Encontrados 15 documentos, a visualizar página 1 de 2
An inelastic neutron scattering study of dietary phenolic acids
Marques, M. P. M.; Batista de Carvalho, Luís A. E.; Valero, Rosendo; Machado, Nelson F. L.; Parker, Stewart F.The conformational preferences and hydrogen-bonding motifs of several potential chemopreventive hydroxycinnamic derivatives were determined by inelastic neutron scattering spectroscopy. The aim is to understand their recognized beneficial activity and establish reliable structure–activity relationships for these types of dietary phytochemicals. A series of phenolic acids with different hydroxyl/methoxyl ring su...
A conformational study of hydroxylated isoflavones by vibrational spectroscopy ...
Machado, N. F. L.; Batista de Carvalho, L. A. E.; Otero, J. C.; Marques, M. P. M.The conformational preferences of a series of hydroxylated isoflavones were studied by optical vibrational spectroscopy (FTIR and Raman) coupled with density functional theory (DFT) calculations. Special attention was paid to the effect of the hydroxyl substitution, due to the importance of this group in the biological activity of these systems. The isoflavones investigated – daidzein, genistein and formononeti...
New sustained release of Zidovudine Matrix tablets − cytotoxicity toward Caco-2...
Santos, Jucimary V.; Pina, Maria Eugénia T.; Marques, M. P. M.; Batista de Carvalho, Luís A. E.Objective: The aim of this study was to adjust the zidovudine (AZT) release from solid tablets to an ideal profile, by developing matrices comprising swellable polymers with nonswellable ones. Methods: Directly compressed matrices comprised different ratios of hydroxypropylmethylcellulose K15M and K100M, ethylcellulose, and methacrylic acid (Eudragit® RS PO and Eudragit® RL PO) were prepared. Technological char...
Applying vibrational spectroscopy to the study of nucleobases – adenine as a ca...
Lopes, Rui P.; Valero, Rosendo; Tomkinson, John; Marques, M. P. M.; Batista de Carvalho, Luís A. E.A full conformational study of solid-state anhydrous adenine is reported, using vibrational spectroscopy techniques coupled to DFT calculations, for the isolated molecule and the solid. In both cases, the N9Hamino tautomer was found to be the predominant species, followed by the N7H-amino form. An excellent agreement was achieved between experiment and theory, both for wavenumbers and intensities (without the n...
A conformational study of hydroxylated isoflavones by vibrational spectroscopy ...
Machado, N. F. L.; Carvalho, L. A. E. Batista de; Otero, J. C.; Marques, M. P. M.The conformational preferences of a series of hydroxylated isoflavones were studied by optical vibrational spectroscopy (FTIR and Raman) coupled with density functional theory (DFT) calculations. Special attention was paid to the effect of the hydroxyl substitution, due to the importance of this group in the biological activity of these systems. The isoflavones investigated – daidzein, genistein and formononeti...
Antioxidant phenolic esters with potential anticancer activity: solution equili...
Machado, N. F. L.; Calheiros, R.; Gaspar, A.; Garrido, J.; Borges, F.; Marques, M. P. M.The solution Raman pattern of a series of structurally related hydroxycinnamic and hydroxybenzoicesters (caffeates and gallates) with potential antioxidant/anticancer activity was studied, for different biologically significant concentrations. The spectra were assigned with the help of theoretical calculations in the light of previously reported experimental data for these compounds in the solid state. Evidence...
Antioxidant phenolic esters with potential anticancer activity: A Raman spectro...
Calheiros, R.; Machado, N. F. L.; Fiuza, S. M.; Gaspar, A.; Garrido, J.; Milhazes, N.; Borges, F.; Marques, M. P. M.A Raman study of hydroxycinnamic and hydroxybenzoic esters (caffeates, ferulates and gallates) displaying antioxidant and anticancer properties was undertaken, with particular emphasis on the analysis of the effect of the ring substituents and the nature of the ester alkyl chain on their spectroscopic features. A complete assignment of the spectra was carried out for all the compounds investigated, in the light...
New insights on the anticancer properties of dietary polyphenols
Fresco, P.; Borges, F.; Diniz, C.; Marques, M. P. M.Cancer, one of the major causes of death across the world, has shown to be a largely preventable disease, highly susceptible to modulation by dietary factors. Phenolic compounds, abundant in vegetables and fruits ubiquitous in diet, were described to play an important role as chemopreventive agents. Since conventional therapeutic and surgical approaches have not been able to control the incidence of most cancer...
Ab initio conformational study of caffeic acid
VanBesien, E.; Marques, M. P. M.A complete conformational analysis of caffeic acid, a phenolic derivative with well known antioxidant properties, was carried out by ab initio calculations, at the density funtional theory (DFT) level. Fourteen different conformers were obtained, the most stable ones being planar, as the conformational preferences of this molecule were found to be mainly determined by the stabilising effect of [pi]-electron del...
Raman spectra of putrescine, spermidine and spermine polyamines and their N-deu...
Costa, A. M. Amorim da; Marques, M. P. M.; Carvalho, L. A. E. Batista deThe experimental and calculated Raman spectra of the N-hydrogenated and N-deuterated biogenic polyamines putrescine, spermidine and spermine and of their N-hydrogenated and N-deuterated hydrochloride salts in the 2000-3400 cm-1 spectral region (at distinct temperatures) are reported and analysed. A complete assignment of the N-H, C-H and N-D stretching modes is carried out, in the light of both steric and hydro...
| Financiadores do RCAAP | |||||||
|
|
|
|
|
|
||