Anti-virulence potential of basil and sage essential oils: Inhibition of biofilm formation, motility and pyocyanin production of Pseudomonas aeruginosa isolates

The effects of basil (Ocimum basilicum) and sage (Salvia officinalis) essential oils on selected virulence factors (biofilm formation, mature biofilm resistance, motility, and pyocyanin production) of Pseudomonas aeruginosa clinical isolates were evaluated in the present study for the first time. The two essential oils were chemically characterized by GC and GC-MS analyses. Linalool and (E)-anethole were found to be the main components of the investigated basil oil, while a-thujone and camphor were the major constituents of the studied sage essential oil. The oils inhibited biofilm formation up to 99.9% vs control, and significant reductions (74.7-99.9%) were also noted when the oils were applied to mature biofilms. Likewise, swimming, swarming, and twitching motility patterns were highly affected by both oils. The basil and sage oils reduced pyocyanin production by 13.32-55.6% and 5.0-58.7%, respectively. Thus, basil and sage essential oils are potentially highly efficient antipseudomonal agents that could be used against both acute and chronic infections.