Licenciatura em Química (Sede)
URI permanente desta comunidadehttps://arandu.ufrpe.br/handle/123456789/26
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APP - Artigo Publicado em Periódico
TAE - Trabalho Apresentado em Evento
TCC - Trabalho de Conclusão de Curso
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Resultados da Pesquisa
Item Síntese e docking molecular de 1,2,4-oxadiazol como potencial agente antioxidante(2024-07-30) Silva, Ryan Henrique Gomes da; Freitas Filho, João Rufino de; http://lattes.cnpq.br/9252404584350850; http://lattes.cnpq.br/6976073462477884The present work aimed to synthesize and characterize 1,2,4-oxadiazoles 29a-c, and to evaluate their antioxidant capacity using in vitro and computational methods. For this purpose, the synthesis of an important precursor, the arylamide oximes 27a-c, was carried out using the magnetic stirring method, obtaining excellent yields (84.9% - 95.7%). Then, the synthesis of 1,2,4-oxadiazoles 29a-c was described using the solvent-free method, which does not use solvents, bases or salts, obtaining low to moderate yields (30.6% - 56.2%). Furthermore, these heterocyclics were characterized by IR, 1H NMR and melting point. Thus, with the application of the DPPH• and ABTS•+ free radical scavenging test, it was found that the 1,2,4-oxadiazoles presented better results in reducing these radicals in the ABTS•+ method than in DPPH•, with emphasis on compound 29b (EC50 = 4.055 μg.mL-1), which presented promising free radical scavenging capabilities very similar to the standard antioxidant TROLOX (EC50 = 4.1 μg.mol-1), used as a positive control. Regarding the computational procedures, the molecular docking method was used to verify the energetic stability and the types of interaction of the complexes formed with compounds 29a-c and a pro-oxidant enzyme, Xanthine Oxidoreductase (ID PDB: 1N5X), which is involved in the superoxide release process. Therefore, based on the LGA calculations of the AutoDock 4.2.6 program, it was observed that the 1,2,4-oxadiazoles used as ligands formed stable complexes with the target enzyme, highlighting compound 29c (ΔH = –7.69 kcal.mol-1), which generated a complex with more stable energy close to the original inhibitor ligand, Tei-6720 (ΔH = –8.63 kcal.mol-1), indicating these compounds as potential antioxidants.Item Análise da composição química do óleo essencial de espécies de Plectranthus cultivadas sob condições de estresse e avaliação Do seu potencial acaricida sobre o Tetranychus urticae(2024-07-31) Silva, Beatriz Steffanie Gomes da; Moraes, Marcílio Martins de; http://lattes.cnpq.br/6957579091162269; http://lattes.cnpq.br/4696332206790980Plants are living organisms capable of producing secondary metabolites as a defense and development mechanism. What stimulates the activation of secondary metabolism are changes in the natural conditions necessary for the survival of the plant, called biotic or abiotic stresses. Essential oils (EOs) are complex mixtures of constituents originating from the secondary metabolism of plants, and have different biological properties, from medicinal purposes to pest control. Thus, the objective of this study was to investigate the variation in the chemical composition of EOs from two species of the genus Plectranthus (P. barbatus and P. ornatus) under controlled stress conditions and the antioxidant and acaricidal potential against Tetranychus urticae (spotted spider mite). The species were separated into groups and subjected to different stress conditions: manual predation (PM), methyl salicylate (SM), methyl jasmonate (MJ), saline (S), water scarcity (E), ultraviolet radiation (UV), and the group without any stress (control). The EOs were obtained by hydrodistillation and the chemical composition was determined by gas chromatography coupled to mass spectrum (GC-MS). The data were subjected to multivariate analyses (PCA, heatmap and molecular network). The acaricidal activity was evaluated comparatively through the LC90 of the positive control Azamax and the antioxidant activity by the ABTS.+ and DPPH methods. For both species, the chemical composition identified in the control groups showed a predominance of constituents derived from sesquiterpenes, with (E)- caryophyllene as the major constituent. However, in the stressed groups, monoterpenes were present in higher percentages, significantly reducing the percentage of the major compound of the control. This variation was confirmed by all multivariate analyses used. The EOs of both species showed low acaricidal activity against the two-spotted spider mite, with mortality rates equal to 12.00% (P. barbatus) and 22.72% (P. ornatus). P. barbatus showed better antioxidant activity for ABTS.+ (62.74 μg/ml) while P. ornatus showed better for DPPH. (163.5 μg/ml). However, compared to the positive controls Trolox (4.13 μg/ml) and ascorbic acid (1.62 μg/ml), respectively, the activities presented by both species were relatively low. Therefore, it was possible to verify that the EOs of these species present antioxidant and acaricidal activities, although low, and that different stress conditions alter the chemical composition of the plant.Item Composição química, atividade acaricida, propriedade antioxidante, inibição da acetilcolinesterase e toxicidade do óleo essencial das folhas de Sparattanthelium botocudorum(2024-03-05) Silva, Mirian Luzinete da; Camara, Cláudio Augusto Gomes da; http://lattes.cnpq.br/5615678215435460; http://lattes.cnpq.br/4499498152298785Sparattanthelium botocudorum is a species endemic to Brazil, commonly known as “Canela-brava”, this shrub is distributed on the coast of Paraíba and in the state of Pernambuco. Due to the scarcity of chemical and biological studies on this plant, the research aimed to