Mestrado em Ciências Farmacêuticas

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http://repositorio.ufes.br/handle/10/17569

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Navegando Mestrado em Ciências Farmacêuticas por Assunto "Ação antioxidante"

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    Avaliação in vitro da atividade anti-Helicobacter pylori e potencial antioxidante de extratos e frações de Baccharis trimera (Less.) DC
    (Universidade Federal do Espírito Santo, 2016-03-22) Nunes, Otalibio Castiglioni; Gonçalves, Rita de Cássia Ribeiro; Vellosa, José Carlos Rebuglio; Borges, Warley de Souza
    One of the major risk factors for the development of ulcers and gastric cancer is the infection by Helicobacter pylori, in which there is a considerable oxidative stress. In Brazil, the plant Baccharis trimera (Less) DC, known as "Carqueja", is commonly used to treat gastrointestinal and liver disorders. Tannins, flavonoids, saponins, diterpene lactones, sesquiterpenes, phenolic compounds and volatile oils were identified in this specie. Thus, the goal of this study was to evaluate the antiHelicobacter pylori activity of the aqueous (AqE), ethanolic (EE), and hydroalcoholic (HE) extracts of B. trimera, as well as the aqueous (AqF), hexane (HxF), and acetonitrile / chloroform (ACF) fractions obtained from the HE. In addition, it aims to analyze the phytochemical composition and its effects on free radicals and biological oxidants. For all extracts and fractions, it was performed a phytochemical screening and the determination of the content of polyphenol, flavonoid and total tannins. The anti- Helicobacter pylori activity was evaluated by microdilution broth assay and urease inhibitory capacity. Bacterial morphology, after sample exposure, was evaluated by scanning electron microscope (SEM) using the extracts and fractions that reached the minimum inhibitory concentration (CIM90). Screening of antioxidant activity for all samples was determined by DPPH and ABTS radical scavenging activities. Assays using the oxidizing biological agents, hydrogen peroxide (H2O2), superoxide anion (O2 •- ), hypochlorous acid (HOCl), hydroxyl radical (HO• ), and nitric oxide (NO• ) were performed with HE and its fractions due the best results in the antiH. pylori and initial screening antioxidant assays, except for the HxF because of its poor performance in the antioxidant screening. The highest concentration of polyphenols was observed in the HE, flavonoids in the ACF, and tannins in the AqF. Anti-H pylori assay presented a CIM90 of 512 μg/mL for HE, and 1024 μg/mL for ACF, the latter being bactericidal. SEM showed morphological changes such as stretching and cell lysis in the samples tested, and may suggest some modifications in the wall, such as alterations in the peptidoglycan synthesis. In the enzyme urease inhibition assay, the most significant result was obtained by the ACF, which inhibited 36.24% in the highest concentration tested. The best result among the extracts in the initial antioxidant screening was achieved by the HE, which obtained the following EC50: DPPH, 17.40 ± 0.52 and ABTS, 9.99 ± 1.21. The best EC50 for the fractions were: DPPH, AqF, 27.41 ± 1.65, and ABTS, AqF, 10.80 ± 1.90. In the O2 •- scavenging activity, AqF showed EC50 of 5.85 ± 0.86 μg/mL. In the inhibition assay of HOCl, all samples tested were able to inhibit greater than 50%, except AqF. In the inhibition assay of HO• , NO• e H2O2, the results were better for ACF and its EC50 was 2.90 ± 0.48, 132.13 ± 7.38 e 66.70 ± 2.30 μg/mL, respectively. The analyzes indicate that B. trimera, in particular the HE and its fractions, AqF and ACF, may exhibit promising compounds for the prevention and treatment of diseases caused by H. pylori. These results were based on the relationship between the presence of phenolic compounds and the inhibition of oxidants, as well as changes in the bacterial membrane.
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    Influência da suplementação com ácido ascórbico e zinco na morfologia testicular de ratos Wistar expostos ao arsenito de sódio
    (Universidade Federal do Espírito Santo, 2016-03-30) Altoé, Luciana Schulthais; Pirovani, Juliana Castro Monteiro; Pancoto, João Alexandre Trés; Gomes, Marcos de Lucca Moreira
    Several studies has shown that exposure to heavy metal arsenic, an environmental contaminant, may result in toxic effects, acute or chronic, causing different disorders, including potentially leading to damage to male fertility. Substances with potential protective action has been investigated. These include zinc and vitamin C, substances with known antioxidant action, are cofactors of cell division and playing an important role in reproduction. The aim of this study was to evaluate testicular function in rats exposed to arsenic in the form of sodium arsenite, and the possible protective role of co-administration of zinc or vitamin C by seminal, biometric and morphological (morphometry and stereology) analysis of the testis. Male Wistar rats (60 days old) were divided into six groups of six animals each: (1) control (distilled water), (2) sodium arsenite (5 mg/kg), (3) vitamin C (100 mg/kg) (4) zinc chloride (20 mg/kg), (5) sodium arsenite and vitamin C and (6) sodium arsenite and zinc chloride. The dosages were administered daily by gavage for 60 days. At the end of the treatment period, all animals were sacrificed and testis and accessory organs were removed and weighed. Testis fragments were processed for analysis by light microscopy and one centimeter of the deferens duct was removed for seminal analysis. There were no significant changes in the biometrics in any groups, but changes in the Leydig cells and in the seminiferous tubules were showed. Arsenic reduces the tubular diameter and the germinal epithelium height, resulting in a lower number of spermatids per testicle gram. Vitamin C and zinc were able to protect the Leydig cells and the proportion of normal spermatozoa of arsenic effects. It can be concluded that chronic exposure to sodium arsenite alter the spermatogenic process, reducing the total number of normal sperm, which can lead reduce fertility in male rats, and that coadministration of vitamin C or zinc although not able to neutralize the numerical damage can increase the proportion of normal spermatozoa.