title: Structure of a Precursor to the Blue Components Produced in the Blue Discoloration in Japanese Radish (Raphanus sativus) Roots.
abstract: The internal blue discoloration in Japanese radish (Raphanus sativus L.) roots has been reported to be a physiological phenomenon after harvest and poses a significant problem for farmers. To avoid this discoloration, the fundamental development of new radish cultivars that do not undergo discoloration and/or improved cultivation methods is required. Elucidating the chemical mechanism leading to this discoloration could help overcome these difficulties. To determine the mechanism underlying this discoloration, this study was designed to probe the structure of a precursor to the blue components generated during the discoloration process. Soaking fresh roots in aqueous H2O2 resulted in rapid blue discoloration, similar to the natural discoloration. Using a H2O2-based blue discoloration assay, the precursor was extracted and isolated from the fresh roots and identified as the glucosinolate, 4-hydroxyglucobrassicin, via spectroscopy and chemical synthesis.
authors.affiliation: Graduate School of Bioresources, Mie University , 1577 Kurimamachiya, Tsu, Mie 514-8507, Japan.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Teranishi
authors.affiliation: Food Research Institute, National Agriculture and Food Research Organization , 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan.
authors.forename: Nagata
authors.initials: N
authors.lastname: Masayasu
mesh_terms: D003116:Color; D005961:Glucosinolates / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000032:analysis; D007211:Indoles / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D007564:Japan; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010084:Oxidation-Reduction; D018517:Plant Roots / Q000737:chemistry* / Q000378:metabolism; D031224:Raphanus / Q000737:chemistry*
chemical_list: C428965:4-hydroxyindol-3-ylmethylglucosinolate; D005961:Glucosinolates; D007211:Indoles; D006861:Hydrogen Peroxide