Conformational behaviour of antioxidant chromones. A vibrational spectroscopy study

Machado, Nelson; Valero, Rosendo; Domingos, Helder S.; Tomkinson, J.; Carvalho, Luís A. E. Batista de; Otero, Juan C.; Marques, M. P. M.

doi:10.1016/j.vibspec.2012.06.010

Cited by 17 publications

(12 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…pH, temperature, ionic strength or exposure to drugs). 22,27,28 Following previous studies by the authors on dietary polyphenolic compounds -both regarding their structural and conformational preferences 17,[29][30][31][32][33][34][35][36][37][38][39][40] and their chemopreventive and/or chemotherapeutic properties towards several cancer cells -the present work reports the effect of daidzein on the biochemical profile of two human breast cancer cell lines: MCF-7 (estrogendependent, ER + ) and MDA-MB-231 (estrogen-independent, ER -). The results thus obtained are expected to help establishing an accurate balance between DAID´s antioxidant and prooxidant capacities, aiming at a prospective use against breast cancer: either as a chemopreventive agent (sole or in combination with other flavones) or as an adjuvant in chemotherapy (coupled with conventional drugs such as tamoxifen, paclitaxel, docetaxel, methotrexate, gemcitabine or doxorubicin 41,42 and cisplatin.…”

Section: A Introductionmentioning

confidence: 88%

Raman microspectroscopy for probing the impact of a dietary antioxidant on human breast cancer cells

et al. 2016

View full text Add to dashboard Cite

Breast cancer is the second most common type of cancer worldwide and the most frequent among women, being the fifth cause of death from neoplastic disease. Since this is an oxidative-stress related neoplasia, it is largely preventable. A dietary isoflavone abundant in soybean -daidzein -was currently investigated as to its chemopreventive and/or chemotherapeutic properties towards the human MDA-MB-231 (metastatic, estrogen-unresponsive) and MCF-7 (estrogen-responsive) breast cancer cell lines. Biological assays for evaluation of antitumour and anti-invasive activities were combined with state-of-theart vibrational microspectroscopy techniques. At 50 and 100 µM concentrations and 48 h incubation time, daidzein was found to induce a marked decrease in cell viability (ca. 50%) for MDA-MB-231 and MCF-7 cells (respectively ca. 50% and 42%) and 40% inhibition of cell migration 48 h. MicroRaman analysis of fixed cells upon exposure to this isoflavone unveiled its metabolic impact on both cell lines. Multivariate data analysis (unsupervised PCA) led to a clear discrimination between control and DAID-exposed cells, with distinctive effects on their biochemical profile, particularly regarding DNA, lipids and protein components, in a cell-dependent way. This is the first reported study on the impact of dietary antioxidants on cancer cells by microRaman techniques. A IntroductionCancer is one of the major causes of morbidity and mortality worldwide, closely following cardiovascular disorders. Breast carcinoma, in particular, is an important public health problem since it is the second most lethal cancer among women worldwide: according to the World Health Organisation (WHO), it affects 28% of the women in Europe 1 , being the second most lethal cancer type in Portugal (16%). 2 Epidemiological evidence has demonstrated a clear difference in breast cancer incidence between eastern and western countries, asian women being the least affected, which can be closely related to dietary habits.Phytochemicals, secondary plant metabolites widespread in fruits, vegetables, cereals and beverages such as tea, coffee and wine, and very abundant in a mediterranean diet, are an abundant source of dietary antioxidants known to significantly decrease the harmful effect of oxidative species, thus being promising chemopreventive agents towards carcinogenesis. [3][4][5][6] Actually, several studies have established a direct relationship between the intake of polyphenols and the prevention of oxidative stress-induced diseases, namely neurodegenerative and cardiovascular disorders, and some types of cancer. 7,8 The isoflavone daidzein (DAID), in particular, is the second most abundant component of soybean (following genistein), a growingly consumed food product, which renders this isoflavone a very suitable target of study regarding its potential health beneficial effects. In addition, it exhibits structural and functional similarities to the endogenous hormone estrogen 9 (Fig. 1). Since some breast cancers are estrogen-dependent (ER + ), DAID may...

