Figure 1.

Schematic illustration of the effect of resveratrol on melanogenesis and related signaling pathways in melanocytes. The cyclic AMP-dependent protein kinase (PKA), protein kinase C (PKC), and mitogen-activated protein kinase (MAPK) signaling pathways induce the activation of transcription factors for several genes related to melanogenesis and lead to melanocyte proliferation and melanin synthesis. Resveratrol not only inhibits these signaling pathways, but also directly inhibits tyrosinase activity. AC = adenylate cyclase; CaMK = Ca²⁺/calmodulin-dependent protein kinase; DG = diacylglycerol; ERK = extracellular signal-regulated kinase; ET = endothelin; JNK = c-Jun N-terminal kinases; MITF = microphthalmia transcription factor; MSH = melanocyte-stimulating hormone; PLC = phospholipase C; Rc = receptor; SCF = stem cell factor; TRP = tyrosinase-related protein; TYR = tyrosinase; and UVR = ultraviolet radiation.