In vitro antimycoplasmal activity of Citrus bergamia essential oil and its major components

Forty-two strains of Mycoplasma hominis (including PG21), 2 strain of Mycoplasma fermentans (Pg18 and K7), 1 strain of Mycoplasma pneumoniae (strain m129) were investigated for their susceptibilities to Citrus bergamia essential oil and to its major components (limonene, linalyl acetate and linalool). C. bergamia essential oil inhibited mycoplasmas at concentrations from 0.5 to 1% (MIC value as % v/v). M. hominis showed MIC(50) values of 0.5% and MIC(90) values of 1%; M. pneumoniae showed a MIC value of 0.5% while M. fermentans strains were inhibited by MIC values of 1%. M. pneumoniae and M. hominis shared the same susceptibility to linalyl acetate, with MIC values of 0.015% (corresponding to MIC(50) and MIC(90) for M. hominis); M. fermentans strains were less susceptible with MIC values of 0.12%. Among the major components tested, linalool showed higher activity against M. pneumoniae and M. fermentans (MIC values of 0.015 and 0.06%, respectively) but was less active against M. hominis (MIC(50) and MIC(90) values of both 1%); limonene was active against M. pneumoniae (MIC value of 0.03%) but was less active against M. fermentans (MIC values of 1%) and M. hominis (both MIC(50) and MIC(90) values of ≥4%). The results indicated that C. bergamia essential oil and its major components had shown an interesting in vitro antimycoplasmal activity.