show abstract

Section: A Introductionmentioning

confidence: 88%

Raman microspectroscopy for probing the impact of a dietary antioxidant on human breast cancer cells

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Given that the widely used Merrick's [45] scale factors do not adequately reproduce the experimental wavenumbers for these highly unsaturated chemical systems, a set of four different factors proposed by the authors for chromone derivatives [46] was used: 1.18 for the low wavenumber region (below 175 cm À1 ); 1.05 from 175 to 400 cm À1 ; 0.985 for the interval between 400 and 1500 cm À1 ; and 0.957 above 3000 cm À1 . For the wavenumber range between 1500 and 1850 cm À1 Merrick's scale factor of 0.9614 [45] was used.…”

Section: Quantum Mechanical Calculationsmentioning

confidence: 99%

A conformational study of hydroxyflavones by vibrational spectroscopy coupled to DFT calculations

Machado

Carvalho

Otero

et al. 2013

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

Self Cite

View full text Add to dashboard Cite

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. The conformational preferences of a series of hydroxyflavones were studied by Raman and FTIR spectroscopies, coupled to Density Functional Theory calculations. Special attention was paid to the effect of hydroxyl substitution, due to its importance on the biological activity of these compounds. Their conformational preferences were found to be determined mainly by the orientation of the hydroxylic groups at C 7 and within the catechol moiety, leading to the occurrence of distinct conformers in the solid state. A complete assignment of the experimental spectra was carried out for these molecules, in the light of their most stable conformers and the corresponding predicted vibrational pattern.

show abstract

“…Furthermore, this effect is exacerbated when the C-3 position is occupied by a carboxylic group, with the spatial proximity between the H atom and the C4=O leading to a strong H-bond type interaction, and forming a rather stable 6-atom ring, as observed in the case of a 5-OH ( Figure 2 IV,V), which is reflected in the anomalous high pka presented by such a compound of ca. 8.85 [ 130 ].…”

Section: Structure-activity Relationship: What Do We Know?mentioning

confidence: 99%

Addressing Facts and Gaps in the Phenolics Chemistry of Winery By-Products

Machado

Domínguez‐Perles

2017

Molecules

View full text Add to dashboard Cite

Grape and wine phenolics display a noticeable structural diversity, encompassing distinct compounds ranging from simple molecules to oligomers, as well as polymers usually designated as tannins. Since these compounds contribute critically to the organoleptic properties of wines, their analysis and quantification are of primordial importance for winery industry operators. Besides, the occurrence of these compounds has been also extensively described in winery residues, which have been pointed as a valuable source of bioactive phytochemicals presenting potential for the development of new added value products that could fit the current market demands. Therefore, the cumulative knowledge generated during the last decades has allowed the identification of the most promising compounds displaying interesting biological functions, as well as the chemical features responsible for the observed bioactivities. In this regard, the present review explores the scope of the existing knowledge, concerning the compounds found in these winery by-products, as well as the chemical features presumably responsible for the biological functions already identified. Moreover, the present work will hopefully pave the way for further actions to develop new powerful applications to these materials, thus, contributing to more sustainable valorization procedures and the development of newly obtained compounds with enhanced biological properties.

show abstract

Conformational behaviour of antioxidant chromones. A vibrational spectroscopy study

Cited by 17 publications

References 41 publications

Raman microspectroscopy for probing the impact of a dietary antioxidant on human breast cancer cells

Raman microspectroscopy for probing the impact of a dietary antioxidant on human breast cancer cells

A conformational study of hydroxyflavones by vibrational spectroscopy coupled to DFT calculations

Addressing Facts and Gaps in the Phenolics Chemistry of Winery By-Products

Contact Info

Product

Resources

About