SUBSTITUTED 2-HYDROXY-1,2-DIHYDROPYRROL-3-ONES - FLUORESCENT MARKERS PERTAINING TO OXIDATIVE STRESS AND AGING

Previous observations that the aging process correlates with occurrenc e of certain fluorescent biological pigments have led to numerous effo rts in elucidating the chemical nature of the fluorophores generated t hrough reactions of primary amines and various products of lipid perox idation. In this study, model reactions of saturated aldehydes with al iphatic amines in the presence of peroxides were found to generate str ucturally unusual fluorescent compounds. Substitution of a lysine-cont aining peptide for simpler amines has also yielded similar fluorescenc e. The spectral excitation and emission maxima (around 360 and 430 nm, respectively) of these fluorophores match those widely reported in pe roxidized biological objects. The fluorescent compounds in our model s tudies have been chromatographically isolated and their structures det ermined through mass spectrometry, NMR spectrometry, and Fourier-trans form infrared spectroscopy. The spectrometric data indicate the fluore scent products to be alkylated 2-hydroxy-1,2-dihydropyrrol-3-ones, obt ained by the action of 1,a,4-triketone intermediates upon the primary amines. Independent syntheses of several 1,2,4-triketones were carried out. One such triketone reacted with hexylamine to form a fluorescent compound spectroscopically identical to the fluorescent reaction prod uct of hexanal, hydrogen peroxide, and hexylamine.