关键词: 白茶, 抗氧化, 美白, 黑色素, 酪氨酸酶

Abstract:

This study systematically evaluated the antioxidant and anti-melanogenic activities of two white tea extracts from distinct geographical regions: Yunnan (Y-WTE) and Fujian (F-WTE). The antioxidant efficacy of the extracts was assessed and compared through DPPH radical scavenging and hydroxyl radical scavenging assays, alongside their ability to repair H₂O₂-induced oxidative damage in human foreskin fibroblast (HFF-1) cells. Additionally, their anti-melanogenic activity was evaluated in mouse melanoma cell B16 via tyrosinase (TYR) activity assay, melanin contents measurement by NaOH method, mRNA expression analysis, and Western blot analysis. The results showed that both white tea extracts possessed certain antioxidant activities at biochemical level and in the H₂O₂-induced oxidative damage model of HFF-1 cells. Notably, Y-WTE exhibited superior antioxidant capacity compared to F-WTE. Furthermore, both extracts significantly inhibited α-melanocyte-stimulating hormone (α-MSH)-mediated melanin synthesis in B16 cell. This anti-melanogenic effect was attributed to the down-regulation of the mRNA expression levels of the key melanogenesis-associated proteins, microphthalmia-associated transcription factor (MITF), TYR, and TYR-related protein 1 (TYRP1), as well as the inhibition of TYR activity and protein expression. This study systematically revealed the antioxidant and anti-melanogenic efficacy of white tea extracts from different origins, highlighting their potential application in cosmetics, food, and medicine. Our findings provide a theoretical basis for the functional development and utilization of white tea.

Key words: white tea, antioxidation, whitening, melanin, tyrosinase