http://hdl.handle.net/10174/183 2026-04-06T13:05:00Z http://hdl.handle.net/10174/24380 Title: Síntese de fosfonatos e avaliação da sua atividade anti-inflamatória e antioxidante Authors: Teixeira, António P. S.; Martins, M. Rosário; Teixeira, Fátima C.; Lopes, Daniela; Parente, Helena Abstract: Os fosfonatos são uma classe importante de compostos químicos, utilizados na terapia de patologias ósseas, tais como a doença de Paget, hipercalcémia e osteólise associada a tumores, devido à sua capacidade para inibir a perda óssea. Estes compostos têm também demonstrado atividade anticancerígena in vitro com inibição da proliferação celular de várias linhas tumorais [1,2]. Neste trabalho procedeu-se à síntese de ácidos fosfónicos e ésteres monofosfónicos, sintetizados a partir de aldeídos, bem como à avaliação da atividade antioxidante e da atividade anti-inflamatória dos compostos obtidos. A atividade antioxidante foi avaliada por três métodos diferentes, nomeadamente o método do radical DPPH, o sistema β-caroteno/ácido linoleico e o poder redutor total, com vista a inferir sobre o mecanismo de ação. Os estudos de atividade anti-inflamatória in vitro foram também avaliados por diferentes mecanismos de ação, com determinação da capacidade de inibição da desnaturação da albumina e de inibição da atividade de lipoxigenases. A toxidade dos fosfonatos em estudo foi avaliada utilizando o teste de letalidade em Artemia salina. Os compostos em estudo apresentaram atividade antioxidante, tendo-se observado que o composto (E)-3-(2-nitrofenil)-1-hidroxipropen-2-ilfosfonato de dimetilo foi o que apresentou melhor resultados na capacidade para sequestrar radicais, de poder redutor total, bem como na capacidade de proteção do substrato lipídico. Alguns dos compostos apresentaram também elevada capacidade anti-inflamatória, designadamente os ésteres 1-(4-bromofenil)-1-hidroximetilfosfonato de dimetilo e 1-(4-formilfenil)-1-hidroximetilfosfonato de metilo, os quais apresentaram elevado potencial para inibir a atividade da lipoxigenase. 2018-04-09T23:00:00Z http://hdl.handle.net/10174/19955 Title: Adsorption of pesticides onto activated carbons from wood composites Authors: Almodôvar, V.; Cansado, I.P.P.; Mourão, P.A.M.; Gomes, J. Abstract: A series of activated carbon was produced from particleboard and medium-density fibreboard monoliths, which are waste originated from the industry, and then characterized and evaluated for potential application for phenoxyacetic acids removals, such 2,4-dichlorophenoxyacetic acid (2,4-D), 2-methyl-4-chlorophenoxy acetic acid (MCPA) and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron), from the liquid phase. All AC retain the shape of the precursor, and displays a microporous structure well-developed, reaching 0.58 cm 3 g -1. The adsorption isotherms for three pesticides were obtained in the optimal conditions and the AC with high superficial area and micropore volume exhibited better performance, allowing to state that, this AC could be a great substitute of those habitually used for this purpose. The pesticides adsorption data were linearized using the Langmuir and Freundlich equation, being the first a very good fit to the experimental data. 2015-06-22T23:00:00Z http://hdl.handle.net/10174/19854 Title: NEW METAL-BASED MICELLES AS ANTICANCER AGENTS Authors: Mendes, Paulo J.; Pinto, Bebiana; Garcia, M. Helena; Valente, Andreia Abstract: Cancer is a leader cause of death worldwide. One of the problems associated with the current chemotherapeutic options is the noxious side effects caused by the lack of selectivity. In this frame, our research group has been committed to the development of a new Ru and Fe macrometallodrugs.[1] The data obtained so far shows that these compounds present an intrinsic selectivity towards cancer cells (relatively to healthy cells) due to the incorporation of polymeric ligands that promote a passive targeting through the cancer cell membrane. These results prompted us to the development of new macrometallodrugs bearing bioessential metals such as Fe, Zn and Co. We used a ‘M(bipy) 3 ’ scaffold (bipy = 2,2’-bipyridine derivatives) for the synthesis of the new compounds due to the promising cytotoxicity results observed for related compounds.[2] As polymeric ligands we have chosen the polylactide-co-polyethylene glycol amphiphilic copolymer that is able to self-assemble into micelles in water, keeping the metal center hidden, like a Trojan horse. We will present the synthesis and characterization of the new compounds and some preliminary data on their ability to form stable micelles (Figure 1). 2016-01-01T00:00:00Z http://hdl.handle.net/10174/19747 Title: DFT STUDIES ON THE MECHANISM OF RING-OPENING POLYMERIZATION OF LACTIDE WITH ADENINE Authors: Mendes, Paulo J.; Ramalho, João P. Prates; Valente, Andreia; Zinck, Philippe; Nogueira, Guilherme; Favrelle, Audrey Abstract: The use of organic molecules as catalysts for the ring-opening polymerization (ROP) of cyclic esters has gained much interest last years.[1] The use of a molecule of biological interest, able to initiate ROP of cyclic esters without any cocatalyst is even more interesting, as the resulting material will not contain any catalytic residue. Nucleobase-polymer conjugates development is thus an emerging area envisaging biomedical applications.[2] However, they are usually synthesized by tedious multistep procedures. Recently, adenine was used as organoinitiator for the ROP of L-lactide.[3] Reaction conditions involving short reaction times and relatively low temperatures enable the access to adenine-polylactide(Adn-PLA)conjugates in a simple one-step procedure, without additional catalyst and in the absence of solvent. In this study, computational investigations with density functional theory (DFT) were performed in order to clarify the reaction mechanism leading to the desired Adn-PLA. The results show that a hydrogen bond catalytic mechanism, involving a nucleophilic attack of the activated amine group of adenine onto the carbonyl group of lactide, seem to be plausible. 2016-01-01T00:00:00Z