title: Caffeic acid inhibits organic anion transporters OAT1 and OAT3 in rat kidney.
abstract: BACKGROUND
  Some food components influence drug elimination. Previously, we found that caffeic acid, present in coffee, fruits, and vegetables, strongly inhibited human homologs of organic anion transporters (OATs) OAT1 and OAT3, which are responsible for renal tubular secretion of anionic drugs. In this study, we examined the effect of caffeic acid on drug transport by OAT1 and OAT3 in the rat kidney.
  
  
  METHODS
  The inhibitory effect of caffeic acid on rat OAT1 and OAT3 was assessed by drug uptake experiment using Xenopus laevis oocytes. Urinary excretion of phenolsulfonphthalein (PSP), a diagnostic agent secreted by renal OATs, was examined in rats, and the influence of caffeic acid was evaluated.
  
  
  RESULTS
  Expression of rat OAT1 (rOAT1) and rOAT3 stimulated uptake of their typical substrates, p-aminohippurate and estrone sulfate, respectively, into oocytes, and caffeic acid inhibited them dose dependently. After intravenous injection of PSP in rats, 42.7% of the dose was excreted into urine up to 60 min, and the simultaneous administration of caffeic acid reduced it to 32.0%.
  
  
  CONCLUSIONS
  These findings show that caffeic acid inhibits OAT1 and OAT3 in the rat kidney.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Uwai
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kawasaki
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Nabekura
mesh_terms: D000818:Animals; D002109:Caffeic Acids / Q000494:pharmacology*; D032083:Citrus paradisi; D018076:DNA, Complementary / Q000235:genetics; D018565:Food-Drug Interactions; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D027362:Organic Anion Transport Protein 1 / Q000037:antagonists & inhibitors* / Q000235:genetics; D029362:Organic Anion Transporters, Sodium-Independent / Q000037:antagonists & inhibitors* / Q000235:genetics; D004364:Pharmaceutical Preparations / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014982:Xenopus laevis
chemical_list: D002109:Caffeic Acids; D018076:DNA, Complementary; D027362:Organic Anion Transport Protein 1; D029362:Organic Anion Transporters, Sodium-Independent; D004364:Pharmaceutical Preparations; C421043:Slc22a6 protein, rat; C114338:organic anion transport protein 3; C040048:caffeic acid