Sabia parviflora, a traditional Chinese herbal medicine, has long been clinically utilized for the treatment of various ailments, including rheumatic bone pain, nephritis edema, and goiter. Despite its established ethnopharmacological profile, the specific bioactivity of its polysaccharide components—particularly their potential anti-inflammatory and antioxidant properties—remains largely unexplored. This study aims to fill this knowledge gap by isolating a novel heteropolysaccharide (SPP) from the stems of S. parviflora and systematically evaluating its structural characteristics, radical scavenging capabilities, and its regulatory effects on inflammatory responses in a cellular model.

The crude polysaccharides were extracted from the dried stems of S. parviflora using an optimized hot water-extraction followed by ethanol-precipitation. The resulting extract was further purified to obtain the target heteropolysaccharide, denoted as SPP. The chemical composition, including total carbohydrate and protein content, was determined using colorimetric assays. Structural elucidation was performed to identify the monosaccharide composition and molar ratios through chromatographic techniques, while the average molecular weight was determined via high-performance size-exclusion chromatography. The antioxidant potential was assessed using four distinct in vitro assays: ABTS, DPPH, superoxide anion, and hydroxyl radical scavenging tests. Furthermore, the anti-inflammatory activity was investigated using lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages as an experimental model, measuring the modulation of key inflammatory mediators and oxidative stress-related factors.

The extraction process achieved a stable yield of 4.16% (w/w) for SPP. Chemical analysis revealed that the purified SPP consisted of 91.29 ± 0.83% (w/w) carbohydrates and a minor protein fraction of 3.47 ± 0.12% (w/w). Structural characterization identified SPP as a high-molecular-weight heteropolysaccharide (533.170 kDa) primarily composed of arabinose, galactose, and glucose, maintaining a specific molar ratio of 0.3874:0.9606:14.6028. In antioxidant assays, SPP demonstrated potent dose-dependent scavenging activities against all tested radicals (ABTS, DPPH, superoxide, and hydroxyl). Most notably, in the RAW 264.7 cell model, SPP significantly attenuated the inflammatory surge induced by LPS. It effectively modulated the levels of pro-inflammatory cytokines and oxidative stress markers, suggesting a robust protective mechanism at the cellular level.

This study represents the first comprehensive report on the extraction, structural characterization, and biological evaluation of a polysaccharide derived from S. parviflora. The findings demonstrate that SPP is a potent natural antioxidant and anti-inflammatory agent, providing a scientific foundation for the traditional use of this plant in treating inflammatory diseases. These results suggest that SPP has significant potential for development as a functional food or a therapeutic candidate in anti-inflammatory therapies. Future investigations will focus on elucidating the precise molecular signaling pathways and the detailed structure-activity relationships that govern its pharmacological effects.