Understanding the antioxidant activity of flavonoids is important to investigate their biological activities as well as to design novel molecules with low toxicity and high activity. Aromaticity is a chemical property found in cyclic structures that plays an important role in their stability and reactivity, and its investigation can help us to understand the antioxidant activity of some heterocyclic compounds. In the present study, we applied the density functional theory (DFT) to investigate the properties of seven flavonoid structures with well-reported antioxidant activity: flavan, anthocyanidin, flavanone, flavonol, isoflavone, flavone, and flavan-3-ol. Conformational, structural, magnetic, and electronic analyses were performed using nuclear magnetic resonance, ionization potentials, electron affinity, bond dissociation energy, proton affinity, frontier molecular orbitals (highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO)), and aromaticity through nucleus-independent chemical shifts to analyze these seven flavonoid structures. We revised the influence of hydroxyl groups on the properties of flavonoids and also investigated the influence of the aromaticity of these seven flavonoids on the antioxidant activity.

Understanding the role of 3CLpro protease for SARS-CoV-2 replication and knowing the potential of flavonoid molecules like rutin, myricetin, and baicalein against 3CLpro justify an investigation into their inhibition. This study investigates possible bonds and reactivity descriptors of rutin, myricetin, and baicalein through conformational and electronic properties. Density functional theory was used to determine possible interactions. Analyses were carried out through the molecular electrostatic potential, electron localization function, Fukui function descriptors based on frontier orbitals, and non-covalent interactions. A docking study was performed using a resolution of 1.55 Å for 3CLpro to analyze the interactions of rutin, myricetin, and baicalein. Scores of structures showed that rutin is the best ligand, followed by myricetin and baicalein. Docking studies showed that baicalein and rutin can establish effective interactions with residues of the catalytic dyad (Cys145 and His41), but just rutin forms a hydrogen bond. Myricetin, in turn, could not establish an effective interaction with Cys145. Baicalein interaction arose with active residues such as Arg188, Val186, Gln189, and Gln192. Interactions of rutin and myricetin with Arg188 and Gln189 were also found. A critical interaction was observed only for rutin with the hydroxyls of ring A with His41, and also for Cys145 with rings B and C, which is probably related to the highest score of rutin.

Este artigo destina-se a apresentar sob uma perspectiva didática os detalhes e procedimentos matemáticos necessários para a construção da equação diferencial quântica, sob regime relativístico, denominada Equação de Klein-Gordon-Fock (EK-G-F), admitindo o sistema de coordenadas da frente de luz. Para tanto, inicialmente, destacamos algumas propriedades algébricas da Teoria da Relatividade Especial de Einstein assim como apresentamos resumidamente as coordenadas da frente de luz em termos das coordenadas cartesianas e do parâmetro de evolução temporal, isto é, do espaço de Minkowski, obtendo dessa forma a EK-G-F tanto em coordenadas usuais do espaço de Minkowski, quanto em coordenadas da frente de Luz. Em seguida, para essas últimas coordenadas, desenvolvemos detalhadamente a estrutura algébrica da EK-G-F para uma partícula quântica eletricamente carregada em regime de relatividade especial e sob influência de configurações de campos magnéticos clássicos. Além disso, obtemos a EK-G-F com estrutura algébrica similar a uma equação diferencial quântica de Schrödinger. Por fim, como aplicação imediata do uso dessas coordenadas, desenvolvemos os trâmites e passos algébricos necessários para obtenção do operador de aniquilação do tipo integral de movimento, o qual configura-se como estrutura matemática necessária para construção dos estados quânticos coerentes.

The heat shock protein 70 kDa (Hsp70) is critical for the survival of cancer cells, playing a role in developing chemotherapy resistance, since it inhibits apoptosis of these cells and ensures their survival in stressful environments. Due to its structural similarity with heat shock cognate 70 kDa (Hsc70), the design of new selective Hsp70 inhibitors presents significant challenges. Previous studies have reported that the molecule VER-155008 functions as a nonselective inhibitor of Hsp70 by binding to the nucleotide-binding domain of both proteins, thereby acting as a competitive inhibitor of adenosine triphosphate (ATP) binding. In the present study, molecular dynamics (MD) simulations and free energy landscape (FEL) analysis were used to investigate the conformational dynamics of Hsp70 and Hsc70 with the competitive ATPase inhibitor VER-155008, revealing its binding mechanism and its role in inducing a half-open conformation that inhibits ATP binding. Our findings highlight key residues Ser275, Lys271, and Glu268 involved in the stabilization of the inhibitor binding and some conformational states in both proteins due to the inhibitor binding, explaining molecular characteristics that could be used to develop new selective inhibitors at the nucleotide binding site of Hsp70, thus aiming to advance the development of targeted therapies in cancer treatment.

A pandemia da COVID impactou, econômica, sanitária e socialmente, o mundo. É uma consequência da crise ambiental produzida por um modelo socioeconômico globalizado, tornando-se a maior emergência no pós-guerra apresentando situações contextuais e problemáticas diversas. Entretanto, movimentos negacionistas organizados entre 2020 e 2021, em especial no Brasil e EUA, conseguiram alienar uma parcela considerável das populações dos países em questão. O presente texto discute, de uma forma, introdutória, esse fenômeno social por meio, dos pressupostos estabelecidos na Pedagogia do Oprimido, em três partes. Na primeira parte, a explanação dos preceitos fundamentais do texto de Freire, envolvendo as relações entre opressores e oprimidos e a contradição inerente a dualidade opressor-oprimido. Na segunda parte, partimos de uma contextualização da educação antidialógica, através de instrumentos de opressão, por meio, de dispositivos de invasão cultural. Por fim, uma releitura crítica, a partir do cenário atual em maior escala, levando em consideração toda uma crise ambiental que fornece uma visibilidade evidente, no contexto da pandemia.