Abstract

The quorum sensing (QS) aspect of the pathogenic Pseudomonas aeruginosa is a major problem in drug resistance. The development of drugs of natural origin is a therapeutic option or a lead compound in improving the weakness of antibiotics. Xylocarpus granatum is used as traditional medicine for the treatment of several ailments, including infectious diseases. Studies on the activity of QS have not been done much, especially the nonsaponifiable lipid compounds (NSL). The dried leaves of X. granatum were macerated with chloroform: methanol (2:1) for 48 hours. The filtrate was evaporated to yield total lipids (TLs), which were then saponified with 2 M KOH in 50% ethanol at 60°C and shaken for 24 hours. The n-hexane extractable portion was considered NSL. Profiling the compounds using the gas chromatography-mass spectrometry technique. Anti-QS properties were performed against P. aeruginosa. In vitro, it could inhibit growth, bactericidal, and QS activity, including swarming motility, biofilm formation, pyoverdin–pyocyanin production, and protease activity. However, TL was found to suppress virulence factors more effectively. Most NSL compounds can stop the activity of LasR, LasI, and Pseudomonas quinolone signaling receptor protein molecules, which are very important in the QS system. These studies suggest that lipid extract has potential for therapeutic management of P. aeruginosa infections.

Key words: total lipid, non-saponifiable lipid, X. granatum leaves, anti-quorum sensing, molecular docking