Silicon-Based Polymer Carriers in Delivering Natural Plant Extracts for Ulcerative Colitis Treatment

Abstract

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by recurrent inflammation in the colon and rectum. Compound 1, a bioactive component extracted from Coix seed (Coix lacryma-jobi), is known for its anti-inflammatory, immunomodulatory, and antioxidant properties, making it a promising candidate for UC treatment. However, its clinical application is hindered by poor stability, rapid enzymatic degradation, and limited bioavailability in the gastrointestinal tract. To address these challenges, a novel metal–organic framework (MOF), [Zn(L)(bipy)]·H₂O (CP1), was synthesized using Zn(II) ions and organic ligands (H₃L = 2,6-dioxopiperidine-4-carboxylic acid; bipy = 4,4'-bipyridine) as a biocompatible drug carrier. Characterization via single-crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), FT-IR spectroscopy, BET surface area analysis, and elemental analysis confirmed its high porosity (260 m²/g), mesoporous structure, and pH stability, ensuring efficient encapsulation and controlled release of compound 1. To further improve biocompatibility and mitigate potential cytotoxicity from transition metal ions, CP1 was functionalized with 3-aminopropyltriethoxysilane (L-APTES), forming a 1@CP1@L-APTES composite system. Drug loading was validated by a reduction in surface area and pore volume after encapsulation. In UC models, this MOF-based drug delivery system significantly enhanced compound 1 stability, protected it from premature degradation, and facilitated targeted release at the inflammatory site. The composite exhibited notable anti-inflammatory effects, reducing colon inflammation and improving therapeutic efficacy. These findings suggest that 1@CP1@L-APTES serves as an efficient nanocarrier for Coix seed-derived compound 1, offering a novel strategy for enhanced UC treatment.