Review on biological active metabolites of Astragali radix and its mechanisms in treating allergic respiratory diseases.

The global incidence of allergic respiratory diseases (ARDs) is rising, imposing severe socioeconomic and public health burdens worldwide. Astragali Radix (AR), a well-recognized traditional Chinese medicinal botanical drug with proven efficacy in ARDs management, exerts its therapeutic effects primarily through three major classes of bioactive metabolites: polysaccharides (e.g., APS), saponins (e.g., AS-II/IV/VII), and flavonoids (e.g., quercetin, calycosin). Of these, AS-IV and APS are the most extensively investigated, exhibiting prominent anti-inflammatory, immunomodulatory, anti-airway remodeling, and anti-fibrotic activities. Based on a comprehensive literature search across multiple authoritative databases, this narrative review innovatively focuses on ARDs (allergic asthma, ARh, AC, HP) from the perspective of a unified disease spectrum, summarizing the pharmacodynamic mechanisms of these AR metabolites in ARDs--pecifically, targeting core pathogenic signaling pathways (e.g., NF-κB, MAPK, TGF-β1/Smad) and regulating immune homeostasis (e.g., inhibiting ILC2 activation, rebalancing Th1/Th2 polarization, and suppressing Th17/IL-17-mediated inflammation). By integrating AR's pharmacodynamic effects with its molecular targets and correlating preclinical evidence with clinical data (including RCTs), this review establishes a comprehensive foundation for the clinical application of AR and the development of novel targeted therapeutics for ARDs.