Anti-melanogenic effect of <i>Amaranthus tricolorextract</i> on UV radiation-exposed melanoma cells

Abstract

Purpose: To determine the inhibitory effect of A. tricolor extract (ATE) on melanogenesis in UV radiation-exposed B16F10 cells. Methods: Total phenolic and anthocyanin contents of ATE were examined by Folin-Ciocalteu and pH differential methods, respectively. The tyrosinase inhibitory effect of ATE was investigated using L-DOPA as a substrate and the suppressive effect of ATE on melanin production was determined in melanoma cells. Furthermore, the antioxidant activity was assessed by DPPH method and reactive oxygen species formation while protein expression levels were evaluated by western blot method. Results: The total phenolic and anthocyanin contents were identified up to 35 mg/g extract and 0.85 mg/g extract, respectively. ATE was found to inhibit both mushroom and cellular tyrosinase at IC50 values of 242.2 ± 9.5 μg/mL and 202.9 ± 11.6 μg/mL, respectively. Moreover, ATE treatment reduced melanin production up to (30 ± 5) % and suppressed p38 MAPK phosphorylation at the concentration of 400 μg/mL. In addition, ATE significantly scavenged DPPH radical with EC50 value of 189.2 ± 8.9 μg/mL and abolished ROS formation in the cells. Conclusion: These results indicate that A. tricolor extract has a potential protective effect against melanin production, suggesting its potential value in skin-lightening formulations.