Figure 4From: Photoprotective and antioxidant effects of Rhubarb: inhibitory action on tyrosinase and tyrosine kinase activities and TNF-α, IL-1α and α-MSH production in human melanocytes Effects of Rheum rhaponticum L. extract (RRE) and kojic acid AKcp on tyrosine kinase activity in human melanocytes exposed and unexposed to ultraviolet radiation. Data are presented as the mean ± S.E.M. of six individual experiments, performed in triplicate. *P < 0.001 compared with control unexposed to UV radiation; + P < 0.001 compared with control exposed to UV radiation.Back to article page