title: Antibacterial activity of Tribulus terrestris and its synergistic effect with Capsella bursa-pastoris and Glycyrrhiza glabra against oral pathogens: an in-vitro study.
abstract: OBJECTIVE
  In this study, antimicrobial activities of an ethanol extract of Tribulus terrestris aloneand in combination with Capsella bursa-pastoris and Glycyrrhiza glabra were examined in vitro against six pathogens namely Streptococcus mutans, Streptococcus sanguis, Actinomyces viscosus, Enterococcus faecalis Staphylococcus aureus, and Escherichia coli.
  
  
  METHODS
  Antibacterial activities of the extracts were examined using disc and well diffusion methods and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ethanol extracts were determined against these microorganisms using agar and broth dilution methods. Chlorhexidine was used as positive control.
  
  
  RESULTS
  Tribulus terrestris extract exhibited good antibacterial activity against all bacteria. Antibacterial activity of mixed extract was evaluated and exhibited that mixed extract was more effective against all bacteria than any of the cases alone which indicates the synergistic effect between these three extracts (p˂0.05). No strain showed resistance against these extracts. In agar dilution, Tribulus terrestris exhibited MIC values ranging from 35.0 to 20.0 mg/ml and mixed extract showed MIC values ranging from 12.5 to 5.0 mg/ml. The results of broth dilution method were consistent with the findings of the agar dilution method.
  
  
  CONCLUSIONS
  This in-vitro study was a preliminary evaluation of antibacterial activity of the plants. It provided scientific evidence to support uses of T. terrestris and its mixture with C. bursa-pastoris and G. glabra for the treatment of oral infections. In-vivo studies are also required to better evaluate the effect of these extracts.
authors.affiliation: Antimicrobial resistance Research Center, School of medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Saman
authors.initials: S
authors.lastname: Soleimanpour
authors.affiliation: Department of Biology, Neyshabur Branch, Islamic Azad University, Neyshabur, Iran.
authors.forename: Fereshteh Sadat
authors.initials: FS
authors.lastname: Sedighinia
authors.affiliation: Department of Biology, Neyshabur Branch, Islamic Azad University, Neyshabur, Iran.
authors.forename: Akbar
authors.initials: A
authors.lastname: Safipour Afshar
authors.affiliation: Antimicrobial resistance Research Center, School of medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Zarif
authors.affiliation: Antimicrobial resistance Research Center, School of medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Kiarash
authors.initials: K
authors.lastname: Ghazvini
keywords: Antibacterial Activity; Capsella bursa-pastoris; Glycyrrhizaglabra; Oral Pathogens; Tribulusterrestris