ABSTRACT
Tumor immune therapy has been remarkably successful in recent years and several kinds of PD-1/PD-L1 (programmed death-1/programmed death-ligand 1) antibody drugs have been approved by the FDA for treatment of advanced malignant neoplasms. However, as biomacromolecules these antibody drugs have certain drawbacks such as high cost, injection-only administration and immunogenicity; thus, we turned to small molecules that have lower immune risks and better modifiability. Considering the structural diversity of natural products, we chose to investigate the active components in Panax ginseng, a famous and highly valued traditional Chinese medicine. Nine compounds were separated and identified in this research using a HPLC-coupled MS system, and 3 PD-1 binding compounds were identified using the SPR method. The PD-1/PD-L1 inhibitory ability of ginsenoside Rg1, as a representative ginsenoside, was verified by cytopharmacological methods. This research provides a new method for the identification of immune blockade inhibitors in natural products.
ABSTRACT
Objective: To establish a method for determining the content of total polysaccharides in decoction pieces of Polyporus,analyze the content of total polysaccharides in samples with different sources and grades. Method: The relative molecular weight and the polydispersity index of polysaccharides in decoction pieces of Polyporus were measured by a high performance gel chromatography coupled with a multi-angle laser light scattering and refractive index system.Dextran with similar molecular weight as polysaccharides was selected as the reference substance.Orthogonal experiment and single factor tests were used to optimize the pretreatment conditions for the determination of total polysaccharides in Polyporus.Polysaccharides in Polyporus with different areas and grades were determined by anthrone-sulfuric acid colorimetric method at 630 nm. Result: The linearity,stability,precision,repeatability and recovery rate of the established method all reached the standards,respectively.The content of total polysaccharides in samples from different areas ranged from 0.87% to 1.39%.The content of total polysaccharides in samples with different grades was 1.40% for first-grade pieces,1.21% for second-grade pieces, and 1.03% for third-grade pieces. Conclusion: The established method is simple,accurate and reproducible,and it can be used for the determination of polysaccharides in decoction pieces of Polyporus.The content of polysaccharides in samples from different origins varies greatly.The content of polysaccharides in samples with different grades shows a certain regularity.The content of polysaccharides is the highest in the first-grade pieces,followed by the content in the second-grade,and the lowest in the third-grade.The results can provide a reference for formulating limits for the content of total polysaccharides and the grade standard of decoction pieces of Polyporus.