Preparation, Characterization, and Performance Evaluation of Catechin-β-Cyclodextrin Oleate Nanoparticle Inclusion Complexes

Catechins are polyphenolic antioxidants, widely distributed in tea and cocoa. They exhibit significant biological activities, including anti-inflammatory, antibacterial, and anticancer effects. However, they are characterized by poor water solubility, bitter taste, and sensitivity to light, thus limiting their application. In this study, the stability and bioavailability of CATs were enhanced by encapsulating them into β-cyclodextrin oleate nanoparticles through a co-precipitation method. The resulting CAT-CDO inclusion complexes were characterized using Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, SEM and TEM. The encapsulation efficiency, drug loading capacity, adsorption thermodynamics, antioxidant activity, release behavior and cytotoxicity were systematically investigated. The results showed that CATs were successfully encapsulated within the hydrophobic cavity of CDO, forming spherical nanoparticles with an average size of approximately 175 nm. The encapsulation efficiency and drug loading rate were 81.43% and 27.14%, respectively. The water solubility was 13.39 times higher than that of free CAT. The inclusion complexes enhanced antioxidant activity against DPPH, OH·, and NO radicals, improved thermal and photostability, and provided a sustained release profile. Furthermore, cytotoxicity assays conducted on Caco-2 cells revealed reduced toxicity and potential proliferative effects, indicating that CDO is a promising carrier for improving the therapeutic and functional applications of CATs.