Antioxidant activity of carotenoid lutein <i>in vitro</i> and <i>in vivo</i>

Abstract

Carotenoid lutein was evaluated for its antioxidant potential both <i style="">in vitro</i> and <i style="">in vivo</i>. Lutein was found to scavenge superoxide radicals, hydroxyl radicals and inhibited <i style="">in vitro</i> lipid peroxidation. Concentrations needed for 50 % inhibition (IC₅₀) were 21, 1.75 and 2.2 <img src='/image/spc_char/micro.gif' border=0> g/mL respectively. It scavenged 2,2-diphenyl-1-picryl hydrazyl (IC₅₀ 35 <img src='/image/spc_char/micro.gif' border=0> g/mL) and nitric oxide radicals (IC₅₀3.8 <img src='/image/spc_char/micro.gif' border=0> g/mL) while 2,2-azobis-3-ethylbenzthiozoline-6-sulfonic acid radicals were inhibited at higher concentration. Ferric reducing power (50%) of lutein was found to be equal 0.3μmols/mL of FeSO₄.7H₂O. Its oral administration inhibited superoxide generation in macrophages <i style="">in vivo</i> by 34.18, 64.32 and 70.22 % at doses of 50, 100 and 250 mg/kg body weight. The oral administration of lutein in mice for 1 month significantly increased the activity of catalase, superoxide dismutase, glutathione reductase and glutathione in blood and liver while the activity of glutathione peroxidase and glutathione-S-transferase were found to be increased in the liver tissue. Implication of these results in terms of its role in reducing degenerative diseases is discussed.