determine the chemical composition of the essential oil of the leaves as well as the evaluation of the acaricidal, antioxidant and toxicity properties against Artemia salina. The essential oil, extracted from fresh leaves, through the hydrodistillation technique with the aid of a Clevenger-type device, had a yield of 0.40% m/m and its chemical characterization, through Gas Chromatography coupled to the Mass Spectrometer (CG-MS), emerged as the majority constituents were the sesquiterpenes Germanecrene D with (38.28 %), E-Nerolidol (18.95 %), [beta]-Caryophyllene (14.49 %) and Biciclogermacrene (14.18 %) and the single monoterpene Z-[beta]-Ocimene identified in the OE with a percentage of 0.37%. Residual contact bioassays were carried out, with the aim of identifying the effects of the oil on the two-spotted mite, and showed promising toxicity. The residual contact bioassay, in which the mites are arranged on already treated leaves, showed LC50 = 16.5 μL/mL. Furthermore, the oil also demonstrated ovicidal properties with an estimated LC50 of 1.20 μL/mL. And regarding repellency activity, the oil showed a better potential with the LC30 concentration 8.8 μL/mL. After evaluating the inhibition activity of the acetylcholinesterase enzyme, the essential oil from the leaves of S. botocudorum inhibited the enzyme, since the LC50 resulted was 2.9 μg/mL below the LC50 of the positive control, which is 5.95 μg/mL. mL. Furthermore, OE presented antioxidant properties for the free radical DPPH˙, estimating an EC50 = 110.3 μg/mL, while for the free radical ABTS˙+ it was EC50 = 49.23 μg/mL. Finally, the oil exhibited a toxicity concentration of 700 μg/mL for the toxicity test against A. salina, which compared to what described in the literature had no toxicity. Therefore, the study showed that the essential oil presented similar and promising effects compared to already commercialized acaricides, and that the bioassays presented different routes of action, therefore acting with different mechanisms on the pest and presenting a biological property of antioxidant activity.Item Estudo químico e atividade sequestradora de radical livre da própolis de Trigona spinipes Smith (Arapuá)(2022-06-10) Souza, Hélter José Silva de; Silva, Tania Maria Sarmento da; http://lattes.cnpq.br/9185334632055347The stingless bee Trigona spinipes is popularly known as a primordial generalist species in the performance of ecosystem services, due to the speciesization of agri-cul-tural plants, as a dominant species in the interaction networks between plants and bees. Geopropolis, is a resin mixture collected from pro-resin resins, essential oils, pollen, wax, sugars and salivary secretions from bees. This work describes the chemical study of two samples of Trigona spinipes propolis collected in the Caatinga region of the Polo Petrolina-PE, in the areas that comprise the Vale de São Francis-co. The chemical study of the extracts and fractions was carried out by Ultra Perfor-mance Liquid Chromatography coupled with Diode Array detectors and Quadrupole Time-Time Quadruple Mass Spectrometer (UPLC-DAD-QTOF-MS/MS) and coupled Gas Chromatography a Mass Spectrometer (CG/MS). From the chemical study it was possible to observe the presence of substances from the classes of polyamines, fla-vonoids, terpenes, steroids and fatty acids. The two have similar chemical com-posi-tion. The biological study with total phenolics, flavonoids and the DPPH radical showed that propolis are rich sources of bioactive compounds with antioxidant po-tential. The pro-anti-inflammatory action presents protection against bacteria, virus, fungi and anti-inflammatory activities.Item Composição química, atividade citotóxica, acaricida e antioxidante do óleo essencial das flores de Caesalpinia echinata (Pau-brasil)(2021-12-10) Rodrigues, Lucas Vitor Batista; Camara, Cláudio Augusto Gomes da; http://lattes.cnpq.br/5615678215435460; http://lattes.cnpq.br/7934872766687903Belonging to the family Fabaceae, Caesalpinia echinata is a tree endemic to Brazil, popularly known as pau-brasil. It was widely explored because of the quality of its wood and the produc-tion of a red pigment and much coveted in colonial times for dyeing fabrics and due to predatory extractivism, it was almost extinct. Currently, wood is much sought after for the manufacture of bows for violins for its ideal stiffness and density. The scarcity of chemical and biological studies of different parts of the plant motivated the chemical composition of the essential oil of the flowers as well as the evaluation of the acaricide, cytotoxicity properties against saline ar-temia and antioxidant. The flowers of C. echinata were collected on the campus of the Federal Rural University of Pernambuco. The essential oil (EO) was extracted from the hydrodistilla-tion technique by a modified Clevenger type apparatus. The chemical composition of the oil was determined by gas chromatography coupled to a mass spectrometer. Residual contact was the method selected to evaluate the acaricide action on Tetranychus urticae and the biological model selected for cytotoxicity evaluation was That of A. salina. The EO of the flowers pre-sented monoterpenes as the main chemical class. The main compounds identified were linalool (32.33%), Z-jasmona (14.94%) and [beta]-E-ocimene (10.44%). The essential oil for the control of T. urticae presented a LC50 = 290.15 uL/mL. The EO revealed an antioxidant capacity for the free radical DPPH˙ estimated at EC50 = 364.10 ug/mL, while for the free radical ABTS˙+ was EC50 = 280.50 ug/mL. The oil exhibited a LC50 = 97.41ug/mL for the toxicity test against A. salina. This study showed that the essential oil of C. echinata flowers has acaricide, antioxidant and cytotoxic biological property against A. salina.