Encontrados 9 documentos, a visualizar página 1 de 1
Fast Three Dimensional Pharmacophore Virtual Screening of New Potent Non-Steroi...
Neves, Marco A. C.; Dinis, Teresa C. P.; Colombo, Giorgio; Melo, M. Luísa Sá eSuppression of estrogen biosynthesis by aromatase inhibition is an effective approach for the treatment of hormone sensitive breast cancer. Third generation non-steroid aromatase inhibitors have shown important benefits in recent clinical trials with postmenopausal women. In this study we have developed a new ligand-based strategy combining important pharmacophoric and structural features according to the postu...
Efficient Chemoenzymatic Synthesis, Cytotoxic Evaluation, and SAR of Epoxysterols
Carvalho, João F. S.; Silva, M. Manuel Cruz; Moreira, João N.; Simões, Sérgio; Melo, M. Luísa Sá eA library of diastereomerically pure epoxysterols, prepared by combining chemical and enzymatic methodologies, was evaluated for cytotoxicity toward human cancer and noncancer cell lines. Unsaturated steroids were oxidized by magnesium bis(monoperoxyphthalate) hexahydrate in acetonitrile, and the resulting epimeric epoxides were enzymatically separated using Novozym 435 or lipase AY. Some of the synthesized epo...
Biochemical and computational insights into the anti-aromatase activity of natu...
Neves, Marco A. C.; Dinis, Teresa C. P.; Colombo, Giorgio; Melo, M. Luisa Sá eHigh levels of endogenous estrogens are associated with increased risks of breast cancer. Estrogen levels are mainly increased by the activity of the aromatase enzyme and reduced by oxidative/conjugative metabolic pathways. In this paper, we demonstrate for the first time that catechol estrogen metabolites are potent aromatase inhibitors, thus establishing a link between aromatase activity and the processes inv...
Combining Computational and Biochemical Studies for a Rationale on the Anti-Aro...
Neves, Marco A. C.; Dinis, Teresa C. P.; Colombo, Giorgio; Melo, M. Luísa Sá eAromatase, an enzyme of the cytochrome P450 family, is a very important pharmacological target, particularly for the treatment of breast cancer. The anti-aromatase activity of a set of natural polyphenolic compounds was evaluated in vitro. Strong aromatase inhibitors including flavones, flavanones, resveratrol, and oleuropein, with activities comparable to that of the reference anti-aromatase drug aminoglutethi...
Regioselective enzymatic acylation of vicinal diols of steroids
Silva, M. Manuel Cruz; Riva, Sergio; Melo, M. Luísa Sá eMonoacylated derivatives of a complete set of 2,3- and 3,4-vicinal diols of steroids were prepared by regioselective lipase-catalysed transesterification reactions. The enzymes displayed different selectivities towards the vicinal diols depending on the configuration of the hydroxyl groups. ; http://www.sciencedirect.com/science/article/B6THR-4FGX84H-2/1/c23744db4c590d02acf7c82018be5720
Highly selective lipase-mediated discrimination of diastereomeric 5,6-epoxyster...
Silva, M. Manuel Cruz; Riva, Sergio; Melo, M. Luísa Sá eStereoisomerically pure 3[beta]-hydroxy-5,6-epoxysteroids were obtained by combining selective chemical methods for [alpha]- and [beta]-epoxidation of [Delta]5-unsaturated steroids with enzymatic stereoselective esterification of the 3[beta]-hydroxyl group. 5[beta],6[beta]-Epoxy-3[beta]-hydroxysteroids were efficiently acylated by Novozym 435 and lipase AK, whereas 5[alpha],6[alpha]-epoxy-3[beta]-hydroxysteroid...
The biocatalyzed stereoselective preparation of polycyclic cyanohydrins
Silva, M. Manuel Cruz; Melo, M. Luísa Sá e; Parolin, Marco; Tessaro, Davide; Riva, Sergio; Danieli, BrunoThe enzyme-mediated preparation of enantiomerically or diastereomerically enriched polycyclic cyanohydrins has been investigated. Oxynitrilase-catalyzed cyanurations gave excellent results with the bicyclic aldehydes tested. On the other hand, enantio- or diastereoselective acylation, catalyzed by lipase PS or subtilisin, proved to be a more versatile methodology, giving good results even with sterically hinder...
Ultrasound assisted remote functionalization of non-activated carbon atoms: eff...
Costa, Saul C. P.; Moreno, M. J. S. Miranda; Melo, M. Luísa Sá e; Neves, André S. CamposUltrasonic irradiation of bromohydrins in the presence of (diacetoxyiodo)benzene and I2 generates alkoxyl radicals which lead in situ to intramolecular hydrogen abstraction on the C-19 non-activated carbon atoms in steroids producing tetrahydrofurans selectively in very good yields. Photolysis was less effective in promoting such conversions. ; http://www.sciencedirect.com/science/article/B6THS-3YF4638-1R/1/...
Preparation and Electrooxidative SO-Extrusion of Halogenated 7-Thiabicyclo[2.2....
Thiemann, Thies; Melo, M. Luísa Sá e; Neves, André S. Campos; Li, Yuanqiang; Mataka, Shuntaro; Tashiro, Masashi; Geißler, Uwe; Walton, DavidHalogenated thiophenes have been cycloadded oxidatively to maleimides to give halogenated thiabicyclo[2.2.1]heptene S-oxides which have been subjected to an electrochemical extrusion of SO to give various halogeno-substituted phthalimides. ; http://dx.doi.org/10.1039/a707882j
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