RESUMEN
It is known that skin diseases are related to proliferation of cellular components. Green tea has many favorable biologic effects: anti-inflammatory, antibacterial, antiviral effects, lowering of plasma cholesterol and triglyceride levels, reduction of blood pressure and platelet aggregation, antimutagenic, and anticarcinogenic activities. The effects of green tea on various cells in skin has been reported in previous studies; For keratinocytes and human epidermoid carcinoma cells, green tea induces apoptosis only in cancer cells, but no keratinocytes. For endothelial cells, green tea inhibits endothelial cell proliferation. For melanocytes and fibroblast, it is little known. We investigated the effects of green tea polyphenol(GTP) and the major constituents, (-)-epigallocatechin-3-gallate(EGCG) on the proliferation in the cultured human keratinocytes, fibroblasts, melanocytes, endothelial cells and human epidermoid carcinoma cells(A431 cells). The proliferative response was studied by the cell count and the uptake of tritiated thymidine after 48 hours of treatment. And we also observed apoptosis using TUNEL staining. The results were as follows; Number of living cells were significantly decreased(p<0.05) in cultured human epidermal cells, melanocytes, fibroblasts, endothelial cells and A431 cells treated with different concentration of GTP and EGCG for 48 hours. The cells were decreased dose dependently as increase of concentration of the extracts. The [3H]thymidine incorporation were significantly decreased(p<0.05) in cultured human epidermal cells, melanocytes, fibroblasts, endothelial cells and A431 cells treated with different concentration of GTP and EGCG for 48 hours. The dose dependent inhibition was also seen in [3H]thymidine incorporation by green tea extracts. Cell proliferation was significantly more inhibited(p<0.05) by EGCG compared to GTP in the same concentration. We failed to observe apoptosis of cultured human epidermal cells, melanocytes, fibroblasts, endothelial cells and A431 cells by GTP and EGCG. In summary, green tea extracts(GTP, EGCG) showed statistically significant inhibitory effects on cultured human epidermal cells, melanocytes, fibroblasts, endothelial cells and A431 cells. These results suggest that green tea could play a possible role in the treatment of hyperproliferative skin disease.