3.3.5. Antibacterial Activity against *Cutibacterium Acnes*

The major causative microorganism involved in the progression of acne is *Cutibacterium acnes*. This study provides the first report of the extract of *S. perfoliata* against *C. acnes* (ATCC 6919). The ethanolic extract of this species exhibited an MIC of 500 μg/mL, while the positive control, tetracycline had an MIC of 0.78 μg/mL (Table 2). Extracts with an MIC less than 1000 μg/mL are regarded as active [54], which is reflected in the findings of the present study. Additionally, antibacterial activity of *S. perfoliata* has been reported from its essential oil, which inhibited the growth of *Staphylococcus epidermidis* with an MIC of 250 μg/mL, another microorganism involved in progression of acne [55,56]. Kirimer et al. [55] reported the major constituent of the *S. perfoliata* essential oil as limonene (37.70%) followed by sabinene (18.8%), while Ezer et al. [57] also identified limonene as the major constituent making up 22.40% of the EO composition. The essential oils of two Korean citrus varieties containing high quantities of limonene (81.63% and 83.38%), inhibited the growth of *C. acnes* (ATCC 6919) at concentrations of 0.31 μL/mL, as reported by Kim et al. [58]. However, the essential oil of *S. perfoliata* in the present study did not show high concentrations of limonene present as reported by Kirimer et al. [55] and this could be due to different localities, method used for oil preparation, growth stage of the plant and cultivation management.
