A coupled theoretical and experimental study: Construction, properties, and freshness preservation applications of Coumarinic acid/cyclodextrin metal-organic frameworks

Coumaric acid (p-CA), a naturally occurring antimicrobial agent with a broad range of potential applications, is severely limited by its poor water solubility. This study addressed this challenge by encapsulating p-CA within a biocompatible cyclodextrin metal-organic framework (CD-MOF), achieving a maximum drug-loading capacity of 10.217 ± 0.303 %. We performed comprehensive characterization involving X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FT-IR), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Thermogravimetry Analysis (TGA) and Brunauer Emmett Teller (BET) was undertaken to confirm the successful formation of the inclusion complex. It is noteworthy that the water solubility of p-CA at 25 °C increased 10-fold upon encapsulation, with rapid release achieved within 30 min. Encapsulated p-CA showed enhanced oxidation resistance (increased from 81.527 ± 0.871 % to 85.222 ± 0.871 %), as evidenced by DPPH-scavenging assays, and retained the antimicrobial activity of p-CA (Both p-CA and p-CA/CD-MOF exhibited 100 % antibacterial efficacy against Staphylococcus aureus and approximately 90 % efficacy against Escherichia coli ). Molecular docking and dynamics simulations revealed that p-CA inhibited bacterial glucose transport by occupying the active site of enzyme IIC (EIIC). Furthermore, experiments on the preservation of freshness in strawberries demonstrated the efficacy of p-CA/CD-MOF in maintaining fruit quality over 5 days at 25 °C. These findings emphasize the potential of CD-MOF encapsulation to circumvent the solubility limitations of p-CA, thereby facilitating its expanded use in food preservation and biomedical applications.