African Journal of
Pharmacy and Pharmacology

  • Abbreviation: Afr. J. Pharm. Pharmacol.
  • Language: English
  • ISSN: 1996-0816
  • DOI: 10.5897/AJPP
  • Start Year: 2007
  • Published Articles: 2084

Full Length Research Paper

Antibacterial activity of crude extracts and pure compounds isolated from Vernonia galamensis leaves

Geremew Tafesse
  • Geremew Tafesse
  • College of Natural and Computational Sciences, Dilla University, Dilla, Ethiopia.
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Yalemtsehay Mekonnen
  • Yalemtsehay Mekonnen
  • Colleges of Natural Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
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Eyasu Makonnen
  • Eyasu Makonnen
  • Colleges of Natural Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
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Runner R. T. Majinda
  • Runner R. T. Majinda
  • Faculty of Natural Sciences, University of Botswana, Gaborone, Botswana.
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Gomotsang Bojase-Moleta
  • Gomotsang Bojase-Moleta
  • Faculty of Natural Sciences, University of Botswana, Gaborone, Botswana.
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Samuel O. Yeboah
  • Samuel O. Yeboah
  • Faculty of Natural Sciences, University of Botswana, Gaborone, Botswana.
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  •  Received: 11 January 2018
  •  Accepted: 05 February 2018
  •  Published: 22 March 2018

Abstract

The aim of this study was to test the antibacterial property of the extract of the leaves and isolated compounds of Vernonia galamensis that is traditionally claimed to have diverse medicinal use. The disk diffusion method was used to test the successively extracted dried leaves of V. galamensis on Staphylococcus aureus, Escherichia coli, Salmonella typhi and Shigella boydii. Further fractionation of the acetone extract by a combination of column chromatography, gel filtration using Sephadex LH-20 and Prep-TLC afforded two compounds. The results showed that Vernonia Acetone Extract (VAE) of the leaves of V. galamensis showed weak to moderate antibacterial growth inhibition on the test bacteria. Two active compounds; C-I (vernolide) and C-II (vernonioside) were isolated that were not reported from V. galamensis before. C-I (0.6 mg/disc) showed antibacterial activity on all bacteria except E. coli with minimum inhibitory concentration (MIC) value of 2.5 mg/mL and C-II (0.48 mg/disk) showed growth inhibition only against S. boydii and S. typhi with MIC value of 1 mg/mL. In conclusion, V. galamensis leaves have been proved to possess antibacterial chemicals. The plant can possibly be exploited as a source of lead compounds for antibacterial drug development. 
 
Key words: Antibacterial, Vernonia galamensis, Staphylococcus aureus, Escherichia coli, Salmonella typhi, Shigella boydii, vernolide, vernonioside.