Melanogenesis inhibition activity of ethyl acetate fraction from Curcuma zedoaria in B16 cell line

Abstract

Curcuma zedoaria is a traditional medicine used for various purposes in human life. The organic solvent extracts of this plant also exhibit antioxidant, antibacterial, anti-inflammatory, anti- cancer, anti-necrosis, and hepatoprotective properties. However, the prospect of employing this plant extract for skin whitening, particularly its molecular mechanism, has not been reported yet. Therefore, in this study, the total polyphenolic content, antioxidant activity, cytotoxicity, tyrosinase inhibitory, melanin inhibitory, and target gene expression using the ethyl acetate fraction of ethanolic extract from Curcuma zedoaria , were all examined. The TPC result of the sample was 42.18±2.25 mg GAE/g extract with impressive antioxidant activity. Half maximal inhibitory concentration value of 2,2-Diphenyl-1-picrylhydrazyl radical scavenging assay and Ferric reducing antioxidant power FRAP value at a concentration of 2.5 µg/mL were 49.06±0.29 µg/mL and 116±50 μM Fe2+/L, respectively. The extract had no cytotoxicity at 25 µg/mL, inhibited melanin production for 74.02±3.05% and tyrosinase for 137.45±1.38%. In particular, the extract demonstrated the ability to block the expression levels of four melanogenesis-related genes. Moreover, GCMS analysis results also detected 28 different compounds, with two new compounds accounting for a high proportion. These results suggested that C. zedoaria has a significant potential for application in skin-pigmentation treatment cosmetics.

Keywords:
Curcuma zedoaria ; Tyrosinase inhibitory; Melanin inhibitory; Antioxidant activity