Abstract

Background and Objective: Traditional and alternative medicine has been of immense help to developing countries as the source of therapy for many diseases. Recently many drugs are sourced from natural sources because of afford ability and ease of accessibility. This study was carried out to evaluate the in vitro ACE inhibitory activity and antioxidant potentials of aqueous extract of Combretum micranthum leaves and its fractions. Materials and Methods: Aqueous extract of Combretum micranthum leaves was subjected to chromatographic fractionation and the fractions obtained were assayed for in vitro inhibitory activity against rabbit ACE followed by their possible antioxidant potentials. Results: Aqueous extract of Combretum micranthum leaves produced 59.43±4% inhibitory activity comparable to captopril which produced 83.02±2.67% activity. The fractions A, B, C and D were able to inhibit the in vitro activity of rabbit ACE with the inhibitory percentages of 8.21±1.19, 97.69±8.57, 78.32±7.14 and 98.32±2.66%, respectively. The antioxidant potency of these fractions was evident in their free radical scavenging IC50, reducing power ability and total antioxidant capacity which all showed that fraction B may exhibit the highest antioxidant potency as compared to fractions C and D. The bioactive phytochemical constituents from the GC-MS analysis of fraction B of the aqueous extract of Combretum micranthum was found to be Megastigmatrienone, 3,5-Dimethoxy-4-hydroxyphenyl acetic acid and Estra-1,3,5(0)-trien-17β-ol. Conclusion: It was obvious from the findings that aqueous extract of Combretum micranthum has showed the tendency to inhibit the in vitro activity of ACE which could be attributed to its antioxidant activity demonstrated by the reduction power and the total antioxidant capacity of the various fractions.