Soy isoflavones: database development, estrogenic activity of glycitein and hypocholesterolemic effect of daidzein

dc.contributor.advisor Patricia A. Murphy
dc.contributor.author Song, Tongtong
dc.contributor.department Food Science and Human Nutrition
dc.date 2018-08-23T14:06:20.000
dc.date.accessioned 2020-06-30T07:21:40Z
dc.date.available 2020-06-30T07:21:40Z
dc.date.copyright Thu Jan 01 00:00:00 UTC 1998
dc.date.issued 1998
dc.description.abstract <p>Soy isoflavones are proposed to have certain health protective activities, including prevention of cancer, lowering blood cholesterol levels and reducing postmenopausal bone loss. To evaluate the health-enhancing properties of isoflavones, a stable and inexpensive source of these compounds is necessary. Chemical synthesis is a practical way to obtain pure isoflavones. The synthesis of daidzein was modified to a simple, fast and high yield method by cyclizing 2,4,4'-trihydroxydeoxybenzoin (THB) with boron trifluoride etherate and methanesulphonyl chloride. The yield was >86%, and the purity of synthesized daidzein was >98%. The intermediate of daidzein synthesis, THB, with a similar structure to the isoflavones, proved to be an excellent internal-standard in soy isoflavone analysis;The estrogenic activity of glycitein was investigated by using in vivo mice uterine enlargement assay and in vitro estrogen receptor (ER) binding assay. Glycitein demonstrated an estrogenic response in mice uterine enlargement assay 3 times greater than genistein, but 30,000 times less than diethlstillbestrol (DES). Glycitein bound to mice uterine cytosol estrogen receptor proteins with an affinity similar to daidzein, but 20 times lower than genistein. This is the first report demonstrates that glycitein has estrogenic activity comparable to daidzein and genistein. Glycitein, although only accounts for 5 to 10% of the total isoflavones in soybeans, can not be neglected in evaluating isoflavones' health enhancing properties and in development of isoflavone database in foods;The dietary effects of soy protein, with or without isoflavones, daidzein and soygerm on plasma cholesterol levels were investigated in Golden Syrian hamsters. Daidzein, soygerm or soygerm extract, when added to casein diet, lowered plasma total cholesterol by 15% to 28% (P < 0.01) and LDL cholesterol by 15 to 50% (P < 0.01) in both male and female hamsters compared with the casein control group. Soy protein and isoflavone-depleted soy protein, when compared with the casein control, significantly lowered total cholesterol (P < 0.01) and LDL cholesterol (P < 0.01) levels for both genders. These data suggest that the isoflavone daidzein, soygerm and soy protein with or without isoflavones, have the ability to lower plasma cholesterol levels in hamsters.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/12528/
dc.identifier.articleid 13527
dc.identifier.contextkey 6805732
dc.identifier.doi https://doi.org/10.31274/rtd-180813-13796
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/12528
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/65906
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/12528/r_9911644.pdf|||Fri Jan 14 19:23:52 UTC 2022
dc.subject.disciplines Agriculture
dc.subject.disciplines Food Science
dc.subject.disciplines Human and Clinical Nutrition
dc.subject.disciplines Nutrition
dc.subject.keywords Food science and human nutrition
dc.subject.keywords Food science and technology
dc.title Soy isoflavones: database development, estrogenic activity of glycitein and hypocholesterolemic effect of daidzein
dc.type article
dc.type.genre dissertation
dspace.entity.type Publication
relation.isOrgUnitOfPublication 4b6428c6-1fda-4a40-b375-456d49d2fb80
thesis.degree.level dissertation
thesis.degree.name Doctor of Philosophy
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