Inhibition of bacterial virulence factors of foodborne pathogens by paprika (Capsicum annuum L.) extracts

Capsicum annuum extracts of different polarities were tested for their antimicrobial, antibiofilm, and anti-Quorum sensing (QS) activity against several pathogenic microorganisms and possible toxic effects using an in vivo model (Galleria mellonella L.). Hexane (HE) and Chloroform extract (CE) were the most active in inhibiting biofilm formation of the eight bacteria tested, with inhibition percentages between 22 and 88% for a concentration of 100 μg/mL. These extracts were potent inhibitors of Staphylococcus aureus biofilm, and microscopy analysis confirmed a significant reduction in adhered cells. Moreover, polystyrene surfaces coated with these extracts decreased Staph. aureus adhesion resulting in biofilm formation and activity inhibition. In addition, they interfere with the hemolysin and coagulase activities. The extracts inhibited biofilm formation and swarming motility in Gram-negative bacteria. Furthermore, in Pseudomonas aeruginosa, elastase activity and pyocyanin production were reduced. In the most active extracts, the main compound was linoleic acid, followed by oleic and hexadecanoic acids. Paprika extracts capable of controlling bacterial virulence represent a promising alternative as a natural preservative to restrict contamination or spoilage of food.