ヒト赤血球の酸化的傷害に対するクエルセチンの保護効果に関する研究

抄録

Effects of quercetin on photo-induced lysis of human erythrocytes were examined using hematoporphyrin as a photosensitizer. Following results were obtained : 1. Photo-induced hemolysis was suppressed by quercetin : fifty percent inhibition of the hemolysis was observed at 35 μM quercetin. 2. Photo-induced hemolysis was partially suppressed by azide (1 mM) and stimulated by deuterium oxide (about 99%), suggesting the participation of singlet molecular oxygen in the hemolysis. 3. Quercetin suppressed the formation of conjugated dienes and thiobarbituric acid-reactive products which appeared during lipid peroxidation of erythrocytes and erythrocyte membranes. Post-illumination conjugated diene formation was also suppressed by the reagent. 4. Quercetin suppressed the increase of viscosity in erythrocyte membranes and the denaturation of membrane proteins by a photosensitized reaction. 5. During protection of the oxidative damages by quercetin, it was oxidized. The oxidation was stimulated by N-ethylmaleimide and suppressed by sodium ascorbate which did not affect photo-induced hemolysis. The oxidation of quercetin was also observed after cessation of illumination. These data suggest that quercetin can suppress the hemolysis by scavenging singlet molecular oxygen which may initiate lipid peroxidation and lipid radicals which will be formed from lipid peroxide. The quercetin oxidized during the protection of hemolysis seems to be regenerated by ascorbate. Thus quercetin may be able to function as a carrier of reducing equivalent of ascorbate into biomembrane just like as tocopheroles.