Protective effect of green tea (-)-epigallocatechin-3-gallate against the monoamine oxidase B enzyme activity increase in adult rat brains

Abstract

Objective Monoamine oxidase B (MAO-B) levels were observed increasing during aging in rat brains. (-)-Epigallocatechin-3-gallate (EGCG) is the major polyphenolic constituent in green tea. The objective of the present study was to investigate the EGCG compound for its effect on preventing an increase in MAO-B activity in rat brains. The total antioxidant capacity and lipid peroxidation of rats were also assessed. Methods Rats were assigned to three groups: Control, VE (α-tocopherol), and EGCG. Twenty-four male Long-Evans rats were fed normal diets for a total of 11 wk and test diets for a total of 12 wk. The serum analysis, serum total antioxidant capacity, tissue lipid peroxidation, and monoamine oxidase B enzyme activity were measured. The differences between the groups and between the control and experimental groups were analyzed. The correlation among the experimental results was also analyzed. Results The serum total antioxidant capacity of the EGCG group was higher than that observed in the Control and VE groups. In rat brains and livers, the lipid peroxidation levels were lower in the VE and EGCG groups compared with Control groups. EGCG and VE groups showed lower MAO-B enzyme activity in rat brains compared with Control groups. In contrast to the brain findings, there were no significant differences in the MAO-B enzyme activity among groups in rat livers. Conclusion The present study first indicates that EGCG supplementation was able to execute a tissue-selective decrease in the brain MAO-B enzyme activity in adult rats, in which it was actualized by way of preventing physiological peroxidation.