Structural Characterization, Protective Effect on Diabetic Nephropathy of a Novel Polysaccharide From <i>Trichosanthes kirilowii</i> Maxim. Pericarp

In this research, crude polysaccharide (Trichosanthes kirilowii Maxim. Pericarp polysaccharide [TMPP]) was extracted from T. kirilowii Maxim. pericarp by water extraction and alcohol precipitation, and the homogeneous polysaccharide (TMPP-1) was purified by Sephadex G-100 column. Subsequently, the structure of TMPP-1 was characterized by Fourier transform infrared spectroscopy (FT-IR), high-performance liquid chromatography (HPLC), gas chromatography, and nuclear magnetic resonance (NMR). After that, the effect and mechanism of TMPP-1 on kidney function injury in diabetic nephropathy (DN) mice were investigated. TMPP-1 structure analysis results showed that the TMPP-1 with molecular weight (MW) 4.52 kDa was composed of Man, Glc, and Gal with a molar ratio of 2.06:3.02:1.00. The methylation results showed that TMPP-1 was mainly composed of T-d-Glcp(1→, →4)-d-Glcp(1→, →4)-d-Galp(1→, →3)-α-d-Manp-(1→ and →3,6)-d-Glcp(1→ in a ratio of 0.62:2.0:1.0:2.06:0.2. The results of animal experiments showed that TMPP-1 could alleviate hyperglycemia symptoms and improve lipid levels, oxidative stress, and immune response in DN mice. These results revealed that TMPP had the potential to improve the clinical symptoms of DN. This study provided a theoretical basis for the utilization of the by-products of T. kirilowii Maxim.