Effect of essential oils from , and on and role of its symbionts and Mycoplasma girerdii.

Introduction: Trichomoniasis, the most common non-viral sexually transmitted disease, is caused by the protozoon . can establish a symbiosis with two bacteria, and Mycoplasma girerdii, whose intracellular presence may modulate several characteristics of the protozoan, including its sensitivity to 5-nitroimidazoles, the only class of drugs currently effective in treating trichomoniasis. The rising prevalence of strains resistant to metronidazole, the most commonly used antitrichomonal drug, underscores the need for therapeutic alternatives active against the protozoon.

Methods: In this study, we evaluate the antimicrobial activity of essential oils extracted from three plants cultivated in Vietnam - , , and - against thirty strains isolated from symptomatic women in Italy and Vietnam. We also assess the influence of and . M. girerdii on susceptibility to essential oils and metronidazole, through dedicated susceptibility assays. Additionally, given the importance of lactobacilli in maintaining vaginal health, we investigate the effects of the essential oils on and . The cytotoxic activity of the oils against HeLa cells was also tested .

Results: All three essential oils showed effective antitrichomonal activity without inhibiting lactobacilli growth. Among them, oil exhibited the strongest inhibitory effect on , including strains harboring bacterial symbionts. Moreover, the oils demonstrated no cytotoxic activity against HeLa cells at the concentrations effective against the protozoan.

Discussion: The results support the potential of essential oil as a natural antitrichomonal agent. Its effectiveness against both free and symbiont-infected strains positions it as a promising candidate for developing alternative therapies against drug-resistant trichomoniasis.