Glucosamine Hydrochloride and Glucosamine‐Gallic Acid Nanoparticles for the Treatment of Osteoarthritis: Synthesis, Antioxidant, and Anti‐Inflammatory

This study aimed to evaluate the antioxidant and anti‐inflammatory effects of glucosamine nanoparticles (GNPs) grafted with gallic acid (GNPs‐ g ‐GA). Glucosamine hydrochloride (G‐HCl) was produced from shrimp shell, and then GNPs synthesized using ionic gelation method. GNPs‐ g ‐GA was prepared by coupling GNPs with GA via 1‐ethy‐3‐(3‐dimethylaminopropyl)‐carbodiimide (EDC) in combination with N‐hydroxysuccinimide (NHS) cross‐linking agents. The results indicated that the grafting of GA onto GNPs at different ratios increased the average size of the nanoparticles from 195.7 to 294.2 nm with various grafting degrees ranging from 73.3 to 146.4 mg GA/g GNPs‐ g ‐GA. The SEM images revealed the formation of spherical‐shaped GNPs‐ g ‐GA nanoparticles with approximate sizes ranging from 275.3 to 303.6 nm. The appearance of characteristic signals in the FT‐IR (C=C, C–O/C–C, and NH 2 ) and 1 H‐NMR (H‐2 and H‐6 at 6.95 ppm) spectra and the red shift in UV‐Vis spectrum provided further support of GNPs‐ g ‐GA successful synthesis. DPPH radical scavenging (from 20.0 to 70.4%) and ABTS radical scavenging (from 18.7 to 79.0%) activities and reducing power (nearly fivefold) sharply improved in GNPs‐ g ‐GA. Moreover, GNPs‐ g ‐GA was found nontoxic and drastically reduced the level of nitric oxide release and downregulated the synthesis of TNF‐ α , IL‐1 β , and IL‐6 in LPS‐induced RAW2647 murine macrophage cells through NF‐ κ B and MAPKs signaling pathways. Overall, these results suggested that the grafting of GNPs and GA is an effective strategy for the suppression of inflammation response and oxidation reaction in osteoarthritis.