Antioxidant and antimelanogenic properties of chestnut flower extract

In this study, we analyzed the antioxidant and antimelanogenic properties of a variety of solvent extracts of pre-bloom and full-bloom chestnut flowers. Among the solvent extracts, a pre-bloom methanol extract (preM) and an ethanol extract (preE) showed the highest amounts of phenolics (467.92+/-0.45 and 456.24+/-5.88 mg of gallic acid equivalent/g of extract) and flavonoids (60.96+/-1.86 and 41.59+/-8.57 mg of quercetin equivalent/g of extract). These extracts exhibited the highest DPPH radical and reducing activities, as well as the greatest mushroom tyrosinase inhibition activity. In addition, preE effectively protected the skin against ultraviolet (UV) rays. Further, extracts were tested for cytotoxicity on human melanoma cells (SK-MEL-2), and we observed that all the extracts were non-cytotoxic for the cells. Their effects on tyrosinase and melanin inhibitory action were further assessed, and we found that all the extracts reduced the tyrosinase activity and melanin formation of SK-MEL-2 cells as effectively as arbutin. Moreover, the protein level expression of tyrosinase decreased dramatically. However, the protein levels of the other melanogenic enzymes, tyrosinase-related protein 1 (TRP1) and dopachrome tautomerase (DCT), were not altered significantly. Therefore, the antimelanogenic effects of chestnut flower extracts were attributable to their inhibitory effects on tyrosinase via their anti-oxidative action, making them a strong candidate for use in food, cosmetics, and pharmaceutical applications.