Co-assembly of highly active chitosan oligosaccharide with curcumin to improve its bioavailability

Curcumin (CCM), a multifunctional bioactive compound derived from turmeric, exhibits diverse biological activities. However, its extremely low water solubility leads to rapid in vivo metabolism and poor bioavailability, greatly limiting its practical applications. Therefore, developing a simple and efficient delivery system that simultaneously achieves high CCM loading and substantially improves its aqueous solubility and bioavailability remains a major challenge. In this study, chitosan oligosaccharide (COS) was co-assembled with CCM to construct COS-CCM nanoparticles through a simple, efficient, and environmentally friendly process. The obtained COS-CCM nanoparticles exhibited a drug loading content (DLC) of 41.56% and an encapsulation efficiency (EE) of 76.73%. The aqueous solubility of CCM was increased by approximately 1100-fold compared with free CCM. Moreover, the release-derived AUC of COS-CCM nanoparticles under simulated gastrointestinal conditions was more than 15-fold higher than that of free CCM, indicating markedly improved gastrointestinal release performance. These findings demonstrate that the co-assembly of oligosaccharides with hydrophobic bioactive compounds provides a simple and effective strategy for overcoming the limitations of poor aqueous solubility and low bioavailability while maintaining a high loading capacity. This strategy may broaden the application of oligosaccharides as functional nanocarriers and provide new possibilities for constructing co-assembled delivery systems for nutrient delivery and disease treatment.