Abstract

Acne vulgaris is a chronic inflammatory disorder in which Propionibacterium acnes plays a critical role in its development when it overgrows in the pilosebaceous unit.   The present study was conducted to evaluate the antimicrobial and anti-inflammatory activity of fourteen Mediterranean plant extracts separately and in combinations for the treatment of acne. The methanolic plant extracts were tested against P. acnes by determining the minimum inhibitory concentration (MIC). The extracts that showed high antimicrobial activity were studied for their anti-inflammatory effect. They were evaluated for their ability to suppress the pro-inflammatory cytokines IL-1β, IL-8, IL-12 and the TNF-α release from PBMCs and mTNF-α from mouse splenocytes using ELISA assay. Rosmarinus officinalis was found to exhibit the highest antimicrobial activity amongst all of the tested extracts (MIC 0.5 mg/ml) followed by Origanum syriacum (MIC 1 mg/ml) and Punica granatum (MIC 1.25 mg/ml). 100 and 50 μg/ml ofChrysanthemum coronarium, Origanum syriacum or Inula viscosa extracts showed the most effective inhibition for the cytokine release. Six extracts had shown both antimicrobial and anti-inflammatory activities with apparent dose-dependent responses making them potential agents for the treatment of acne. Two mixtures prepared from the plants with the highest antimicrobial activity had shown synergistic antimicrobial and anti-inflammatory effect.

Key words: Cytokines, minimal inhibitory concentration (MIC), enzyme-linked immunosorbent assay (ELISA), peripheral blood mononuclear cells (PBMCs), splenocytes, Propionibacterium acnes.