Crosslines A and B as candidates for the fluorophores in age- and diabetes-related cross-linked proteins, and their diacetates produced by Maillard reaction of α-N-acetyl-L-lysine with D-glucose

A pair of novel fluorophores (N-diacetates of crosslines A and B), (3R,4S)-3,4-dihydroxy-5-[(1S or 1R,2S,3R)-1,2,3,4-tetrahydroxybutyl]-1,7-bis[6-(N-acetyl-L-norleucyl)]-1,2,3,4-tetrahydro-1,7-naphthyridinium chloride and its epimer, were isolated from the Maillard reaction mixture of α-N-acetyl-L-lysine and D-glucose, and their properties are similar to those of fluorophores in age- and diabetes-related cross-linked proteins, and a pair of homologues derived from n-pentylamine.