IC(50)) and 100% (IC(100)) inhibitory concentrations of 20 and 95 µg/mL, respectively, which was similar to the effect of butylated hydroxyanisole. Activity of AR from rat lens was assayed in the presence of FRC (1-31.6 µg/mL) at 25℃ using glyceraldehyde as a substrate. FRC inhibited lens AR by 50% (IC(50)) and 90% (IC(90)) at approximately 2 and 31.6 µg/mL, respectively, comparable to the effect of quercetin. The results indicate that ERC could be a promising candidate for the improvement of eye injury and visual dysfunction of dry eye and diabetic patients.