28 research outputs found
Estimativa do intervalo pós-morte em um canino (Canis lupus familiaris Linnaeus 1758) pela entomologia forense em Cabedelo-PB, Brasil: relato de caso
Os artífices da metrópole: anotações sobre a transformação da vida urbana carioca depois da Belle Époque
Conversion of cerrado into agricultural land in the south-western Amazon: carbon stocks and soil fertility
Soybean meal or cotton by-products associated with urea as source of nitrogen in the diet of lactating goats
Sistemas produtivos de caprinocultura leiteira no semiárido paraibano: caracterização, principais limitantes e avaliação de estratégias de intervenção
Recurso polínico coletado por abelhas sem ferrão (Apidae, Meliponinae) em um fragmento de floresta na região de Manaus - Amazonas
História da educação brasileira: a produção científica na biblioteca eletrônica SCIELO
Four-dimensional quantitative structure-activity analysis of 1,4-naphthoquinone derivatives tested against HL-60 human promyelocytic leukemia cells
Four-dimensional quantitative structure-activity relationship (4D-QSAR) models were developed to predict biological activity of 1,4-naphthoquinones derivatives tested against human HL-60 leukemic cells, in order to better investigate the action mode of these compounds. Quinones can generate reactive oxygen species (ROS) through the activation by the cytochrome P450 and P450 reductase enzymes acting as anticancer agents. Molecular dynamics (MD) simulations were performed in the 3D optimized geometries, and the field descriptors were calculated. Partial least squares (PLS) regression method was applied to build the QSAR model, which presented the following statistics, with two factors and explaining 51.11% of total variance: R 2 = 0.83; SEC = 0.28; Q 2 = 0.77; SEV = 0.31. For external validation, the results were R 2 pred = 0.76 and SEP = 0.30. Among the nine Coulomb (C) and Lennard-Jones (LJ) descriptors selected by the model, one of them, C13838, is located close to quinone oxygens involved in the production of radical anions (O 2 −· ) and to hydroxyl in position 5 that may stabilize catalytically important water molecules. The negative LJ descriptors around R 1 and R 2 substituents might indicate that apolar substituents in these regions are unfavorable to the activity. Coulomb descriptors located at the vicinities of the substituent R 2 gave information about the bioactive conformation34CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informaçãosem informaçã