Chinese Medicine Linseed Chemical Composition Study

In this research, 8 compounds were isolated from the seeds of Linum Usitutissimum L. by modern technologies of extraction, isolation, purification, and identification, furthermore structures of 6 compounds among them, including β -sitosterol, daucosterine, stearic acid, linustatin, α-linolenic acid methyl ester, have been established and identified on the basis of physico-chemical data, GC analysis and spectrographic evidence. Moreover it is the first time to obtain compound V from the genus and compound II and compound IV in the seeds of Linum Usitutissimum L. from China.By the orthogonal test, the optimum technology of oil extractive with alcohol from the seeds of Linum Usitutissimum L. were determined and the content of a-linolenic acid was determined by GC in the flaxseed oil, including the extractive of petroleum ether permeating, 95% alcohol refluxing, expressing and supercritical fluid extraction. Through comparing it, the content of a-linolenic acid in the seed oil of expressing (56%) was higher than the contents in the other three extractives.The conditions for preparing a-linolenic acid from the seed oil of Linum Usitutissimum L. with the means of urea fractionation and silver nitrate complexation were optimized through orthogonal test. In the end, it was found that silver nitrate complexation, which could make the purity of a-linolenic acid over 90%, even reaching to 97.53%, was better than urea fractionation, which could just only make the purity of a-linolenic acid reach to 80% or so.The contents of a-linolenic acid and linoleic acid in the seed of Linum Usitutissimum L. from different habitats in China were determined by GC so as to evaluate their quality and find the optimal habitats of Linum Usitutissimum L. It was showed that the average content of α-linolenic acid was 17.07% in crude drug and the content of a-linolenic acid in crude drug of Qinghai was 19.71%, which was higher than the others'. But the contents of linoleic acid (25.70%) and a-linolenic acid (53.27%) in the oil from the seed of Neimeng are highest in the six habitats. The content of linoleic acid and the sum content of the two unsaturated fatty acid in the crude drug of Yunnan are higher than the others'. Then in the end, it was concluded that the quality of Linum Usitutissimum L. from Qinghai, Yunnan and Neimeng are the best.