Thymol essential oil/ β-cyclodextrin inclusion complex into chitosan nanoparticles: Improvement of thymol properties in vitro studies

Thymol (TH) is a natural compound extracted from plants. In the present study, the beta-cyclodextrin (beta CD) complex of TH as the main constituent of thyme essential oil, was synthesized by freeze-drying (FD) method and TH/beta CD inclusion complexes loaded chitosan (CS) nanoparticles (NPs). Phase solubility studies presented that the formation of inclusion complex enhanced water solubility of TH in the presence of beta CD also the stability constant was obtained 965 M-1. The TH/beta CD-ICs and TH/beta CD-CS NPs were characterized using UV-Vis absorption, FT-IR, (HNMR)-H-1, XRD, and SEM. Moreover, the theoretical study of molecular modeling demonstrated the most desirable mode of TH encapsulated into the beta CD cavity. Complexes exhibited 1:1 host: guest stoichiometry. The antibacterial effect of TH/beta CD-ICs and TH/beta CD-CS NPs was investigated against gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacteria. The antioxidant test indicated that complexes exhibited better antioxidant activities compared to the pure TH through free radical scavenging assay. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this study, the inclusion complex of TH/β-CD was synthesized and loaded into CS nanoparticles, resulting in improved solubility and stability of TH. The complexes showed antibacterial effects against Staphylococcus aureus and Escherichia coli, and exhibited better antioxidant activities compared to pure TH.