title: Cleavage of α-dicarbonyl compounds by terpene hydroperoxide.
abstract: The highly reactive α-dicarbonyl compounds, glyoxal, methylglyoxal (MGO), and 3-deoxyglucosone, react with the amino groups of proteins to form advanced glycation end-products (AGEs) which have been implicated in diabetic complications, aging, and Alzheimer's disease. We found that a test sample of terpinen-4-ol (T4) containing hydroperoxides showed cleaving activity toward an α-dicarbonyl compound, but that the freshly isolated pure sample did not. Prepared terpinen-4-ol hydroperoxide (T4-H) also efficiently cleaved the C-C bond of the α-dicarbonyl compounds via Baeyer-Villiger-like rearrangement and subsequent hydrolysis of an acid anhydride moiety in the rearranged product to give carboxylic acids. Other terpene hydroperoxides, as well as T4-H, showed significant cleaving activities, and all these hydroperoxides protected RNase A from the lowering of enzyme activity induced by MGO. The cleaving mechanism via Baeyer-Villiger-like rearrangement was confirmed by time-interval NMR measurements of the reaction mixture of the symmetrical α-dicarbonyl compound, diacetyl with T4-H.
authors.affiliation: Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, Japan.
authors.forename: Ryu-ichiro
authors.initials: R
authors.lastname: Nagamatsu
authors.forename: Shinya
authors.initials: S
authors.lastname: Mitsuhashi
authors.forename: Kengo
authors.initials: K
authors.lastname: Shigetomi
authors.forename: Makoto
authors.initials: M
authors.lastname: Ubukata
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry* / Q000378:metabolism; D008610:Menthol / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism
chemical_list: C534301:4-methyl-1-(1-methylethyl)-3-cyclohexen-1-ol; D002264:Carboxylic Acids; D007659:Ketones; D008610:Menthol; D006861:Hydrogen Peroxide