Journal of
Medicinal Plants Research

  • Abbreviation: J. Med. Plants Res.
  • Language: English
  • ISSN: 1996-0875
  • DOI: 10.5897/JMPR
  • Start Year: 2007
  • Published Articles: 3676

Full Length Research Paper

Antimicrobial activity of Thymus schimperi Ronninger (Lamiaceae) against standard and clinical isolates of human pathogenic bacteria

Abreham Bekele*
  • Abreham Bekele*
  • Department of Biotechnology, College of Natural and Computational Sciences, University of Gondar, Gondar, Ethiopia. 2Department of Biotechnology, College of Natural and Computational Sciences, Wolkite University, Ethiopia.
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Rahel Abera
  • Rahel Abera
  • Department of Biotechnology, College of Natural and Computational Sciences, University of Gondar, Gondar, Ethiopia.
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Taye Mebratu
  • Taye Mebratu
  • Department of Biotechnology, College of Natural and Computational Sciences, University of Gondar, Gondar, Ethiopia.
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Workabebe Dessie
  • Workabebe Dessie
  • Department of Biotechnology, College of Natural and Computational Sciences, University of Gondar, Gondar, Ethiopia.
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Awokech Getu
  • Awokech Getu
  • Department of Biotechnology, College of Natural and Computational Sciences, University of Gondar, Gondar, Ethiopia.
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Birtukan Getnet
  • Birtukan Getnet
  • Department of Biotechnology, College of Natural and Computational Sciences, University of Gondar, Gondar, Ethiopia.
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  •  Received: 08 February 2015
  •  Accepted: 12 March 2015
  •  Published: 17 March 2015

Abstract

Thymus schimperi Ronninger (Lamiaceae) locally known as Tosign, is a multipurpose endemic plant that has been used for various remedies as constituents of traditional medicine in Ethiopia. The objective of this study is to evaluate antibacterial activity of water, ethanol, methanol and chloroform extracts of T. schimperi using agar well diffusion and broth dilution methods against human pathogenic bacterial strains. Amongst the solvents used for this study, chloroform extract possess the highest potential of inhibiting the growth of all bacteria under study at concentrations of 50 mg/ml while ethanol and methanol extract fail to inhibit three gram negative bacteria, namely: Escherichia coli (ATCC 25922), Klebsiella pneumoniae (clinical isolate) and Shigella flexneri (ATCC 12022) at the same concentration. Water extract did not show any zone of inhibition on all test bacteria as compared to other solvents. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were performed only for chloroform extracts that showed inhibition against all test organisms. This study revealed that, the highest inhibition with chloroform extract was exhibited against Methicillin-Resistant S. aureus (MRSA)  with mean zones of inhibition of 22.6+2.5 mm whilst the minimum inhibition zone was observed for E. coli with mean zone of inhibition of 14.6+2.3 mm. The MIC value ranged from 6.25 to 12.5 mg/ml while the MBC value ranged from 6.25 mm to 25 mg/ml. This study clearly indicates that the crude chloroform extract of T. schimperi showed highest antibacterial activity against all studied bacterial strains as compared to the three solvents used in this study. Thus, further study and characterization of active compounds of chloroform extract of this plant is required.

 

Key words: Antibacterial activity, MBC, MIC, Thymus schimperi, Tosign, zone of inhibition.