Target identification of traditional Chinese medicine polysaccharides: Experimental strategies, evidence hierarchy, and future perspectives

Traditional Chinese medicine polysaccharides (TCMPs) have diverse pharmacological activities, yet their mechanisms are often difficult to interpret because direct polysaccharide-target recognition must be distinguished from downstream signaling and microbiota-mediated effects.

This review evaluates current strategies for TCMP target discovery and validation and develops a structure-informed framework for interpreting target claims.

A critical narrative review focused on purified or fraction-defined TCMPs, target-discovery workflows, validation methods, and representative evidence patterns.

A targeted literature search integrated affinity capture, chemical probes, omics-assisted prioritization, biophysical assays, NMR, computational methods, and structure-target-activity analysis. Evidence was organized into a six-level hierarchy from phenotypic activity to in vivo target-causal validation.

Direct-binding evidence has been reported for structurally characterized TCMPs interacting with lectins, immune receptors, adhesion-related proteins, enzymes, and other disease-relevant proteins, with target-dependent functional evidence available in a subset of cases, whereas in vivo target-causal validation remains limited. Other findings are better interpreted as proximal functional nodes or microbiota-metabolite-host axes. Across studies, target confidence depends on ligand definition, assay format, specificity controls, orthogonal binding validation, and functional perturbation. The review links the six-level hierarchy with four classes of ligand definition and emerging structure-target-activity relationships.

A structure-first workflow that couples carbohydrate characterization with direct-binding measurements, functional perturbation, and in vivo validation can move TCMP research from pathway association toward testable ligand-target mechanisms and more comparable target evidence.