Table 1_Physicochemical characteristics and anti-colorectal cancer activity of Salvia miltiorrhiza Bunge polysaccharides.docx

IntroductionSalvia miltiorrhiza (S. miltiorrhiza) Bunge is a traditional, medicinal and edible plant with diverse biological properties.
MethodsIn this study, a novel acidic polysaccharide (SMP-3) was extracted from S. miltiorrhiza roots using hot water extraction, followed by purification through DEAE-52 cellulose and Sephadex G-100 column chromatography. Structural characterization was performed utilizing FT-IR, NMR, XRD, and CD spectroscopy. The anti-colorectal cancer activity and underlying mechanisms of SMP-3, both alone and in combination with regorafenib (REG), were evaluated in vitro using HCT116 colorectal cancer cells and normal FHC cells through cytotoxicity, Western blot, and immunofluorescence analyses.
ResultsThe purified SMP-3 exhibited a total polysaccharide content of 96.52% with a weight-average molecular weight of 61.3 kDa. Monosaccharide composition analysis revealed that SMP-3 was primarily composed of galacturonic acid, glucuronic acid, glucose, mannose, galactose, and rhamnose in a molar ratio of 52.6:24.1:7.5:6.8:6.0:3.0, preliminarily suggesting a possible pectin-like structural feature with uronic acids accounting for 76.7% of the total content. Structural characterization indicated the presence of both α- and β-glycosidic linkages, an amorphous structure, and an ordered conformation in aqueous solution. Biologically, SMP-3 exhibited dose- and time-dependent cytotoxicity against HCT116 cells while showing minimal toxicity to normal FHC cells. Notably, combination treatment with SMP-3 and REG demonstrated combined effects, significantly enhancing G0/G1 cell cycle arrest, apoptosis induction, and inhibition of cell migration and invasion compared to single-agent treatments. Mechanistically, the combination treatment upregulated p21, Bax, and caspase-3 expression while downregulating cyclin D1, CDK4, and Bcl-2, and profoundly suppressed the phosphorylation of STAT3, AKT, and ERK signaling pathways.
DiscussionThese findings suggest that SMP-3 possesses distinct structural characteristics and significant anti-tumor efficacy, making it a promising medical food candidate for colorectal cancer treatment.