- Benzoflavone derivatives as potent antihyperuricemic agents
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Two series of benzoflavone derivatives were rationally designed, synthesized and evaluated for their xanthine oxidase (XO) inhibitory potential. Among both series, eight compounds (NF-2, NF-4, NF-9, NF-12, NF-16, NF-25, NF-28, and NF-32) were found to exert significant XO inhibition with IC50 values lower than 10 μM. Enzyme kinetic studies revealed that the most potent benzoflavone derivatives (NF-4 and NF-28) are mixed type inhibitors of the XO enzyme. Molecular modeling studies were also performed to investigate the binding interactions of these molecules (NF-4 and NF-28) with the amino acid residues present in the active site of the enzyme. Docking results confirmed that their favorable binding conformations in the active site of XO can completely block the catalytic activity of the enzyme. Benzoflavone derivatives exhibiting potent XO enzyme inhibition also showed promising results in a hyperuricemic mice model when tested in vivo.
- Singh, Jatinder V.,Mal, Gurbachan,Kaur, Gurleen,Gupta, Manish K.,Singh, Amritpal,Nepali, Kunal,Singh, Harbinder,Sharma, Sahil,Bedi, S. Preet Mohinder
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p. 128 - 147
(2019/01/30)
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- Application of α- and β-naphthoflavones as monooxygenase inhibitors of Absidia coerulea KCh 93, Syncephalastrum racemosum KCh 105 and Chaetomium sp. KCh 6651 in transformation of 17α-methyltestosterone
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In this work, 17α-methyltestosterone was effectively hydroxylated by Absidia coerulea KCh 93, Syncephalastrum racemosum KCh 105 and Chaetomium sp. KCh 6651. A. coerulea KCh 93 afforded 6β-, 12β-, 7α-, 11α-, 15α-hydroxy derivatives with 44%, 29%, 6%, 5% and 9% yields, respectively. S. racemosum KCh 105 afforded 7α-, 15α- and 11α-hydroxy derivatives with yields of 45%, 19% and 17%, respectively. Chaetomium sp. KCh 6651 afforded 15α-, 11α-, 7α-, 6β-, 9α-, 14α-hydroxy and 6β,14α-dihydroxy derivatives with yields of 31%, 20%, 16%, 7%, 5%, 7% and 4%, respectively. 14α-Hydroxy and 6β,14α-dihydroxy derivatives were determined as new compounds. Effect of various sources of nitrogen and carbon in the media on biotransformations were tested, however did not affect the degree of substrate conversion or the composition of the products formed. The addition of α- or β-naphthoflavones inhibited 17α-methyltestosterone hydroxylation but did not change the percentage composition of the resulting products.
- Janeczko, Tomasz,Pop?oński, Jaros?aw,Koz?owska, Ewa,Dymarska, Monika,Huszcza, Ewa,Kostrzewa-Sus?ow, Edyta
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p. 178 - 184
(2018/03/26)
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- Silver-catalyzed Double Decarboxylative Radical Alkynylation/Annulation of Arylpropiolic Acids with α-keto Acids: Access to Ynones and Flavones under Mild Conditions
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Ynones are privileged building blocks in various organic syntheses of heterocyclic derivatives due to their multifunctional nature, and flavones are an important class of natural products with a wide range of biological activities. We describe the catalytic double decarboxylative alkynylation of arylpropiolic acids with α-keto acids. With Ag(I)/persulfate as the catalysis system, the valuable ynones bearing various substituents could be easily obtained. The introduction of hydroxyl substituent on ortho-site of α-keto acids make this strategy further applicable to the construction of flavone derivatives via heteroannulation in moderate to good yields with a similar silver-catalyzed system. The reactions proceed under relatively mild reaction conditions and tolerate a wide variety of functional groups. Control experiments indicated that both the reactions undergo radical processes. (Figure presented.).
- Meng, Mengting,Wang, Guofang,Yang, Liangfeng,Cheng, Kai,Qi, Chenze
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supporting information
p. 1218 - 1231
(2018/02/16)
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- 5,6-Benzoflavones as cholesterol esterase inhibitors: Synthesis, biological evaluation and docking studies
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In a continued effort to develop potent cholesterol esterase (CEase) inhibitors, a series of 5,6-benzoflavone derivatives was rationally designed and synthesized by changing the position of the benzene ring attached to the flavone skeleton in previously reported 7,8-benzoflavones. All the synthesized compounds were checked for their inhibitory potential against cholesterol esterase (CEase) using a spectrophotometric assay. Among the series of forty compounds, seven derivatives (B-10 to B-16) exhibited above 90 percent inhibition against CEase in an in vitro enzymatic assay. Compound B-16 showed the most promising activity with an IC50 value of 0.73 nM against cholesterol esterase. To determine the type of inhibition, enzyme kinetic studies were carried out for B-16, which revealed its mixed-type inhibition approach. Moreover, to figure out the key binding interactions of B-16 with the amino acid residues of the enzyme's active site, molecular protein-ligand docking studies were also performed. B-16 completely blocks the catalytic assembly of CEase and prevents it from participating in the ester hydrolysis mechanism. The favorable binding conformation of B-16 suggests its prevailing role as a CEase inhibitor. Overall, the study showed that the cisorientation of ring A with respect to the carbonyl group of ring C is responsible for the potent CEase inhibitory activity of the newly synthesized compounds.
- Singh, Jatinder V.,Kaur, Anumeet,Bhagat, Kavita,Gupta, Manish K.,Singh, Manwinder,Singh, Harbinder,Bedi, Preet Mohinder S.
