title: [Effect of Tribulus terrestris L decoction of different concentrations on tyrosinase activity and the proliferation of melanocytes].
abstract: OBJECTIVE
  To study the effects of the decoction of Tribulus terrestris L on tyrosinase activity and melanogenesis.
  
  
  METHODS
  MTT was employed to study the proliferation of human melanocytes cultured in vitro, and tyrosinase activity was estimated by measuring the rate of oxidation of DL-dopa, after the cells were treated with different concentrations of decoction of Tribulus terrestris L.
  
  
  RESULTS
  The treatment with the decoction increased the amount of melanin at higher concentrations but act to the reverse effect at lower concentrations, with the best concentrations for promoting and inhibiting the cell growth being 1.5 mg/ml (P<0.05) and 0.5 mg/ml (P<0.05) respectively. At high concentrations the decoction enhanced the tyrosinase activity that was inhibited at low concentrations. The best concentrations for enhancing and inhibiting tyrosinase activity were 100 mg/ml (P<0.05) and 10 mg/ml (P<0.05) respectively.
  
  
  CONCLUSIONS
  Tribulus terrestris L decoction exercises a two-way regulation on the activity of tyrosinase and the proliferation of melanocytes.
authors.affiliation: Department of Traditional Chinese Medicine, First Military Medical University, Guangzhou 510515, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Deng
authors.forename: Liu
authors.initials: L
authors.lastname: Yang
authors.forename: Sheng-Li
authors.initials: SL
authors.lastname: An
mesh_terms: D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D006801:Humans; D008544:Melanocytes / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D032444:Tribulus / Q000737:chemistry*
chemical_list: D004365:Drugs, Chinese Herbal; D014442:Monophenol Monooxygenase