Background: Epigallocatechin-3-gallate (EGCG), a major flavonoid in green tea, possesses potent antioxidant, antiviral, and anticancer properties. However, excessive EGCG exposure has been associated with mitochondrial dysfunction.
Objectives: This study aimed to evaluate the effects of high-dose EGCG on interleukin-2 (IL-2) expression and T cell subsets in mice.
Methods: For immunohistochemical analysis of spleen of IL-2, BAX, and BCL-2 expression, the animals were assigned to two groups: control and EGCG (750 mg/kg) for three days. For flow cytometric spleen evaluation of CD4⁺ and CD8⁺ T cells, the animals were divided into four groups receiving 0, 250, 500, or 750 mg/kg EGCG for five days.
Results: High-dose EGCG (750 mg/kg) induced a non-significant decrease in IL-2 expression (p > 0.05), a non-significant increase in BAX (p > 0.05), and a significant elevation of BCL-2 expression (p < 0.05). Flow cytometric analysis revealed a dose-dependent decline in CD4⁺ and CD8⁺ T cell proportions, with significant reductions observed only at 750 mg/kg (p < 0.05). Correlation and regression analyses confirmed a significant negative association between EGCG dose and both T cell subsets.
Conclusion: These findings suggest that high-dose EGCG modulates IL-2–mediated activation and attenuates CD4+ and CD8+ populations. Collectively, these results indicate that excessive EGCG exposure alters T cell homeostasis and survival-associated signaling.