Effect of turmeric, turmerin and curcumin on H₂O₂-induced renal epithelial (LLC-PK₁) cell injury

Cell injury by oxidative stress is an important mechanism for renal epithelial cell destruction. This study observed the protective effect of turmeric and its constituents on H₂O₂-induced injury. Turmeric consists of a water soluble turmerin and lipid soluble curcumin with potent antioxidant properties. Confluent LLC-PK₁ cells were labelled with ³H-arachidonic acid at 0.1 μCi/ml over 18 h and then further labelled with ⁵¹Cr. Turmeric (100 μg/ml-0 1 μg/ml), turmerin (800 ng/ml-0.8 ng/ml), curcumin (100 μg/ml-0.1 μg/ml), vitamin E (100 μM) and 21-aminosteroid (20 μM) were added and incubated for 3 h at 37°C in 24-well plate. The adherent cells were washed and incubated for 3 h with 1 5 mM H₂O₂ at 37°C ³H-arachidonic acid release, ⁵¹Cr release and lipid peroxidation by the thiobarbituric acid reaction was determined. Turmeric (100 μg/ml) and curcumin (100 μg/ml, 10 μg/ml) gave as much protection as did vitamin E in both chromium release assay and lipid degradation while Turmeric (100 μg/ml) and curcumin (100 μg/ml) gave comparable inhibition of lipid peroxidation. Turmerin and 21- aminosteroid showed no protection. These findings provide evidence that turmeric and curcumin provide protection against oxidative stress in a renal cell line.