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

Aims: Cell injury by oxidative stress is an important mechanism for renal epithelial cell destruction. Previously it has been shown that antioxidants provide protection by inhibiting lipld peroxidation (Am. J. Physiol. 268: F30-F38, 1995). This study observes the effect of turmeric and its individual constituents on lipid peroxidation in renal epithelial cells. Turmeric consists of a water soluble part turmerin and lipid soluble part curcumin. Methods: LLC-PK₁ cells were labelled with ⁵¹Cr and various concentrations of turmeric (10mg-1ng), turmerin (5μg-0.5pg), curcumin (10 mg-1ng), vitamin E (50 μM) and 21-aminosteroid (20 μM) for 3hrs at 37°C in 24-well plate. The adherent cells were washed and Incubated for 4hrs with 1.5 mM H₂O₂ at 37°C. The radioactivity of the supernatants and the cell lysates were used to determine specific release, an indicator of cell Injury while the supernatant was concomitantly used to determine lipid peroxidatlon by the thiobarbituric acid reaction. Results: Turmeric (10μg), turmerin (5ng) and curcumin (10μg) gave similar protection as did 21-aminosteroid and vitamin E in both chromium release assay and lipid peroxidation. Conclusions: These findings provide evidence that turmeric and its products provide protection against oxidative stress in a renal cell line.