Dissertações em Farmacologia e Bioquímica (Mestrado) - FARMABIO/ICB

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/13299

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Efeito da temperatura e molaridade na avaliação das atividades antimicrobiana, citotóxica e antioxidante do bio-óleo da semente do açaí (Euterpe oleracea, Mart.)
(Universidade Federal do Pará, 2024-08) SILVA, Iago Castro da; MACHADO, Nélio Teixeira; http://lattes.cnpq.br/5698208558551065; MONTEIRO, Marta Chagas; http://lattes.cnpq.br/6710783324317390; https://orcid.org/0000-0002-3328-5650
Açaí, a fruit from the Amazon, is valuable both economically and nutritionally. Its seeds, which are typically discarded, can be converted into bio-oil through pyrolysis (a process of thermochemical degradation of residual biomass), offering a sustainable alternative to fossil fuels. This study explores how temperature and molarity with Potassium Hydroxide (KOH) and Hydrochloric Acid (HCl), which are chemical impregnation reagents in the process, affect the antimicrobial, antioxidant, and cytotoxic activities of the produced bio-oil. Tests were conducted using Gas Chromatography coupled with Mass Spectrometry (GC-MS) and assays to evaluate antimicrobial, antioxidant, and cytotoxic activities at different temperatures (350, 400, and 450 °C) and molarities (0.5 M, 1.0 M, and 2.0 M). Phenolic compounds were the most abundant in the bio-oil (55.70%), followed by cyclic and aromatic hydrocarbons (11.89%) and linear hydrocarbons (9.64%). Despite a reduction in oxygenated compounds, the bio-oil retained bacteriostatic activity against Escherichia coli and Staphylococcus aureus across various temperature ranges, with notable effectiveness at 350 °C. Antioxidant activity was highest at 350 °C and at lower molarities. Furthermore, lower concentrations of acidic impregnation exhibited cytotoxic effects at high temperatures. Thus, bio-oil from açaí seeds generated through pyrolysis shows potential for antioxidant and antimicrobial activities, suggesting feasibility for further testing in dilutions with lower cytotoxicity.
Acesso aberto (Open Access)
Efeitos citotóxicos e mecanismo de ação da eleuterina isolada de Eleutherine plicata em modelo in vitro de células c6
(Universidade Federal do Pará, 2024-05) SHINKAI, Victória Mae Tsuruzaki; NASCIMENTO, José Luiz Martins do; http://lattes.cnpq.br/7216249286784978; https://orcid.org/0000-0003-3647-9124
Glioblastoma multiforme (GBM) is the most prevalent malignant primary tumor of the central nervous system (CNS). GBM cells are characterized by rapid proliferation and aggressive migration. There is growing demand for new therapies to treat this tumor, due to current therapeutic limitations. Quinone derivatives from plants have received increased interest as potential antiglioma drugs due to their diverse pharmacological activities such as inhibition of cell growth, inflammation, tumor invasion and promotion of tumor regression. The herb Eleutherine plicata, popularly known as Marupazinho, is widely used in popular medicine due to its pharmacological properties, containing quinone derivatives, more specifically naphthoquinones. Previous studies have demonstrated the antiglioma activity of Eleutherine plicata, which is related to three main naphthoquinone compounds – eleutherine, isoeleutherine and eleutherol – but mechanism of action remains unclear. Thus, the objective of this study was to investigate the potential cytotoxic and antiproliferative effect of eleutherin in an in vitro model of glioblastoma (C6 lineage). In vitro cytotoxicity was assessed by the MTT assay; Morphological changes were assessed by phase contrast microscopy. Apoptosis was determined by the annexin V-FITCpropidium iodide assay, and antiproliferative effects were assessed by the colony formation assay. Protein kinase B (AKT/pAKT) expression was measured by western blot, and telomerase reverse transcriptase mRNA was measured by quantitative real-time polymerase chain reaction (qRT-PCR). The results obtained indicated that eleutherin, isolated from the Hexanic fraction, had a cytotoxic effect on the C6 lineage. Structural changes were observed by image capture, with a significant reduction in colony formation, induction of apoptosis, inhibition of pAKT and reduction in telomerase expression after treatment. Thus, our study showed that the eleuterin molecule has cytotoxic activity in C6 lineage glioma.
Acesso aberto (Open Access)
Efeitos do estresse crônico sobre o estado redox e tecidual das glândulas salivares parótida e submandibular: um estudo in vivo
(Universidade Federal do Pará, 2025-03) MONTEIRO, Deiweson de Souza; LIMA, Rafael Rodrigues; http://lattes.cnpq.br/3512648574555468; https://orcid.org/0000-0003-1486-4013
Stress is a reaction to mental and emotional pressure, anxiety, or trauma. Chronic stress is defined as constant exposure to such events. It can affect various body systems, increase blood pressure, and weaken immunity, thereby interfering with physiological health processes. From this perspective, several organs may exhibit responses or alterations under conditions of chronic stress. Therefore, this study aimed to evaluate the effects of chronic stress on the salivary glands of rats, investigating their oxidative biochemistry and histomorphological parameters. For this purpose, 32 male albino Wistar rats were randomly divided into two groups: chronic stress and control. The animals in the chronic stress group were subjected to an immobilization protocol, being placed in a polyvinyl tube for 4 hours daily for 28 days, which restricted their movement. Subsequently, the animals were euthanized for the collection of the parotid and submandibular salivary glands. The redox status of the glands was assessed using the antioxidant capacity against peroxyl radicals (ACAP) assay and thiobarbituric acid reactive substances (TBARS) assay. Histological analysis was performed through morphometry of tissues stained with hematoxylin and eosin, and histochemistry using the PicroSirius Red technique. Both the parotid and submandibular glands of the stressed rats exhibited oxidative stress, characterized by a reduction in ACAP levels and an increase in TBARS levels. However, the parotid glands proved to be more susceptible to harmful tissue alterations, such as an increase in stromal area and collagen area fraction, a reduction in acinar area, and smaller size of acini and ducts. In contrast, the submandibular glands did not show any histomorphological alterations. Our results suggest that chronic stress can cause a harmful modulation of the redox status of the salivary glands, with different histological repercussions between the glands.

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