title: Sulfate conjugation of daphnetin by the human cytosolic sulfotransferases.
abstract: BACKGROUND
  In Turkey, daphnetin-containing Daphne oleoides is used as a folk medicine for treating rheumatic pain and lumbago. A daphnetin-containing traditional Chinese medicine tablet, named Zushima-Pian, is available in China for treating rheumatoid arthritis. The present study aimed to investigate the metabolism of daphnetin through sulfation in cultured human cells and to identify the human cytosolic sulfotransferase(s) (SULT(s)) that is(are) capable of mediating the sulfation of daphnetin.
  
  
  METHODS
  Cultured HepG2 human hepatoma cells and Caco-2 human colon carcinoma cells were labeled with [(35)S]sulfate in the presence of different concentrations of daphnetin. Thirteen known human SULTs, previously expressed and purified, as well as cytosols of human kidney, liver, lung, and small intestine, were examined for daphnetin-sulfating activity using an established sulfotransferase assay.
  
  
  RESULTS
  [(35)S]sulfated daphnetin was found to be generated and released by HepG2 cells and Caco-2 cells labeled with [(35)S] sulfate in the presence of daphnetin. Among the 13 known human SULTs, SULT1A1, SULT1A2, SULT1A3, SULT1B1, and SULT1C4 displayed significant sulfating activity toward daphnetin. Of the four human organ samples later tested, small intestine and liver cytosols displayed considerably higher daphnetin-sulfating activity than those of lung and kidney.
  
  
  CONCLUSIONS
  The results derived from the present study showed unequivocally that daphnetin could be sulfated in cultured human cells and by purified human SULT enzymes as well as human organ cytosols. The information obtained provided a basis for further studies on the metabolism of daphnetin through sulfation in vivo.
authors.affiliation: Department of Pharmacology, College of Pharmacy and Pharmaceutical Sciences, University of Toledo Health Science Campus, Toledo, OH 43614 USA.
authors.forename: Zhengyang
authors.initials: Z
authors.lastname: Han
authors.affiliation: Department of Pharmacology, College of Pharmacy and Pharmaceutical Sciences, University of Toledo Health Science Campus, Toledo, OH 43614 USA.
authors.forename: Yuecheng
authors.initials: Y
authors.lastname: Xi
authors.affiliation: Department of Pharmacology, College of Pharmacy and Pharmaceutical Sciences, University of Toledo Health Science Campus, Toledo, OH 43614 USA; School of Pharmacy, North Sichuan Medical College, Nanchong, Sichuan, China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Luo
authors.affiliation: Department of Pharmacology, College of Pharmacy and Pharmaceutical Sciences, University of Toledo Health Science Campus, Toledo, OH 43614 USA; School of Pharmacy, North Sichuan Medical College, Nanchong, Sichuan, China.
authors.forename: Chunyang
authors.initials: C
authors.lastname: Zhou
authors.affiliation: Department of Pharmacology, College of Pharmacy and Pharmaceutical Sciences, University of Toledo Health Science Campus, Toledo, OH 43614 USA; Department of Biochemistry and Applied Biosciences, University of Miyazaki, Miyazaki 889-2192, Japan.
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Kurogi
authors.affiliation: Department of Biochemistry and Applied Biosciences, University of Miyazaki, Miyazaki 889-2192, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Sakakibara
authors.affiliation: Department of Biochemistry and Applied Biosciences, University of Miyazaki, Miyazaki 889-2192, Japan.
authors.forename: Masahito
authors.initials: M
authors.lastname: Suiko
authors.affiliation: Department of Pharmacology, College of Pharmacy and Pharmaceutical Sciences, University of Toledo Health Science Campus, Toledo, OH 43614 USA. Electronic address: ming.liu@utoledo.edu.
authors.forename: Ming-Cheh
authors.initials: MC
authors.lastname: Liu
mesh_terms: D018938:Caco-2 Cells; D003593:Cytoplasm / Q000201:enzymology*; D004365:Drugs, Chinese Herbal / Q000378:metabolism*; D056945:Hep G2 Cells; D006801:Humans; D007421:Intestine, Small / Q000201:enzymology*; D007527:Isoenzymes; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology*; D008168:Lung / Q000201:enzymology; D050217:Metabolic Detoxication, Phase II; D009928:Organ Specificity; D011994:Recombinant Proteins / Q000378:metabolism; D013379:Substrate Specificity; D015238:Sulfotransferases / Q000378:metabolism*; D014468:Umbelliferones / Q000378:metabolism*
chemical_list: D004365:Drugs, Chinese Herbal; D007527:Isoenzymes; D011994:Recombinant Proteins; D014468:Umbelliferones; D015238:Sulfotransferases; C039952:daphnetin
keywords: Cytosolic sulfotransferase; Daphne papyracea; Daphnetin; SULT; Sulfation