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Studies of the Antioxidative Effects of Green and Black Tea (Camellia sinensis) Extracts in Rats.

Ojo OO, Ladeji O, Nadro MS

Chevron Biotechnology Centre, Federal University of Technology, Yola.

This paper reports a comparative study of the antioxidative effects of black and green tea extracts in sodium oxalate-challenged rats. A dose of 10 mg/kg of body weight of sodium oxalate was used to induce lipid peroxidation in vivo. Rats treated with sodium oxalate had 42.06 +/- 3.10 nM/hour, 45.39 +/- 9.75 mg/100 mL, 10.95 +/- 1.52%, 15.95 +/- 3.19 mg/dL, 112.25 +/- 5.15 mg/dL, 59.21 +/- 2.95 IU, 39.55 +/- 2.51 IU, and 150.62 +/- 9.62 KA/unit for serum levels of malondialdehyde, reduced ascorbic acid, catalase, cholesterol, phospholipid, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP), respectively. These values are significantly (P < .05) different from values obtained from normal rats. Rats pretreated with 100 mg/kg of body weight of green tea had 27.59 +/- 3.56 nM/hour, 79.11 +/- 5.13 mg/100 mL, 4.23 +/- 0.36%, 50.09 +/- 5.24 mg/dL, 97.58 +/- 4.73 mg/dL, 23.10 +/- 1.59 IU, 31.14 +/- 1.26 IU, and 96.48 +/- 2.36 KA/unit for serum levels of malondialdehyde, reduced ascorbic acid, catalase, cholesterol, phospholipid, AST, ALT, and ALP, respectively, compared with 37.28 +/- 2.07 nM/hour, 72.62 +/- 2.10 mg/100 mL, 6.23 +/- 1.52%, 37.25 +/- 2.84 mg/dL, 78.05 +/- 2.36 mg/dL, 36.08 +/- 1.80 IU, 29.00 +/- 3.02 IU, and 109.23 +/- 6.32 KA/unit recorded for the same parameters in rats treated with black tea. The cholesterol to phospholipid ratio was increased from 0.14 +/- 0.04 in control rats to 0.47 +/- 0.02 and 0.51 +/- 0.01 by black and green tea extracts, respectively. These results suggest that tea extracts have antioxidant properties and that green tea extract is more potent.

Published 26 July 2007 in J Med Food, 10(2): 345-9.
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