Quorum-Quenching Activity of Myrtus communis Corsican Essential Oil Against the Marine Bacterium Aliivibrio fischeri

The <i>quorum-quenching</i> activity of essential oils (EOs) from Corsican aromatic plants was evaluated using the marine bacterium <i>Aliivibrio fischeri</i> as a model system. Among the eleven EOs screened, <i>Myrtus communis</i> EO showed significant interference with QS-regulated phenotypes (swimming motility, bioluminescence, and biofilm formation). Its activity was compared to <i>Origanum vulgaris</i> EO, known for its high carvacrol content and potent QS inhibition. The fractionation of <i>M. communis</i> EO revealed that its most polar fractions exhibited comparable levels of QS-disrupting activity. These chromatographic fractions significantly affected QS-controlled traits, indicating that minor or less volatile compounds may contribute to, or enhance, the overall bioactivity. Furthermore, <i>M. communis</i> EO and its polar fractions displayed stronger anti-QS effects against <i>A. fischeri</i> than <i>O. vulgaris</i> EO. These results highlight <i>M. communis</i> EO as a promising source of natural QS inhibitors and underscore the importance of exploring both complete EOs and their active fractions. This study supports the valorization of Mediterranean endemic flora as a reservoir of bioactive compounds, tested on a model system <i>A. fischeri</i>, and encourages future research on the potential of <i>Myrtus communis</i> against clinical bacterial isolates and the development of novel anti-virulence strategies.