Evaluation of carvacrol and eugenol as prophylaxis and treatment of vaginal candidiasis in an immunosuppressed rat model

Objectives: Anticandidal activity of carvacrol and eugenol, the major phenolic components of oregano and clove essential oils, respectively, were tested in vivo. Methods: Efficacy evaluation of carvacrol and eugenol in the prophylaxis and treatment of experimental vaginal candidiasis was performed in immunosuppressed rats. The anticandidal activity was analysed by microbiological and histological techniques and was compared with that of nystatin. Results: Microbiologically, prophylactic treatment with carvacrol eradicated the vaginal fungal burden of infected rats, whereas eugenol reduced the number of colony counts of Candida albicans in vaginas of infected rats by 98.9% 10 days after inoculation. Therapeutic treatment for 7 consecutive days with carvacrol was able to eradicate the vaginal candidal burden in 7/9 of the infected rats and reduced the number of colony counts of C. albicans in vaginas of the two remaining rats by 98%. Treatment with eugenol completely cured 2/9 of the infected animals, but the 7/9 still infected showed an 84% reduction of colony counts of C. albicans in their vaginas. Histologically, in all treated rats, no Candida organisms were found in the lumina of the vagina; this was in contrast to control groups in which many yeasts, strongly stained with periodic acid-Schiff, were observed. The results obtained with nystatin used at 10-fold minimal inhibitory concentration confirm the validity of this model. Conclusions: Carvacrol and eugenol could be considered as promising products in the treatment of vaginal candidiasis. This work is a preliminary contribution to the development of a new generation of efficient and natural antifungal agents for curative treatment and prophylaxis.