title: Simultaneous determination of all polyphenols in vegetables, fruits, and teas.
abstract: Polyphenols, which have beneficial effects on health and occur ubiquitously in plant foods, are extremely diverse. We developed a method for simultaneously determining all the polyphenols in foodstuffs, using HPLC and a photodiode array to construct a library comprising retention times, spectra of aglycons, and respective calibration curves for 100 standard chemicals. The food was homogenized in liquid nitrogen, lyophilized, extracted with 90% methanol, and subjected to HPLC without hydrolysis. The recovery was 68-92%, and the variation in reproducibility ranged between 1 and 9%. The HPLC eluted polyphenols with good resolution within 95 min in the following order: simple polyphenols, catechins, anthocyanins, glycosides of flavones, flavonols, isoflavones and flavanones, their aglycons, anthraquinones, chalcones, and theaflavins. All the polyphenols in 63 vegetables, fruits, and teas were then examined in terms of content and class. The present method offers accuracy by avoiding the decomposition of polyphenols during hydrolysis, the ability to determine aglycons separately from glycosides, and information on simple polyphenol levels simultaneously.
authors.affiliation: Department of Life Science, Graduate School of Science and Technology, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sakakibara
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Honda
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nakagawa
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ashida
authors.forename: Kazuki
authors.initials: K
authors.lastname: Kanazawa
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005419:Flavonoids / Q000032:analysis; D005612:Freeze Drying; D005638:Fruit / Q000737:chemistry*; D006868:Hydrolysis; D000432:Methanol; D010636:Phenols / Q000032:analysis*; D018515:Plant Leaves / Q000737:chemistry; D011108:Polymers / Q000032:analysis*; D015203:Reproducibility of Results; D013662:Tea / Q000737:chemistry*; D014675:Vegetables / Q000737:chemistry*
chemical_list: D005419:Flavonoids; D010636:Phenols; D011108:Polymers; D013662:Tea; D000432:Methanol