Abstract

  Methanolic extracts of six plants (Arbutus andrachne, Chrysanthemum coronarium, Inula viscosa, Origanum syriacum, Punica granatum, and Rosmarinus officinalis) used in traditional medicine for the treatment of bacterial and fungal infections were evaluated. The present  study  was  conducted  to  evaluate  the  antimicrobial  and  anti-inflammatory  activity  of  some  medicinal  plants  in  lowering  the  risk  of opportunistic infections of the oral cavity caused by Staphylococcus aureus, Pseudomonas aeruginosa, and Candidaalbicans. Extracts were evaluated separately and in a mixture. Methodology: The methanolic plant extracts were tested against three opportunistic microorganisms by determining the minimum inhibitory concentration (MIC).  They  were  also  evaluated  for  their  ability  to  suppress  the  release  of  the  pro-inflammatory  cytokine  IL-6  while  not suppressing the release of the anti-inflammatory cytokine IL-10 from peripheral blood mononuclear cells using ELISA. Results: All extracts showed both antimicrobial and anti-inflammatory activities. However, O. syriacumexhibited the highest antimicrobial activity for the three microorganisms among all of the tested extracts (MIC S. aureus: 1 mg/mL; P. aeruginosa: 2 mg/mL; and C. albicans: 1 mg/mL).  The  extracts  inhibited  the  expression  of  the  pro-inflammatory  cytokine  IL-6  with  apparent  dose-dependent  responses  while  they attenuated the secretion of the anti-inflammatory cytokine IL-10. The mixture of O. syriacumand R.  officinalis showed an anti-inflammatory effect, with a synergistic antimicrobial effect.