Toward sustainable obesity management: A review of extraction, properties, and structure-activity relationships of antioxidant and anti-obesity polysaccharides.

Polysaccharides are multifunctional bioactive macromolecules with growing potential in addressing obesity, a complex metabolic disorder associated with oxidative stress. However, their structure-activity relationships (SAR) remain incompletely understood. This review examines recent advances in extraction, structural characterization, and bioactivity of natural polysaccharides, focusing on antioxidant and lipid-lowering effects. Physical field-assisted extraction technologies, such as microwave and ultrasound, are emphasized for enhancing polysaccharide yield while reducing extraction time and energy consumption, as well as minimizing degradation of critical structural features, including molecular weight, esterification degree, and glycosidic linkages, properties essential to their antioxidant and anti-obesity bioactivities. The mitigation of oxidative stress by polysaccharides is closely linked to structural features such as uronic acid content, degree of polymerization, and glycosidic configuration, providing mechanistic insight into their SAR. Discussion centers on SAR, highlighting acidity, solubility, monosaccharide composition, molecular weight, esterification degree, glycosidic linkages, branching patterns, and homogalacturonan/rhamnogalacturonan-I content, attributes directly related to biological functions in obesity management. Despite growing interest, knowledge gaps persist regarding optimal extraction conditions and mechanistic SAR insights. This review aims to bridge those gaps, offering future perspectives for the rational design of polysaccharide-based interventions with therapeutic potential against obesity and related metabolic disorders through their antioxidant and lipid-lowering activities.