Scavenging action of zinc and green tea polyphenol on cisplatin and nickel induced nitric oxide generation and lipid peroxidation in rats.

OBJECTIVE Toxic metal ions have been implicated in the generation of reactive oxygen species (ROS) and nitric oxide (NO). Metallothionines (MT) and plant flavonoids have been reported in the intervention against oxidative damage. We investigated the effect of zinc induced MT and green tea polyphenol (GTP) in reducing the oxidative responses induced by nickel and platinum. METHODS Zinc (10 mg/kg b. wt, sc) was administered to rats twice at a gap of 24 hrs and GTP (10 mg/100 mL in drinking water) was fed ad libitum for 8 days. Nickel chloride (150 umol/kgb.wt, ip) and cisplatin (50 mumol/kg b.wt, sc) was administered to rats 24 h after Zn or GTP pre-treatment. Animals of all the groups were sacrificed 16 hrs after treatment and biochemical markers for toxicity were monitored. RESULTS Zinc or GTP pre-treatment caused significant protection against nickel or cisplatin enhanced mortality in rats, and reduction in lipid peroxidation and NO. CONCLUSION It is proposed that inhibition of ROS and NO by GTP and zinc may prove useful as a selective pharmacological agent in the amelioration of metal toxicity.