MODULATION OF LUMINOL-DEPENDENT CHEMILUMINESCENCE OF MURINE MACROPHAGES BY FLAVONE AND ITS SYNTHETIC DERIVATIVES

The effect of flavone (CAS 525-82-6, 2-phenylbenzopyran-4-one, 1), fla vone-8-acetic acid (CAS 87626-55-9, FAA, 2) and 10 substituted flavone s on the luminol-dependent chemiluminescence of murine macrophages was studied in vitro. The synthetic derivatives were variously substitute d with halo, nitro, amino, hydroxy and methoxy substituents in the 3' and 4' positions. Chemiluminescence was used in this study as an indic ator for the production of reactive oxygen species by macrophages, sti mulated in vitro by phorbol myristate acetate (PMA). All flavones exce pt FAA (2) showed more than 20% inhibition at 10 mu mol/l or 100 mu mo l/l. 3'-Amino-4'-hydroxyflavone (8) was the most potent inhibitor. The IC(50)s for inhibition of chemiluminescence were 4.2 +/- 1.1 mu mol/l , 5.0 +/- 1.0 mu mol/l and 3.3 +/- 1.4 mu mol/l for resident, elicited and LPS-Poly I:C-primed macrophages, respectively. Small but statisti cally significant enhancements of chemiluminescence were caused by low concentrations of flavone (1), FAA (2) and 4'-methoxyflavone (6). The se results suggest that modulation of the chemiluminescent capacity of macrophages depends on the nature of the substituents and the concent ration of the flavones.