title: Assessment of isoflavone aglycones variability in soy food supplements using a validated HPLC-UV method.
abstract: OBJECTIVE
  Soy supplements are often recommended in the management of menopause symptoms. The declared content of soy supplements is commonly expressed as total isoflavones per dosage form. Given that soy isoflavones have different estrogenic potencies, pharmacokinetics and metabolism, the aim of this study was to evaluate the total isoflavone content and the aglycone profile of seven soy supplements and one soy seed extract. Label accuracy was assessed, in relation to the precise content and the recommended posology for estimating whether the optimal dose is achieved for alleviating menopause symptoms.
  
  
  METHODS
  A high performance liquid chromatography method was developed for evaluating the aglycone content (genistein, daidzein, glycitein). After extraction and acidic hydrolysis, the aglycones were separated on a C18 column, using 0.1% acetic acid and acetonitrile as mobile phases. The flow rate was 1.5mL min(-1) and the UV detector wavelength was set at 260nm. A linear relationship was found in the range 5-80μg mL(-1). The method was validated using the accuracy profile methodology.
  
  
  RESULTS
  The total isoflavone content ranged from 6.07 to 41.68mg dosage form(-1). Various aglycone profiles were obtained for each supplement which can result in a different estrogenic activity, bioavailability and finally, in a different efficiency in alleviating menopause symptoms. In most clinical trials where soy isoflavones were evaluated, little attention was paid to determining the exact aglycone profile of the employed soy extracts.
  
  
  CONCLUSIONS
  As clinical outcomes continue to be controversial, this study highlights the need of standardization in genistein, rather than total isoflavones and labeling accuracy for soy supplements.
authors.affiliation: Department of Pharmaceutical Analysis, Faculty of Pharmacy, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania.
authors.forename: Alina
authors.initials: A
authors.lastname: Uifălean
authors.affiliation: Department of Mathematics and Computer Science, Faculty of Pharmacy, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania.
authors.forename: Anca
authors.initials: A
authors.lastname: Farcaş
authors.affiliation: Department of Pharmaceutical Analysis, Faculty of Pharmacy, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania.
authors.forename: Maria
authors.initials: M
authors.lastname: Ilieş
authors.affiliation: Department of Pharmaceutical Analysis, Faculty of Pharmacy, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania.
authors.forename: Simona Codruţa
authors.initials: SC
authors.lastname: Hegheş
authors.affiliation: Department of Pharmaceutical Biochemistry and Clinical Laboratory, Faculty of Pharmacy, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania.
authors.forename: Corina
authors.initials: C
authors.lastname: Ionescu
authors.affiliation: Department of Pharmaceutical Analysis, Faculty of Pharmacy, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania.
authors.forename: Cristina Adela
authors.initials: CA
authors.lastname: Iuga
keywords: HPLC; food supplement; genistein; isoflavones; standardization