A comparison of the antioxidant activity with the Total Phenolic and Total Flavonoid Contents of the leaves and stem-bark of Anogeissus leiocarpa (DC.) Guill& Pirr. (Combretaceae)

Abstract

Background: Anogeissus leiocarpa is used in traditional medical practice for the treatment of many diseases such as asthma, malaria, diabetic ulcers, dysentery,  blood clots, cough, tuberculosis, parasitic infections and general body pain. Free radicals are known to play a major role in the aetiology of several these diseases. Thus, radical scavenging as well as antioxidant potentials of the plant are good indications of its effectiveness in disease management.
Objective: This study evaluates the antioxidant activity of the extracts from the leaves and stem bark of Anogeissus leiocarpa..
Materials and Methods: Dried powdered leaves and bark were extracted with  methanol. The extracts were subjected to DPPH Free Radical Scavenging Activity, Ferric Reducing Antioxidant Power (FRAP), Total Antioxidant Capacity (TAC), ABTS Cation Decolourization, Cupric Reducing Antioxidant Capacity (CUPRAC), and Metal Chelating (MC) assays. The Total Phenolic Content (TPC), Total Flavonoid Content (TFC), total anthocyanidin Content (tAC), and proanthocyanidin Content (pAC) were also determined.
Results: The extract and ethyl acetate fraction of the stem bark had more  antioxidant potential. The stem bark extract had an IC50 of 12.44+2.32 in the  DPPH radical scavenging assay, the ferric reducing antioxidant power of 98.43+1.63 and ABTS radical decolourisation activity of 96.55+0.54 while the DPPH radical scavenging activity and the ABTS radical decolourisation effect for ascorbic acid and trolox were 39.25+ 1.11 and 379.24 + 0.08 respectively. The Total Antioxidant Capacity as well as the Total Phenolic Content and Total Flavonoid Content was highest in the ethyl acetate fraction of the bark.
Conclusion: The extract of A. leiocarpa showed good antioxidant activity which  compares well with the high phenolic content and thus have potential for use in the management of several diseases.

Keywords: Anogeissus leiocarpa. Antioxidant, Radical Scavenging, Total Phenolic, Total Flavonoid