title: Formation scheme and antioxidant activity of a novel Maillard pigment, pyrrolothiazolate, formed from cysteine and glucose.
abstract: We recently identified 6-hydroxy-3[R],7a[S]-dimethyl-7-oxo-2,3-dihydropyrrolo[2,1-b]thiazole-3-calboxylic acid, a novel pyrrolothiazole derivative carrying a carboxy group and named pyrrolothiazolate, as a Mallard pigment formed from l-cysteine and d-glucose. Here we described the formation of its enantiomer, the plausible formation scheme of pyrrolothiazolate, and its antioxidant activity. When d-cysteine was used instead of l-cysteine in the reaction mixture, the enantiomer of pyrrolothiazolate was obtained. The carbon at position 1 of glucose was incorporated into two methyl groups of pyrrolothiazolate. The pigment was considered to be formed through 1-deoxyglucosone (1-DG). The dehydrated isomer of 1-DG would be condensed with the thiol and amino groups of cysteine. This condensate was dehydrated and cyclized to form pyrrolothiazolate. This compound was an antioxidant showing radical scavenging activity.
authors.affiliation: Department of Nutrition and Food Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo, 112-8610 Japan. murata.masatsune@ocha.ac.jp.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Noda
authors.forename: Naoko
authors.initials: N
authors.lastname: Terasawa
authors.forename: Masatsune
authors.initials: M
authors.lastname: Murata
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D003500:Cyclization; D003545:Cysteine / Q000737:chemistry*; D003847:Deoxyglucose / Q000737:chemistry; D005947:Glucose / Q000737:chemistry*; D017127:Glycation End Products, Advanced / Q000737:chemistry*; D007536:Isomerism; D011758:Pyrroles / Q000737:chemistry*; D013844:Thiazoles / Q000737:chemistry*
chemical_list: C000626410:6-hydroxy-3(R),7a(S)-dimethyl-7-oxo-2,3-dihydropyrrolo(2,1-b)thiazole-3-calboxylic acid; D000975:Antioxidants; D017127:Glycation End Products, Advanced; D011758:Pyrroles; D013844:Thiazoles; D003847:Deoxyglucose; D005947:Glucose; D003545:Cysteine