Navegando por Autor "MARINHO, Victor Hugo de Souza"

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Acesso aberto (Open Access)
New isoflavones from the leaves of Vatairea guianensis Aublé
(2013-11) SOUZA, Ronilson Freitas de; MARINHO, Victor Hugo de Souza; SILVA, Geilson Alcantara da; COSTA JUNIOR, Livio Martins; SILVA, Joyce Kelly do Rosário da; BASTOS, Gilmara de Nazareth Tavares; ARRUDA, Alberto Cardoso; SILVA, Milton Nascimento da; ARRUDA, Mara Silvia Pinheiro
Four isoflavones were isolated from Vatairea guianensis Aublé leaves and identified as 5,3'-dihydroxy-4'-methoxy-2",2"-dimethylpyrano-(5",6":8,7)-isoflavone ( 1: ), 5,7-dihydroxy-3',4'-methylenedioxy-8-prenyl-isoflavone ( 2: ), 5,3'-dihydroxy-4'-methoxy-7-O-β-glucopyranoside-8-prenyl-isoflavone ( 3: ) and derrone ( 4: ) together with five triterpenes identified in mixture, lupeol, α-amyrin, β-amyrin, germanicol and betulinic acid. Substances 1: 3: are novel natural products, although 1: and 2: have been cited as synthetic products. However, all these compounds are first reported from this species. Their chemical structures were elucidated based on their 1D and 2D nuclear magnetic resonance (NMR) data and high resolution mass spectrometry. The ethanol extract from the leaves and 1: 3: were evaluated for their potential in scavenging DPPH• (2,2-diphenyl-1-picrylhydrazylradical) and the results showed that the extract presented high activity (IC50 = 6.2 ± 0.4 µg mL-1), while the isolated compounds showed low antioxidant power (IC50 ≥ 29.5 ± 2.5 µg mL-1) when compared to Trolox (IC50 = 4.5 ± 0.4 µg mL-1).
Acesso aberto (Open Access)
O papel do colesterol na biossíntese da parede celular de Mycobacterium smegmatis
(Universidade Federal do Pará, 2015-02-26) MARINHO, Victor Hugo de Souza; SENA, Chubert Bernardo Castro de; http://lattes.cnpq.br/8620752020290438
Different Mycobacterium species are causative agents of disease in humans, for example, the tuberculosis. All mycobacteria have a complex cell wall, distinct of others bacteria, conferring specific physic-chemical characteristic to Mycobacterium genus, due to protect against immune system and waterproofing against the intake of much antibiotics. During infection, the bacillus is able to adapter to harsh environment, due to consumption of cholesterol from itself host cell (macrophages) as alternative carbon and energy source. That nutritional aspect has been considered as essential for division of bacilli and consecutive progress of tuberculosis disease. The present study has as objective to evaluate in vitro the modulation of saprophytic Mycobacterium smegmatis cell wall biosynthesis after cholesterol consumption as primordial energy and carbon source. As results, we are found by Thin Layer Chromatography (TLC) that bacillary adaptation to microenvironment with poor nutrient (minimal media – MM) maintained the biosynthesis and accumulation of essential cell wall components, when the growth occurs in presence of someone defined carbon and energy source (glycerol and/or cholesterol). Among them without changes, we analyzed Trehalose Dimicolate (TDM) and the phospholipids (phosphatidylinositol (PI), phosphatidylinositol manosides (PIMs), Cardiolipin (CL) and phosphatidylethanolamine (PE)). Differently of these results, the micolic acid showed representative accumulation, comparing with 7H9 culture, only when the MM was supplemented with glycerol. This result was confirmed by alcohol-acid staining using fluorescent auroamine dye, suggesting some changes in physic-chemistry cell wall properties. On the other hands, the MM culture induced the accumulation of glycopeptidolipids (GPLs), independently of glycerol/cholesterol supplementation. Such disturbance in cell wall biosynthesis also changed the bacillary hydrophobicity in all MM groups, but does not change the resistance and sensibility to antibiotics. Those results clearly show that cell wall biosynthesis might be modulate during nutritional shortage, and such presence or absence of cholesterol, as occurs during infection, does not significantly change the bacillary physiology to become vulnerable for antibiotics. It suggests that such modulations might also occur during infection, maintaining the bacilli available to develop the tuberculosis diseases.