Anti-oxidant effect of quercetin on type 2 diabetic erythrocytes

There is much evidence that oxidative stress is involved in the etiology of several diabetic complications. Many in vitro and in vivo studies have demonstrated that several parameters of red blood cell function and integrity are negatively affected by increased oxidative stress. Quercetin (3,3', 4',5,7-pentahydroxyflavone) is one of the most abundant bioflavonoids commonly present in most edible fruits and vegetables. Quercetin has been reported to prevent oxidant damage and cell death by scavenging free radicals. The present study was undertaken to evaluate the antioxidant effect of quercetin on markers of oxidative stress in erythrocytes from type 2 diabetic patients. Quercetin (at micromolar concentration) shows significant antioxidant effect in protecting erythrocytes from tert-butylhydroperoxide induced oxidative changes. These results suggest that a diet rich in quercetin may provide protection to diabetic patients against some late complications. In recent years, there has been heightened interest in the possible therapeutic role of plant polyphenols for large number of human diseases. Among other known biological effects, plant polyphenols are known to have strong antioxidant properties. Out of more than 4,000 different types of plant polyphenols, relatively few are known to be effectively absorbed in the human digestive system. Among this group is the flavonoid quercetin that is present in many fruits and vegetables. We present here experimental proof of the protecting effect of this bioflavonoid on erythrocytes subjected to increased oxidative stress. Since diabetic patients are known to have increased oxidative stress, our results add to the scientific knowledge that a higher intake of diet rich in quercetin may protect diabetic patients from some late complications arising due to oxidative stress.