Investigations on the Reaction of C3 and C6 α-Dicarbonyl Compounds with Hydroxytyrosol and Related Compounds under Competitive Conditions

alpha-Dicarbonyl compounds are interrriediates in reactions that lead to the formation of potentially harmful advanced glycation end-products. Carbonyl-trapping capacities of antiglycative substances have been traditionally limited to C2 and C3 alpha-dicarbonyl structures. Glyoxal (GO), methylglyoxal (MGO)-, 3-deoxyglucosone (3 DG), 3-deoxygalactosone (3-DGaI)-, 3,4-dideoxyglucoson-3-ene-, and ghicosone trapping capacities of hydroxytyrosol (HT), hydroxytyrosol acetate (HTA), and 3,4-dihydroxyphenylacetic acid (DOPAC) in simple (phenoliadicarborryl) and competitive model systems (phenolic/dicarbonyl(1)/dicarbonyl(2)) were investigated. HT and HTA were more effective for MGO than 3-DG and 3-DGal. Furthermore, DOPAC exerted higher trapping capacity than HT- and HTA for C3 and C6 alpha-dicarbonyl compounds. In the competitive systems, HT related substances did not show preference for trapping 3-DG Or 3-DGal and behaved-as in the simple. systems. In the presence of MGO, however, HT-related substances were more effective for trapping MGO than C6 structures. The results demonstrate the C6 alpha-dicarbonyl-trapping capacities of HT, HTA, and DOPAC, with DOPAC exerting the highest activity.