PROTECTIVE ROLE OF GREEN TEA POLYPHENOLS AGAINST PARAQUAT INDUCED OXIDATIVE STRESS IN RAT LIVER

The potential protective roles of green tea polyphenols against oxidative damage induced by paraquat were investigated. Forty male albino rats were used, and divided randomly into four groups. The First group served as a control, the second was injected with paraquat (10 mg/kg body weight, i. p.) for the 24 hrs dose and for 4-day consecutive doses, the third group drank green tea (12.5 gm/L), and the fourth group drank green tea for 1 week pre and 4 days post-paraquat treatment. The contents of microsomal proteins, some microsomal enzymes, blood plasma total antioxidant capacity (TAC) and lactate dehydrogenase (LDH) were determined in animals after treatment. Results indicated that drinking green tea had no significant effect on hepatic contents of microsomal proteins. In addition, drinking green tea enhanced (P 0.001) activities of cytochrome P-450 and cytochrome bs after treatment for 4 consecutive days. TAC in blood plasma was not significantly affected by 24 hrs treatment with paraquat or green tea, but polyphynols in green tea plus paraquat slightly enhanced (P 0.05) TAC. Paraquat treatment caused significant increases (P 0.001) in TBARS after treatment for 24 hrs as a single dose and for 4 consecutive days as repeated doses. Green tea alleviated the paraquat-induced increase in TBARS after 4 days repeated doses. Similar trend was also noted for NADPH cytochrome C reductase activity. LDH activity was significantly increased (P 0.01) after 24 hrs of paraquat treatment. Green tea slightly enhanced (P 0.05) LDH activity, but it alleviated the paraquat-induced increase in LDH activity.