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Monteiro Martins Minas da Piedade, Maria de Fátima
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- Improvement of glycaemia and endothelial function by a new low-dose curcuminoid in an animal model of type 2 diabetesPublication . Oliveira, Sara; Alfredo, Tamaeh Monteiro-Alfredo; Tamaeh Monteiro; Henriques, Rita; Ribeiro; Seica, Raquel; Cruz, Maria Teresa; Cabral, C; Fernandes, Rosa; Piedade, Maria; Robalo, Maria Paula; Matafome, Paulo; Silva, SóniaCurcumin has been suggested as a promising treatment for metabolic diseases, but the high doses required limit its therapeutic use. In this study, a new curcuminoid is synthesised to increase curcumin anti-inflammatory and antioxidant potential and to achieve hypoglycaemic and protective vascular effects in type 2 diabetic rats in a lower dose. In vitro, the anti-inflammatory effect was determined through the Griess reaction, and the antioxidant activity through ABTS and TBARS assays. In vivo, Goto-Kakizaki rats were treated for 2 weeks with the equimolar dose of curcumin (40 mg/kg/day) or curcuminoid (52.4 mg/kg/day). Fasting glycaemia, insulin tolerance, plasma insulin, insulin signalling, serum FFA, endothelial function and several markers of oxidative stress were evaluated. Both compounds presented a significant anti-inflammatory effect. Moreover, the curcuminoid had a marked hypoglycaemic effect, accompanied by higher GLUT4 levels in adipose tissue. Both compounds increased NO-dependent vasorelaxation, but only the curcuminoid exacerbated the response to ascorbic acid, consistent with a higher decrease in vascular oxidative and nitrosative stress. SOD1 and GLO1 levels were increased in EAT and heart, respectively. Altogether, these data suggest that the curcuminoid developed here has more pronounced effects than curcumin in low doses, improving the oxidative stress, endothelial function and glycaemic profile in type 2 diabetes.
- Novel "ruthenium cyclopentadienyl" - peptide conjugate complexes against human FGFR(+) breast cancerPublication . Machado, João Franco; Machuqueiro, Miguel; Marques, Fernanda; Robalo, M. Paula; Piedade, M. Fatima M.; Garcia, M. Helena; Correia, João D. G.; Morais, TâniaIn this work we explored the possibility of improving the selectivity of a cytotoxic Ru complex [RuCp(PPh3)(2,2'-bipy)][CF3SO3] (where Cp = eta(5)-cyclopentadienyl) TM34 towards FGFR(+) breast cancer cells. Molecular dynamics (MD) simulations of TM34 in a phosphatidylcholine membrane model pinpointed the cyclopentadienyl group as a favorable derivatization position for the peptide conjugation approach. Three new Ru(II) complexes presenting a functionalized eta(5)-cyclopentadienyl were synthesized, namely [Ru(eta(5)-C5H4COOH)(2,2'-bipy)(PPh3][CF3SO3] (TM281) and its precursors, [Ru(eta(5)-C5H4COOCH2CH3)(eta(2)-2,2'-bipy)(PPh3)][CF3SO3] (3) and [Ru(eta(5)-C5H4COOCH2CH3)(PPh3)(2)Cl] (2). Complex TM281 was prepared by the hydrolysis of the ethyl ester group appended to the eta(5)-cyclopentadienyl ligand of complex 3 with K2CO3 in water/acetonitrile, followed by mild protonation using an ion exchange resin. The newly synthesized complexes were fully characterized by NMR, FTIR and UV-vis spectroscopic techniques. Also, electrochemical studies were carried out by means of cyclic voltammetry in order to evaluate the stability of the compounds. Single crystal X-ray diffraction studies were carried out for compounds 3 and TM281 which crystallized in the monoclinic system, space group P21/n. The unprecedented synthesis and characterization of three half-sandwich ruthenium(II)-cyclopentadienyl peptide conjugates and their preliminary biological evaluation against human FGFR(+) and FGFR(-) breast cancer cells are also reported.
- Synthesis of Substituted 4-Arylamine-1,2-naphthoquinones in One-Pot Reactions Using CotA-Laccase as BiocatalystPublication . Sousa, Ana Catarina; Santos, Iolanda; Piedade, M. Fatima M.; Martins, Lígia O.; Robalo, M. PaulaAn efficient and environmentally benign biocatalytic strategy for the synthesis of substituted 4-arylamino-1,2-naphthoquinones was developed, through a cross-coupling reaction in which the 1,2-naphthoquinone nucleus, formed in the biocatalytic process mediated by CotA-laccase from Bacillus subtilis, is the key synthetic intermediate. Electrochemical data and kinetic parameters were determined revealing a significant higher specificity of CotA-laccase for 4-amino-3-hydroxynaphthalene-1-sulfonic acid (AHNSA). This ability of CotA-laccase to discriminate between oxidisable aromatic amines allows the set-up of one-pot reactions in the presence of the enzyme, between AHNSA and a set of appropriate aromatic amines under mild reaction conditions.