Determination of in vitro Antimicrobial Activity of three Species of the genus Juniperus against Staphylococcus aureus ATCC 25923

Background and Objectives: With increasing resistance due to overuse of chemical antibiotics, it is necessary to find alternative drugs that have both antibacterial and minimal side effects for humans. Medicinal plants used in traditional medicine can be identified as potential candidates to combat against antibiotic-resistant bacteria. The main aim of the present study was to determine the potential antimicrobial effects of aqueous extract and essential oil of the genus Juniperus against Staphylococcus aureus ATCC 25923. Materials and Methods: The leaf of the three species of the genus Juniperus (excela, Sabina l, and communis l) were collected from the western mountains of Mazandaran province. The essential oil and aqueous extract were obtained by water distillation using Clevenger and Soxhlet extractor, respectively. Antibacterial activity of plant extracts was monitored using the agar diffusion method. Different concentrations of each positive plant extract were used to determine the minimum inhibitory concentration (MIC) using broth microdilution assay. Results: Aqueous extract and essential oil of the plants had significant antibacterial activity (the zone between 18-24 mm) against the studied strains on the Mueller-Hinton agar. The MIC values of aqueous extract of J. excela, J. Sabina l, and J. communis l was 15 mg/ml, 30 mg/ml and 30 mg/ml, respectively. On the other hand, the MIC values of essential oil of these extracts were 2 mg/ml, 0.5 mg/ml and 0.5 mg/ml against S. aureus ATCC 25923. Conclusion: It can be concluded that the aqueous extract of the plants had more antibacterial potential than essential oil. Overall, aqueous and essential oil of the studied species of the genus Juniperus exhibited significant in vitro antibacterial activity against S. aureus, and the active compounds of the plants can be potential sources for the synthesis of antibacterial drugs.