Green tea has been used in traditional medicines for centuries due to its protective and soothing properties. Many of the properties of green tea stem from its polyphenol constituents that can also benefit skin health and wound healing. Green tea polyphenols include epicatechin-3-gallate (ECG) and epigallocatechin-3-gallate (EGCG). Tissue repair and wound healing are complex events that can be delayed by persistent inflammation or by inadequate angiogenic responses. The complexities involved in these events include the interaction of inflammation, re-epithelialization, angiogenesis, granulation and tissue formation, and collagen deposition. Delayed healing leads to chronic wounds and over-healing leads to keloids and hypertrophic scarring. In vivo research indicates that the topical application of ECG results in a significant improvement in scar formation and collagen fiber orientation. This work demonstrates that ECG significantly improves the quality of wound healing due in part to acceleration of the angiogenic response. Many laboratories have also shown that topical treatment with tea polyphenols inhibits chemical carcinogen or ultraviolet radiation-induced skin tumorigenesis in different animal models. Tea polyphenols activate the FOX03a gene, which has been shown to induce cell cycle arrest in cancer cells. In addition, studies have shown that green tea extract possesses anti-inflammatory activity, which is also due to its polyphenolic constituents. Topical treatment with EGCG on mouse skin resulted in the prevention of UVB-induced immunosuppression, and oxidative stress. Epidermal keratinocyte proliferation and differentiation is critical in skin care and wound healing. Normal epidermal turnover takes 1-2 months but this rate is altered by disease states and wounding. Topical application of EGCG increases cellular activities including new DNA synthesis in aged keratinocytes, keratinocyte regeneration, and the differentiation of keratinocytes located in the basal layer of the epidermis.
1. Mini Rev Med Chem 2011; 1 (14): 1200-1215.
2. Am J of Pathol 2004; 165 (1): 299-307.
3. Cancer Res 2007; 67 (12): 5763-5770.
4. J Pharmacol Exp Ther 2003; 306 (1): 29-34.