Biological effects of essential oils and extracts
S. Moslemi; N. Kashef
Abstract
Bacterium Pseudomonas aeruginosa is an opportunistic human pathogen and one of the most important causes of nosocomial infections in a wide range of immunocompromised patients including those with malignancies, cystic fibrosis, and burns. This bacterium produces many virulence factors and is highly resistant ...
Read More
Bacterium Pseudomonas aeruginosa is an opportunistic human pathogen and one of the most important causes of nosocomial infections in a wide range of immunocompromised patients including those with malignancies, cystic fibrosis, and burns. This bacterium produces many virulence factors and is highly resistant to lots of common antibiotics due to its biofilm formation. The production of many virulence factors in this bacterium is under the control of quorum sensing systems (QS). The QS is an attractive target for the development of novel therapeutics. Eugenol is the major component of clove (Eugenia caryophylata) oil. The previous studies have shown its antibacterial activities. This study aimed to determine the in vitro anti-QS activity of eugenol on QS-regulatedbiofilm formation and virulence factors production in P. aeruginosa strains. The minimum inhibitory concentration (MIC) of eugenol was determined against two strains of this bacterium ATCC 27853 and PAO1, and three clinical isolates. Then the effect of eugenol on bacterial proliferation was determined by monitoring the growth curve. The biofilm formation, the production of exopolysaccharide (EPS), pyocyanins, rhamnolipids, the motility of swimming, swarming, and twitching were evaluated after the eugenol treatment. The MICs against two strains of the bacterium ATCC 27853 and PAO1 were obtained 0.3% and 0.6% (v/v), respectively. Different concentrations of eugenol (≤0.15%) significantly reduced the production of virulence factors including pyocyanin and rhamnolipid. The biofilm formation, EPS production, and swarming, swimming, and twitching motility were also reduced after the eugenol treatment. In general, according to the results of this study, the use of eugenol, as a potent QS inhibitor and anti-biofilm agent, could be an effective therapeutic strategy against P. aeruginosa infections.
N. Saidi; H. Saderi; E. Taghian; F. Sefidkon; I. Rasooli; R. Mohammad Salehi; P. Owlia
Abstract
Pseudomonas aeruginosa is one of the most common opportunistic bacteria in nosocomial infections, which has a significant resistance to antimicrobials. Due to the restrictions in the use of antibiotics, the tendency to replace them with natural products has increased. In this study, the antimicrobial ...
Read More
Pseudomonas aeruginosa is one of the most common opportunistic bacteria in nosocomial infections, which has a significant resistance to antimicrobials. Due to the restrictions in the use of antibiotics, the tendency to replace them with natural products has increased. In this study, the antimicrobial effect of four species of Satureja essential oils (S. mutica, S. bachtiarica, S. rechingeri and S. khuzestanica) on virulence factors of P. aeruginosa was evaluated. The minimum inhibitory concentration of Satureja essential oils was determined by microdilution broth method against standard strains of P. aeruginosa including PAO1 and 8821M. In the following, the effect of sub-minimum inhibitory concentrations (sub-MIC) of essential oils was investigated on virulence factors of this bacterium including motility, biofilm formation and alginate, elastase, and alkaline protease production of these two strains. All four Satureja essential oils had antimicrobial effects against the standard strains of P. aeruginosa, and also sub-MIC concentrations of the essential oils significantly reduced the virulence factors production of these strains. In this study, the suitable antagonistic effects of Satureja essential oils were observed against P. aeruginosa standard strains. By further study, these essential oils can be used as an antimicrobial compound against this bacterium.
