Two novel polysaccharides from Spatholobus uniauritus: Extract optimization, purification, structural characterization, hypoglycemic and immunomodulatory effects

Wang, Hanlei

INDUSTRIAL CROPS AND PRODUCTS

2026

249

Zhang, YM

Spatholobus uniauritus (S. uniauritus) is a traditional medicinal plant and has gained attention for its use as a substitute for Spatholobi caulis. However, there is an absence of research on S. uniauritus polysaccharides. We established the optimal parameters for the hot water extraction of polysaccharides from its vine stems, from which two novel homologous polysaccharides (SUW-1 and SUW-2) were isolated. Structural characterization identified that the SUW-1 (4.57 kDa) and SUW-2 (1.96 kDa) had similar structures, consisting of a backbone of -*6)-alpha-Glcp-(1-* with substituents at C2, C3, and C4, along with -*4)-alpha-Glcp-(1-* side chains. In vitro evaluation revealed that SUW-1 could increase the glucose uptake in L02 cells and 3T3-L1 adipocytes, while SUW-2 acted on C2C12 cells and L02 cells, showing differential effects across cell types. Additionally, both SUW-1 and SUW-2 potently stimulated proliferation, phagocytosis, and cytokine secretion in RAW264.7 macrophages, indicating immunomodulatory potential. These two glucans exhibited distinct bioactivity profiles: SUW-1 demonstrated superior immunostimulatory activity, while SUW-2 was more effective in promoting glucose uptake. Furthermore, molecular simulation suggested that the dual functions of SUW-1 and SUW-2 might be mediated by interactions with TLR4, INSR, and TLR2. These results provide a basis for the industrial utilization of S. uniauritus resources and promote the development of high-value therapeutic agents employed in the management of diabetes and related complications.