〔Abstract〕 To investigate the extraction , purification , and identification methods of Polygonum cuspida- tum-derived exosomes and to obtain high-purity exosomes , and thus providing a reliable material foundation for their functional studies . Methods Exosomes were isolated from fresh P. cuspidatum using ultracentrifugation combined with sucrose density gradient centrifugation . Morphological characteristics , size distribution , and surface charge properties were analyzed by transmission electron microscopy (TEM) , nanoparticle tracking analysis (NTA) , and Zeta potential measurements . Results The purified P. cuspidatum exosomes exhibited characteristic cup-shaped or spherical bilayer morphology with a predominant size distribution of 100 ~ 200 nm , consistent with established plant exosome characteristics . The surface of these exosomes exhibits a negative charge , with the Zeta potential absolute value of root-derived exosomes being slightly higher than that of stem/leaf-derived counterparts . Conclusion The study successfully isolates and characterizes P. cuspidatum exosomes , with comprehensive analysis confirming their distinctive structural and biophysical properties . It lays a good material foundation for further exploration of its ac- tive ingredients and biological functions .