Study On Puerarin Extraction Technology From Pueriae In Aqueous Two-Phase System

Radix puerariae is a kind of Chinese herbal medicine, it is the root of kudzu which is a kind of legume. Its available composition is puerarin that has much efficacy like expanding coronary artery, reducing blood pressure, anti-arrhythmic activity, improving microcirculation, lowering blood sugar and so on. Now it is one of first three kind of drugs which is used for treating cardio-cerebral disease. With the increasing of the patients who get cardio-cerebral disease, there is considerable interest in the development of efficient and scalable processes to obtain natural puerarin from puerariae.Aqueous two-phase system, originated from fifties in the last century as a new kind of extractive system, is constituted with two different hydrophilic solutes with certain concentration and can shape two different phases at normal pressure and room temperature. It has been considered as a useful tool to achieve separation and purification of Chinese machine for its many advantages, such as gentle extraction, high capacity, easy scale-up, simple operation and suitability for continuous large-scale operations and so on. Now ATPS has become an important part of the extracting available compounds from natural plants and has been widely used for the separation and purification of natural compounds such as glycyrrhizic acid, rutin and flavone in baika skullcap and so on.The article studied the partition behaviors of pueratin in PEG/(NH₄)₂SO₄ ATPS and Ethanol/(NH₄)₂SO₄ ATPS, then some pilot-scale experiments were investigated according to the conclusion of its partition property in ATPS and two different processes were applied for the puerarin separation and purification in ATPS. It showed that we can extract much more puerarin with higher purification in ATPS than other methods.The experimental results indicates that puerarin is mainly parted in the PEG phase in the PEG./(NH₄)₂SO₄ ATPS. The partition radio of puerarin increases with the molecular weight and the concentration of PEG. Electrolytes can improve the partition radio of puerarin because it changes the interfacial character of ATPS and puerarin's surface hydrophobicity. But lower alcohol has not this function and it will decrease puerarin's partition radio if it exists in the system. It also shows that puerarin's partition radio directs radio with the value of pH in the system, and has not much relation with temperature of system during25～40℃.In the ethanol/(NH₄)₂SO₄ aqueous two-phase system, pueratin is mainly parted in the ethanol phase and its parted radio directs radio with ethanol's concentration. PEG that with low molecular weight can promote much more pueratin to part in the top phase, and higher value of pH has the same effect, but the temperature almost doesn't affect puerarin's parted radio during 25～40℃.On the base of the above experiments, the article did some pilot-scale experiments to research the partition of puerariae extracting solution and perariae isoflavone with diffenent purity such as 80% and 40% and got the same results with the partition of standard puerarin. But the PEG/(NH₄)₂SO₄ ATPS is not fit for industry because PEG does not volatilize and its boiling point is high that will increase the difficulty of reextraction. It brought forward and compared two different processing routes to get puerarin from the puerariae extracting solution in ethanol/ammoniate sulfate aqueous two-phase system. It showed that we can get higher purity of puerarin when we made ATPS before microwave extraction than after that, and their corresponding value of purity was 85%and 82%.