Evaluation of Antimicrobial Activity of Trachyspermum ammi (L.) Sprague Essential Oil and Its Active Constituent, Thymol, against Vaginal Pathogens

Vaginal infections are one of the major reasons women visit a gynecologist. Increased resistance to conventional antibiotics is one of the main factors mitigating the development of new antimicrobial agents, especially those of natural origin. In traditional Persian medicine, Trachyspermum ammi has been claimed to clear vagina from excessive discharge. Therefore, in this study, the antimicrobial activity of Ajwain essential oil was evaluated against some vaginal pathogens. The essential oil of ajwain was picked up and the minimum inhibitory and bactericidal concentrations (MIC and MBC) were revealed. The most frequently detected microorganisms involved in genital infections including Candida spp., Gardnerella vaginalis, Escherichia coli, Staphylococcus aureus, Streptococcus agalactiae and Lactobacillus acidophilus were considered. Evaluation of the essential oil of Trichomonas vaginalis was done by calculation of percent of growth inhibition. The essential oil showed a remarkable activity against the studied bacteria and fungi with MIC at a range of 0.0315 - 0.5 mg/ml and MBC at a range of 0.125 - 4 mg /ml. The highest inhibition and bactericidal activity was observed in S. agalactiae and G. vaginalis. 100% inhibition of T. vaginalis growth was shown at a concentration of 2000 μg/ml after 48 h by essential oil. The antimicrobial activity of the essential oil was more than that of thymol. Supposedly essential oil of Trachyspermum ammi fruit could inhibit vaginal pathogens growth. Further preclinical and clinical studies are required to confirm the efficacy of this natural agent in vaginitis.