Melanin Regulation and Autophagy Modulation by Rosa centifolia L. Extract and Its Key Compounds (Astragalin and Ellagic Acid)

Rosa centifolia, a widely used rose species, has been extensively studied for its antioxidant and anti-inflammatory properties. However, little research has been conducted on its skin-whitening properties. Therefore, this study investigated the application of R. centifolia for skin whitening in vitro. We conducted a flash extraction of R. centifolia (RCFE), quantified the total flavonoid and proanthocyanidin content, established the high-performance liquid chromatography/diode array detection testing method, and analyzed the contents of three active ingredients: ellagic acid (ECA), astragalin (ASG), and isoquercitrin. A B16 cell model was established to screen three components for their activity. The results indicated that 3.00 µg/mL of ellagic acid and 6.00 µg/mL of astragalin were particularly effective in inhibiting melanogenesis and tyrosinase activity. We further investigated the whitening mechanism of RCFE, ECA, and ASG using enzyme-linked immunosorbent assay and Western Blot methods. The RCFE, ASG, and ECA inhibited melanogenesis, suppressed tyrosinase activity, inhibited microphthalmia-associated transcription factor expression, affected tyrosinase-related protein 1 and 2 expression, and increased cellular autophagy, as evidenced by the elevation of the light chain 3 (LC3)-II/LC3-I ratio, the upregulation of Beclin-1 expression, and the downregulation of p62 protein expression. These findings provide a theoretical basis for developing new pharmaceutical and skin care ingredients.