Dissertações em Química Medicinal e Modelagem Molecular (Mestrado) - PPGQMMM/ICS
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/14431
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Dissertação Acesso aberto (Open Access) Planejamento, síntese e aplicações de derivados naftosalicílicos como antioxidantes(Universidade Federal do Pará, 2017-08-30) BARROS, Valéria Araújo; BORGES, Rosivaldo dos Santos; http://lattes.cnpq.br/4783661132100859; https://orcid.org/ 0000-0003-4072-7573Salicylate derivatives are successfully applied as analgesics, antipyretics, anti-inflammatories and in cancer prevention, especially rectal colon. They reduce the risks of many diseases associated with elderly. However, adverse effects related to gastrointestinal events are always associated to its main constituent acetylsalicylic acid. These aspects are linked to their chemical stability and affinity for some biological receptors. The aims of this work are the design, synthesis and applications of naphthalene-salicylic derivatives as antioxidants. Thus, a theoretical study of the studied compounds was carried out. Calculations of electronic properties such as frontier orbitals HOMO-LUMO, ionization potential (IP), bond dissociation energy of phenolic moiety (BDEOH), and spin density contributions were performed by using density functional theory (DFT) at the B3LYP/6-31G (d, p) level of theory on Gaussview and Gaussian computational packages. Some of these compounds were synthesized by using classical methods. The theoretical results showed that both additional hydroxyl or substitution on benzene ring for naphthalene increase the antioxidant capacity in the same values with small dissimilarities among acid, ester, and amide derivatives. A synergistic effect was observed when both are used together, producing the most potent molecules. In addition, spin density calculations indicated a regioselective pathway can be gotten from monohydroxylic derivatives, with high possibility of in vivo generating of dihydroxy derivatives mainly at the para position relative to the phenolic group, through enzymatic or non-enzymatic reactions. Finally, the replacement of the naphthalene ring instead of the benzene ring increases both reactivity and chemical stability for the quinone-type intermediates, explaining how these compounds will play a role in the preventive mechanisms and way treatment of cancer. Anti cancer and anti-inflammatory activities are being performed for some of the synthesized compounds.Dissertação Acesso aberto (Open Access) Planejamento, síntese e avaliação dos derivados da edaravona quanto à atividade antioxidante(Universidade Federal do Pará, 2018-03-28) AIRES, Wanessa Castilho; OLIVEIRA, Karen Renata Matos; http://lattes.cnpq.br/3032008039259369; BORGES, Rosivaldo dos Santos; http://lattes.cnpq.br/4783661132100859; https://orcid.org/ 0000-0003-4072-7573Edaravone is a commercial drug released on the Japanese Market, indicated in the treatment and prevention of ischemic stroke. Its action is due to its scavenger properties of free radical released in the ischemia. However, its use may lead to a kidney toxic effect. Therefore, in this work, a new bioisostere derivative from Edaravone was proposed, by the change of a pyrazolone ring for an indolone. Antioxidant properties was determined through computational methods. Calculations were undertaken in the software Gaussian, through the B3LYP method, with the set of bases 6-31G (d, p). Antioxidant activity was predicted from HOMO, LUMO, Gap, Ionization potential (IP) and Bond dissociation energy (BDE). Results indicate analogous compounds showed higher ClogP values compared to Edaravone, which means higher facility to pass through biological barriers, with higher liposoluble properties. Edaravone derivative, called Imidazone, also showed higher antioxidant potential than Edaravone. Methyl group in second position of heterocyclic ring was essential to more stable resonance structures formation to semiquinone form. All new derivatives proposed were extremely promising with antioxidant capacity superior to Edaravone.