In vitro antimycobacterial potential, acute toxicity and GC-MS analysis of Berlinia grandiflora (Vahl) Hutch. & Dalziel and Senna occidentalis (L.) link leaves extracts

Senna occidentalis and Berlinia grandiflora are medicinal plants used traditionally in managing infections of pneumonia, cough, tuberculosis, malaria, typhoid, asthma, gastrointestinal disorders, gonorrhea, hemorrhoids liver problems, labour pain during childbirth and as a purgative. This study aimed to determine the antituberculosis activity, acute oral toxicity, and Gas chromatography-mass spectrometry (GC-MS) analysis of the leaves extracts of these plants. 70 % hydro-ethanol extracts and fractions of these plants were tested for antituberculosis activity against clinical Mycobacterium tuberculosis isolate, Mycobacterium bovis (ATCC 27290), and Mycobacterium Smegmatis (ATCC 607). The standard checkerboard assay was utilized to investigate the synergistic effect of the most active fractions. Acute oral toxicity of the most active fractions were studied in mice. The bioactive components in the most active fractions were determined using GC-MS. S. occidentalis extract showed the lowest MIC (391 μg/mL) and MBC (781 μg/mL) against M. tuberculosis significantly at p < 0.05. The hexane fraction of S. occidentalis also showed the lowest MIC (156 μg/mL) and MBC (313 μg/mL) against M. tuberculosis significantly at p < 0.05. The combinatorial study of the n-hexane fractions of these plants against M. tuberculosis, M. bovis and M. smegmatis revealed a synergistic action of ΣFIC= 0.19, ΣFIC= 0.26, and ΣFIC= 0.38 respectively. The acute oral toxicity testing of the n-hexane fractions of these plants revealed no signs of toxicity throughout the observation period. GC-MS analysis of the n-hexane fraction of B. grandiflora revealed 40 components while the n-hexane fraction of S. occidentalis revealed 18 components. The synergistic effect of these two plants can serve as lead in drug development for the treatment of tuberculosis.