Effect of aqueous extracts of black and green teas in arsenic-induced toxicity in rabbits.

Arsenic causes oxidative stress in the body. Its administration (3 mg/kg/day) for 14 days in rabbits resulted in a significant reduction of whole blood glutathione (GSH), and elevation of thiobarbituric acid reactive substances (TBARS) and the index of nitrite/nitrate (NOx) levels. These are the markers of oxidative stress. Both black tea (BT) and green tea (GT) (Camellia sinensis), when administered to the arsenic-treated rabbits for 14 days, caused a significant elevation of the depleted GSH level to 53.12% and 57.47%, respectively. On the contrary, in the placebo group the level was 26.59%. The BT and GT reduced the elevated TBARS level to 43.27% and 62.28%, respectively, whereas the corresponding level in the placebo groups was 21.24%. The NOx levels were also reduced to 63.62%, 67.67% and 58.94% in BT, GT and the placebo groups, respectively. When arsenic and black tea were given concurrently to another group the results were even more pronounced. The polyphenol components of black and green tea were 27.69% and 29.71% of the dry weight of the total extracts, respectively. These results indicated that arsenic-induced toxicities in rabbits were significantly reversed by the black and green tea polyphenols. The greater activity of green tea than that of black tea correlates with the slightly higher content of polyphenols in green tea.