ISOLATION AND IDENTIFICATION OF ANTI-TUBERCULAR AGENTS FROM SOME SELECTED MEDICINAL PLANTS (Chrysophyllum albidum G. Don, Mezoneuron benthamianum Baill, Phyllanthus muellerianus Kuntze Exell and Acalypha fimbriata Schumach & Thonn)

Abstract

Tuberculosis is a contagious airborne infection that mostly affects the lungs and is caused by Mycobacterium tuberculosis. The medicinal plants screened for antibacterial activity were Alafia barterii, Bambusa vulgaris, Baphia nitida, Celastrus indica, Chasmanthera dependens, Chrysophyllum albidum, Clerodendrum volubile, Curcuma domestica, Emilia coccinea, Jatropha curcas, Mezoneuron benthamianum, Musa paradisiaca, Nauclea latifolia, Occimum gratissimum, Opuntia dillenii, Phyllanthus muellerianus, Senna alata, Sphenocentrum jollyanum, Tabernamontana pachsyfon, Tetrapleura tetraptera, Xylopia aethiopica and Zingiber officinale. Butanol, ethylacetate and hexane fractions from M. benthamianum exhibited MIC values 0.5 mg/ml, 1.25 mg/ml and 1.25 mg/ml respectively against M. tuberculosis (Mtb). Ethylacetate and hexane fractions from P. muellerianus had MIC values of 0.5 mg/ml and 1.25 mg/ml respectively against Mtb. Ethylacetate and hexane fractions from A. fimbriata showed MIC values 0.5 mg/ml and 2.5 mg/ml respectively while the MIC values of hexane fraction and hexane extracts of C. albidum are 0.5 mg/ml and 0.4 mg/ml respectively against Mtb. The four antitubercular medicinal plants are rich in phytochemicals. C. albidum had the lowest calculated IC50 for DPPH 0.913 mg/ml. C. albidum demonstrated stronger NO scavenging activity with IC50 of 117.819 μg/ml. A. fimbriata showed strongest Reducing Power potential with IC50 of 11.007 μg/ml. A. fimbriata also demonstrated the closest dose dependent chelation potential to the standard EDTA. C. albidum had the highest total antioxidant capacity. The antinutrient content of the plants are within WHO permissible limit. The three amino acids of high concentration are glutamic acid, aspartic acid and arginine. The GC-MS metabolic profiling of the active hexane fraction of M. benthamianum showed the presence of twenty three compounds which include vitamin E and gamma sitosterol. The GC-MS of derivatized component from active ethylacetate fraction showed a substituted tetrazole derivative while the IR spectroscopy revealed functional groups of carboxylic acids. The GC-MS metabolic profiling of the active hexane fraction of A. fimbriata revealed the presence of eighteen compounds which include antimycobacterium tuberculosis phytol and squalene. The IR analysis showed a flavonoid. The metabolic profiling of the active hexane fraction of P. muellerianus showed presence of fatty acids, esters and phytol. The metabolic profiling of the active hexane fraction of raw C. albidum cotyledonous seeds showed presence of fatty acid esters. The metabolic profiling of the active hexane extracts of roasted cotyledonous seeds of C. albidum at 50oC, 100 oC and 120 oC showed the presence of more compounds. The UV and IR analysis of a component of active hexane fraction of raw seeds showed presence of a glycosidic flavonoid. The antimycobacterium tuberculosis activities of the medicinal plants could be attributed to the synergistic effect of the identified bioactive compounds.