Characterization and anti-inflammatory studies of supramolecular assemblies of chlorogenic acids with metal ions

Self-assembled natural small molecules are believed to have numerous potential applications, particularly in the material and pharmaceutical industries, as self-assembly increases the anti-inflammatory, antitumor, antiviral, and other biological activities. In this study, we synthesized more potent potential anti-inflammatory agents by combining chlorogenic acids with metals (iron and copper).

Supramolecular assemblies were synthesized by combining chlorogenic acids with iron and copper. The synthesis conditions were optimized using mass spectrometry. The resulting complexes were comprehensively characterized by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, and mass spectrometry to confirm their formation and stoichiometry. The anti-inflammatory activity was evaluated in vitro using lipopolysaccharide-induced RAW264.7 macrophages. The production of inflammatory mediators (NO, IL-6, IL-1β, TNF-α) was measured. Mechanistic studies were conducted to assess the effects on the NF-κB signaling pathway and the expression of downstream proteins iNOS and COX-2.

Characterization data confirmed the successful formation of chlorogenic acid-metal supramolecules, primarily in a 1:1 stoichiometry. These metal-based complexes exhibited significantly enhanced anti-inflammatory effects compared to the parent chlorogenic acid molecules. In vitro assays demonstrated their potent suppression of key inflammatory mediators, including NO, IL-6, IL-1β, and TNF-α. Mechanistic investigations revealed that the enhanced activity was achieved through the effective inhibition of the NF-κB signaling pathway, leading to the downregulated expression of iNOS and COX-2 proteins.

The findings confirm that complexation with metals (iron and copper) successfully enhances the anti-inflammatory efficacy of chlorogenic acids. The primary mechanism involves the inhibition of the NF-κB pathway. This study provides a novel and efficient strategy for augmenting the bioactivities of natural products and highlights the considerable potential of chlorogenic acid-metal supramolecular assemblies as a promising new class of anti-inflammatory agents.