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-dimethylthiazol2-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.

Epidemiology shows that the most common psoriasis is psoriasis vulgaris. The common traditional Chinese medicine (TCM) syndrom is the blood-heat type, which is equivalent to the progressing stage of psoriasis. This article summarized the experimental research of TCM in treating psoriasis vulgaris which is considering as the blood-heat type on the basis of the differentiation of symptoms and signs. The mechanism of clinical efficacy on treating psoriasis vulgaris which is at the blood-heat type was explained in different layers such as Th lymphocytes subgroups, Notchsignalpathway, PTH and hemorheology. This study aimed to help scholars to understand the mechanism of therapeutic effect of TCM on the treatment of psoriasis vulgaris.