Protective effects of black tea-TV 25 on the cognitive impairments and some peripheral immune responses in intracerebroventricular colchicine injected rats

India is the largest consumer of black tea in the world, which has been reported to have different protective functions in several diseases. TV 25 variety back tea has high content of polyphenols and has anti-oxidant potential. This anti-oxidant property of black tea (TV 25 variety) may prove to be effective in ameliorating the oxidative stress, neuroinflammation linked cognitive impairments and peripheral immune responses in intracerebroventricular colchicine injected rats (ICIR). However, there is no report in literature in this regard. Aim of the study: Therefore, this study has been designed to investigate the effects of black tea (BT) (TV 25 variety) on the colchicine induced cognitive impairments, acetylcholine esterase activity and peripheral immune responses along with oxidative/ nitrosative stress. The oxidative stress (OS)/ nitrosative stress (NS) and increased acetylcholine esterase level in the hippocampus of ICIR were associated with working and reference memory impairments along with changes of stress markers of serum and alteration of peripheral immune responses (higher phagocytic activity of blood WBC and splenic PMN, higher cytotoxicity and lower leukocyte adhesion inhibition index of splenic MNC). Administration of BT in ICIR resulted in recovery of colchicine induced memory impairments, acetylcholine esterase level in the hippocampus, OS and NS in hippocampus and serum along with recovery of peripheral immune responses and serum corticosterone level. Therefore, it appears that the anti-oxidant potential of BT (TV 25) is potent enough to protect the colchicine induced OS/ NS and related memory impairments in ICIR.