title: Antimycobacterial and cytotoxic activity of selected medicinal plant extracts.
abstract: BACKGROUND
  Tuberculosis (TB) caused by Mycobacterium tuberculosis remains an ongoing threat to human health. Several medicinal plants are used traditionally to treat tuberculosis in Ghana. The current study was designed to investigate the antimycobacterial activity and cytotoxicity of crude extracts from five selected medicinal plants.
  
  
  METHODS
  The microplate alamar blue assay (MABA) was used for antimycobacterial studies while the CellTiter 96® AQueous Assay, 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 were used to compare the activity of crude extracts against nonpathogenic strains and the pathogenic Mycobacterium tuberculosis subsp.tuberculosis.
  
  
  RESULTS
  Results of the MIC determinations indicated that all the crude extracts were active on all the three tested mycobacterial strains. Minimum inhibitory concentration values as low as 156.3µg/mL against M. tuberculosis; Strain H37Ra (ATCC® 25,177™) were recorded from the leaves of Solanum torvum Sw. (Solanaceae). Cytotoxicity of the extracts varied, and the leaves from S. torvum had the most promising selectivity index. Activity against M. tuberculosis; Strain H37Ra was the best predictor of activity against pathogenic Mycobacterium tuberculosis subsp.tuberculosis (correlation coefficient=0.8).
  
  
  CONCLUSIONS
  The overall results of the present study provide supportive data on the use of some medicinal plants for tuberculosis treatment. The leaves of Solanum torvum are a potential source of anti-TB natural products and deserve further investigations to develop novel anti-TB agents against sensitive and drug resistant strains of M. tuberculosis.
authors.affiliation: Department of Clinical Pathology, Noguchi Memorial Institute for Medical Research, University of Ghana, Ghana; Department of Public Health, Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Nairobi, Kenya.
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, 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, 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, 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, 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, Ghana.
authors.forename: Isaac
authors.initials: I
authors.lastname: Otchere
authors.affiliation: Department of Clinical Pathology, Noguchi Memorial Institute for Medical Research, University of Ghana, Ghana.
authors.forename: Abena
authors.initials: A
authors.lastname: Kissi-Twum
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects*; D006801:Humans; D019684:Magnoliopsida; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves; D010946:Plants, Medicinal
chemical_list: D000995:Antitubercular Agents; D010936:Plant Extracts
keywords: Alamar blue (PubChem CID: 11077); Antimycobacterial; Crude extracts; Cytotoxicity; Ethambutol (PubChem CID: 3279); Glycerol (PubChem CID: 753); Isoniazid (PubChem CID: 3767); MTS (PubChem CID: 4182497); Medicinal plants; Penicillin (PubChem CID: 5904); Rifampicin (PubChem CID: 5381226); Selectivity; Streptomycin (PubChem CID: 19649); Trypsin (PubChem CID: 23729580); Tuberculosis; Tween-80 (PubChem CID: 443315)