Study On The Chemical Constituents And Biological Activities Of The Hydrolysates Of Panax Quinquefolius

Xi Yang Shen?Panax quinquefolius L.?,also known as American ginseng and guangdong ginseng,is a perennial herb of the ginseng genus of acanthaceae,which is native to Canada and the United States.It is mainly distributed in changbai mountain and Beijing huaiyou in China.P.quinquefolius is a widely recognized,acceptable,reliable,natural food and drug.Its main active ingredient is ginsenoside,which has the functions of regulating central nervous system,delaying senility,improving immunity,resisting fatigue,improving blood insufficiency of cardiovascular and cerebral vessels,inhibiting tumor cell growth and so on.But studies have shown that the direct use of ingredients like saponin may with toxic or adverse reactions such as stimulating.More importantly saponins class composition in the human body will be affected by hydrolysis or damage,leading to the structure change,in order to find more than saponins kind of secondary triterpene sapogenin,so,this experiment the chemical constituents from hydrolyzed products of total saponins of P.quinquefolius and their biological activities were studied.We used the classical silica gel column chromatography and recrystallization to separate and purify eight compounds from the acid hydrolysis products of total saponins of P.quinquefolius,and identified their structures by physical and chemical properties,¹H-NMR,¹³C-NMR and other NMR spectroscopy tests.They are 20?S?-panaxadiol?1?,?20S,24R?-dammarane-20,24-epoxy-3?,6?,12?,25-tetraol?2?,20?R?-dammarane-3?,12?,20,25-tetraol?3?,20?S?-dammarane-3?,6?,12?,20,25-pentol?4?,20?R?-dammarane-3?,12?,20,25-tetrahydroxy-3?-O-?-D-glucopyranoside?5?,?-sitosterol?6?,oleanolic acid?7?and 20?S?-protopanaxadiol?8?.Compound 5 was isolated from the hydrolysate of P.quinquefolius saponins for the first time.Compound 5 was isolated from the total saponoside hydrolysate of P.quinquefolius for the first time.Therefore,this experiment can also provide a reference for the search of novel structure and more active lead compounds,and confirmed that P.quinquefolius has an excellent prospect of development and application as a functional food.In vitro by three methods of antioxidant for American ginseng total saponins acid hydrolysate,American ginseng total saponins,ginseng total saponins to determine the antioxidant capacity,respectively is:1,1 diphenyl-2-trinitrobenzene radical scavenging ability of hydrazine?DPPH·?,2,2-hydrazine-2?3-ethyl benzothiazole-6-sulfonic acid?ammonium salt free radicals?ABTS+·?and 2,2'-azo 2 second isobutyl amidine hydrochloride?PSC?three methods to evaluate three kinds of the antioxidant activity of the sample.The experimental results show that the three samples have certain antioxidant capacity under the same mass concentration,but the scavenging ability of free radicals is weak.In general,the antioxidant activity of total saponins of Panax quinquefolius was better than that of total ginsenosides and total saponins of Panax quinquefolius.The hypoglycemic activity of eight compounds was determined by in vitro inhibition of?-glucosidase and PTP1B,and the possible mechanism was further explored.The inhibitory effect of compound 5?-glucosidase was better than that of acarbose(IC₅₀=9.455 m M).Further use of compound 5 in combination with acarbose significantly increased the CI index.Compound 5 can significantly improve the hypoglycemic effect of acarbose,indicating that compound 5 has a synergistic effect with acarbose and can avoid or alleviate the adverse reactions caused by acarbose by reducing the dosage of acarbose in half.The results of PTP1B inhibition in vitro showed that compound 5 had the best hypoglycemic activity,and its IC₅₀ value was 5.905?M.Kinetic analysis of enzyme reaction indicated that the inhibitory effects of four ginsenosides on protein tyrosine phosphatase and alpha-glucosidase were competitive inhibition.Its unique pharmacological and chemical properties provide a theoretical basis and reference for the better application of American ginseng and its health care products in the prevention or treatment of abnormal elevation of blood glucose.This study provides a theoretical basis and important reference for the search of lead compounds with novel structure and stronger activity,and for the better application of P.quinquefolius,a drug and food homologous product,in the prevention or treatment of abnormal elevation of blood glucose.