Cytoprotective effect of baicalein against peroxynitrite-induced toxicity in LLC-PK1 cells

The various reactions of peroxynitrite (ONOO−) with enzymes, macromolecules and lipids, have been shown to influence cellular functions and may be involved in the pathogenesis of various diseases. Therefore, targeting ONOO−-induced cytotoxicity is now accepted as a viable strategy to alleviate disease signs in numerous diseases. There is a growing interest in the antioxidant characteristics and use of dietary flavonoids in the management of ONOO−-related diseases. Baicalein, a major bioactive flavonoid constituent of Scutellaria baicalensis Georgi, possesses a multitude of pharmacological activities that have been associated with its antioxidant effects. In this study, we have investigated the ONOO− scavenging ability of baicalein and its protective effect on ONOO−-induced cell death in cultured LLC-PK1 cells. Baicalein was able to scavenge ONOO− in a concentration-dependent manner, which was comparable to penicillamine. In addition, baicalein at the concentration range of 10–50 μM increased cell viability and decreased LDH leakage in 3-morpholinosydnonimine (SIN-1)-treated cells, reflecting its prevention of ONOO−-induced cytotoxicity. These results suggest that the protective effects of baicalein can be explained with respect to its ability to scavenge ONOO− and may be useful as a possible therapeutic strategy for the treatment of involved diseases.