Abstract
BACKGROUND/AIM: Oxidative stress is a major contributor to melanocyte dysfunction and hair graying by impairing key signaling pathways. Eucommia ulmoides bark extract (EUE), rich in antioxidant phytochemicals, has shown potential in combating oxidative damage. This study investigated the protective and promelanogenic effects of EUE under hydrogen peroxide (H(2)O(2))-induced oxidative stress, with a focus on the Wnt/β-catenin signaling pathway. MATERIALS AND METHODS: An oxidative stress model was established using B16 cells and a C57BL/6 mouse hair follicle model. RESULTS: EUE significantly improved melanocyte survival and reduced intracellular reactive oxygen species (ROS). Mechanistically, EUE activated the Wnt/β-catenin pathway, leading to upregulation of the microphthalmia-associated transcription factor (MITF) and its downstream melanogenic enzymes (TYR, TRP-1, TRP-2), thereby enhancing tyrosinase activity and restoring melanin synthesis. In vivo, topical application of EUE protected hair follicles from H(2)O(2)-induced depigmentation and promoted follicular pigmentation. CONCLUSION: Our results demonstrate that EUE mitigates oxidative stress and promotes melanogenesis primarily by activating the Wnt/β-catenin-MITF signaling axis. These findings provide strong mechanistic evidence supporting EUE as a potential therapeutic strategy for oxidative stress-related hair graying.