Radical scavenging and NO-releasing properties of selected beta-adrenoreceptor antagonists.

It is claimed that novel beta-adrenolytic drugs possess superior antioxidant properties as compared to classical selective or non-selective beta-adrenoceptor antagonists. Here we tested this notion by analyzing radical scavenging properties of selected beta-adrenolytic drugs and their ability to release nitric oxide in biological preparations. Selective beta1-adrenolytics such as nebivolol, atenolol, metoprolol and non-selective beta-adrenolytics with alpha1-receptor blocking properties such as carvedilol and labetalol were chosen for analysis. NO-releasing properties of nebivolol and carvedilol distinguished third generation beta-adrenolytics from their older counterparts while the reactivity towards hydroxyl and peroxyl radicals discerns only carvedilol but not nebivolol. Thus, superior clinical efficacy of third generation beta-adrenolytics may be related to their ability to release NO rather then to their direct antioxidant properties.