title: FT-IR Method for the Quantification of Isoflavonol Glycosides in Nutritional Supplements of Soy (Glycine max (L.) MERR.).
abstract: Due to increasing health consciousness, a lot of food supplements are sold and used. Dietary supplements of Glycine max (L.) MERR. are used as an alternative treatment for menopausal complaints such as hot flashes. Thereby, the effective soy compounds are the isoflavones daidzin, genistin, and glycitin. However, only the total soy extract content of the nutritional supplements is indicated. The aim of this study is to introduce a fast, efficient, and economic Fourier transformation infrared (FT-IR) spectroscopy method to quantify the active ingredients in the complex matrix of soy-based supplements. Five different nutritional supplements of Glycine max (L.) MERR. were purchased from a German pharmacy and were extracted with 80% aqueous methanol. A high-performance liquid chromatography (HPLC) method was used for the separation. The samples were concentrated and measured with infrared spectroscopy. An FT-IR method was established to quantify the active ingredients in the complex matrix of soy-based nutritional supplements. The partial least-squares algorithm was used to develop the method, which enabled the estimation of the content of particular isoflavones (daidzin R(2) = 0.86, glycitin R(2) = 0.94, genistin R(2) = 0.96) and the quantification of the total isoflavone content (R(2) = 0.92) despite peak overlap in the infrared (IR) spectra. The method for the quantification of the isoflavonol glycosides is precise with the standard error of prediction being 13.54%.
authors.affiliation: Institute of Pharmacy, Department of Pharmaceutical Biology, Freie Universitaet Berlin, Königin-Luise-Str. 2+4, 14195 Berlin, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Mulsow
authors.affiliation: Institute of Pharmacy, Department of Pharmaceutical Biology, Freie Universitaet Berlin, Königin-Luise-Str. 2+4, 14195 Berlin, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Eidenschink
authors.affiliation: Institute of Pharmacy, Department of Pharmaceutical Biology, Freie Universitaet Berlin, Königin-Luise-Str. 2+4, 14195 Berlin, Germany.
authors.forename: Matthias F
authors.initials: MF
authors.lastname: Melzig
keywords: Fourier Transformation Infrared; Glycine max (L.) MERR.; Isoflavones; Quantification
references.citation: Biol Pharm Bull. 2001 Apr;24(4):351-6
references.pmid: 11305594
references.citation: Environ Toxicol Pharmacol. 1999 Jul;7(3):201-7
references.pmid: 21781926
references.citation: Acta Pol Pharm. 2000 Mar-Apr;57(2):135-55
references.pmid: 10934794
references.citation: Endocr J. 2006 Feb;53(1):7-20
references.pmid: 16543667
references.citation: J Clin Endocrinol Metab. 2001 Nov;86(11):5217-21
references.pmid: 11701680