Antitubercular activities, antioxidant properties and GCMS fingerprinting of Acacia hebecladoides , Acacia albida and Gmelina arborea .

Abstract

Background : It is a practice to use traditional medicine for curing various illnesses in West Africa. Acacia hebecladoides , Acacia albida and Gmelina arborea were selected based on their traditional belief for treating various ailments such as: hallucinations, inflammation and tuberculosis. The study sought to validate the antitubercular activity, antioxidant properties and phytochemical components of extracts and fractions of the leaves of selected plants. Method: The antitubercular activities of the plants were evaluated against Mycobacterium tuberculosis (MTB), multidrug-resistant Mycobacterium tuberculosis (MDR-TB) and non-mycobacterium tuberculosis (NTM) using the Lowenstein Jensen (LJ) proportion method. Gas chromatography mass spectrometer (GCMS) assay and the antioxidant assays (1,1- diphenyl -2-picryhydrazyl (DPPH) radical assay, total phenolic content (TPC), β-carotene bleaching activity and nitric oxide scavenging activity) were all carried out. Results: All three plant extracts used in the study inhibited Mycobacterium tuberculosis with G. arborea showing the lowest MIC value of 31.25μg/ml. Also, G. arborea inhibited MDR-TB with an MIC value of 125μg/ml. The most active plant, G. arborea was fractionated into four partitions, three (aqueous, n-hexane and ethyl acetate) fractions showed inhibitory activity against MTB with an MIC value of 62.5μg/ml. Also n-hexane and chloroform fractions of G. arborea showed inhibitory activities against MDR-TB with the lowest MIC value of 31.25μg/ml. The nitric oxide activity of the plant fractions showed that ethyl acetate fraction of G. arborea had high nitric oxide antioxidant activity. The ethanolic extract A. hebecladoides and G. arborea , while fractions of G. arborea (aqueous, ethyl acetate and chloroform) showed DPPH scavenging activity. The ethanolic extract A. hebecladoides and A. albida , while aqueous fraction of G. arborea had high total phenolic content. The ethanolic extract G. arborea and its fractions (aqueous and n hexane) showed β-carotene bleaching inhibition. Twelve compounds were found in the n-hexane fraction of G. arborea as 2,3-dihydro-3,5,-6-methy 4H-Pyran-4-one and 5-hydroxymethylfurfural were abundant with 35.81% and 19.03% respectively, followed by 3,5-dihydroxy-2-methy-4H-Pyran-4-one (9.82%) and n-Hexadecanoic acid (8.45%). Conclusions: The study carried out showed that ethanolic extract and fractions of G. arborea possess inhibitory activities against MTB and MDR-TB. Also ethyl acetate and aqueous fractions of G. arborea showed high antioxidant activities.