Protective effect of lutein against benzo(a)pyrene-induced oxidative stress in human erythrocytes.

The present study was carried out to evaluate the in vitro antioxidant properties and protective effect of lutein in human erythrocyte against benzo(a)pyrene (B(a)P). It is a well-known environmental carcinogen that produces free radicals under normal metabolic circumstances. B(a)P reacts with cellular macromolecules and produces oxidation of protein, lipid and DNA. Lutein is a carotenoid possessing antioxidant, anticarcinogenic and anti-inflammatory properties. In the present investigation, the protective effect of lutein was assessed in vitro against B(a)P-induced oxidative stress by monitoring antioxidant enzymes, lipid peroxidation (LPO), protein carbonyl content, total sulfhydryl (SH) and nonprotein SH groups and methemoglobin in five groups of erythrocytes that include (i) control group, (ii) vehicle control group, (iii) B(a)P-exposed group, (iv) lutein-exposed group and (v) B(a)P coincubation with lutein group. It was observed that the activities of antioxidant enzymes and SH groups were significantly decreased in B(a)P-treated group when compared with control group. LPO level and protein carbonyl and methemoglobin contents were increased in B(a)P-treated group when compared with control group. The erythrocyte that was coincubated with B(a)P and lutein showed significant increase in the  antioxidant enzyme activities and a significant reduction in the level of LPO, methemoglobin and protein carbonyl contents  when compared with B(a)P-treated group. The results of the present investigation suggest that lutein possess protective effect against B(a)P-induced oxidative stress, possibly by combating oxidative stress by its  free radical scavenging activity.