Preparation, characterization, and evaluation of the antimicrobial effects of farnesol- and tyrosol-bearing nanoniosomes on Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli

Recently, it has been found that tyrosol and farnesol can replace antibiotics due to their known antimicrobial and medicinal effects. Niosomes have been extensively researched for drug delivery during the last few decades, and their efficiency has been proven. The current study aimed to investigate the physical properties and antibacterial effects of niosomes loaded with tyrosol and farnesol.

Nanoniosomes loaded with farnesol and tyrosol were synthesized by the thin-layer hydration method. The physical properties of nanoformulations were measured using dynamic light scattering and scanning electron microscopy (SEM), and the release of farnesol and tyrosol from the nanocarrier was examined using a dialysis bag. In addition, Fourier-transform infrared spectroscopy was used to check the functional groups, and the stability studies of nanoniosomes were performed at temperatures of 25 °C and 4 °C for two months. Finally, its antimicrobial properties against the bacterial pathogens Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Pseudomonas aeruginosa (P. aeruginosa) underwent investigation. The cytotoxicity of free and farnesol- and tyrosol-loaded nanoniosomes on human foreskin fibroblast cells was also evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide method.

The size of nanoniosomes and farnesol- and tyrosol-loaded nanoniosomes was estimated to be 208 nm and 240 nm, respectively. SEM results indicated the spherical structure of niosomes. The slow release of farnesol and tyrosol from niosomes was observed, so that almost half of the drug was released from nanoniosomes after 72 hours. Nanoniosomes loaded with the above-mentioned drugs demonstrated good stability at 4 °C for 60 days. The results of the minimum inhibitory and bactericidal concentrations confirmed the antibacterial effects of both free farnesol and tyrosol and nanoniosomes loaded with farnesol and tyrosol against all three bacterial species, although these effects were more considerable for the nanoniosomes formulation.

Nanoniosomes loaded with farnesol and tyrosol have the potential to be used in the treatment of some common bacterial wound infections. However, clinical studies are needed in this field.

Farnesol- and tyrosol-loaded nanoniosomes had strong inhibitory effects on S. aureus, E. coli, and P. aeruginosa.