Hepatoprotective and antioxidant properties of extract of Carmellia sinensis (black tea) in rats

Abstract

Hepatoprotective and antioxidant effects of water extracts of black tea (Camellia sinensis) were studied
in sodium oxalate treated rats. Lipid peroxidation was induced in rats by administration of 100 mg/kg
body weight sodium oxalate. The protective effect of black tea was assessed by monitoring the serum
and tissue levels of malondialdehyde, catalase activity, aspartate transaminase (AST) and alanine
transaminase (ALT) as well as serum vitamin C content in the normal, control and experimental rats
after 10 and 20 days of tea administration. It was observed that tea administration lowers significantly
(p<0.05) the serum and tissue levels of malondialdehyde, as well as AST and ALT activities in a dose
dependent manner. The serum level of vitamin C and activity of catalase in the serum and tissues were
however shown to be significantly elevated (p<0.05). After 10 days of administration of 200 mg/kg body
weight of tea extract, serum level of malondialdehyde was reduced from 47.8551.050 to 32.1860.882
nm/h, AST activity from 592.95 to 311.40 IU and ALT activity from 392.51 to 251.25 IU. Moreover,
administration of 200 mg/Kg body weight of tea for 10 days caused an increase in serum catalase
activity from 7 to 10% and serum vitamin C level was increased from 45.399.75 to 79.115.13 mg/100
ml. In the tissues, the same trend was observed. The result also indicated that prolonged tea
administration (for 20 days) significantly increased serum vitamin C level and the activity of catalase in
both the serum, liver and the kidney (p<0.05). Also, the serum and tissue levels of malondialdehyde and
transaminase activities (AST and ALT) were significantly reduced (p<0.05).