Homogalacturonan enriched pectin based hydrogel enhances 6-gingerol's colitis alleviation effect via NF-κB/NLRP3 axis

A nanolipidcarrier (NLC) loaded homogalacturonan enriched pectin (citrus modified pectin, MCP4) hydrogel was designed as a novel colon inflammation site-specific oral delivery system for 6-gingerol (6G) (6G-NLC/MCP4 hydrogel) administration, and its colitis alleviation effect were investigated. 6G-NLC/MCP4 exhibited typical "cage-like" ultrastructure with 6G-NLC embedded in the hydrogel matrix as observed by cryoscanning electron microscope. And due to the homogalacturonan (HG) domain in MCP4 specifically combined with Galectin-3, which is overexpressed in the inflammatory region, the 6G-NLC/MCP4 hydrogel targeted to severe inflammatory region. Meanwhile, the prolonged-release characteristics of 6G-NLC provided sustained release of 6G in severe inflammatory regions. The matrix of hydrogel MCP4 and 6G achieved synergistic alleviation effects for colitis through NF-κB/NLRP3 axis. Specifically, 6G mainly regulated the NF-κB inflammatory pathway and inhibited the activity of NLRP3 protein, while MCP4 regulated the expression of Galectin-3 and peripheral clock gene Rev-Erbα/β to prevent the activation of inflammasome NLRP3.