Essential Oil from Tagetes minuta Has Antiquorum Sensing and Antibiofilm Potential against Pseudomonas aeruginosa Strain PAO1

Biofilms are complex communities of microorganisms that are enclosed in a matrix that shows increased resistance to antimicrobial and immunological encounters. Mostly, the traditional methods to control biofilm are exhausted; therefore, the aim is to evaluate the potential of essential oil (EO) from Tagetes minuta to encounter biofilm and other related virulence factors. The EO of T. minuta was extracted through steam-distillation, analyzed on gas chromatography-mass spectrometry, and the biofilm inhibition assays were performed with various concentrations of EO. Mainly the EO from T. minuta contains cis-beta-ocimene (29.1%), trans-tagetenone (23.1%), and cis-tagetenone (17.7%). The virulence factors were monitored while applying different concentrations of EO and it was recorded that the EO from T. minuta significantly inhibited the virulence factors linked with quorum sensing (QS), such as pyocyanin production, protease production, and swarming motility. Biofilm formation is one of the most important virulence factors associated with the QS pathway and was inhibited up to 79% in the presence of EO. Antibacterial activity against the PAO1 of EO was not so promising particularly and it has high MIC (325 mu g/mL) and MBC (5000 mu g/mL). EO is quite efficient to inhibit biofilm in a very small concentration of 20 mu g/mL, which confirms that the biofilm inhibition by EO is not by killing bacterial cells but by inhibiting the QS pathway. The study on PAO1 constructs carrying various QS reported genes confirmed that the EO interferes with the QS pathway that ultimately controls various virulence factors caused by PAO1.

Automated summary

This study evaluated the potential of Tagetes minuta essential oil (EO) to inhibit biofilm and related virulence factors. The EO significantly inhibited virulence factors linked with quorum sensing (QS), such as pyocyanin production, protease production, and swarming motility. It also inhibited biofilm formation, indicating that the inhibition of biofilm by EO is through the inhibition of the QS pathway. However, the EO showed limited antibacterial activity. The study confirmed that the EO interferes with the QS pathway that controls various virulence factors.