Anti-biofilm Potential of Nanonized Eugenol against Pseudomonas aeruginosa.

AIMS: The purpose of this study was to synthesize a nanoform of eugenol (an important phytochemical with various pharmacological potentials) and to investigate its anti-biofilm efficacy on Pseudomonas aeruginosa biofilm.

METHODS AND RESULTS: Colloidal suspension of eugenol-nanoparticles (ENPs) was synthesized by the simple ultrasonic cavitation method through emulsification of hydrophobic eugenol into hydrophilic gelatin. Thus, the nanonization process made water-insoluble eugenol into water-soluble nano-eugenol, making the nano-form bioavailable. The size of the ENPs was 20-30 nm, entrapment efficiency of eugenol within gelatin was 80% and release of eugenol from gelatin cap was slow and sustained over five-days. Concerning the clinically relevant pathogen Pseudomonas aeruginosa, ENP had higher anti-biofilm (for both formation and eradication) activities than free eugenol. Minimal biofilm inhibitory concentration and minimal biofilm eradication concentration of ENP on P. aeruginosa biofilm were 2.0 and 4.0 mM respectively. In addition, the measurement of P. aeruginosa biofilm biomass, biofilm thickness, amount of biofilm extra-polymeric substance, cell surface hydrophobicity, cell swarming and twitching efficiencies, cellular morphology and biofilm formation in catheter demonstrated that the anti-biofilm efficacy of nano-eugenol was 30-40% higher than that of bulk eugenol.

CONCLUSION: These results signify that future pharmacological and clinical studies are very much required to investigate whether ENP can act as an effective drug against P. aeruginosa biofilm-mediated diseases. Thus, the problem of intrinsic antibiotics-tolerance of biofilm-forming cells may be minimized by ENP. Moreover, ENP may be used as a potential catheter-coating agent to inhibit pseudomonal colonization on catheter surfaces and therefore, to reduce catheter-associated infections and complications.