Highlights

The crude polysaccharide was extracted from Anemarrhena asphodeloides rhizomes.

The polysaccharides stimulated RAW264.7 cells to produce nitric oxide and cytokines.

Polysaccharides inhibited AGS growth through MAPKs and STAT3 signaling pathways.

F₂ fraction was composed of (1 → 4)-linked mannose and (1 → 3)-linked galactose residues.

Abstract

The crude polysaccharide was extracted from A. asphodeloides rhizomes and further purified to produce two fractions F₁ (50.0%) and F₂ (19.6%). The chemical constitutions of the polysaccharides were neutral sugars (51.4%–89.7%), uronic acids (1.0%–30.2%) and sulfate esters (3.4%–8.1%), with various ratios of monosaccharides including rhamnose (1.4%–6.1%), arabinose (7.1%–21.2%), xylose (0.2%–4.8%), mannose (39.9%–79.0%), glucose (6.0%–11.1%) and galactose (2.6%–22.0%). The molecular properties of the polysaccharides were investigated by the HPSEC-UV-MALLS-RI system, revealing the M_w 130.0 × 10³–576.5 × 10³ g/moL, R_g 87.6–382.6 nm and SV_g 0.3–54.3 cm³/g. The polysaccharides stimulated RAW264.7 cells to produce considerable amounts of NO and up-regulate the expression of TNF-α, IL-1 and COX-2 genes. Polysaccharides exhibited the growth inhibitory effects on cancer cells lines of AGS, MKN-28 and MKN-45, in which F₂ fraction exhibited prominent bioactivities. The AGS cells treated with F₂ experienced condensed cytoplasm, shrinkage of nucleus and chromatin marginalization with the highest number of cells at early-stage apoptosis reaching 54.6%. The inhibitory effect of F₂ polysaccharide on AGS cells was through MAPKs and STAT3 signaling pathways. The backbone of the F₂ was mainly linked by (1 → 4)-linked mannopyranosyl and (1 → 3)-linked galactopyranosyl. Taken together, the polysaccharide from A. asphodeloides rhizomes could be utilized as medicinal, pharmacological and functional food ingredients.