Isolation Of Flaxseed Lignans And Effect Of IT On The Human Breast Cancer Xenografts In Nude Mice

PurposeTo isolate and purify Secoisolariciresinol diglycoside(SDG) from flaxseed with two different methods and compare the yield and purity of it. To study the effect of SDG on the human breast cancer xenografts in nude mice.MethodsSDG was isolated from flaxseed and purified with two different chromatographic methods(1.by silica gel column,2.by reverse-phase column).The yield was calculated and the purity was determined by high performance liquid chromatography (HPLC); Nude mice were xenografted with human breast cancer cell line MDA-MB-231;At week 6,mice were randomly divided into 3 groups(n=5 in each group):control group, SDG group, Flaxseed group. Body weight and food intake were recorded weekly. Tumors were measured and the surface areas were calculated. Mice were sacrificed at week 10.At necropsy, body weight, primary tumor weight and volume and the number of intumescent lymph node were recorded. Lung and live were analyzed at pathology. The expression of Cyclin D1 and p21 were detected by RT-PCR.ResultsPurified SDG was obtained and the yield of SDG with the two different methods was 2.39% and 1.92%. Correspondingly, the purity of isolated SDG was about 82.38% and 87.96% on the analysis of HPLC. The human breast cancer model was set up successively with the MDA-MB-231 cell line on the nude mice; The tumor surface areas, tumor weight and volumes of the SDG and Flaxseed group were significantly lower than control group. The mean number of intumescent lymph node were also lowed in the two groups. No significant difference in food intake or body weight change was recorded between groups. No tumor metastasis in lung and live was found in each group. Compared with BD group, p21 mRNA level in mammary tumor was significantly increased in SDG group, while not in FS group. The expression of Cyclin D1 was detected, with no significant difference between the treatment groups.ConclusionCompared with method 2,the yield was increased by 0.47 percentage point in method 1.Although the purity was a little lower than it in method 2,the method 1 was more suitable for the large-scale preparation in workshop;Dietary SDG can inhibit the growth of tumor in nude mice bearing human breast cancer cells MDA-MB-231,in which the increased expression of p21 by SDG was important.SignificanceIn the past 20 years, the flaxseed is paid attention to in the medical field. Firstly, it was known that flaxseed is rich in ω-3 polyunsaturated fatty acid and than it was found that it contains lignans which is beneficial to health. Flaxseed, the richest source of lignans, has been regarded as one of the 6 kinds of anticancer plant by the national tumor research institute of U.S.A. In recent years, the western developed countries, such as Canada, Australia, Britain and U.S.A., have done a large amount of work on the flaxseed regarding it as a functional food. Many relevant products of flaxseed and SDG are appearing on the market constantly. Our country is still a blank so far in this respect, so it is very urgent to research the flaxseed and its functional composition. There are extremely abundant flaxseed resources in our country. Inner Mongolia, the Northeast, Xinjiang and Shanxi,etc. are the high producing area. Researching the flaxseed and its lignans has very positive meaning and enormous value space in a great deal of fields such as medicine and food industry.Breast cancer has already become a malignant tumour with highest morbidity in the whole women's world. Diet rich in lignans have exhibited anticancer activity with the lowed morbidity by 33%.It has been proved that SDG has anticancer activity, but the related mechanism is not clear. So, it is important to further study of it for probing into the early preventing and treatment of breast cancer.In this article, we compared and analyzed the yield and purity of SDG of two different separation methods, which can make for providing more simple process for large-scale preparation of SDG in workshop; Further research is performed to study the inhibitory effect of SDG on the human breast cancer xenografts in nude mice., which is meaningful to the development of flaxseed and prevention and cure of human breast cancer.