Antioxidant Activity and Tyrosinase Inhibitory Activity of Three Phenolic Compounds from Quezui Tea

In order to deeply explore the utilization value of Quezui tea, the antioxidant activity and tyrosinase inhibitory activity of its three phenolic compounds including 6'-O-caffeoylarbutin (CA), β-arbutin, and chlorogenic acid were analyzed in this study. The results indicated that all three phenolic compounds of Quezui tea had excellent antioxidation activity. The IC₅₀ values of CA, β-arbutin, and chlorogenic acid on DPPH radical scavenging were 13.56±0.14, 104.41±6.52 and 8.42±0.21 μg/mL, respectively. The IC₅₀ values of ABTS⁺ radical scavenging were 18.01±0.06, 50.60±1.25 and 26.93±0.38 µg/mL, respectively. The IC₅₀ values of OH radical scavenging were 2.64±0.06, >10.00 and <1.00 mg/mL, respectively. The intensity of total iron reduction was in the order of chlorogenic acid>CA>β-arbutin. In addition, the inhibitory activities of all three phenolic compounds of Quezui tea were significantly different. CA had inhibitory effects on both monophenolase and diphenolase activities with IC₅₀ values of 1.114±0.035 and 95.198±1.117 μmol/L, respectively. β-arbutin only had inhibitory effects on monophenolase activities with IC₅₀ value of 681.335±17.975 μmol/L, and chlorogenic acid had no inhibitory effect on either monophenolase activity or diphenolase activity. The results would provide an important foundation for the development and utilization of the active compounds from Quezui tea.