Tannase-converted green tea catechins and their anti-wrinkle activity in humans

Background: This study was performed to investigate the anti-wrinkle effects of topical applications of green tea extract with high antioxidant activity by tannase treatment. Increases in gallic acid (GA), (-)-epigallocatechin (EGC), and (-)-epicatechin (EC) were observed in the green tea extract after tannase treatment. Objectives: This study was performed to investigate the anti-wrinkle effects of topical applications of green tea extract exhibiting high antioxidant activity after tannase treatment. Methods: Subjects, randomly divided into two groups, received the application of either tannase-converted green tea extract (TGE) or normal green tea extract (NGE) on their crow's feet for 8 weeks. The anti-wrinkle effects were evaluated with two methods: (i) self-assessment; and (ii) average roughness of skin surface (R_a, R_z, and R_t value) using skin replica and Skin-Visiometer SV 600. Results: The scavenging abilities of TGE against radicals were significantly higher compared to NGE. The evaluation of skin wrinkle index values after 8 weeks of treatment showed that reductions of R_a, R_z, and R_t values in the TGE group were significantly greater than in the NGE group, which indicated that tannase treatment improved the anti-wrinkle effects of green tea extract. According to the overall ratings for wrinkle treatment by applying the formulations, most of the TGE group (63.60%) reported marked or moderate improvement in wrinkles compared with only 36.30% of the NGE group. Conclusion: Tannase treatment can improve the antioxidant activity of green tea extract, conferring anti-wrinkle activities. These results suggest that TGE may have beneficial properties as an anti-wrinkle agent.