title: Some South African Rubiaceae Tree Leaf Extracts Have Antimycobacterial Activity Against Pathogenic and Non-pathogenic Mycobacterium Species.
abstract: Tuberculosis (TB) caused by Mycobacterium tuberculosis remains an ongoing threat to human health. Many plant species contain antimycobacterial compounds, which may serve as template molecules for new anti-TB drugs. The Rubiaceae family is the largest family of trees in southern Africa, and preliminary evidence revealed antimycobacterial activity in several species of the genus, motivating further studies. Leaf extracts of 15 tree species from the Rubiaceae family were screened for antimycobacterial activity against pathogenic M. tuberculosis and non-pathogenic Mycobacterium smegmatis, Mycobacterium aurum and Mycobacterium bovis BCG (Bacillus Calmette-Guérin) using a twofold serial microdilution assay. Cytotoxicity was determined using a tetrazolium-based colorimetric assay against C3A liver cells and Vero kidney cells. Minimum inhibitory concentration values as low as 0.04 mg/mL against M. smegmatis and M. tuberculosis were recorded. Activity against M. aurum was the best predictor of activity against pathogenic M. tuberculosis (correlation coefficient = 0.9). Bioautography indicated at least 40 different antimycobacterial compounds in the extracts. Cytotoxicity of the extracts varied, and Oxyanthus speciosus had the most promising selectivity index values.
authors: Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
authors: Abimbola O
authors: AO
authors: Aro
authors: Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.|Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon.
authors: Jean P
authors: JP
authors: Dzoyem
authors: Bacteriology Section, Agricultural Research Council-Onderstepoort Veterinary Institute, Private Bag X5, Onderstepoort, 0110, South Africa.
authors: Tiny M
authors: TM
authors: Hlokwe
authors: Bacteriology Section, Agricultural Research Council-Onderstepoort Veterinary Institute, Private Bag X5, Onderstepoort, 0110, South Africa.
authors: Evelyn
authors: E
authors: Madoroba
authors: Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
authors: Jacobus N
authors: JN
authors: Eloff
authors: Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
authors: Lyndy J
authors: LJ
authors: McGaw
mesh_terms: D000353:Africa, Southern; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002460:Cell Line; D002522:Chlorocebus aethiops; D006801:Humans; D008826:Microbial Sensitivity Tests; D009161:Mycobacterium / Q000187:drug effects*; D009163:Mycobacterium bovis / Q000187:drug effects; D020102:Mycobacterium smegmatis / Q000187:drug effects; D009169:Mycobacterium tuberculosis / Q000187:drug effects; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D019666:Rubiaceae / Q000737:chemistry*; D014197:Trees / Q000737:chemistry; D014709:Vero Cells
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts
keywords: Rubiaceae; antimycobacterial; cytotoxicity; selectivity; tuberculosis