| The flower bud of Tussilago farfara L.has been the traditional Chinese medicine, it belongs to the genus Tussilago of family Compositae.Tussilago farfara L.has been used in Chinese folk medicine for the treatment of cough,bronchitis,and asthmatic disorders.The literatures of Tussilago farfara L.have been mainly about chemical and pharmacological aspects,but the extraction and purification process of the total flavonoids which are the active ingredient has not been reported.In this paper,the total flavonoids from Tussilago farfara L.were studied systematicly,in order to provide a theoretical foundation for the applications of Tussilago farfara L.in medicine,food, cosmetics and other fields.The main contents and conclusions are provided as follows:1.This paper,it was established an aluminium salt spectrophotometry method with rutin as a standard,in order to detect the total flavonoids from Tussilago farfara L..The regression equation of the standard curve was C=0.08594A-0.00369 and the correlation coefficient was 0.99992.Through this method,the linear relationship was good,the precision was high,the stability was reliable,the recovery rate was high, this method was very applicable to the determination of the content of total flavonoids.2.The effects of different solvents in extracting total flavonoids from Tussilago farfara L.were studied,the results indicated that alcohol was the optimal extraction solvent.Then the effects of saxhlet method,thermo-refluxing method,ultrasound diffusion method,and flash-type extraction on the extraction rate of total flavonoids were discussed.The results indicated that the yield was respectively 9.03%,7.44%, 7.23%,4.70%(n=3),and the saxhlet method had the highest extraction rate.3.The effects of extraction solvent,ethanol concentration,ratio of the solid to solution,extraction temperature,extraction time,and extraction times on the extraction rate of total flavonoids were discussed,and the extraction condition of thermo-refluxing method was optimized by orthogonal experimental design(L9(34)). The results indicated that the order of factors which affected the flavonoids extraction was ethanol concentration＞extraction temperature＞ratio of the solid to solution＞extraction time.The best extraction condition was as following:ethanol concentration 50%,extracting duration 2 hours,solid/solution ratio 1:30,extracting temperature 80℃,extracting number once.Its maximum yield was 8.15%.The extraction condition of thermo-refluxing method was improved by this extraction process,which was convenient and feasible,provided a basis for industrial production.4.Macroporous adsorption resins were employed to enrich total flavonoids from Tussilago farfara L..The absorption-desorption characteristics of AB-8,NKA,X-5, NKA-Ⅱ,SP825 and HP20 were studied.Experimental results of the static and dynamic adsorption-desorption experiments shown that SP825 resin possessed good adsorption capacity and desorption rate.Therefore,the SP825 resin was suitable for the purification of total flavonoids.5.The purification conditions of SP825 resin was studied.The results showed that the effect was perfect when the total flavonoids concentration in the liquid,which was 29.09 mg/ml,was diluted 5-fold,the pH was adjusted at 3～4,the adsorb velocity of flow was 2BV/h,the deal capability was 44BV;the flavonoids could be desorbed by using 3BV 70%grain alcohol in velocity of flow of 1～2 BV/h.At the above condition,the flavonoids content of purified product was above 60%which was four times that in the rough extraction solid.The results provided a test basis for the industrial production of the purification of total flavonoids.6.Through the color reaction and infrared absorption spectroscopy,the solid extract of Tussilago farfara L.was recognized as flavonoids which were preliminarily identified to contain flavonol. |
