Phytochemicals, Antioxidant and Antimalarial Activities of <i>Combretum micranthum</i> G. Don. Leaves

Abstract

In Nigeria, the identification of novel compounds for the development of more effective and
safe treatments to fight malaria is urgently needed. Medicinal plants are one of the main
opportunities in the discovery of such new compounds. Combretum micranthum is a medicinal plant widely known and used in Africa to treat a variety ofconditions such as diabetes, fever, coughs, bronchitis, diarrhea, pain, malaria and liver disorders, among others. The study was aimed to evaluate the phytochemical, antioxidant, antimalarial and acute toxicity studies of Combretum micranthum leaves. Phytochemical and antimalarial evaluations were carried out using the standard methods. The antioxidant activities of the methanol extract was determined by means of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay. Alkaloid, flavonoids, saponins, tannins, glycosides, phenols, triterpenes and steroids while anthraquinones was absent in the Combretum micranthum leaf extract. The DPPH radical scavenging ability of the extract showed the following trend methanol extract Ascorbic acid. The inhibitory effects of Combretum micranthum leaves crude extract against P. falciparum at concentrations of 500, 250, 125, 62.5 and 31.25 mg/ml with percentage growth inhibitions of 88.8-66.6 %. The FTIR analysis showed the presence of alcohol, phenol, carboxylic acid, aldehyde and ketone functional groups. GCMS analysis revealed different compounds with antioxidant and antimalarial properties. The LD₅₀ of Combretum micranthum leaves was found to be greater than 5000 mg /kg and could be considered practically safe for consumption. The extract was found to possess constituents that may be associated with its antioxidant and antimalarial effects observed at doses tested.