High purity isoflavones were obtained through a continuous procedure of hydrolysis, deposition, alkali dissolution, membrane separation and column chromatography. The application of membrane separation technology was a key progress. Through this, on one hand, the purity of isoflavone glycoside was raised. On the other hand, the sample solution prior to the column chromatography over macroporous adsorption resin was cleansed, as a result of  which the damage to the resin was reduced and the service life was extended.

　  The technique is simple, safe with less pollution and low cost and can be applied in industrial production since only edible ethanol is used. The technique has made further use of the red clover, which lays the technological foundation for the research on health food and medicine with isoflavone as the active component. It is of great social and economic significance.

Background knowledge:

　  Red clover is a kind of perennial herb (trifolium-leguminosae). In China, people have used its branch leaves with blossoms as medicine to relieve muscular spasm, cough and asthma. It can also be used to make ointment to cure ulceration.

　  Isoflavone is a kind of raw materials for health food and medicine. In recent years, phytoestrogen-like substances have replaced hormone therapy. And significant progress has been achieved in the treatment of female climacteric syndrome, osteoporosis and senile dementia using isoflavone compound from natural sources.

　  Previous research has indicated that red clover is a rare kind of plant containing four estrogenic isoflavones. Its activity is six times higher than that of most isoflavones and it has dual-directional regulation effects.

　  Currently, the extracts from red clover isoflavones are widely recognized as the plant medicine to efficiently treat female climacteric syndrome. In America, their sales volume has been among the top ten plant medicine for years. In China, great amount of red clover isoflavones have been exported every year. 

Red clover