Studies On The Quality Standard Of Flavonoids In Licorice

The glycyrrhizin and flavonoids are one of the important components in Licorice, However, people had been put the high emphasis on glycyrrhizin in the past. So the content of glycyrrhizic acid was only determined in Licorice for appreciating the quality of Licorice. Obviously, It's difficult to reflect the quality of Licorice. On the development of the study on Licorice, these pharmacological actions of the flavonoids in Licorice have been shown, such as anti-inflammation, anti-tumour, ant-virus and so on. It's very important for studying and exploiting the flavonoids in Licorice. To fulfill the mission of the People's Republic of China Pharmacopoeia of 2005, that is to say, the determination of the chemical of flavonoids in Licorice will be added. This thesis includes five parts as follows:Part I: Review. A review of the flavonoids in licorice and the quality standard of Chinese traditional medicine were given.Part II: Extraction and separation of the flavonoids from the rootstalk of Licorice. The medicinal material power was extracted by boiled water, and then the ethanol was added to water solution for depositing some impurities. The ethyl acetate and 1-butanol were added to extract the water solution respectively. The silica gel column and the polyamide column were used to separate the part of ethyl acetate in turn. At last, a same compound was gained from the two column respectively, which was liquiritin identified by chemical and spectral method. The result showed that liquiritin was easily gained by using the silica gel column and the content of liquiritin was high in Licorice from the He-yang County of Shaanxi Province.Part III: Recension the content of Licorice of the People's Republic of China Pharmacopoeia of 2005. The sample was extracted by ultrasonic method, which the reagent was seventy-percent ethanol. A method for determination of liquiritin in Licorice by HPLC was established. The mobile phase was consisted of acetonitrile-0.5% acetic acid (1:4) and the detection wavelength was at 276nm. Then thecontent of liquiritin in twenty-four samples was determined by this method. The result showed the content of liquiritin was between 0.86%~3.72%, the linear correlation was good (r=0.9998) and the average recovery was between 97.66%~103.5%. This method was simple, reproducible and rapid, which was suitable for determination of liquiritin in Licorice. According these results, the text (draft) of the determination content item on Licorice for the People's Republic of China Pharmacopoeia of 2005 was established.Part IV: Determination the content of total flavones in Licorice by UV-spectrophotometer. Based on the characteristic that flavanonols are easily transformed chalcones under alkali condition, a UV-spectrophotometry was developed. By this method, the content of total flavones was determined for forty-six samples. The result showed the average content of total flavones in Licorice was 4.37%, the linear correlation was good (r=0.9992) and the average recovery was between 95.0%~100.5%. This method was simple, reproducible, accurate comparing the usual method.Part V: Study on the fingerprint of the flavonoids in Licorice. The ultrasonic method was used to extract samples, which the reagent was seventy-percent ethanol. Then the ethyl acetate was added to extract the water solution of sample. The mobile phase was consisted of acetonitrile-0.2% acetic acid and detection wavelength was at 31 Onm. Under grads eluting condition, ten patches of samples from different producing area were determined. The result showed that the eleven mutual characteristic peaks were detected for ten patches of samples. At the same time, different similarity software systems were adopted to appraise the result. The result showed the similarity was between 0.781~0.931, which indicated these samples existed difference. By establishing the fingerprint on flavonoids of Licorice, the genuine or fake from the medicinal material was differentitated. In a word, a new method controlling the quality of Licorice was established.