Abstract: The aim of this study is to investigate the protective effect of ethanolic extract from Fuzhuan brick tea (FTE) on H₂O₂-induced oxidative damage in LLC-PK1 cells. Various concentration (10~200μg/mL) of FTE were pre-incubated with LLC-PK1 cells for 24h, and then exposed to H₂O₂ (500μmol/L) for 4h. The cell viability was determined by MTT assay, contents of malondialdehyde (MDA) were determined by thiobarbituric acid reactive substances (TBARS) assay. Intracellular antioxidant enzyme activities, including catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) were determined by colorimetric assay according to the protocols of the commercial kit. The cell viabilities of H₂O₂ treated LLC-PK1 cells were increased, and the contents of MDA were decreased after 24h pre-incubated with different concentrations of FTE. In addition, the antioxidant enzymes (CAT, SOD and GSH-px) levels were also increased in FTE compared with H₂O₂ treated group. There was statistical significant difference between the FTE treated groups and untreated H₂O₂ treated groups (all P<0.05). Those results suggested that pre-incubated with FTE showed a protective effect against H₂O₂-induced oxidative damage in LLC-PK1 cells.

Key words: Fuzhuan brick tea, oxidative damage, antioxidant, LLC-PK1 cells