Dermal toxicity of topical (-)epigallocatechin-3-gallate in BALB/c and SKH1 mice

(-)Epigallocatechin-3-gallate (EGCG), the major polyphenolic component of green tea, inhibits experimental chemical and physical carcinogenesis, yet little toxicological data has been reported. Therefore, we performed studies on the dermal toxicity of EGCG applied in an ointment formulation in mice. Female BALB/c mice were dehaired with a topical depilatory and administered 75 microl EGCG in hydrophilic Ointment U.S.P. at three concentrations (10, 3, and 1%, all w/w) daily for 30 days. At the 10% concentration, gross toxicity was manifested by the formation of erythema and papular lesions by day 5. A 7% reduction in weight was observed by day 15. No toxicity was observed at the two lower concentrations or in the vehicle control group. Also, no toxicity was observed when mice were dehaired by shaving. This study was repeated in female SKH1 mice, an outbred hairless strain that does not require depilation. No toxicity was observed in the SKH1 mice, indicating that daily topical EGCG appears non-toxic in normal skin. However, use of topical depilatories may potentiate dermal toxicity of EGCG.