p-Coumaric acid, a constituent of Sasa quelpaertensis Nakai, inhibits cellular melanogenesis stimulated by α-melanocyte stimulating hormone

Summary Background Recent study has demonstrated that Sasa quelpaertensis (Korean name, Jeju‐Joritdae) extracts inhibit cellular melanogenesis implicating potential use in the control of skin pigmentation. Objectives The purpose of the present study was to elucidate the active constituents of this plant inhibiting melanogenesis and the associated mechanism. Methods The effect of the plant‐derived materials on melanin production and/or tyrosinase expression was examined in murine melanoma B16/F10 cells and neonatal human melanocytes. Results When tested in melanoma B16/F10 cells treated with the α‐melanocyte stimulating hormone (α‐MSH), the aqueous ethanol extract of S. quelpaertensis culm inhibited the cellular melanogenesis more effectively than its leaf extract. A major active compound was isolated from the culm extract by solvent fractionation and column chromatography, and identified to be p‐coumaric acid by spectroscopic and chromatographic analyses. The compound (p‐coumaric acid) inhibited α‐MSH‐stimulated cellular melanogenesis more effectively than arbutin or other structurally similar compounds including 3‐(4‐hydroxyphenyl) propionic acid, cinnamic acid and caffeic acid. It also attenuated α‐MSH‐dependent increase of tyrosinase protein. The antimelanogenic effect of p‐coumaric acid was also verified in neonatal human melanocytes. Conclusions The present study identified p‐coumaric acid as a main constituent of S. quelpaertensis inhibiting cellular melanogenesis. Because of its structural similarity, p‐coumaric acid may interfere with l‐tyrosine action in the control of tyrosinase expression in response to α‐MSH.