Inhibitive Mechanism of Loquat Flower Isolate on Tyrosinase Activity and Melanin Synthesis in Mouse Melanoma B16 Cells

作者：Qianqian Chen, Wenyang Tao, Jianfeng Wang, Jingrui Li, Meiyu Zheng, Yinying Liu, Shengmin Lu, Zhongxiang Fang · 发表于：Biomolecules · 年份：2024 · DOI：10.3390/biom14080895 · 被引用次数：7 · 研究领域：melanin and skin pigmentation、Garlic and Onion Studies、Antioxidant Activity and Oxidative Stress

Melanin naturally exists in organisms and is synthetized by tyrosinase (TYR); however, its over-production may lead to aberrant pigmentation and skin conditions. Loquat (Eriobotrya japonica (Thunb.) Lindl.) flowers contain a variety of bioactive compounds, while studies on their suppressive capabilities against melanin synthesis are limited. Loquat flower isolate product (LFP) was obtained by ethanol extraction and resin purification, and its inhibitory efficiency against TYR activity was investigated by enzyme kinetics and multiple spectroscopy analyses. In addition, the impact of LFP on melanin synthesis-related proteins’ expression in mouse melanoma B16 cells was analyzed using Western blotting. HPLC-MS/MS analysis indicated that LFP was composed of 137 compounds, of which 12 compounds, including flavonoids (quercetin, isorhamnoin, p-coumaric acid, etc.) and cinnamic acid and its derivatives, as well as benzene and its derivatives, might have TYR inhibitory activities. LFP inhibited TYR activity in a concentration-dependent manner with its IC50 value being 2.8 mg/mL. The inhibition was an anti-competitive one through altering the enzyme’s conformation rather than chelating copper ions at the active center. LFP reduced the expression of TYR, tyrosinase-related protein (TRP) 1, and TRP2 in melanoma B16 cells, hence inhibiting the synthesis of melanin. The research suggested that LFP had the potential to reduce the risks of hyperpigmentation caused by tyrosinase and provided ...