Study On Content Change Of Catalpol In Rehmannia Glutinosa Libosch. During The Processing

Rehmannia refers to the root of Rehmannia glutinosa,an herb of the Scrophulariaceae family.Rehmannia glutinosa has been used widely as an herbal medicine in Eastern Asia for more than 2000 years,Depending on different processing methods,Rehmannia glutinosa has been categorized into three types, named fresh rehmannia root,dried rehmannia root,and steamed rehmannia root,The changes in the properties of the root is due to the chemical constituent changes during the processing,Modern researches have demonstrated that catalpol is the main active ingredient performing pharmacological action in rehmannia so that rehmannia is ofen identified using catalpol as standard preparetion.Studies have found that catalpol makes up about 4%of the fresh root,with considerably less(not less than 0.2% prescribed by pharmacopoeia of the P.R China,2005)in the dried root because the drying process evidently destroys this component,converting it into another compound that may or may not be active.In order to know how changes the content of catalpol during prosessing and what catalpol invert to be,some research works have been carried out and the results are as follows: 1.20g catalpol was separated from the flesh rehmannia roots and identified by IR, MS,¹H NMR and ¹³C NMR(600MHz).The purity of the compound was more than 99.2%purity by high-performance liquid chromatography(HPLC)analysis.2.The pH changes of the processing system was mensurated and the content of catalpol was mensurated and analyzed,the results revealed that the pH of the processing system declined continuously,and the contents of catalpol was lower due to higher temperature of the processing.3.The pH changes of the simulated processing system(60℃,70℃,80℃,90℃separately)and the content of catalpol was mensurated during different time,the results revealed that the pH of the processing system declined incessantly too,but the content of catalpol was invariably after little declined at the early time.It is interested that the catalpol contents of comparison group(5℃)was declined sharply.Obviously, catalpol was katalyzed byβ-Glu.4.Research works on how to choose the processing temperature(25℃,35℃, 45℃,55℃,60℃separately)was carried out,it is obvious that the contents of catalpol was lower due to lower temprature,so the temperature on which theβ-Glu die is about 60℃.5.80mg glutinoside was synthesized from catalpol and identified by IR,MS,¹H NMR,¹³C NMR,HMQC and HMBC,besides,some possible decompose compound was analyzed.Based on above results,we concluded that the catalpol degradation was affected byβ-Glu,the mechanism is likely that the catalpol meet theβ-Glu and decompounded after cracking of karyotheca and vacuole induced by high tempetature,the fact that the contents of catalpol is lower due to higher temperature through peocessing may be explained as follow:β-Glu die quicker due to higher precessing temperature,the cracking of karyotheca and vacuole too,actually,it is likely that the cracking of karyotheca and vacuole more quicker and the content of catalpol declined more,but in the simulated processing,the catalpol andβ-Glu meet quickly after the fresh root was smashed,so theβ-Glu die quicker due to higher temperature and less catalpol be decomposed.Of course,the H⁺ may be contribute to the catalpol decompose.Innovation in this dissertation:1.The pH changes of the processing system and simulated processing system was mensurated and the content of catalpol during the different processing time was mensurated by HPLC for the first time,Research works on how to choose the processing temperature was carried out.2.Possible decompose compound from catalpol was analyzed.3.It is worth to optimize the arts and crafts for industrial manufacture based on our reseach work.