61541-06-8Relevant articles and documents
Polyphenolic constituents of cynomorium songaricum Rupr. and antibacterial effect of polymeric proanthocyanidin on methicillin-resistant staphylococcus aureus
Jin, Shangwu,Eerdunbayaer,Doi, Airi,Kuroda, Teruo,Zhang, Guixia,Hatano, Tsutomu,Chen, Guilin
experimental part, p. 7297 - 7305 (2012/10/08)
Oligomeric and polymeric flavan-3-ols were obtained by chromatographic fractionation of extracts from Cynomorium songaricum Rupr. The structure of the polymeric constituent, cynomoriitannin, was characterized using spectral and chemical data. Results from acid-catalyzed degradation indicated that cynomoriitannin is a polymeric proanthocyanidin predominantly composed of epicatechin, together with low proportions of epicatechin-3-O-gallate and catechin as extension units. The terminal unit was chiefly composed of catechin, with an admixture of epicatechin. Size exclusion chromatographic analysis demonstrated a mean polymerization degree of 14. Two new phloroglucinol adducts (cynomoriitannin-phloroglucinol adducts A and B) obtained by acid-catalyzed degradation of cynomoriitannin in the presence of phloroglucinol were characterized using spectral analyses. Six oligomeric flavan-3-ols were also identified as follows: procyanidin B3, catechin-(6'-8)-catechin, catechin-(6′-6)-catechin, epicatechin-(4β-8)- epicatechin-(4β-8) -catechin, epicatechin-(4β-6)-epicatechin-(4β-8)-catechin, and arecatannin A1, respectively. These flavan-3-ols were isolated from C. songaricum. This is the first time that this procedure has been described. The antibacterial activity of the fractions and constituents was tested against methicillin-resistant Staphylococcus aureus (MRSA). The crude acetone-water (7:3) extract had moderate activity against MRSA. Cynomoriitannin was the most effective of the plant constituents against MRSA.
Synthesis and ribonuclease A inhibition activity of resorcinol and phloroglucinol derivatives of catechin and epicatechin: Importance of hydroxyl groups
Dutta, Sansa,Basak, Amit,Dasgupta, Swagata
experimental part, p. 6538 - 6546 (2010/10/03)
The reported ribonuclease A inhibitory activity of the green tea extracts prompted us to synthesize novel catechin/epicatechin based conjugates with resorcinol and phloroglucinol with the aim to increase the number of phenolic OH groups. These are found to be more effective inhibitors of ribonuclease A as compared to catechin and epicatechin thus indicating the importance of number of phenolic OH groups for the inhibition of ribonucleolytic activity. Fluorescence studies have been carried out to evaluate the binding parameters. The protein-ligand docking studies are also performed to gain insight into the protein-polyphenols interactions. The epicatechin based polyphenols 1 and 2 also showed inhibition of angiogenin-induced angiogenesis, as determined by chorioallantoic membrane (CAM) assay.
Synthesis and preliminary anticancer activity studies of C4 and C8-modified derivatives of catechin gallate (CG) and epicatechin gallate (ECG)
Hayes, Christopher J.,Whittaker, Benjamin P.,Watson, Susan A.,Grabowska, Anna M.
, p. 9701 - 9712 (2007/10/03)
We have developed an improved and reliable method for stereoselective functionalization at C4 of naturally occurring (+)-catechin. Our method utilizes DDQ oxidation followed by trapping of the quinonemethide intermediate with allyl alcohol. The quinonemethide intermediate can be regenerated from the allyl ether by exposure to boron trifluoride diethyl etherate. This reactive intermediate can be trapped with a wide range of external nucleophiles. NBS bromination, lithium halogen exchange, and alkylation gave access to C8-allyl derivatives of (+)-catechin, and this allyl group was used in a series of cross-metathesis experiments to prepare novel dimeric catechin-derived products. Gallate ester derivatives of the novel C4- and C8-substituted catechins were prepared, and these materials were screened for potential anticancer activity in a range of human cancer cell lines. From these preliminary cytotoxicity assays (MTT) we found that C8-propyl-catechin gallate was more active (IC50 = 31 μM) than catechin gallate (CG, IC50 = 53 μM) or epicatechin gallate (ECG, IC50 = 76 μM) against the colorectal adenocarcinoma cell line HCT116. Differential sensitivity in pancreas (Pan1), bladder (RT112), stomach (MGLVA1), liver (HepG2), and fibroblasts (46Br.1G1) cell lines was also observed.
