Elucidating the structures and antitumor activities of Pleione bulbocodioides polysaccharides

Breast cancer stands as the most prevalent malignant tumor among women globally, yet effective treatments remain elusive. As one of the primary botanical sources of Shancigu, Pleione bulbocodioides (Franch.) Rolfe pseudobulbs have been extensively utilized in traditional Chinese medicine for heat-clearing, detoxification, and the elimination of swelling and dissipating nodules. Polysaccharides constitute the primary bioactive components of P. bulbocodioides with structurally dependent bio-functions. In this study, novel P. bulbocodioides polysaccharide (PBP) was isolated, and its primary glycosidic linkage was structurally characterized as →4)-β-D-Manp-(1→4)-β-D-Glcp-(1→4)-β-D-Manp-(1→4)-β-D-Manp-(1→4)-β-D-Glcp-(1→, with minor O-2/O-3 acetylation. In vitro studies revealed that PBP strongly restrained the LPS-induced propagation and translocation of MDA-MB-231 triple-negative breast cancer (TNBC) cells, reduced pro-inflammatory cytokines (TNF-α, IL-6, IL-1β), and inhibited both the activation of Wnt/β-catenin signaling and downstream expression of target-genes, which demonstrated anti-tumor/metastatic efficacy. It was found that the in vivo administration of PBP curbed the growth of tumor and proliferation of cancer cells in a TNBC xenograft model, without inducing obvious hepatorenal toxicity, which indicated favorable biosafety. These findings provided a theoretical basis for the development of novel PBP-based anti-tumor therapies.