title: Aloin, cinnamic acid and sophorcarpidine are potent inhibitors of tyrosinase.
abstract: OBJECTIVE
  To evaluate the effects of aloin, cinnamic acid and 15 other kinds of natural chemicals on the activity of tyrosinase, in order to provide lightening agents in the treatment of hyperpigmentation disorders and cosmetic additives.
  
  
  METHODS
  Tyrosinase activity was estimated by measuring the oxidation rate of L-dopa. Inhibition of the enzyme was deduced according to the Lineweaver-Burk plots compared to the control.
  
  
  RESULTS
  Cadabine, paeonal, farrerol, evodin, cinnamic acid, aloin and sophorcarpidine had different levels of inhibition of tyrosinase. The inhibitory rates of cinnamic acid (2 mmol/L, 0.5 mmol/L), aloin (2 mmol/L) and the rest were significantly higher than that of hydroquinone (0.5 mmol/L) (P < 0.05).
  
  
  CONCLUSIONS
  Tyrosinase activity can be greatly inhibited by cinnamic acid, aloin and sophorcarpidine, of which sophorcarpidine functions as an uncompetitive inhibitor, compared to aloin and cinnamic acid, which are mixed-type inhibitors.
authors.affiliation: Department of Dermatology, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China. tancheng@jschina.com.cn
authors.forename: Cheng
authors.initials: C
authors.lastname: Tan
authors.forename: Wenyuan
authors.initials: W
authors.lastname: Zhu
authors.forename: Yan
authors.initials: Y
authors.lastname: Lu
mesh_terms: D002934:Cinnamates / Q000494:pharmacology*; D003358:Cosmetics / Q000494:pharmacology; D004642:Emodin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D017495:Hyperpigmentation / Q000188:drug therapy; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors*; D028321:Plant Preparations / Q000494:pharmacology*
chemical_list: D002934:Cinnamates; D003358:Cosmetics; D004791:Enzyme Inhibitors; D028321:Plant Preparations; C029010:cinnamic acid; D014442:Monophenol Monooxygenase; D004642:Emodin; C006457:alloin