Inhibitory Effects of Water Extracts of Longan Leaves on Mutation and Tyrosinase

Abstract

The antityrosinase and antimutation effects of longan leaves and its bioactive compounds was investigated. The water extracts of longan leaves (WLL) inhibited the mutagenicity of 2-aminoanthracene, an indirect mutagen, and 4-nitroquinoline-N-oxide, a direct oxidative mutagen toward Salmonella typhimurium TA 98 and TA 100. WLL at 0-0.6 mg/ml displayed free radical scavenging activity, reducing power, chelating ability and protection against lipid oxidative damage. In addition, the inhibitory actions of WLL on tyrosinase activity and nitric oxide (NO) production in lipopolysaccharide (LPS) stimulated macrophages RAW 264.7 cell increased in concentration-dependent manner. According to HPLC-DAD analysis showed that epicatechin, ellagic acid and gallic acid, the major phenolic compounds, were present in WLL. The phenolic components may in part account for contributing the protective effects of WLL. On the basis of the results obtained, WLL can display biological functions and effectively protective against oxidation, mutation, tyrosinase, and inflammation.