Extra-weak chemiluminescence of drugs. XI. Quenching effects of purine and pyrimidine derivatives on the extra-weak chemiluminescence derived from the Maillard reaction

Quenching effects of purine and pyrimidine derivatives on the extra-weak chemiluminescence (CL) derived from the Maillard reaction of L-lysine with D-arabinose were investigated. The pyrimidine derivatives 2'-deoxy cytidine, uridine, and uracil quenched the CL. Cytidine did not quench the CL. Purine derivatives, e.g. uric acid and 1-methyl adenosine were particularly effective in quenching the CL. 5-Methyl adenine and xanthine also quenched the CL, but adenosine had no effect. A comparison of the CL-quenching abilities of compounds that have common basic structure was made; those with ribose at the 5-position were the strongest quenchers. A linear relationship between CL-quenching activity and the HOMO energy of the pi orbital for the various compounds was shown.