Structural Characterization Of Polysaccharides From Radix Hedysari And Its Anti-Gastric Ulcer Activity

It is a unique species in China,and the dried root of Hedysarum polybotrys Hand.-Mazz,known as"Hong Qi",is a specialty herb in Gansu.It is recorded that Radix Hedysari（RH）has the effect of“healing sore and promoting granulation”in the 2020 edition of the Pharmacopoeia of the People’s Republic of China,whereas little scientific research had been reported on it.This study was centered on the screening of natural products with potential gastric mucosal protective activity and drug-generating potential,and two disease models in experimental animal and cellular dimensions were successfully constructed.Through three levels of pharmacodynamic studies on the activity of the active part group of RH,crude Hedysarum polysaccharides（HPS）and homogenized polysaccharides.Then an active component（HPS-80-1）with industrial development potential was finally discovered.It was elucidated that the extremely complex structure of it.The main studies are as follows:（1）The animal models of gastric ulcer were established by water immersion-stress method,ethanol method and acetic acid cauterization method.The comprehensive,systematic simulation and evaluation were conducted based on the general condition of their animals,survival rate,ulcer index.It was indicated that acetic acid-induced ulcer in rats is the suitable models used to conduct pharmacological studies for screening for potential anti-ulcer drug activity.Then,the modelling approach and the means of anesthesia were optimized in order to reduce the postoperative mortality of the experimental animals,improve the ulcer formation rate.The use of acetic acid filter paper patching instead of direct cauterization to generate ulcers.Finally,through the study of the self-healing pattern of the acetic acid patch method,the optimal time for drug intervention was determined to be three days after the start of the molding procedure and continued administration about 7 days,which avoided the interference of self-healing against the action of anti-ulcer drugs and ensured the effectiveness of potential active screening.（2）The gastric mucosal protection effect of different extracted parts of RH was compared,and it was clear that the AF（aqueous fractions）had the best activity.Among them,Hedysarum polysaccharides（HPS）are very important bioactive constituents in AF.The present study was further undertaken to explore the gastric mucosal protection effect of HPS（HPS-50,HPS-80）,which were extracted by a extraction method involving a complex enzyme combined with ultrasonication.The effects of antioxidant factors,anti-inflammatory cytokines,and mucosal blood flow regulatory factors in the gastric tissue homogenate of rats were analyzed for the bioactivities of HPS.The results showed that,compared with the acetic acid-induced ulcerated group,the ulcer inhibition rate of HPS-treated rats was significantly increased.The pathological findings suggested that mucosal regeneration,cell migration,and inflammatory cell infiltration were decreased,and collagen fibers were significantly reduced.Extensive granulation tissue proliferation indicated the healing stage was initiated,suggesting a good prognosis.The oxidative stress status of the gastric ulcer rats was improved.HPS-80-H（400 mg/kg）may be a further gastric mucosal protective drug.（3）Three polysaccharides,namely HPS-80-1,HPS-80-2,and HPS-80-3 were purified by DEAE-52 column chromatography.Then a mature Human Gastric Mucosa Epithelium Cell-1（GES-1）oxidative stress cell model induced by H₂O₂was established to screen out the optimal fractions of activity.It turned out that HPS-80-1had a desirable protective effect,which was confirmed by analyses of cell cycle＆apoptosis,and oxidative stress-related factors,and so on.These findings provide a scientific basis for further research and development of HPS-80-1 as a drug for the gastric mucosal protection.（4）Partial acid hydrolysis,periodate oxidation＆smith degradation,methylation,and NMR analysis were used to indicate the main structure of HPS-80-1.It was discovered that the main backbone of HPS-80-1 was composed of→4)-α-D-Glcp-（1→,→4,6）-β-L-Glcp-（1→,and→6）-α-D-Galp-（1→,with branches at O-1,O-4,and O-6 position consisting of→2,4）-β-D-Rhap-（1→,→1）-α-D-Galp-（4→,and→3,4）-α-D-Manp-(1→.The above-mentioned research content has enriched the biological activity of HPS and provided a theoretical basis for its exploitation in the field of medicine and health.It greatly improves the modern technology of HPS and fully exploits its medicinal value.