Loading...
180 results
Search Results
Now showing 1 - 10 of 180
- Ionic Liquids Synthesis – MethodologiesPublication . Ferraz, Ricardo; Prudêncio, Cristina; Vieira, Mónica; Fernandes, Rúben; Noronha, João Paulo; Petrovski, ZeljkoIonic Liquids (IL) are salts with at least one organic cation. The term “Ionic Liquid” has been restricted to salts with melting point below 100° C [1]. In the recent years, (ILs) have gained popularity in science and technology. The large number of possible cation/ anion combinations allows a great variety of tunable interactions; also their unique properties and characteristics make it a promising and an attractive to work with in several fields. However, how ILs are produced? This editorial pretends to make a brief commentary of some of the main methodologies of ILs synthesis
- Evaluation of valproic acid toxicity in duckweed, Lemna minorPublication . Machado, Beatriz; Prudêncio, Cristina; Ferraz, Ricardo; Barros, PiedadeIn the last years the contamination of water caused by drugs has increased significantly. The main cause is the increase of the number and quantities of drugs that is being used. Many of these compounds cannot be removed effectively by wastewater treatment plants. This problem affects the water cycle and, consequently, all the environment as well as the human health, so it is important to find new methods that can help the removal of drugs from the water. This research is aimed to understand the influence of different concentrations of valproic acid on the growth of the duckweed Lemna minor. After 7 days of exposure it was analysed the number of fronds, the length of the root and the chlorophylls content. The chlorophylls of the Lemna minor samples were analysed by spectrophotometry. The number of fronds was influenced by the concentration of valproic acid. The higher concentrations (0,1 mg/mL; 0,05 mg/mL; 0,025 mg/mL) showed an inhibitory effect while the lower concentrations (0,005 mg/mL; 0,0001 mg/mL) showed a stimulating effect. Relative to the control, the number of fronds was lower in the higher concentrations and higher in the lower concentrations. The root length was affected in all the concentrations. Comparative to the control the higher concentrations presented a diminution of the root’s length while the higher ones had an increase. Like the other parameters the concentration of chlorophylls was affected in all the samples. In the higher concentrations (0,1 mg/mL; 0,05 mg/mL; 0,025 mg/mL) the quantity was lower, comparatively to the control, and in the lower ones (0,01 mg/mL; 0,005 mg/mL; 0,0001 mg/mL) it was higher. In general, the valproic acid influenced all the parameters evaluated: number of fronds, length of the root and concentration of chlorophylls. In the higher concentrations it is notable an inhibitory effect while the lower concentrations have a stimulating one.
- Antitumor Activity of Ionic Liquids Based on AmpicillinPublication . Ferraz, Ricardo; Costa-Rodrigues, Joao; Fernandes, Maria H.; Santos, Miguel M.; Marrucho, Isabel M.; Rebelo, Luís Paulo N.; Prudêncio, Cristina; Noronha, João Paulo; Petrovski, Željko; Branco, Luís C.Significant antiproliferative effects against various tumor cell lines were observed with novel ampicillin salts as ionic liquids. The combination of anionic ampicillin with appropriate ammonium, imidazolium, phosphonium, and pyridinium cations yielded active pharmaceutical ingredient ionic liquids (API-ILs) that show potent antiproliferative activities against five different human cancer cell lines: T47D (breast), PC3 (prostate), HepG2 (liver), MG63 (osteosarcoma), and RKO (colon). Some API-ILs showed IC50 values between 5 and 42 nm, activities that stand in dramatic contrast to the negligible cytotoxic activity level shown by the ampicillin sodium salt. Moreover, very low cytotoxicity against two primary cell lines—skin (SF) and gingival fibroblasts (GF)—indicates that the majority of these API-ILs are nontoxic to normal human cell lines. The most promising combination of antitumor activity and low toxicity toward healthy cells was observed for the 1-hydroxyethyl-3-methylimidazolium–ampicillin pair ([C2OHMIM][Amp]), making this the most suitable lead API-IL for future studies.
- New ionic liquids and salts derived from β-Lactam antibioticsPublication . Ferraz, Ricardo; Branco, Luís; Marrucho, Isabel; Fernandes, Rúben; Prudêncio, Cristina; Noronha, João Paulo; Petrovski, ZeljkoIn recent years ionic liquids (ILs) have been increasing the popularity and the number of applications. Ionic liquids were used mainly as solvent in organic synthesis, but in recent years they are also used in analytical chemistry, separation chemistry and material science. Additional to significant developments in their chemical properties and applications, ionic liquids are now bringing unexpected opportunities at the interface of chemistry with the life sciences. Ionic liquids (ILs) are currently defined as salts that are composed solely of cations and anions which melt below 100ºC. Our goal in this work is to explore the dual activity of the ionic liquids, due to the presence of two different ions, an anion with bacterial activity as β-lactam antibiotics and different kinds of cations. In this work the anions of ILs and salts were derived from three different antibiotics: ampicillin, penicillin and amoxicillin. The cations were derived from substituted ammonium, phosphonium pyridinium and methylimidazolium salts, such as: tetraethyl ammonium, trihexiltetradecilphosphonium, cetylpyridinium, choline (an essential nutrient), 1-ethyl-3-methylimidazolium, and 1-ethanol-3-methyl imidazolium structures. Commercial ammonium and phosponium halogen salts were first transformed into hydroxides on ionic exchange column (Amberlite IRA-400) in methanol. The prepared hydroxides were then neutralized with β-lactam antibiotics. After crystallization we obtained pure ILs and salts containing β-lactam antibiotics. This work presents a novel method for preparation of new salts of antibiotics with low melting point and their chemistry and microbiological characterization.
