In vitro investigation of antibacterial properties of Citrus medica essential oil against some human pathogenic bacteria

The medicinal plants are used in treatment of diseases caused by the human pathogenic bacteria due to their antimicrobial compounds. The aim of this study was to investigate antibacterial and antioxidant activity of Citrus medica essential oil on some human pathogenic bacteria.

The plant samples of Citrus medica were collected from North of Iran. Samples were transferred to the biotechnology laboratory, Bu Ali Sina University, Hamadan. The essential oil was extracted by Clevenger device. Antibacterial activity and minimum inhibitory  concentration (MIC) and minimum bactericidal concentration (MBC) were determined by agar well diffusion and by micro dilution broth methods, respectively. Antiradical activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl assay (DPPH).

The highest and lowest inhibitory activity of essential oil was observed on Bacillus cereus and Escherichia coli, respectively. Leaf essential oil showed the highest IC50 value than the skin essential oil. The essential oil of Citrus medica skin showed more inhibitory effect than the leaf essential oil. The MIC of leaf essential oil on B. subtilis, B. cereus and E. aerogenes and the MBC on B. cereus were found to be 3.12 mg ml-1. The MIC of skin essential oil on M. luteus was 1.56 mg ml-1 and the MBC on M. luteus and S. aureus was 3.12 mg ml-1.

 The results confirmed the efficacy of C. medica essential oil as natural antimicrobial and suggested the possibility of employing it in drugs for the treatment of diseases caused by the test organisms.