Antimicrobial Activity of <i>Peganum harmala</i> Against Methicillin-Resistant <i>Staphylococcus aureus</i> Strains and Assessment of Its Cytotoxicity Effect on HEK-293 Cells

Abstract

Background: Medicinal plants have been playing important roles in the treatment of different diseases. Peganum harmala is a famous medicinal plant used in the Iranian traditional medicine, due to the antimicrobial compounds found in its seeds and roots. Objectives: The main objective of the present study was to investigate the antibacterial activities of alcoholic extracts of P. harmala seeds on MRSA strains and cytotoxicity assessment of ethanolic extract of P. harmala seeds on HEK-293 cell line using MTT assay. Methods: During an 11-month descriptive cross-sectional study, 90 MRSA strains isolated from hospitalized patients in ICU wards were investigated. Micro-broth dilution method was employed to evaluate the antimicrobial effects of the extract on MRSA strains. HEK-293 cells were exposed to different concentrations of ethanolic extract of P. harmala and cytotoxicity was evaluated using MTT assay. Results: The minimum inhibitory concentration of P. harmala extract was observed in the range from 3.125 mg/ml to 25 mg/mL. The most antibacterial activity of the extract was found to be at 12.5 mg/ml concentration. MRSA strains were inhibited by P. harmala extract at MIC50 and MIC90 of 12.5 mg/mL and 25 mg/ml, respectively. MTT assay showed that the extract concentrations more than 0.5 mg/mL were toxic and caused more than 50% HEK-293 cell death. Conclusions: The results revealed that the P. harmala extract was very effective against MRSA strains isolated from ICU patients and may be useful to treat some of the infections although further investigation is recommended to assess their toxicity prior to in vivo use.