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p. 490 - 502
(2018/03/28)
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- PRODUCTION OF RED BLOOD CELLS AND PLATELETS FROM STEM CELLS
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This disclosure provides methods of making a megakaryocyte-erythroid progenitor cell (MEP), comprising differentiating a stem cell into a MEP in culture in the presence of an aryl hydrocarbon receptor (AhR) agonist. In some embodiments the stem cell is a pluripotent stem cell. In some embodiments the MEP co-expresses CD41 and CD235. In some embodiments the number of MEPs produced in the culture increases exponentially. Methods of making a red blood cell (RBC) by culturing a MEP in the presence of an AhR agonist are also provided. Methods of making a megakaryocyte and/or a platelet, comprising culturing a MEP in the presence of an AhR modulator are also provided. In some embodiments the AhR modulator is an AhR antagonist. This disclosure also provides compositions comprising at least 1 million MEPs per ml and compositions in which at least 50% of the cells are MEPs.
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- Synthesis and biological evaluation of flavones and benzoflavones as inhibitors of BCRP/ABCG2
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Multidrug resistance (MDR) often leads to a failure of cancer chemotherapy. Breast Cancer Resistance Protein (BCRP/ABCG2), a member of the superfamily of ATP binding cassette proteins has been found to confer MDR in cancer cells by transporting molecules with amphiphilic character out of the cells using energy from ATP hydrolysis. Inhibiting BCRP can be a solution to overcome MDR.We synthesized a series of flavones, 7,8-benzofl avones and 5,6-benzo flavones with varying substituents at positions 3, 3′ and 4′ of the (benzo)fl avone structure. All synthesized compounds were tested for BCRP inhibition in Hoechst 33342 and pheophorbide A accumulation assays using MDCK cells expressing BCRP. All the compounds were further screened for their P-glycoprotein (P-gp) and Multidrug resistance-associated protein 1 (MRP1) inhibitory activity by calcein AM accumulation assay to check the selectivity towards BCRP. In addition most active compounds were investigated for their cytotoxicity. It was observed that in most cases 7,8-benzoflavones are more potent in comparison to the 5,6-benzoflavones. In general it was found that presence of a 3-OCH3 substituent leads to increase in activity in comparison to presence of OH or no substitution at position 3. Also, it was found that presence of 3′,4′-OCH3 on phenyl ring lead to increase in activity as compared to other substituents. Compound 24, a 7,8-benzoflavone derivative was found to be most potent being 50 times selective for BCRP and showing very low cytotoxicity at higher concentrations.
- Juvale, Kapil,Stefan, Katja,Wiese, Michael
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p. 115 - 126
(2013/10/01)
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- β-Naphthoflavone analogs as potent and soluble aryl hydrocarbon receptor agonists: Improvement of solubility by disruption of molecular planarity
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The physiological role of aryl hydrocarbon receptor (AhR) is not yet fully understood, and investigation is hampered by the limited solubility of reported AhR ligands in aqueous media. To achieve improved solubility, we focused on our previous finding tha
- Fujita, Yuji,Yonehara, Mitsuhiro,Tetsuhashi, Masashi,Noguchi-Yachide, Tomomi,Hashimoto, Yuichi,Ishikawa, Minoru
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experimental part
p. 1194 - 1203
(2010/04/06)
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- Benzoflavone activators of the cystic fibrosis transmembrane conductance regulator: Towards a pharmacophore model for the nucleotide-binding domain
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Our previous screen of flavones and related heterocycles for the ability to activate the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel indicated that UCCF-029, a 7,8-benzoflavone, was a potent activator. In the present study, we describe the synthesis and evaluation, using cell-based assays, of a series of benzoflavone analogues to examine structure-activity relationships and to identify compounds having greater potency for activation of both wild type CFTR and a mutant CFTR (G551D-CFTR) that causes cystic fibrosis in some human subjects. Using UCCF-029 as a structural guide, a panel of 77 flavonoid analogues was prepared. Analysis of the panel in FRT cells indicated that benzannulation of the flavone A-ring at the 7,8-position greatly improved compound activity and potency for several flavonoids. Incorporation of a B-ring pyridyl nitrogen either at the 3- or 4-position also elevated CFTR activity, but the influence of this structural modification was not as uniform as the influence of benzannulation. The most potent new analogue, UCCF-339, activated wild-type CFTR with a Kd of 1.7 μM, which is more active than the previous most potent flavonoid activator of CFTR, apigenin. Several compounds in the benzoflavone panel also activated G551D-CFTR, but none were as active as apigenin. Pharmacophore modeling suggests a common binding mode for the flavones and other known CFTR activators at one of the nucleotide-binding sites, allowing for the rational development of more potent flavone analogues.
- Springsteel, Mark F.,Galietta, Luis J. V.,Ma, Tonghui,By, Kolbot,Berger, Gideon O.,Yang, Hong,Dicus, Christopher W.,Choung, Wonken,Quan, Chao,Shelat, Anang A.,Guy, R. Kiplin,Verkman,Kurth, Mark J.,Nantz, Michael H.
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p. 4113 - 4120
(2007/10/03)
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- Photochemical transformations in 1-(o-hydroxyaryl)-1,3-diketones
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Irradiation (using pyrex glass filter) of o-hydroxybenzoylacetophenone (1a), o-hydroxybenzoylacetone (1b), 2-hydroxy-1-naphthoylacetophenone (5a), 2-hydroxy-1-naphthoylacetone (5b) and 1-hydroxy-2-naphthoylacetone (9) in Br2/CHCl3 and I2/MeOH solutions leads to various chromone derivatives.Parallel reactions of these 1,3-diketones in the dark record no perceptible change in them.Enhanced photoenolisation of the diketones, in the presence of bromine or iodine, is deemed to be the key step in these transformations.
- Garg, S.,Ishar, M. P. S.,Sarin, R.,Gandhi, R. P.
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p. 1123 - 1128
(2007/10/02)
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