Dihydro Quercetin Production Process Improvement

Dihydroquercetin,also named Taxifolin,is a kind of dihydroflavonols compound.Its chemical name is 3,5,7,3',4'—pentahydroxydihydroflavone.It also has been embodied by Russia Pharmacopoeia and United States Pharmacopeia.Content of Dihydroquercetin is low in plants,generally only 2-3%,but the main plant resources of Dihydroquercetin—Douglas-fir located in the Russian Siberia region,rarely seen in other regions.These factors make the price of Dihydroquercetin more expensive, which further hindered its industrial production and applications.This dissertation summarize literature from home and abroad,in order to comparing and improving its production processes.At the same time,this article was also summarized synthetic method of Dihydroquercetin,in order to study the worthy synthesis process.Specific studies are as follows:1.SynthesisThe article also summarizes a series of Dihydroquercetin synthetic method:①Algar-Flynn-Olyamada reaction literature yield 20%,but the need to use of carcinogenic -chloromethyl ether,it makes higher requirements to the industrial production of space, equipment,personnel and operations;②Mitsunobu reaction literature yield 30%,but the need to use rare reagents and harsh reaction conditions;③Semi-synthetic method is simple to catechin as raw materials.However,the literature yield about 5%,the yield is too low that does not have practical value;④Biological synthesis by genetically modified strains of E.coli to fermentation other flavonoids into Dihydroquercetin,the process is currently at the stage of research only,do not have practical application.According to the current literature shows that immediately synthesis Dihydroquercetin do not have the conditions for industrialization.The synthetic methods of dihydroquercetin were also reviewed and compared,in order to find a suitable method for large scale production.2.ExtractionThis paper summarizes a large number of domestic and foreign literature about Dihydroquercetin extracting and found that the extraction of dihydroquercetin can be divided into two types:①To Engelhardtia roxburghiana Wall Leaf or Rosa davurica Pall Stems as raw materials to extract the Dihydroquercetin glycosides derivatives,through acid hydrolysis to be dihydroquercetin monomer,generally this kind of literature yield about 1%;②To larch bark or wood chips as raw material,directly extracted Dihydroquercetin monomer, generally this kind of literature yield about 1-2%.The paper optimize the extraction of Dihydroquercetin from Larix raw materials,the 2.6%yield with 96%HPLC Purity,the process which uses only acetone as organic solvent and does not heat in extraction process,so the consumption of solvent is very small,significant cost savings.3.DeterminationA suitable experimental method of the determination ofdihydroquercetin was established. The contents of dihydroquercetin in the bark and larch extracts were determined by the Pharmacopoeia(2005) method.Dihydroquercetin HPLC of linear relationship,stability, recovery and processing precision are carried out in the inspection...