title: Evaluation of cost versus antioxidant determinants in green tea dietary supplements.
abstract: OBJECTIVE
  To investigate the association between cost and (a) chemical constituents and (b) antioxidant activity as quality determinants of select green tea supplements available in the United States.
  
  
  METHODS
  Laboratory analysis of green tea using HPLC and antioxidant assay methods.
  
  
  METHODS
  Correlation between selected quality parameters and daily cost based on the serving size as stated in the label. Quality was defined in terms of (a) catechin levels (validated high-performance liquid chromatography method), (b) total phenolic content (Folin-Ciocalteu method), and (c) antioxidant activity (total antioxidant capacity and diphenylpicryl hydrazyl free-radical scavenging).
  
  
  RESULTS
  A wide range of variation in marker levels and antioxidant activity was observed in the evaluated products. Catechin levels correlated well with the total phenolic content in each product while antioxidant activities were not as consistent when correlated with catechin/polyphenol levels. There was also a low correlation between product cost and quality.
  
  
  CONCLUSIONS
  Our results indicate that product cost does not always reflect quality, at least within the selected range of products. Thus, for a pharmacist to be able to recommend quality green tea dietary supplements, factors other than cost should be considered.
authors.forename: Cindy Leslie
authors.initials: CL
authors.lastname: A Roberson
authors.forename: Ehab A
authors.initials: EA
authors.lastname: Abourashed
authors.forename: Nancy
authors.initials: N
authors.lastname: Elsharkawy
mesh_terms: D000975:Antioxidants / Q000032:analysis* / Q000191:economics* / Q000592:standards; D002626:Chemistry, Pharmaceutical; D002851:Chromatography, High Pressure Liquid; D003362:Cost-Benefit Analysis; D019587:Dietary Supplements / Q000032:analysis* / Q000191:economics* / Q000592:standards; D004304:Dosage Forms; D016527:Drug Costs; D006801:Humans; D008517:Phytotherapy; D010936:Plant Extracts / Q000032:analysis* / Q000191:economics* / Q000592:standards; D010946:Plants, Medicinal; D011786:Quality Control; D019984:Quality Indicators, Health Care; D013662:Tea; D014481:United States
chemical_list: D000975:Antioxidants; D004304:Dosage Forms; D010936:Plant Extracts; D013662:Tea