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8323700 
Journal Article 
Inhibitory effect of lemon essential oil on mushroom tyrosinase activity in vitro 
Hu, JJ; Li, X; Liu, XH; Zhang, WP 
2015 
1 
Xiandai Shipin Keji
ISSN: 1673-9078 
South China University of Technology 
31 
6 
97-105 
English 
The mechanism of tyrosinase inhibition by lemon essential oil and its six individual components was studied in terms of tyrosinase activity, radical-scavenging activity, and copper-chelating capability. The results indicated that lemon essential oil and some of its volatile components exhibited good inhibitory effect on tyrosinase activity through non-active-site-inhibition mechanisms such as steric effect and oxygen radical-scavenging activity. Among the components of lemon essential oil, inhibitory rate on tyrosinase activity exerted by citral (2.16% m/m) and beta-pinene (14.30% m/m) was 76.64% and 61.82%, respectively, while that of d-limonene (61.41% m/m) was only 33.25%. Additionally, inhibition exerted by the mixture of all six volatile components was higher than that of lemon essential oil due to a synergistic effect and the inhibitory effect was higher with increasing concentration. Moreover, the inhibitor concentration causing 50% loss of activity (IC50 value) was 620±15.72 µg/mL. The Lineweaver-Burk plot showed that inhibitory activity of lemon essential oil (Km=0.30±0.003 mM) was noncompetitive. The 1,6-bis(diphenylphosphino) hexane (DPPH) assay showed that lemon essential oil and citral had relatively strong radical-scavenging activity, with IC50 values of 123.65±20.20 and 176.54±23.20 mg/mL, respectively. Copper chelating demonstrated that the six components did not bind to the active sites of tyrosinase while exhibiting good inhibitory effect. These results indicate that lemon essential oil is a natural material with potential biological function that can be applied to food and cosmetic industries. ©, 2015, South China University of Technology. All right reserved. 
Chelation of copper ion; Gas chromatography mass spectrometry; Lemon essential oil; Radical-scavenging activity; Tyrosinase; Volatile components