- Diabetic neuropathy and oxidative stress: a systematic review focused on oxidative stress biomarkers analysisPublication . Cunha, Sofia; Nascimento, Ana Paula; Vieira, Mónica; Prudêncio, CristinaDiabetic neuropathy is a worldwide disease with great impact in modern society. Diabetes may lead to the overproduction of reactive oxygen species, resulting in an imbalance in body’s redox homeostasis. Oxidative stress is pointed as an important phenomenon associated with several disease states, including diabetic neuropathy.
- Childhood depression in a portuguese sample: towards an emerging prevention programPublication . Correia, Liliana; Gianformaggio, Rafael; Douglas, Kissungo; Teixeira, Ricardo J.; Prudêncio, CristinaDepression can be defined as a constant shifting of one’s humor. Children’s depression results from the interaction between environmental variables and genetic predisposition factors. Depression has increased notably in the past century in this population. In Portugal, data concerning depression in children are very scarce.
- Estudo de novos compostos sintéticos para o tratamento do cancro da mamaPublication . Magalhães, Ângela; Vieira, Filipa Quintela; Vieira, Mónica; Ferraz, Ricardo; Prudêncio, Cristina; Jerónimo, Carmen; Silva, ReginaO cancro da mama (CaM) apesar dos avanços no tratamento e deteção precoce desta neoplasia, permanece como uma das principais causas de morte por cancro nas mulheres devido à progressão e disseminação sistémica. Cerca de 80% dos CaM invasivos são positivos para o recetor de estrogénios sendo candidatos à terapia de bloqueio. No entanto, 30- 40% das doentes desenvolvem recidiva, evoluindo para um fenótipo hormono-resistente. Nestes estadios, as opções terapêuticas apresentam uma reduzida eficácia. Assim, é importante a descoberta de novos agentes anti-neoplásicos. Os líquidos iónicos e as quinoxalinas são sais orgânicos com potencial anti-tumoral que têm vindo a ser alvo de estudo na indústria farmacêutica devido às suas propriedades medicinais e composição flexível no caso dos líquidos iónicos.
- Distúrbios alimentares – anorexia: da auto-imagem às atitudes e comportamentosPublication . Fernandes, Rúben; Reis, AC.; Esteves-Pinto, A.; Fonte, R.; Coelho, Pedro; Prudêncio, CristinaSão ainda escassos os estudos sobre distúrbios alimentares em alunos do ensino universitário em Portugal. Estudos mais recentes indicam que poderá existir uma predisposição genética para a anorexia, no entanto, os fatores ambientais são os que apresentam um papel determinante, em particular factores sócio-económicos, psicológicos, biológicos entre outros. Entre esses diversos factores, sabe-se que a auto-imagem pode relacionar-se como múltiplos distúrbios alimentares como a anorexia e bulimia.
- Repurposing antiplasmodial leads for cancer: Exploring the antiproliferative effects of N-cinnamoyl-aminoacridinesPublication . Fonte, Mélanie; Rôla, Catarina; Santana, Sofia; Ferraz, Ricardo; Prudêncio, Miguel; Almeida, Joana; Ferraz, Ricardo; Prudêncio, Cristina; Teixeira, Cátia; Gomes, PaulaDrug repurposing and rescuing have been widely explored as cost-effective approaches to expand the portfolio of chemotherapeutic agents. Based on the reported antitumor properties of both trans-cinnamic acids and quinacrine, an antimalarial aminoacridine, we explored the antiproliferative properties of two series of N-cinnamoyl-aminoacridines recently identified as multi-stage antiplasmodial leads. The compounds were evaluated in vitro against three cancer cell lines (MKN-28, Huh-7, and HepG2), and human primary dermal fibroblasts. One of the series displayed highly selective antiproliferative activity in the micromolar range against the three cancer cell lines tested, without any toxicity to non-carcinogenic cells.
- Ensino e aprendizagem da Bioquímica em Ciências da Saúde: retenção de conhecimentos adquiridos e sucesso académico versus tipo de exame preferido, sua preparação e stress associadoPublication . Prudêncio, Cristina; Fernandes, Rúben; Ferraz, Ricardo; Vieira, Mónica; Fonte, RosáliaNum contexto de reestruturação da formação em Ciências da Saúde baseada em competências, torna-se necessário estudar as diferentes formas de avaliação e o stress que lhe está associado, observando de que forma estas poderão interferir no sucesso académico dos alunos e real aquisição de competências. O objectivo do trabalho foi avaliar estas questões no âmbito da Bioquímica de diferentes cursos de Tecnologias da Saúde. A metodologia foi adaptada de controlled pre-test-postest, e os resultados obtidos apontam para que os alunos que mais estudam, ao longo do ano e não no “sprint final”, parecem possuir menor stress e serem melhor sucedidos.