Human erythrocytes were subjected to induced oxidative damage and the following biomarkers of oxidative stress were monitored: lipid peroxidation [induced by tert-butyl hydroperoxide (tBHP) or by 2,2鈥?azobis (2-methylpropionamidine) dihydrochloride (AAPH)] and AAPH-induced oxidation of hemoglobin and depletion of glutathione.
When tBHP was used to induce lipid peroxidation, lycopene was the most efficient carotenoid (IC50 = 2.2 卤 0.4 渭M), while lutein was the most efficient (IC50 = 2.5 卤 0.7 渭M) when peroxyl radicals (ROO) were generated by AAPH. In relation to the hemoglobin oxidation induced by AAPH, 尾-carotene and zeaxanthin were the most efficient antioxidants (IC50 = 2.9 卤 0.3 渭M and 2.9 卤 0.1 渭M, respectively). Surprisingly 尾-cryptoxanthin and lycopene did not inhibit hemoglobin oxidation or lipid peroxidation when induced by AAPH, even at the highest tested concentration (3 渭M). Additionally, the tested carotenoids did not prevent ROO-mediated GSH depletion and GSSG formation probably due to the lack of interaction between carotenoids (apolar) and glutathione (polar).
Our study contributes with important insights that carotenoids may exert therapeutical potential to act as a natural antioxidant to prevent ROO-induced toxicity in human erythrocytes.