Abstract: Wu Yanhua*, Tang Nan, Cai Lanhua, Li Qilin. *Fourth Affiliated Hospital of Jinan University School of Medicine; Department of Traditional Chinese Medicine, Guangzhou Red Cross Hospital, Guangzhou 510220, China Corresponding author: Wu Yanhua, Email: wuyanhua368@163.com 【Abstract】 Objective To evaluate the in vitro effect of ferulic acid on the proliferation of, as well as melanin synthesis, tyrosinase activity and expressions of c-kit and ERK proteins in cultured normal human epidermal melanocytes. Methods Cultured normal human epidermal melanocytes were treated with various concentrations of ferulic acid for different durations, and those remaining untreated served as the control. Then, 3-（4,5-dimethylthiazol-2-yl）-5-（3-carboxymethoxyphenyl）-2-（4-sulfophenyl）-2H-tetrazolium, inner salt （MTS） assay was performed to estimate cell proliferative activity at 24, 48 and 72 hours, sodium hydroxide solubilization method to quantify melanin content in melanocytes at 72 hours, dopa oxidation assay to evaluate tyrosinase activity at 72 hours, Western blot to measure the expressions of c-kit and ERK1/2 proteins at 72 hours. Results Cellular proliferative activity was significantly inhibited in melanocytes treated with ferulic acid of 0.01, 0.1 and 1 mg/ml for 24, 48 and 72 hours compared with untreated melanocytes （all P < 0.05）, and the 72-hour treatment with ferulic acid of 1 mg/ml showed the strongest inhibitory effect. Ferulic acid at 0.01, 0.1 and 1 mg/ml all markedly suppressed melanin synthesis and tyrosinase activity, decreased the expressions of c-kit and ERK1/2 proteins in melanocytes, with significant differences in these parameters between ferulic acid-treated and untreated melanocytes （all P < 0.05）. Conclusions Ferulic acid could downregulate the proliferation of, as well as melanin synthesis, tyrosinase activity, and expressions of c-kit and ERK proteins in cultured human epidermal melanocytes.

Key words: Ferulic acid, Melanocytes, Cell proliferation, Tyrosine, Proto-oncogene proteins c-kit