Influence of Moringa (Moringa oleifera) leaf extracts on the antioxidant and angiotensin-1 converting enzyme inhibitory properties of lisinopril

Abstract

This study investigated the in vitro effect of various combinations of aqueous extracts of moringa (Moringa oleifera) leaves on the ACE inhibitory and antioxidant properties of lisinopril, which is a popular synthetic ACE inhibitor. Moringa leaves were air-dried and blended into powdery form. Thereafter, the aqueous extract was prepared and freeze-dried. The following sample mixtures were prepared: L = 100% lisinopril (1 mg/ml); M = 100% moringa extract (1 mg/ml); 1L + 3M = 25% lisinopril + 75% moringa extract; L + M = 50% lisinopril + 50% moringa extract; 3L + 1M = 75% lisinopril + 25% moringa extract. The results revealed that 100% moringa and the various combinations showed higher ACE inhibition than 100% lisinopril in both rat heart and lung homogenates. Furthermore, all the samples caused the inhibition of Fe2+-induced lipid peroxidation in rat heart and lung tissue homogenates, with moringa leaf extract having the highest inhibitory ability. All the samples also showed antioxidant properties (ferric reducing antioxidant property, 2,2’-azino-bis (-3-ethylbenzthiazoline-6-sulphonate [ABTS*] and 1,1-diphenyl-2-picrylhydrazyl [DPPH] free radicals scavenging abilities, and Fe2+ chelating ability). This study revealed that moringa leaf extracts could improve the antioxidant and ACE inhibitory properties of lisinopril. However, further in vivo experiments and clinical trials are recommended.