Study On Extraction And Isolation Technology Of Natural Coumarin From Melilotus

In this paper, the extraction process of coumarin from melilotus was researched and optimized, and the process was developed, which not only was low cost and less pollution, but also was suitable for magnified production. The objective of research was to provided scheme and experiment data for utilization of melilotus.Firstly, analysis method of coumarin in melilotus was researched. Compared with UV spectrophotometry, HPLC with XDB-C₁₈ column, mobile phase of methanol-water (65:35) and flow rate of 1.0mL/min was rapid and accurate. The content of coumarin from different areas was analysed, and the content of coumarin from flower and leaf of Yin Chuan was 0.664%, which was the highest, to provided available data for extraction and purification.Secondly, extraction method of coumarin from melilotus was investigated. Coumarin in melilotus was extracted in the method of acid-alkali, and the content of coumarin in product was too low and its configuration was changed in evidence. Coumarin in melilotus was extracted in the method of steam distillation, and the content of coumarin in product was less than 2% and plentiful tar as the by-product was found at the same time.Thirdly, extraction method of coumarin from melilotus in the method of solvent was studied. According to explore the extracting process of coumarin from melilotus, include extracting with ethanol, decoloring with petroleum ether and extracting with chloroform was determined. To choose the optimum technique through the single factor and the orthogonal experiments, the optimal technology is as follows: extracting three times with 80% ethanol at 50°C, extracting by petroleum ether three times and by chloroform once. By this way, the yield of the product was about 0.5%, and the content of coumarin was about 20%.Lastly, through filtration of different macroporous resin, LSA-40 macroporous resin was selected to purify coumarin, and the technic parameter was determined through the research of factors. After purification the content of final product reached 78.9%. According to the research of adsorption kinetics, the results showed that the process of adsorption was accord with Freundlich adsorption model and this process was controlled by film diffusion.