Figure 7: Effects of resveratrol and p-coumaric acid on melanin synthesis in HEMs. HEMs were repeatedly treated with 1.0 mM L-tyrosine (substrate) in the absence or presence of test material (inhibitor) at indicated concentrations for 6 days. Effect of L-tyrosine on intracellular melanin content was determined (a). The effects of resveratrol or p-coumaric acid on cellular melanin synthesis stimulated by L-tyrosine (b) and cell viability (c) were examined. Data are presented as percentages of vehicle controls (means ± SE, ). versus vehicle control.