Research progress on resource distribution, extraction technology, anti-inflammatory mechanisms, and structure-activity relationships of natural anti-inflammatory pectins.

Inflammation is a fundamental protective response, yet its chronic form drives many non-communicable diseases. Conventional anti-inflammatory drugs carry significant side effects, prompting interest in natural alternatives such as pectin polysaccharides (PPs), which are generally recognized as safe, structurally diverse, and anti-inflammatory in preclinical models. This narrative review offers a comprehensive overview of anti-inflammatory PPs, from sources to functions. We discuss conventional and emerging green methods and their effects on yield, structural integrity, and bioactivity. Anti-inflammatory mechanisms are systematically covered, including modulation of canonical signaling pathways, cytokine networks, immune cell functions, oxidative stress, and gut microbiota-host crosstalk. Structure-activity relationships (SAR) are summarized across multiple scales. Source and extraction method influence PPs anti-inflammatory activity and structural properties, including molecular weight (Mw), monosaccharide composition, degree of esterification (DE), branching, and advanced conformation. Emerging techniques, such as physical wave-assisted, enzyme-assisted, and deep eutectic solvent, can maximize extraction efficiency while preserving structural integrity. PPs act through multimodal pathways, including modulation of gut microbiota, inhibition of key inflammatory signaling cascades, and enhancement of intestinal barrier integrity. Despite progress in elucidating structure-function relationships, challenges remain in conducting high-quality clinical trials, and translating PPs into functional foods or therapeutics is hindered by inconsistent product characterization, unclear dose-response relationships, and limited understanding of human-specific efficacy.