Study On Antidiabets Compound Of Panax Quinquefoliu L.

Diabetes has become a common disease in many nations. Statistics show that diabetes affects 3 - 5 % of the population worldwide annually. The incidence rate of diabetes in our country is about 3.21%. The diabetes incidence rate is tending to increase in the world and now the trend is more obvious in developing countries particularly. It has the third highest mortality rate after cardio-cerebrovascular disease and cancer. It has become a social public hygiene problem in international communities. November 14 has been designated as "World Diabetes Day"by World Health Organization and International Diabetes Federation, therefore, it is very urgent to protect people from diabetes and treat it actively.In recent years, more and more medical workers have utilized Chinese medicine combined with Western medicine to cure diabetes, thus the exploitation of natural antidiabetes medicinal plants also becomes more and more important. The study of using medicinal herbs to cure diabetes has become a hot topic in new medicinal development. For many years, American ginseng (Panax quinquefolius L.) has been used to cure various weak diseases using traditional Chinese medicine. Research result of the American ginseng indicated that American ginseng is antidiabetes and has already been applied in clinics, therefore, the antidiabetes material qualities of American ginseng were studied in this experiment.Through long-term clinical practical observation, some medicine experts have proved that the compound-prescribing product of American ginseng has the effect of alleviating the symptom of diabetes, lowering the blood sugar and uric sugar and controlling the development of type 2 diabetes. However, the valid material for antidiabetes in American ginseng is still unknown. Therefore, the purpose of this study is to find the antidiabetes material existing in American ginseng, which lay the foundation for the study on the antidiabetes effectiveness of American ginseng.A Japanese scholar once reported that water extract of Panax ginseng C. A. Meyer could lower blood sugar. Pyroglutamic acid within ginseng has an insulin-like effect. American ginseng has been utilized to treat diabetes clinically and the results in this experiment have proved that pyroglutamic acid exists in American ginsengThe extraction method of pyroglutamic acid is studied in this experiment. The result of screening extractive menstruum showed that the difference of extraction rates among 100%methanol, absolute alcohol and 50% alcohol are not significant. So 50% alcohol was adopted as extractive menstruum. The method is as follows: the experimental material was soaked in sequence by its 8 volume, 6 volume, 4 volume of 50% ethanol for 24 hours and then was extracted by ultrasonic for 40 mins, power at 200w, frequency at 40 KHz. After the extracting solution was combined and condensed, extractive containing pyroglutamic acid was obtained. This method is a simple operation. Menstruum cost is lower and pyroglutamic acid can be extracted thoroughly. So it is a time saving method, saving energy and benefiting the economy.The method used in isolateing pyroglutamic acid from American ginseng in this experiment has been screened successfully. Firstly, the condensed extraction liquid was treated in 10 times (v/v) of 100% methanol. Secondly, condensed treatment liquid was isolated in macro reticular resin Djoi and then the component eluted with distilled water was isolated in SaphadexLH-20 with 50% ethanol elution. According to the results of thin layer chromatography, the portion containing pyroglutamic acid was separated twice in silica gel column and the eluting solvents were chloroform-methanol ( 9:1), n-butyl alcohol-glacial acetic acid-water (6:2:2), in turn, and pyroglutamic acid was gained eventually.An HPLC method for the determination content of pyroglutamic acid was established. The analytical column was the Nucleosil Cig (5um, 150 mm><4.6 mm ID), the flow rate was 0.4ml /min, the UV detection wavelength was 210 nm, methanol and 0.005N NaAc buffer solution were adopted as the mobile phase (A: Methanol; B: 0.005N NaAc; A: B=8%: 92%). regression equation: Y=69498.75x-183.3607, the linear range: 0.05-0.30mg /mL ,r = 0.99924, The average recovery (n = 6) was 99.09%, RSD = 2.354%. This HPLC method has been proved to be feasible.This research measures for pyroglutamic acid content of different parts in American ginseng. The results indicated that stem and leaf content is 0.0401%, 0.2248% in American ginseng root and 0.34278% in American ginseng berry.Past pharmacology experiments showed that some ginsenosides have antidiabetes effects and can raise the insulin level in serum, therefore, the content of single ginsenoside of antidiabetes materials were measured in this experiment. The results are: Re, Rbi, Rb2 in American ginseng berry is 0.8929%, 0.5013%, 0.3233%, separately and the total content of three ginsenosides in American ginseng berry is 1.7157%. Re, Rbi, Rb2 in American ginseng root is 0.8487%, 0.9796%, 0.3635%, separately and the total content of three ginsenosides inAmerican ginseng root is 2.1918%. Re, Rbi, Rb2 in American ginseng stem and leaf is 0.6190%, 0.4049%, 0.2232%, separately and the total content of three ginsenosides in American ginseng stem and leaf is 1.2479%.The monomer saponin content measurement result is not the same as that in previous reports. The cause of this may be varied, such as: species, years of growth, growth environment, cultivation condition, sampling time, sampling part, sample treatment method and mensuration method. All these differences may affect the measurement result.Pharmacology studies reports concerning pyroglutamic acid indicated that pyroglutamic acid not only can prevent epinephrine-induced lipolysis but also slightly elevated lipogenesis from glucose both in the presence and absence of insulin. Thus, pyroglutamic acid is called an insulin-like substance. Pyroglutamic acid is found in American ginseng which has provided theoretic referent for utilizing American ginseng to cure diabetes.Pharmacology results in this research indicated that inhibitory effects of monomer ginsenoside Re, Rb,, Rb2, Rg, Re and Rd on a-glucose enzyme are not significant. Ginsenoside Re has inhibitory effects on a-amylase, along with an increased ginsenoside Re concentration, its inhibitory effects on a-amylase also increase. At the concentration of 5 mg/ mL, it inhibited 45.4% of the activity of a-amylase. Ginsenoside Re has hypoglycemic activity in hyperglycemic rats caused by strepozotocin and has inhibitory actions on blood sugar ascension in glucose load rats. These research results have provided the experimental basis for evaluating the pharmaceutical function and the clinical drug effect of American ginseng.To sum up, the achievements of this research are as follows:1. A new compound was isolated from the berry, root of American ginseng .On the basis of the physical constants, chemical evidence and spectrum analysis (*H NMR, 13C NMR, IR, UR, MS and DEPT), it has been identified as pyroglutamic acid.2. An HPLC method for the determination content of pyroglutamic acid was established. The pyroglutamic acid content of American ginseng was first determined by HPLC. The method of HPLC was proved simple, intelligent and accurate, and can act as a valid assessment method for pyroglutamic acid content.