Pu-erh black tea supplementation decreases quinocetone-induced ROS generation and oxidative DNA damage in Balb/c mice

Quinocetone (3-methyl-2-quinoxalinbenzenevinylketo-1,4-dioxide, QCT), a new feed antibacterial agent of quinoxaline-1,4-dioxides family, has been used as an animal growth promoter. However, few data about its potential toxicity in vivo were available. In this study, genotoxicity of QCT and the relationship with oxidative stress were investigated. Balb/c mice with both sexes were administrated with QCT (12000, 6000 and 3000 mg/kg/bw, respectively) by gavage acutely. DNA damage, generation of reactive oxygen species (ROS) and activity of antioxidative system (total antioxidative capacity, glutathione, glutathione peroxidase, superoxide dismutase and catalase) in liver and kidney were determined. Moreover, Pu-erh black tea extract (BTE) was co-administrated with QCT to evaluate its protective effect against QCT-induced genotoxicity. The DNA damage was observed in all the groups treated with single QCT except the liver with dose of 3000 mg/kg/bw. ROS was accumulated and antioxidative system was suppressed both in liver and kidney. However, the DNA damage, as well as the ROS, was decreased, while the activity of antioxidative system was increased in mice after co-administration of QCT and BTE. These data demonstrate that oxidative stress mediated the genotoxicity induced by QCT in vivo. Furthermore, this oxidative DNA damage can be attenuated by pre-supplementation of BTE.