Protection of protein carbonyl formation by quercetin in erythrocytes subjected to oxidative stress

Quercetin, 3,3’,4’,5,7-pentahydroxyflavone, is one of the most abundant naturally occurring polyphenolic compounds. Evidences suggest that quercetin has biological properties that may play an important role in prevention of human diseases, such as cancer, cardiovascular diseases, diabetes, and allergies. Many of the biological actions of this flavonoid have been attributed to its antioxidant properties. In the present study, we have determined the protection of protein carbonyl formation by quercetin in erythrocytes subjected to oxidative stress. In vitro oxidative stress in human erythrocytes was induced by incubating with 10⁻⁵ M tert-butylhydroperoxide. This resulted in a significantly increased level of carbonyl content in erythrocyte membrane. Treatment with quercetin caused a decrease in the carbonyl content. The effect of quercetin was concentration and time-dependent. The protection of carbonyl formation in proteins substantiates the strong biological antioxidant property of quercetin.