Study On The Preparation And Application Of Huangqin Reference Extract Used In TLC

Reference extract is a kind of standard substance with multi-component which could be used in thin-layer chromatography (TLC), determination and examination. It plays an important role in multiple-indexe quality control. Huangqin is from the roots of Scutellaria baicalensis Georgi and widely used in clinic. In the current China pharmacopeia (CP), there are 118 preparations containing huangqin and being identified with huangqin in TLC. Among them, there are 23 preparations using standard Scutellariae Radix as control, while 93 preparations using baicalin as control. Hence, baicalin represented few information and standard Scutellariae Radix was relatively complicated to prepare. In order to improve the control level and efficiency of huangqin and preparations, this study focused on the preparation procedure of huangqin reference extract and its quality standard. Then the applicability and feasibility in the application of preparations were also researched. The main details and results were as follows:1 Study on the preparation procedure of Huangqin reference extract used in TLCA simple and accurate method to determine the content of 4 flavonoids in Scutellaria baicalensis was established. This study made some control on the quality of huangqin collected which showed that they were qualified. Then preparation parameters of extraction, purification, constration and driness of huangqin reference extract were invstigated. The preparation procedure was as follows:take Scutellariae Radix coarse powder and add 12 times of 54% ethanol extracting 2 times with 135 min for each time. Then merge the solution and recyle ethanol and dilute to a certain volume with water. And then the relution was obsorbed by macroporous adsorption resin D101 and eluted with water to be colorless and 75% ethanol to be collected. The elution was consentrated and dried and crushed to get the huangqin reference extract. The preparation procedure was stable and feasible with good repeatability.2 Study on the quality control of Huangqin reference extract used in TLCOur research focused on the amount of huangqin reference extract and standard Scutellariae Radix and the results showed that 100 mg of huangqin reference extract was equivalent to 1 g standard scutellariae radix. Then the study about shape and properties, identification, examination, content determination and stability showed that the reference extract is a kind of yellow to brown-yellow powder and sensitive to water. The identification method of TLC was established. The amount of water was less than 5%, while ash content was less than 5%. The limit content of baicalin, wogonwide, baicalein, wogonin should not be less than 30.5%,7.0%,3.0%,1.0% in the reference extract without water.3 Study on the applicability and feasibility of huangqin reference extract used in TLCThis study summarized the preparation methods and developers of standard Scutellariae Radix in the current CP and studied the spots in TLC of reference extract with variety of preparation methods and developers. In the further study, three representative preparations were chosen for an in-depth research. The results that huangqin reference extract was feasible to be used in TLC of Scutellariae Radix and related preparations with no deference between the spots of them indicated.