RESUMO
ABSTRACT: The increasing number of cases of canine ehrlichiosis caused by Ehrlichia canis in hospitals and veterinary clinics has demonstrated the need for a new drug protocol for this disease. Doxycycline is used to treat ehrlichiosis, but the resistance of the microorganism to this treatment protocol, as well as the various side effects to the animals, has become a concern. Several studies have shown a positive interaction with extracts of plants and drugs, which allow for the reduction of the concentration necessary to produce the desired effect, minimizing adverse effects. This study determined the efficiency of the combination of the dichloromethane (DCM) fraction of Ageratum conyzoides L. with anti-Ehrlichia activity and doxycycline by using the checkerboard assay. Plant material was collected in São Luís, northeastern Brazil, followed by extraction in MeOH: H2O (8:2) and partitioning of the DCM fraction. After determining the Minimum Inhibitory Concentration (MIC) of the fraction under study against DH82 cells infected with Ehrlichia canis, it was combined with doxycycline to derive the Fractional Inhibitory Concentration Index (CIF Index). A reduction of 5.83 times the doxycycline minimum inhibitory concentration was observed, showing that this fraction of A. conyzoides composed predominantly by the class of lignans, identified by mass spectrometry notably intensified the activity of doxycycline against E. canis, resulting in a synergistic effect.
RESUMO: O crescente número de casos de erliquiose canina por Ehrlichia canis em hospitais e clínicas veterinárias tem demonstrado a necessidade de um novo protocolo de medicamentos para essa doença. A doxiciclina é usada para tratar a erliquiose, mas a resistência do microrganismo a esse protocolo de tratamento, bem como os diversos efeitos colaterais para os animais, tornou-se uma preocupação. Vários estudos têm demonstrado interação positiva com extratos de plantas e fármacos, que permitem a redução da concentração necessária para produzir o efeito desejado, minimizando os efeitos adversos. Este estudo determinou a eficiência da combinação da fração diclorometânica (DCM) de Ageratum conyzoides L. com atividade anti-Ehrlichia canis associada com doxiciclina por meio do ensaio de Checkerboard. O material vegetal foi coletado em São Luís, Maranhão, nordeste do Brasil, seguido pela extração em MeOH:H2O (8:2) e partição da fração diclorometânica. Após a determinação da Concentração Inibitória Mínima (CIM) da fração em estudo frente às células DH82 infectadas com Ehrlichia canis, a mesma foi combinada com a doxiciclina para derivação do Índice de Concentração Inibitória da Fração (Índice CIF). Observou-se uma redução de 5,83 vezes a concentração inibitória mínima da doxiciclina mostrando que esta fração de A. conyzoides, composta predominantemente por lignanas identificadas por espectrometria de massas, notavelmente intensificou a atividade desse fármaco contra E. canis, resultando em um efeito sinérgico.
RESUMO
Aim: Since other species of the Bignoniaceae Family presented of antispasmodic activity, it was decided, by chemotaxonomic criterion, to determine the antispasmodic activity of the leaves of Arrabidaea brachypoda. Methodology: the segments of the rat jejunum were suspended in glass vats containing specific saline solution, at an appropriate temperature, and after stabilization period, were stimulated by a contractile agent to observe the inhibitory or relaxing effect of EH-FAB. Results: EH-FAB showed the presence of 10 compounds, mainly rutin and it has an antispasmodic activity as it inhibits the phasic component and relaxes the tonic component of the contraction in isolated rat jejunum. To assess the mechanism of antispasmodic action, cumulative curves to the CCh were performed in which a non-competitive antagonism was observed, due to a displacement of the control curve to the right and reduction of the maximum contraction effect (Emax). Afterward, the participation of the calcium and/or potassium channels was evaluated by increasing the extracellular potassium, and it was observed that the EH-FAB relaxed the rat jejunum, suggesting the participation of the Ca2+ channels. To corroborate that hypothesis, the EH-FAB was tested against cumulative curves to Ca2+ in a free depolarizing solution of Ca2+, and it was observed that there was a shift of the curve to the right with a reduction in Emax. Conclusions: EH-FAB presents antispasmodic activity in isolated rat jejunum and it is suggested to block the influx of Ca2+ through voltage-gated calcium channels, signaling the therapeutic potential for the treatment of colic and/or diarrhea.(AU)
Assuntos
Animais , Masculino , Ratos , Parassimpatolíticos/uso terapêutico , Extratos Vegetais/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Bignoniaceae/química , Potássio , JejunoRESUMO
The properties of oil-resin of copaiba, Copaifera multijuga are commonly mentioned in the literature, but there are few studies on extracts from its stem bark. We evaluated the antioxidant effects of ethanolic (EE) and ethyl acetate (EA) crude stem bark extracts from copaiba and compared them to rutin in a paracetamol (PCM)-induced oxidative stress model in mice. All test comparisons differed significantly. Hepatic catalase (CAT) and glutathione-S-transferase (GST) activity decreased in the PCM group, and there was an increase of protein carbonyls in the liver, kidney and brain. However, the protein carbonyls decreased in the liver for the PCM + EE group, in the kidneys for the PCM + EA and PCM + Rutin groups, and in the brain for all treatments. Hepatic GSH decreased in the PCM group and increased in the PCM + EE group. The extracts showed a positive effect on ascorbic acid (ASA), since they were able to restore the levels of parameters that had been changed by PCM. There was an increase of ALT and AST activity in the plasma within the PCM group. Even though ALT decreased in the PCM + Rutin, PCM + EE and PCM + EA groups, EE and EA did not have an effect on AST. The strongest antioxidant effect was observed for EE, due to the presence of the phenolic compounds epicatechin and epiafzelechin, as well as the highest concentration of total phenols and an excellent antioxidant potential observed in the DPPH· test.
As propriedades do óleo-resina da copaíba, Copaifera multijuga são comumente citadas na literatura, mas há poucos estudos sobre extratos da casca do caule. Avaliamos os efeitos antioxidantes de extratos brutos etanólico (EE) e acetato de etila (EA) da casca do caule da copaíba e os comparamos à rutina no modelo de estresse oxidativo induzido por paracetamol (PCM) em camundongos. Todas as comparações de teste diferiram significativamente. A atividade da catalase hepática (CAT) e da glutationa-S-transferase (GST) diminuiu no grupo PCM, e houve um aumento de proteínas carboniladas no fígado, rim e cérebro. No entanto, as proteínas carboniladas diminuíram no fígado para o grupo PCM + EE, nos rins para os grupos PCM + EA e PCM + rutina, e no cérebro para todos os tratamentos. A GSH hepática diminuiu no grupo PCM e aumentou no grupo PCM + EE. Os extratos mostraram um efeito positivo sobre o ácido ascórbico (ASA), uma vez que foram capazes de restaurar os níveis dos parâmetros que foram alterados pelo PCM. Houve um aumento da atividade de ALT e AST no plasma dentro do grupo PCM. Embora a ALT tenha diminuído nos grupos PCM + rutina, PCM + EE e PCM + EA, EE e EA não afetaram a AST. O efeito antioxidante mais forte foi observado para o EE, provavelmente devido à presença dos compostos fenólicos epicatequina e epiafzelequina, assim como à maior concentração de fenóis totais e um excelente potencial antioxidante observado no teste DPPH·