Research: CONCENTRATION-EFFECT RELATIONSHIP FOR THE RADICAL SCAVENGING ACTIVITY OF TELMISARTAN IN NITRITE-INDUCED HEMOGLOBIN OXIDATION: In-vitro STUDY

Several free radical species are generated during the course of nitrite-induced oxidation of hemoglobin. Many chemical substances, including drugs with pleotropic activity demonstrate inherited radical scavenging activity. The present study was designed to evaluate the dose-effect relationship for the radical scavenging activity of the angiotensin receptor blocker telmisartan in models of nitrite-induced oxidation of hemoglobin (Hb) and formation of methemoglobin (MetHb) in hemolysate and intact erythrocytes. Blood samples were obtained from a healthy volunteer for preparation of hemolysate and erythrocytes suspension, and the effect of different concentrations of telmisartan on nitrite-induced oxidation of Hb and MetHb formation was monitored spectrophotometrically at 631 nm. Incubation of both intact erythrocytes and the lysate with different concentrations of telmisartan resulted in a concentration-dependent slowing in the rate of Hb oxidation, as predicted by the increment in the time required to form 50% MetHb. In conclusion, telmisartan protects against nitrite-induced methemoglobin formation in hemolysate and intact erythrocytes in a concentration-dependent manner.