Anti-Biofilm Activity of Chlorogenic Acid against Pseudomonas Using Quorum Sensing System

Chlorogenic acid is a secondary metabolite produced by many traditional Chinese medicines. Its physiological activities (antibacterial, anti-inflammatory, antioxidant activities, etc.) have been well described. This study aimed to investigate the effects of chlorogenic acid on the biofilm of drinking water bacteria. The effects of chlorogenic acid on the metabolites of the biofilms were also evaluated. Chlorogenic acid was found to have an anti-biofilm effect against Pseudomonas, resulting in biofilm formation in a dose-dependent manner (0.53-25.4 mM CGA). Moreover, the biofilm structure was visibly attenuated. Furthermore, we identified and characterized 23 differential metabolites and associated two metabolic pathways involving beta-alanine metabolism and pyrimidine metabolism that were altered mostly during biofilm formation. A quantitative real-time PCR assay revealed that chlorogenic acid interfered with the signaling molecule synthesis and transcription regulators using the Las, Pqs and Rhl systems. These findings suggest that chlorogenic acid can be a quorum sensing (QS) inhibitor and inhibit biofilm formation. It may be a promising natural product for the prevention of contaminated drinking water.

Rapid extraction of bioactive compounds from gardenia fruit using new and recyclable deep eutectic solvents

The utilization of deep eutectic solvent as an alternative and environmentally friendly option has gained significant attention. This study first proposed a series of benzylammonium chloride based-deep eutectic systems for the extraction of bioactive compounds from Gardenia jasminoides Ellis. Through the implementation of response surface methodology, the optimal solvent was determined to be dodecyldimethylbenzylammonium chloride-levulinic acid (1:3, mol/mol) with 35% (v/v) water, specifically tailored to extract geniposide, genipin-1-β-d-gentiobioside, crocin-1, and crocin-2 from gardenia fruits with the ratio of solid to liquid of 1:20 at 86°C for 16 min. Their total extraction yields could reach 70.6 mg/g, outperforming those obtained by other solvents and corresponding techniques. Furthermore, the eutectic system was retrieved after first-cycle extraction, and then applied in the subsequent extraction progress, yielding a consistent extraction efficiency of 97.1%. As compared to previous traditional methods, a quick, high-yielding, and green extraction procedure was achieved through simple heating settings that did not constrain the instrument. Therefore, dodecyldimethylbenzylammonium chloride-levulinic acid could serve as a sustainable and reusable solvent for efficient extraction of natural bioactive compounds from plant-based raw materials. The application of deep eutectic solvents has demonstrated their potential as designable solvents with stronger extraction capabilities than traditional organic solvents.