Abstract: Background: Phytochemicals such as anthocyanin are gaining great importance because of their contribution to human health as potent antioxidants with radical scavenging and cytoprotective effects. The present study was designed to evaluate the concentration-antioxidant relationship of anthocyanins using in vitro model of nitrite-induced hemoglobin oxidation. Methods: Blood samples were collected from healthy volunteers for the preparation of erythrocyte hemolysate. Different concentrations of anthocyanin (10-12-1.0 mg mL-1) were incubated concomitantly with 1 mL of sodium nitrite (final concentration 1 mM) and the formation of met-Hb was monitored spectrophotometerically at 631 nm each min for 35 min compared with sample without anthocyanin (control). Results: Nitrite-induced rapid oxidation of Hb to met-Hb in the absence of anthocyanins, while oxidation process was delayed in a concentration dependent manner in presence of different concentrations of anthocyanins according to the time required to induce 50% oxidation of Hb relative to control. Anthocyanin also has protective effect when added before, together and early after the addition of nitrite. Conclusion: In conclusion, anthocyanin protects hemoglobin against oxidative reaction induced by nitrite in time and concentration depended manner and such protection found to be extended over long period of time.