title: Effects of riboflavin photosensitization on daidzein and its photosensitized derivatives.
abstract: Photosensitized compounds from daidzein were studied in a riboflavin model system under visible light irradiation by high-performance liquid chromatography (HPLC). As the period of light irradiation increased, concentration of daidzein decreased significantly (P < 0.05) and new peaks of daidzein derivatives were observed and changed during photosensitization. Three new peaks from photosensitized daidzein were tentatively identified as 7-, 3', 4'-trihydroxyisoflavone (or 3'-hydroxydaidzein) and 2 dimmers of daidzein by a combination of HPLC-mass spectrometry (MS) and retention times of standard compounds by HPLC. Addition of sodium azide and removal of headspace oxygen treatment affected the formation of newly formed peaks. The type I pathway of riboflavin photosensitization played more important roles than type II pathways on the formation of daidzein derivatives. Practical Application: Isoflavones are important phytochemicals found in soy foods. Generally, many foods containing soy ingredients are displayed under visible light irradiation. Also, riboflavin can be found in many foods containing vegetables. The results of this study can be used to understand the stability and changes of isoflavone aglycones in soy and soy-based foods under visible light irradiation.
authors.affiliation: Dept. of Food Science and Technology, Ewha Womans Univ., Seoul 120-750, Korea.
authors.forename: ChanUk
authors.initials: C
authors.lastname: Park
authors.forename: JuDong
authors.initials: J
authors.lastname: Yeo
authors.forename: MinHee
authors.initials: M
authors.lastname: Park
authors.forename: Jin-Byung
authors.initials: JB
authors.lastname: Park
authors.forename: JaeHwan
authors.initials: J
authors.lastname: Lee
mesh_terms: D002851:Chromatography, High Pressure Liquid; D019281:Dimerization; D016166:Free Radical Scavengers / Q000737:chemistry; D007529:Isoflavones / Q000032:analysis / Q000737:chemistry* / Q000528:radiation effects*; D008027:Light; D008956:Models, Chemical; D009994:Osmolar Concentration; D010084:Oxidation-Reduction / Q000187:drug effects / Q000528:radiation effects; D010100:Oxygen / Q000737:chemistry; D017319:Photosensitizing Agents / Q000737:chemistry*; D012256:Riboflavin / Q000737:chemistry*; D026082:Singlet Oxygen / Q000037:antagonists & inhibitors; D019810:Sodium Azide / Q000737:chemistry; D045730:Soy Foods / Q000032:analysis / Q000528:radiation effects*; D021241:Spectrometry, Mass, Electrospray Ionization; D013997:Time Factors
chemical_list: C538958:3'-hydroxydaidzein; D016166:Free Radical Scavengers; D007529:Isoflavones; D017319:Photosensitizing Agents; D026082:Singlet Oxygen; C004742:daidzein; D019810:Sodium Azide; D010100:Oxygen; D012256:Riboflavin