Green tea polyphenols, epicatechin gallate and epigallocatechin gallate, alleviated aberrant metabolic changes caused by olanzapine in rats.

Objective: Olanzapine, a well-known antipsychotic drug, causes considerable weight gain and metabolic abnormalities in patients. Green tea (Camellia sinensis) has anti-obesity, antihypertensive, antihyperlipidemic, and anti-diabetes effects. The aim of this study was to investigate the potential effects of epicatechin gallate (ECG) and epigallocatechin gallate (EGCG) as green tea polyphenols on metabolic changes induced by olanzapine.

Materials and methods: We used fourteen groups of rats and subjected them to intraperitoneal injections once a day for eleven days: 1: Control. 2: Olanzapine (5 mg/kg/day). 3, 4, and 5: Olanzapine + EGCG (10, 20, and 40 mg/kg/day, respectively). 6, 7, and 8: EGCG (10, 20, and 40 mg/kg/day, respectively). 9, 10, and 11: Olanzapine + ECG (10, 20, and 40 mg/kg/day, respectively). 12, 13, and 14: ECG (10, 20, and 40 mg/kg/day). The body weights were recorded every three days and food consumption was evaluated every day. At the end of the study, lipid profile, systolic blood pressure (SBP), leptin and fasting blood sugar (FBS) levels, and locomotor activity were assessed.

Results: Olanzapine considerably increased weight, food intake, triglycerides, low-density lipoprotein (LDL), cholesterol, SBP, leptin, and FBS, and decreased high-density lipoprotein (HDL), and locomotor activity. Co-administration of ECG or EGCG at different doses significantly suppressed olanzapine-induced weight gain, and elevated plasma lipids, SBP, leptin, and FBS levels. Both compounds also considerably increased locomotor activity and HDL levels.

Conclusion: These findings suggest that ECG and EGCG could be promising adjunct therapies to counteract the metabolic side effects of olanzapine.