Valencene from the Rhizomes of Cyperus rotundus Inhibits Skin Photoaging-Related Ion Channels and UV-Induced Melanogenesis in B16F10 Melanoma Cells

Ultraviolet (UV) radiation deeply penetrates skin and causes inflammation and pigmentary changes and triggers immune responses. Furthermore, accumulating evidence suggests that calcium ion channels, such as TRPV1 and ORAI1, mediate diverse dermatological processes including melanogenesis, skin wrinkling, and inflammation. The rhizomes of Cyperus rotundus have been used to treat inflammatory diseases including dermatitis. However, their effects on UV-induced photoaging-related ion channels remain unknown. Therefore, this study was undertaken to evaluate the antagonistic effects of C. rotundus extract and their constituents on TRPV1 and ORAI1 channels. Electrophysiological analysis revealed that valencene (1) isolated from the hexane fraction potently inhibited capsaicin-induced TRPV1 and ORAI1 currents at 90 mu M (69 +/- 15% and 97 +/- 2% at -60 and -120 mV, respectively). The inhibitory effect of 1 on cytoplasmic Ca2+ concentrations in response to ORAI1 activation (85 +/- 2% at 50 mu M) was also confirmed. Furthermore, 1 concentration dependently decreased the melanin content after UVB irradiation in murine B16F10 melanoma cells by 82.66 +/- 2.14% at 15 mu g/mL. These results suggest that C. rotundus rhizomes have potential therapeutic effects on UV-induced photoaging and indicate that the therapeutic and cosmetic applications of 1 are worth further investigation.