Study On The Chemical Constituents Of MinShan Trifolium Pratense L. And Extraction Process Of Isoflavones

MinshanTrifolium pratense L., a legume and an important forage plant grown around the world. They are originally used as a medicinal herb by native indigenous people of North America for whooping cough, gout and cancer, and others traditionally have used it in the treatment of asthma, bronchitis, coughs, athlete's foot and for eczema, psoriasis. Trifolium pratense L. contains several kinds of isoflavones in resent research. These isoflavones have a high potential in the prevention of "Western diseases" like atherosclerosis, osteoporosis, cardiovascular diseases, several kinds of cancer and postmenopausal complaints. Is a sort of natural medicinal material which have the prospect of a good exploiture. Extracts of Trifolium pratense L. are commercially available as functional healthy dietay supplements in the international market. Our nation's planting area of Trifolium pratense L. is large, but the most of it is often used for fodder and low-usage. So it is very significant to study on our nation's native Trifolium pratense L. resource.Minshan trifolium pratense L. which is the native resource of Min county of GanSu province, is selected for the object of study in this paper. The chemical constituents of it were investigated and ten pure compounds were isolated by chromatography methods. Of these compounds, the structure of eight were elucidated on the basis of spectral evidence such as IR, ¹H NMR, ¹³C NMR, ESI-MS. and chemical methods. They are tetracosane ( â…  ), myristic acid ( â…¡ ),β-sitosterol (â…¢), daucosterol (â…£), formononetin ( â…¤ ), biochanin A (â…¥), ononis (â…¦), L-quebrachitol (â…§) .Those compounds â… , â…¡,â…¢,â…£ and â…¥ were isolated from this plant for the first time.Extraction process of isoflavones of Minshan trifolium pratense L. is studied in this paper. Optimum extraction process condition is obtained by a series of scientific experiments. 1. Ethanol heat under reflux is used as extraction method. Optimum extraction condition is as follows: ethanol volume fraction 80%;ethanol dosage(solid-to-liquid ratio) 1 : 15;extraction temperature 85℃;extraction time 2h. 2. Mixed-solvent extraction is used as the accumulation method. The optimum accumulation conditions is chloroform and ethyl acetate (ratio 2 : 1). The average value of isoflavones contents in extract is more than 50% by this operation process. This extraction process of isoflavones of Minshan trifolium pratense L. is simple and effective.