- Preparation method and application of hydroxyl cinnamyl ester type catechin
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The invention relates to a preparation method and application of hydroxyl cinnamyl ester type catechins. The hydroxyl cinnamyl ester type catechins comprise four catechins which are respectively namedas epicatechin trans-coumarate, epicatechin trans-caffeic acid ester, epigallocatechin trans-coumarate and epigallocatechin trans-caffeic acid ester. The hydroxyl cinnamyl ester type catechins are prepared by the following steps: carrying out four steps of full acetylation on epicatechin and epigallocatechin, removal of acetyl on phenolic hydroxyl, silanizing of phenolic hydroxyl and removal of 3-acetyl, then respectively esterifying with acetylated caffeic acid or coumaric acid acyl chloride, and removing a protecting group. The preparation method of the four catechins is simple and mild inconditions, and can be completed under general experimental conditions. The four hydroxycinnamyl ester type catechins have a certain inhibition effect on the activity of alpha-glucosidase, can be usedfor hypoglycemic drugs, and have important significance in the fields of agriculture and medicine.
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Paragraph 0065; 0071; 0074-0075
(2020/06/24)
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- ACYLATED CATECHIN POLYPHENOLS AND METHODS OF THEIR USE FOR THE TREATMENT OF CANCER
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Disclosed herein are acylated active agents and methods of their use, e.g., for modulating a cancer marker or for treating cancer.
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Page/Page column 47; 57
(2019/12/28)
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- Structure-activity relationships for inhibition of human 5α-reductases by polyphenols
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The enzyme steroid 5α-reductase (EC 1.3.99.5) catalyzes the NADPH-dependent reduction of the double bond of a variety of 3-oxo-Δ4 steroids including the conversion of testosterone to 5α-dihydrotestosterone. In humans, 5α-reductase activity is critical for certain aspects of male sexual differentiation, and may be involved in the development of benign prostatic hyperplasia, alopecia, hirsutism, and prostate cancer. Certain natural products contain components that are inhibitors of 5α-reductase, such as the green tea catechin (-)-epigallocatechin gallate (EGCG). EGCG shows potent inhibition in cell-free but not in whole-cell assays of 5α-reductase. Replacement of the gallate ester in EGCG with long-chain fatty acids produced potent 5α-reductase inhibitors that were active in both cell-free and whole-cell assay systems. Other flavonoids that were potent inhibitors of the type 1 5α-reductase include myricetin, quercitin, baicalein, and fisetin. Biochanin A, daidzein, genistein, and kaempferol were much better inhibitors of the type 2 than the type 1 isozyme. Several other natural and synthetic polyphenolic compounds were more effective inhibitors of the type 1 than the type 2 isozyme, including alizarin, anthrarobin, gossypol, nordihydroguaiaretic acid, caffeic acid phenethyl ester, and octyl and dodecyl gallates. The presence of a catechol group was characteristic of almost all inhibitors that showed selectivity for the type 1 isozyme of 5α-reductase. Since some of these compounds are consumed as part of the normal diet or in supplements, they have the potential to inhibit 5α-reductase activity, which may be useful for the prevention or treatment of androgen-dependent disorders. However, these compounds also may adversely affect male sexual differentiation.
- Hiipakka, Richard A.,Zhang, Han-Zhong,Dai, Wei,Dai, Qing,Liao, Shutsung
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p. 1165 - 1176
(2007/10/03)
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- CHARACTERIZATION AND TRYPSIN INHIBITOR ACTIVITY OF PROANTHOCYANIDINS FROM VICIA FABA
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In a chemical investigation epicatechin, epigallocatechin, the procyanidins B-1, B-3 and B-4, and the prodelphinidins gallocatechin-(4α,8)-catechin, gallocatechin-(4α,8)-epicatechin and gallocatechin-(4α,8)-epigallocatechin have been isolated from the testa of faba beans and characterized by means of spectroscopic methods.Proanthocyanidin samples were compared for their trypsin inhibitory activity.The results suggest that the degree of polymerization, the number of phenolic hydroxyl groups and the 2,3-stereochemistry of the constituent units affect remarkably the strength of the inhibition.
- Helsper, Johannes P. F. G.,Kolodziej, Herbert,Hoogendijk, Johanna M.,Norel, Arend van
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p. 1255 - 1260
(2007/10/02)
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