Spatholobus uniauritus is a climbing vine belonging to the Fabaceae family, traditionally used in Xishuangbanna as a local substitute for Spatholobi caulis (known as Ji Xue Teng in Chinese medicine) for nourishing blood, enhancing circulation, and alleviating pain. Although the plant is known to contain abundant steroids, phenolic acids, and terpenoids, its polysaccharide constituents and their biological activities had remained unexplored.
In a study published in Industrial Crops and Products, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences have, for the first time, systematically characterized the polysaccharides derived from Spatholobus uniauritus. Their work uncovered two new compounds with significant hypoglycemic and immunomodulatory effects, offering a scientific foundation for developing these polysaccharides into functional ingredients for diabetes management and immune support.
Using single-factor experiments and response surface methodology to optimize hot-water extraction conditions, the researchers isolated two new homologous polysaccharides from the stem vines, designated SUW-1 and SUW-2. Structural analysis revealed that both are glucans, with molecular weights of 4.57 kDa and 1.96 kDa, respectively.
The researchers evaluated glucose uptake in three major insulin-responsive tissues: skeletal muscle, liver, and adipose tissue. SUW-2 exhibited potent, dose-dependent enhancement of glucose uptake in muscle cells across all tested concentrations, outperforming the positive control insulin. SUW-1, by contrast, showed significant effects only at the highest concentration, but notably increased mitochondrial content, suggesting a distinct mechanism involving mitochondrial biogenesis.
In liver cells, both polysaccharides significantly promoted glucose uptake at 24 and 48 hours, approaching the efficacy of metformin and insulin. The effects of both polysaccharides in adipocytes were time-dependent: SUW-1 significantly increased glucose uptake after 48 hours, while SUW-2 showed inhibition at high concentrations. Importantly, neither compound exhibited cytotoxicity across any tested concentration.
Molecular docking simulations suggested that the dual activities of SUW-1 and SUW-2 may be mediated through interactions with key receptors, including TLR4, the insulin receptor (INSR), and TLR2.
"Traditional anti-diabetic drugs typically act through a single mechanism, which limits their efficacy and often leads to side effects such as gastrointestinal discomfort, hepatorenal toxicity, and hypoglycemia," said ZHANG Yumei of XTBG. "Natural products like these polysaccharides offer structural diversity and excellent safety profiles, making them valuable candidates for the development of novel multifunctional therapeutic agents.”
Available online: 15 June 2026
