Antioxidant, cytotoxic and antibacterial activity of Rosmarinus officinalis L. essential oil against bacteria isolated from urinary tract infection

Abstract

IntroductionUrinary tract infection (UTI) is a common infection in humans. The main disadvantage of antibiotic usage for UTI treatment is the emergence of antibiotic-resistant bacteria, which endanger antibiotic efficacy. The essential oil of some plants have antimicrobial activity without enhancing the antibiotic resistance. MethodsIn this study, Rosmarinus officinalis L. from Marivan (Kurdistan Province, Iran) was selected, and essential oil was prepared using a solvent-free microwave extraction method. The essential oil components were evaluated by Gas Chromatography-Mass Spectrometry. The agar diffusion and broth microdilution methods were used to investigate essential oil antibacterial effects against standard reference strains and clinical microbial strains isolated from UTI samples of Al-Zahra hospital in Najaf, Iraq. The antioxidant and cytotoxic activity of the oil was also examined by the β-carotene bleaching assay and brine shrimp lethality test, respectively. ResultsThe main components of the essential oil were 1,8-cineole (17.16 %) and α-pinene (16.95 %). The essential oil showed antibacterial activity against all the tested strains, with inhibition zones and minimum inhibitory concentrations (MIC) in the range of 7.00 ± 0.00–9.6 ± 0.32 mm and 0.06 ± 0.00 to 0.16 ± 0.07 mg/mL, respectively. The minimum bactericidal concentration (MBC) values were equal to MIC values. The greatest microbial inhibitory effect was against Staphylococcus aureus, Klebsiella pneumoniae, and Proteus vulgaris, respectively. Furthermore, the oil indicated good antioxidant capacity and high cytotoxicity. ConclusionThis study demonstrated that R. officinalis L. essential oil from Marivan has noteworthy antibacterial activity and can be useful for the treatment of UTI.