Mediterranean herb extracts inhibit microbial growth of representative oral microorganisms and biofilm formation of Streptococcus mutans

PLoS One. 2018 Dec 12;13(12):e0207574. doi: 10.1371/journal.pone.0207574. eCollection 2018.

Abstract

In light of the growing antibiotic resistance, the usage of plant-derived antimicrobial agents could serve as an effective alternative treatment against oral infections. The aim of this study was to investigate the antimicrobial and antibiofilm activity of Mediterranean herb extracts against representative oral microorganisms. The extraction procedures and the analysis of the obtained extracts were performed under established experimental conditions. The minimum inhibitory (MIC) and bactericidal (MBC) concentrations of the methanol extracts of Cistus creticus ssp. creticus, Cistus monspeliensis, Origanum vulgare, Rosmarinus officinalis, Salvia sclarea and Thymus longicaulis against eight typical oral bacteria and the fungus Candida albicans were determined. The antibiofilm activity against Streptococcus mutans was also quantified using the microtiter plate test. Overall, all tested extracts inhibited effectively the screened obligate anaerobic microorganisms and in concentrations ≥0.3 mg ml-1 had moderate to high antibiofilm activity comparable to that of chlorhexidine (CHX) against S. mutans. In particular, R. officinalis (MIC: 0.08-5.00 mg ml-1) and S. sclarea (MIC: 0.08-2.50 mg ml-1) showed the highest antibacterial activity, while Cistus spp., R. officinalis and S. sclarea significantly inhibited S. mutans biofilm formation at 0.60, 1.25 and 2.50 mg ml-1, respectively. Porphyromonas gingivalis and Parvimonas micra were high susceptible to O. vulgare (MIC = 0.30 mg ml-1), whereas T. longicaulis eradicated all oral bacteria (MBC: 0.15-2.50 mg ml-1). Nevertheless, C. albicans showed no sensitivity to the tested extracts. In conclusion, the tested plant extracts could serve as alternative natural antibacterial and antibiofilm components against oral infections.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Infective Agents / chemistry
  • Anti-Infective Agents / pharmacology*
  • Biofilms / drug effects*
  • Candida albicans / drug effects
  • Chromatography, High Pressure Liquid
  • Cistus / chemistry
  • Cistus / metabolism
  • Mass Spectrometry
  • Mediterranean Region
  • Microbial Sensitivity Tests
  • Phytochemicals / analysis
  • Phytochemicals / chemistry
  • Plant Components, Aerial / chemistry
  • Plant Components, Aerial / metabolism
  • Plant Extracts / chemistry
  • Plant Extracts / pharmacology*
  • Plants, Medicinal / chemistry*
  • Plants, Medicinal / metabolism
  • Rosmarinus / chemistry
  • Rosmarinus / metabolism
  • Streptococcus mutans / physiology

Substances

  • Anti-Infective Agents
  • Phytochemicals
  • Plant Extracts

Grants and funding

This study was supported in part by the German Research Foundation (DFG, AL 1179/2-1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. There was no additional external funding received for this study.