title: In vitro antimycobacterial activity and toxicity of eight medicinal plants against pathogenic and nonpathogenic mycobacterial strains.
abstract: Tuberculosis (TB) caused by Mycobacterium tuberculosis remains a serious public health challenge towards which new hits are urgently needed. Medicinal plants remains a major source of new ligands against global infectious illnesses. In our laboratories, we are currently investigating locally used ethnobotanicals for novel compounds against zoonotic tuberculosis. The microplate alamar blue assay (MABA) was used to study the anti-TB activity while the CellTiter 96® AQueousAssay, which is composed of solutions of a novel tetrazolium compound [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt; MTS] and an electron coupling reagent (phenazine methosulfate) PMS, was used for cytotoxic studies. Correlation coefficients (R2) were used to compare the relationship between antimycobacterial activity of the eight crude extracts against nonpathogenic strains and the pathogenic Mycobacterium bovis. Minimum inhibitory concentration (MICs) values indicated that all the eight tested medicinal plant species had activity against all the three tested mycobacterial strains. Minimum inhibitory concentration value as low as 19.5µg/mL was observed against non-pathogenic strains M. bovis. Activity of the crude extracts against M. aurum was the best predictor of natural product activity against the pathogenic Mycobacterium bovis strain, with a correlation coefficient value (R2) of 0.1371. Results obtained from the current study validate, in part, the traditional utilization of the tested medicinal plants against tuberculosis. The unripe fruits from Solanum torvum are a potential source of safe and efficacious anti-TB crude drugs as well as a source for natural compounds that act as new anti-infection agents, and thus deserve further investigation towards development of a new class of molecules with activity against sensitive and drug resistant strains of M. bovis.
authors.affiliation: Department of Clinical Pathology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana; Department of Public Health, Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Nairobi, Nairobi, Kenya. Electronic address: joseph.nguta@uonbi.ac.ke.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Nguta
authors.affiliation: Department of Clinical Pathology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
authors.forename: Regina
authors.initials: R
authors.lastname: Appiah-Opong
authors.affiliation: Department of Clinical Pathology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
authors.forename: Alexander K
authors.initials: AK
authors.lastname: Nyarko
authors.affiliation: Department of Bacteriology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
authors.forename: Dorothy
authors.initials: D
authors.lastname: Yeboah-Manu
authors.affiliation: Department of Animal Experimentation, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
authors.forename: Phyllis G A
authors.initials: PG
authors.lastname: Addo
authors.affiliation: Department of Bacteriology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
authors.forename: Isaac Darko
authors.initials: ID
authors.lastname: Otchere
authors.affiliation: Department of Clinical Pathology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
authors.forename: Abena
authors.initials: A
authors.lastname: Kissi-Twum
keywords: Alamar blue (PubChem CID: 11077); Catalase (PubChem CID: 784); Crude extracts; EDTA (PubChem CID: 6049); Ethambutol (PubChem CID: 3279); Glycerol (PubChem CID: 753); Isoniazid (PubChem CID: 3767); L-glutamine (PubChem CID: 5961); MABA assay; MTS (PubChem CID: 4182497); MTS assay; Mycobacteria; Rifampicin (PubChem CID: 5381226); Selectivity index; Streptomycin (PubChem CID: 19649); Trypsin (PubChem CID: 23729580); Tuberculosis