Exploring antibacterial ethyl cinnamate/cyclodextrin inclusion complex electrospun nanofibers

Abstract

Ethyl cinnamate (EC), a natural ester from Cinnamomum essential oils, possesses excellent biological activities but faces challenges in bioavailability owing to poor water solubility. Herein, nanofibers (NFs) of EC inclusion complexes (ICs) with 2-hydroxypropyl-β-cyclodextrin (HPβCD) and methyl-β-cyclodextrin (MβCD) were successfully fabricated using electrospinning to enhance the aqueous solubility and apparent stability of EC. Phase solubility and modeling studies showed that the inclusion complex (IC) of EC with HPβCD and MβCD significantly increases water solubility and encapsulates EC at a 1:1 M ratio. The NFs were characterized using field-emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR), powder x-ray diffraction (XRD), ¹H NMR, thermogravimetry differential thermal analysis (TG-DTA), ultraviolet–visible diffuse reflectance spectroscopy, and photoluminescence. FESEM analysis revealed uniform fiber morphology with average fiber diameters ranging from 545 ± 95 nm to 620 ± 115 nm. FT-IR and ¹H NMR spectra confirmed the effective IC and interaction of the entire EC molecule with the HPβCD and MβCD cavities. XRD and TG-DTA results showed improved thermal stability (from 51–140 °C to 310–405 °C) and an amorphous distribution of EC in the EC-CD-IC-NFs. Water solubility analysis of the NFs revealed a tenfold enhancement in EC. Optical property analysis revealed higher absorption and emission in EC-CD-IC-NFs. Furthermore, antibacterial studies showed enhanced inhibitory effects against Escherichia coli and Staphylococcus aureus. In summary, encapsulating EC with βCD derivatives effectively increases the water solubility of oily essential oil components, and the electrospinning of EC-CD-ICs shows promise for antibacterial applications.