title: In vitro effects of rosmarinic acid on glutathione reductase and glucose 6-phosphate dehydrogenase.
abstract: BACKGROUND
  Glutathione reductase (GR, NADPH:oxidized glutathione oxidoreductase, E.C 1.6.4.2) is a flavoprotein that catalyzes the NADPH-dependent reduction of oxidized glutathione (GSSG). GR is a crucial enzyme in the antioxidant system by maintaining reduced glutathione (GSH). Glucose 6-phosphate dehydrogenase (G6PD, glucose 6-phosphate (G6P):NADP(+) oxidoreductase, EC 1.1.1.49) is the key regulatory enzyme of the pentose phosphate pathway and maintains NADPH for reductive reactions.
  
  
  OBJECTIVE
  Rosmarinic acid (RA; α-O-caffeoyl-3,4-dihydroxyphenyl lactic acid) is an ester of caffeic acid (CA) and 3,4-dihydroxyphenyllactic acid. It has a number of interesting biological activities. The inhibiting activities of the RA on GR and G6PD are investigated here for the first time.
  
  
  METHODS
  GR and G6PD were purified from tissues, then the effects of RA are investigated.
  
  
  RESULTS
  This study reports that RA, which was isolated from Echium vulgare L. (Boraginaceae), inhibits purified GR and G6PD in a concentration-dependent manner. Kinetic characterizations and inhibition constants are investigated.
  
  
  CONCLUSIONS
  Because of their importance in the antioxidative defense system, investigation of the inhibitors of these enzymes is important for drug development.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Hacettepe University, Sıhhiye/Ankara Turkey.
authors.forename: Berivan
authors.initials: B
authors.lastname: Tandogan
authors.forename: Ayşe
authors.initials: A
authors.lastname: Kuruüzüm-Uz
authors.forename: Cihangir
authors.initials: C
authors.lastname: Sengezer
authors.forename: Zuhal
authors.initials: Z
authors.lastname: Güvenalp
authors.forename: L Ömür
authors.initials: LÖ
authors.lastname: Demirezer
authors.forename: N Nuray
authors.initials: NN
authors.lastname: Ulusu
mesh_terms: D000818:Animals; D002417:Cattle; D002540:Cerebral Cortex / Q000187:drug effects / Q000201:enzymology; D002934:Cinnamates / Q000302:isolation & purification / Q000494:pharmacology*; D053630:Depsides / Q000302:isolation & purification / Q000494:pharmacology*; D036661:Echium / Q000737:chemistry; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005954:Glucosephosphate Dehydrogenase / Q000037:antagonists & inhibitors*; D005980:Glutathione Reductase / Q000037:antagonists & inhibitors*; D066298:In Vitro Techniques; D020128:Inhibitory Concentration 50; D007668:Kidney / Q000187:drug effects / Q000201:enzymology; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D012756:Sheep; D015003:Yeasts / Q000187:drug effects / Q000201:enzymology; D000097123:Rosmarinic Acid
chemical_list: D002934:Cinnamates; D053630:Depsides; D004791:Enzyme Inhibitors; D005954:Glucosephosphate Dehydrogenase; D005980:Glutathione Reductase; D000097123:Rosmarinic Acid