Malabaricone C from <i>Myristica cinnamomea</i> Exhibits Anti-Quorum Sensing Activity

A methanol-soluble extract of the bark of <i>Myristica cinnamomea</i> was found to exhibit anti-quorum sensing activity, and subsequent bioassay-guided isolation led to the identification of the active compound malabaricone C (<b>1</b>). Compound <b>1</b> inhibited violacein production by <i>Chromobacterium violaceum</i> CV026 when grown in the presence of a cognate signaling molecule, <i>N</i>-3-oxohexanoyl-homoserine lactone. Furthermore, <b>1</b> inhibited the quorum sensing-regulated pyocyanin production and biofilm formation in <i>Pseudomonas aeruginosa</i> PAO1. These results suggest that the anti-quorum sensing activity of <b>1</b> and related molecules should be investigated further