Investigation on the formation mechanism and antibacterial activity of novel citric acid-based ionic liquids applied in the food field

As a novel green solvent, ionic liquids (ILs) have broad application prospects in natural product separation and the food industry. Although the research on ILs is extensive, the formation mechanism of oxymatrine (OMT)-citric acid (CA) IL remains unclear. This study aimed to explore the formation mechanism of IL between OMT and CA and evaluate its antibacterial activity. Through spectroscopy, theoretical calculations, and relevant formula derivations, it was found that the primary ionization of CA mainly formed OMT-CA IL to produce anions. Subsequently, OMT accepted protons to form cations, and then IL was generated through ionic bond interactions. In addition, antibacterial tests showed that IL significantly inhibited various bacteria, indicating its potential to become a novel antibacterial agent. Cell experiments further confirmed its good biocompatibility. In conclusion, this study explored the formation mechanism of IL, providing valuable insights into the synthesis of novel ILs and their potential applications in the food industry. • This study developed a novel bacteriostatic agent that can be used in the food field. • This study elucidated the formation mechanism of the OMT-CA IL. • This study found that the OMT-CA IL possesses good antibacterial activity.