Study On Extraction And Purification Process Of Luteolin From Peanut Shell And Its Synthesization

Luteolin is a flavone compound and high percent in the peanut shell. Luteolin has many pharmacological functions such as codein, immunoregulation, antibacterial, diminishing inflammation and killing tumours. Luteolin exists rarely in plant and the method of extraction and isolation is so incomplete, as to little luteolin has been obtained and its clinical application has been limited. To solve those problems, luteolin was synthesized in this experiment. It is significant to produce luteolin by the method of chemosynthesis. Under the consinderation of saving rude materials, decreasing production cost and improving production ability, in this paper, mature peanut shell was used as the experimental material. The purification of luteolin and its semi-synthesis starting from rutin had been studied. The main research is as follows.(1) The optimum extraction condition was confirmed. The optimum extraction process was studied by using the single-factor design, the orthogonal design and the uniform design. The single-factor desigh to determine the best extraction temperature 80℃, ethanol as extraction solvent; The optimum extracting conditions obtained from the orthogonal design were as adding 25 times amount of 65% ethanol, extracting for two times and 3h per time under the temperature of 80℃, at this point, the extraction of luteolin value of 25.7 mg.g-1; The optimum extracting conditions obtained from the uniform design were as adding 25 times amount of 65% ethanol, extracting for three times and 2h per time under the temperature of 80℃, at this point, the results of the highest, the extraction of luteolin value of 27.4 mg.g-1. The results show that the uniform design was superior to the orthogonal design, and as the optimum extraction process.(2) The luteolin carried out quantitative analysis using IR spectroscopy and UV-visible spectrophotometry. From the IR spectroscopy of luteolin standard and samples can be seen on the main characteristic peaks of luteolin:3423cm-1,1656cm-1,1612cm-1,1443cm-1,1267cm-1, 1195cm-1,1164cm-1,1032cm-1,862cm-1,839cm-1,565cm-1 etc. This indicates that they can be used as a basis for qualitative analysis of luteolin, because they contain the same or similar active ingredients. The UV-visible spectrophotometry determines the absorbance of luteolin, by external standard method to determine the content of products obtained.(3) The optimum purification condition was confirmed. In this paper, macroporous resin adsorption method of purification of luteolin process was studied. The macroporous resin that suitable for the purification of luteolin was selected, and the important factors that affect the purification of the macroporous resin were detail studied. AB-8 macroporous resin was selected from four different types of resin for the purification resin, and the optimum condition of the important factors that affect the purification of the macroporous resin was confirmed. This best purification process has good stability, and easy to be applied to industrial large-scale production.(4) The purification of luteolin has certain limitations using the macroporous resin because of there are many falconoid compounds similar with structures of luteolin. In this paper, this preliminary study of high-purity preparation of luteolin, determined to ethyl acetate as an extraction agent, by adding ammonium sulfate as the salting-out agent of purification methods, further purified luteolin with this method, the content of luteolin from 58.2% to 86.1%, after recrystallization can reach 92.3%. The results showed that:the purification of luteolin extraction with ethyl acetate has the following advantages, high recovery rate and easy to operate, thus can be used for actual production.(5) Two methods of synthesis luteolin with hesperidins were studied in this paper. The first line of synthesis is that:in alkaline environment, the rutin and the Na2S2O4 generated luteolin under the conditions of microwave heating. The second line is that:firstly, hesperidins hydrolyzed to hesperidins, and then demethylation generates San grass phenol, finally restore to luteolin. We identified the structure and content of the product by analyzing the IR and spectrophotometry. An experimental product yield and the content of luteolin as an index, we can see the first method better, for the chemical synthesis of luteolin has laid a solid foundation.