In vitro activity of extracts and constituents of Pelagonium against rapidly growing mycobacteria.
Extracts of the roots of plants of the Geraniaceae family have been used for many years in South Africa as native herbal remedies and there is circumstantial evidence for efficacy in the treatment of pulmonary tuberculosis. We have examined dried roots of Pelargonium reniforme and P. sidoides for antibacterial activity against rapidly growing mycobacteria. Fractions with activity against Mycobacterium aurum and M. smegmatis were obtained from both plant species by bioassay-guided fractionation of n-hexane extracts and were found to contain mixtures of straight-chain fatty acids. Analysis by gas chromatography-mass spectrometry (GC-MS) of the corresponding fatty acid methyl esters revealed structures with chain lengths ranging from C12 to C26. Unsaturated compounds were analysed as the corresponding dimethyl disulfide adducts to determine double-bond positions. Active mixtures differed in the relative abundance of their components, but all contained 16:0 (palmitic), Delta9-18:1 (oleic) and Delta9,12-18:2 (linoleic acid) as the major components. When tested against M. aurum, M. smegmatis and other rapidly growing mycobacteria (M. fortuitum, M. abscessus and M. phlei), all saturated compounds except 12:0 were devoid of antimycobacterial activity, whereas unsaturated compounds showed antimycobacterial activity related to their degree of unsaturation, their chain length and the bacterial species tested. The most potent compound was linoleic acid, with MIC of 2 mg/l against M. aurum.
Seidel
Veronique
V
Microbiology Group, School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX, UK.
Taylor
Peter W
PW
D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D005227:Fatty Acids / Q000032:analysis / Q000737:chemistry; D005231:Fatty Acids, Unsaturated / Q000032:analysis / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D019787:Linoleic Acid / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D009161:Mycobacterium / Q000187:drug effects*; D019907:Mycobacterium fortuitum / Q000187:drug effects; D009168:Mycobacterium phlei / Q000187:drug effects; D020102:Mycobacterium smegmatis / Q000187:drug effects; D019301:Oleic Acid / Q000302:isolation & purification; D019308:Palmitic Acid / Q000302:isolation & purification; D031316:Pelargonium / Q000737:chemistry*; D010936:Plant Extracts / Q000302:isolation & purification* / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry
D000900:Anti-Bacterial Agents; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D010936:Plant Extracts; D019301:Oleic Acid; D019308:Palmitic Acid; D019787:Linoleic Acid