title: Caffeine alters mitochondrial dehydrogenase and alkaline phosphatase activity of human gingival fibroblasts in vitro.
abstract: OBJECTIVE
  Caffeine is one of the most widely consumed behaviorally active substances in the world. Although its effects on the central nervous system and bone metabolism have been documented, as yet there is no report on its effect on tissues in the oral cavity. In this study we analyzed the viability of human gingival fibroblasts (HGF) and alkaline phosphatase (ALP) enzyme activity after exposure to different concentrations of caffeine for different exposure time periods.
  
  
  METHODS
  The HGF were cultured with different concentrations of caffeine. Viability of cells exposed to caffeine was analyzed by the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay to assess mitochondrial dehydrogenase activity. The activity of ALP was analyzed at specific time intervals after caffeine addition.
  
  
  RESULTS
  Our results showed that caffeine of concentrations <1 mm did not affect the viability of HGF and the ALP enzyme activity. Nevertheless, caffeine at 5 and 10 mm dramatically decreased the viability and ALP activity of the cells after 4 days such that, by day 9, the viability of cells declined to near zero in the 10 mm group.
  
  
  CONCLUSIONS
  These results provided evidence that caffeine in high concentrations can decrease cellular viability and ALP activity in HGF.
authors.affiliation: Department of Microbiology, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Shabnam Soltani
authors.initials: SS
authors.lastname: Bozchaloei
authors.forename: Siew-Ging
authors.initials: SG
authors.lastname: Gong
authors.forename: Ahmad R
authors.initials: AR
authors.lastname: Dehpour
authors.forename: Parisa
authors.initials: P
authors.lastname: Farrokh
authors.forename: Mohammad R
authors.initials: MR
authors.lastname: Khoshayand
authors.forename: Mahvash
authors.initials: M
authors.lastname: Oskoui
mesh_terms: D000469:Alkaline Phosphatase / Q000037:antagonists & inhibitors / Q000187:drug effects*; D002110:Caffeine / Q000008:administration & dosage / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects; D018929:Cell Culture Techniques; D002460:Cell Line; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000494:pharmacology*; D004396:Coloring Agents; D005347:Fibroblasts / Q000187:drug effects* / Q000201:enzymology; D005881:Gingiva / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D006801:Humans; D008928:Mitochondria / Q000187:drug effects* / Q000201:enzymology; D013385:Succinate Dehydrogenase / Q000187:drug effects*; D013778:Tetrazolium Salts; D013844:Thiazoles; D013997:Time Factors
chemical_list: D000697:Central Nervous System Stimulants; D004396:Coloring Agents; D013778:Tetrazolium Salts; D013844:Thiazoles; D002110:Caffeine; D013385:Succinate Dehydrogenase; D000469:Alkaline Phosphatase; C022616:thiazolyl blue