Chemical composition, toxicological aspects and antifungal activity of essential oil from Lippia sidoides Cham

Objectives The aims of this study were to test the essential oil from Lippia sidoides Cham. for antifungal activity, in vitro, against Candida spp. and Microsporum canis, to evaluate its acute and subchronic toxicological effects, in vivo, and to determine its chemical constituents. Methods The antifungal activity, in vitro, was initially evaluated by the agar-well diffusion technique, and the MIC and minimum fungicidal concentration (MFC) were determined by the broth microdilution method. The acute and subchronic toxicological effects were determined in mice and rats, respectively. The chemical composition of the essential oil was determined by gas chromatography coupled to mass spectroscopy. Results The essential oil obtained from L. sidoides was effective against all tested strains by the agar-well diffusion method. The MICs of L. sidoides essential oil for strains of M. canis ranged from 4 to 70 mg/L and the MFCs ranged from 9 to 150 mg/L. The MICs for strains of Candida spp. ranged from 620 to 2500 mg/L and the MFCs ranged from 1250 to 5000 mg/L. The main constituents of L. sidoides essential oil were thymol (59.65%), E-caryophyllene (10.60%) and p-cymene (9.08%). The acute administration of the essential oil up to 3 g/kg by the oral route to mice was devoid of overt toxicity. The 30 day oral administration of L. sidoides oil (117.95 mg/kg/day) to rats did not induce any significant histopathological, haematological or serum biochemical alterations. Conclusions The essential oil from L. sidoides may be a promising source in the search for new antifungal drugs due to its efficacy and low toxicity.