Publications by authors named "Joao M De Siqueira"

A previous study reported the in vivo anti-inflammatory and antinociceptive activities of essential oil of the underground stem bark of Duguetia furfuracea, termed EODf. This study aimed to obtain a phenylpropanoid-enriched fraction from the D. furfuracea (EFDf) essential oil and to investigate its anti-inflammatory and antinociceptive effects.

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The recent outbreaks of mosquito-borne diseases highlighted the pivotal importance of mosquito vector control in tropical areas worldwide. Several strategies have been developed to control vector populations and disease transmission in endemic areas. The steps to obtain natural active compounds involve the pre-selection in a biological model and subsequently evaluation on specific models.

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Here, we aim to evaluate the antileishmanial activity of compounds with a benzoxazinoid (BX) skeleton, previously synthesized by our group, against and promastigotes. Anti-promastigote activity, as well as cytotoxicity, were determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assays. The selectivity index (SI) for each compound was calculated using a ratio of the cytotoxicity of compounds and the geometric mean (GM) of antileishmanial concentrations to each species tested.

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Alpha-asarone has been found to possess many pharmacological activities, which can improve cognitive function and exert anti-oxidant, anxiolytic, anti-epileptic and protective effects against endothelial cell injury. The anti-inflammatory activity of α-asarone was evaluated using lipopolysaccharide (LPS)-induced paw oedema. Moreover, leukocyte migration, inducible nitric oxide synthase (iNOS) expression and tumour necrosis factor-alpha (TNF-α) levels were quantified in footpads.

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Plants of the Asteraceae family have been traditionally used as medicinal plants. The species Achyrocline satureioides and Achyrocline alata present anti-inflammatory properties and great chemical similarity. However, no study has been performed to evaluate the influence of these plants on skin wound healing in vivo.

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Culex quinquefasciatus (Say, 1823), known as the domestic mosquito, is a common and abundant species throughout the world, and a cosmopolitan species. The adults of this mosquito are important in terms of public and animal health since they display adaptability to different hosts. In humans, they are responsible for the transmission of various diseases.

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An ethnopharmacological survey indicates that the genus Byrsonima has some medicinal species that are commonly found in the Brazilian Cerrado and has been used as an anti-inflammatory and for gastroduodenal disorders. The aim of this study was to evaluate the anti-inflammatory and antioxidant activity along with qualitative chemical characterization of the methanolic extract of the leaves of Byrsonima verbascifolia (BvME) obtained by exhaustive percolation. The data from the chemical analyses by liquid chromatography-mass spectrometry led to tentative identification of 42 compounds belonging to proanthocyanidins, galloyl quinic acid derivatives, flavonoids, and triterpene glycoside derivatives.

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The leaves of Byrsonima verbascifolia (Malpighiaceae) are traditionally used to treat various diseases including inflammatory conditions. The main goal of this study was to evaluate the in vivo anti-inflammatory activity of the polar constituents from the butanolic fraction of B. verbascifolia leaves (BvBF), as well as to investigate the mechanisms involved in the anti-inflammatory activity.

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Ethnopharmacological Relevance: Achyrocline alata is a locally marketed (Mato Grosso do Sul/ Brazil) herb used in folk medicine as an anti-inflammatory and a sedative. Evaluate the anti-inflammatory properties of Achyrocline alata in both in vivo and in vitro models.

Materials And Methods: A hydroethanolic extract from inflorescences of Achyrocline alata (HEAa) was characterized by HPLC-DAD and compared to standards (chlorogenic acid; isoquercetrin; quercetin; 4,2',4'-trihydroxy-6'-methoxychalcone; gnaphalin; 3-O-methyl-quercetin; 3,5-dicaffeoyl-quinic acid and 4,5-dicaffeoyl-quinic acid).

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The refractionation of an alkaloidal extract of the leaves and twigs of Duguetia furfuracea has provided a minor aporphinoid alkaloid, named (+)-8-nitrous-isocorydine or (+)-1,2,3-trymethoxy-11-hydroxy-8-nitrous- aporphine. The structure of the new compound was elucidated by spectroscopic methods, notably 2D NMR and HRESIMS.

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The utility of benzoxazinones and some of their synthetic derivatives in the search for new leads for herbicide model development has been explored. The work described focuses on obtaining derivatives that present selectivity in the system Oryza sativa- Echinochloa crus-galli. To achieve this goal the influence of lipophilicity in this system has been studied by preparing 14 ester derivatives at the N-4 position of D-DIBOA along with other compounds with different functionalization and chain lengths at position C-2.

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Aim Of The Study: This investigation evaluated the effect of a hydroethanolic extract of Baccharis trimera on pregnant Wistar rats, once the plant is well-known consumed in pregnancy and little is known on its potentially toxic effects on pregnant women.

Material And Methods: Thirty-five female rats were distributed into three groups. Those in treatments 1 and 2 were given 8.

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The utility of benzoxazinones and some of their synthetic derivatives in the search for new leads for herbicide model development has been widely discussed. As the benzoxazinone skeleton contains three different potential areas for functionalization (C-2, N-4, and aromatic protons H-5, H-6, H-7, and H-8), and the first two have already been optimized, the main objective of this work was the substitution of aromatic protons for different substituent types and the study of the effects of the prepared chemicals on selected standard target species (STS) and weeds. Thus, different combinations of aromatic substituents, including methoxy, methoxycarbonyl, fluorine, chlorine, and trifluoromethyl, were introduced at different positions.

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Two new aporphine alkaloids, N-nitrosoanonaine (1) and N-nitrosoxylopine (2), were isolated from the aerial parts of Duguetia furfuracea, a weed found in several Brazilian regions. Their structures were elucidated by NMR analysis, CHN analysis, CD, IR, and MS data. The single-crystal X-ray structural determination of the structure of 1 was also performed.

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