title: Formation mechanism and characterization of dilysyl-dipyrrolones, the Maillard-type yellow pigments.
abstract: Our group has recently isolated and identified novel yellow compounds named dilysyl-dipyrrolones A (DPL A; 1) and B (DPL B; 2) in a heated aqueous solution containing xylose and lysine under weakly acidic conditions. In this study, we isolated and identified a novel DPL derivative (DPL C; 3), which has the same structure as DPL B, except for containing a hydroxymethyl group. To estimate the formation mechanism of DPL derivatives, (13)C-labeled DPLs were prepared and analyzed with LC/MS and NMR. (13)C-labeling experiments using [1-(13)C] ribose showed that the formation pathway of DPL C was different from those of DPLs A and B. In addition, (13)C-labeling experiments using [u-(13)C5] ribose and [1-(13)C] lysine showed that C-6 of a methine moiety in DPL C was derived from C-5 of ribose or acetic acid in buffer. Based on these results, we postulated the formation mechanism of DPLs. We then showed that DPLs A and B had potent antioxidant activities.
authors.affiliation: Institute of Environmental Science for Human Life, Ochanomizu University, Bunkyo-ku, Tokyo 112-8610, Japan. noumi.yuri@ocha.ac.jp
authors.forename: Yuri
authors.initials: Y
authors.lastname: Nomi
authors.forename: Ruriko
authors.initials: R
authors.lastname: Masuzaki
authors.forename: Naoko
authors.initials: N
authors.lastname: Terasawa
authors.forename: Makiko
authors.initials: M
authors.lastname: Takenaka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ono
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Otsuka
authors.forename: Masatsune
authors.initials: M
authors.lastname: Murata
mesh_terms: D000614:Aminocaproates / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D000975:Antioxidants / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D008239:Lysine / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015416:Maillard Reaction; D013058:Mass Spectrometry; D015394:Molecular Structure; D011758:Pyrroles / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D012266:Ribose / Q000737:chemistry; D014994:Xylose / Q000737:chemistry
chemical_list: C545999:6-((1-(5-amino-1-carboxypentyl)-3-hydroxypyrrol-2-yl)-2-methylidene-5-methyl-1,2H-pyrrol-3-one-1-ly)-2-aminohexanoic acid; C546000:6-((1-(5-amino-5-carboxypentyl)-3-hydroxy-pyrrol-2-yl)-2-methylidene-5-methyl-1,2H-pyrrol-3-one-1-yl)-2-amino-hexanoic acid; D000614:Aminocaproates; D000900:Anti-Bacterial Agents; D000975:Antioxidants; D011758:Pyrroles; D012266:Ribose; D014994:Xylose; D008239:Lysine