Ethanolic Extract of Origanum vulgare Suppresses Propionibacterium acnes-Induced Inflammatory Responses in Human Monocyte and Mouse Ear Edema Models

Molecules. 2018 Aug 9;23(8):1987. doi: 10.3390/molecules23081987.


Acne vulgaris (acne) is a common inflammatory skin disorder, and Propionibacterium acnes plays a major role in the development and progression of acne inflammation. Herbs possessing antimicrobial and anti-inflammatory activity have been applied as a medical option for centuries. In this study, we examined the suppressive effect of ethanolic oregano (Origanum vulgare) extract on live P. acnes-induced in vivo and in vitro inflammation. Following ethanol extraction of oregano leaves, four compounds with strong antioxidant activity, including rosmarinic acid, quercetin, apigenin, and carvacrol, were identified by high-performance liquid chromatography. Using the mouse ear edema model, we demonstrated that ethanol oregano extracts (EOE) significantly suppressed P. acnes-induced skin inflammation, as measured by ear thickness (32%) and biopsy weight (37%). In a separate study, using the co-culture of P. acnes and human THP-1 monocytes, EOE reduced the production of interleukin (IL)-8, IL-1β and tumor necrosis factor (TNF)-α up to 40%, 37%, and 18%, respectively, as well as the expression of these three pro-inflammatory mediators at the transcriptional level. Furthermore, EOE inhibited the translocation of nuclear factor-kappa B (NF-κB) into the nucleus possibly by inactivating toll-like receptor-2 (TLR2). The suppressive effect of EOE on live P. acnes-induced inflammatory responses could be due, in part, to the anti-inflammatory and antioxidant properties, but not the anti-microbial effect of EOE.

Keywords: NF-κB; Propionibacterium acnes; TLR2; anti-inflammatory; oregano.

MeSH terms

  • Animals
  • Cell Line
  • Chromatography, High Pressure Liquid
  • Cytokines / biosynthesis
  • Cytokines / genetics
  • Disease Models, Animal
  • Ear / pathology*
  • Edema / drug therapy*
  • Edema / microbiology
  • Edema / pathology
  • Ethanol / chemistry*
  • Humans
  • Inflammation / drug therapy*
  • Inflammation / microbiology
  • Inflammation / pathology
  • Male
  • Mice, Inbred ICR
  • Monocytes / drug effects
  • Monocytes / microbiology*
  • Monocytes / pathology
  • NF-kappa B / genetics
  • NF-kappa B / metabolism
  • Origanum / chemistry*
  • Phenols / analysis
  • Plant Extracts / pharmacology
  • Plant Extracts / therapeutic use*
  • Propionibacterium acnes / drug effects*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Toll-Like Receptor 2 / metabolism


  • Cytokines
  • NF-kappa B
  • Phenols
  • Plant Extracts
  • RNA, Messenger
  • Toll-Like Receptor 2
  • Ethanol