PROTECTIVE EFFECT OF NATURAL FLAVONOIDS ON RAT PERITONEAL-MACROPHAGESINJURY CAUSED BY ASBESTOS FIBERS

Exposure of macrophages to asbestos fibers resulted in enhancement of the production of oxygen radicals, determined by a lucigenin enhanced chemiluminescence (LEG) assay, a formation of thiobarbituric acid reac tive substances (TEARS), a LDH release into the incubation mixture, an d a rapid lysis of the cells. Rutin (Rut) and quercetin (Qr) were effe ctive in inhibiting LEG, TEARS formation, and reducing peritoneal macr ophages injury caused by asbestos. The concentrations of antioxidants that were required to prevent the injury of peritoneal macrophages cau sed by asbestos by 50% (IC50) were 90 mu M and 290 mu M for Qr and Rut , respectively. Both flavonoids were found to be oxidized during expos ure of peritoneal macrophages to asbestos and the oxidation was SOD se nsitive. The efficacy of flavonoids as antioxidant agents as well as s uperoxide ion scavengers was also evaluated using appropriate model sy stems, and both quercetin and rutin were found to be effective in scav enging O-2(.-). These findings indicate that flavonoids are able to pr event the respiratory burst in rat peritoneal macrophages exposed to a sbestos at the stage of activated oxygen species generation, mainly as superoxide scavengers. On the basis of this study it was concluded th at natural flavonoids quercetin and rutin would be promising drug cand idates for a prophylactic asbestos-induced disease.