Avaliação da Atividade Antibacteriana, Antioxidante e Toxicológica do Flavonoide isolado de Lonchocarpus araripensis (Leguminosae): Estudos in silico e in vitro

Bacterial infections, which affect millions of people around the world, have progressively increased in recent years, impacting the rate of morbidity and mortality. The spread of drug-resistant bacteria is one of the most serious threats to successful treatment of bacterial diseases, in addition, some drugs are very toxic, making it difficult to adhere to treatment. In this context, flavonoids have been distinguished by their diverse pharmacological activities, such as: bactericide, fungicide and antioxidant. Based on this, the antibacterial and antioxidant effects, the theoretical oral bioavailability and the toxicological profile of the flavonoid 2,4-cis-3,4-cis-3,4,5,8- tetramethoxy- [1 '', 2 '': 6,7] –furanoflavane (TMFF), isolated from the hexane extract of the bark of the roots of Lonchocarpus araripensis. To analyze the antimicrobial potential of flavonoid, in silico analysis with the Pass online software was used. For the accomplishment of the antibacterial studies the microdilution test with different strains of the bacteria Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa was used to evaluate the Minimum Inhibitory Concentration (MIC). In addition, the Minimum Bactericidal Concentration (MBC) was also determined. In the study of association of flavonoid with clinically used antibiotics, the ability of flavonoid to promote synergism, indifference or antagonism after association. In the accomplishment of the studies of antioxidant activity in vitro was used the technique of the chelating effect on the ferrous ion. For the in silico toxicological analysis the tool was used admetSAR and for the evaluation of oral bioavailability theoretically in silico was used the program Molinspiration Cheminformatics. The in silico study demonstrated that flavonoid presented a high probability of being active against several microorganisms, including bacteria. The experiments of antibacterial activity revealed that the flavonoid had a bacterial effect against gram positive and gram negative species, with MIC50 of 64 μg/mL for some strains of Pseudomonas aeruginosa, on different strains of Staphylococcus aureus, the flavonoid presented MIC50 of 256 μg/ml and on one of the tested strains of Escherichia coli the MIC50 was 512 μg/ml. Flavonoid has been shown to be bacteriostatic for all bacterial species tested and also showed a synergistic effect. In the antioxidant activity studies, flavonoid presented a chelating effect on the ferrous ion. Flavonoid demonstrated low theoretical toxicity as well as good oral bioavailability through in silico analysis. These results suggest that flavonoid has an antibacterial and antioxidant effect, with a low toxicological effect.As infecções bacterianas, que acometem milhões de pessoas em todo o mundo, têm aumentado progressivamente nos últimos anos, impactando na taxa de morbidade e mortalidade. A disseminação de bactérias resistentes aos medicamentos é uma das mais graves ameaças para o sucesso do tratamento das doenças bacterianas, além disso, algumas drogas são muito tóxicas, dificultando a adesão ao tratamento. Nesse contexto, os flavonoides têm se destacado por apresentarem diversas atividades farmacológicas, tais como: bactericida, fungicida e antioxidante. Com base nisto, foram estudados os efeitos antibacteriano e antioxidante, a biodisponibilidade oral teórica e o perfil toxicológico do flavonoide 2,4-cis-3,4-cis-3,4,5,8-tetrametoxi-[1'',2'':6,7]-furanoflavana (TMFF), isolado do extrato hexânico das cascas das raízes de Lonchocarpus araripensis. Para a análise do potencial antimicrobiano do flavonoide foi utilizado a análise in silico com o software Pass online. Para a realização dos estudos antibacterianos utilizou-se o teste de microdiluição com diferentes cepas das bactérias Staphylococcus aureus, Escherichia coli e Pseudomonas aeruginosa para avaliação da Concentração Inibitória Mínima (CIM). Além disso, determinou-se também a Concentração Bactericida Mínima (CBM). No estudo de associação do flavonoide com antibióticos usados clinicamente, avaliou-se a capacidade do flavonoide em promover sinergismo, indiferença ou antagonismo, após a associação. Na realização dos estudos de atividade antioxidante in vitro utilizou-se a técnica do efeito quelante sobre o íon ferroso. Para a análise toxicológica in silico utilizou-se a ferramenta admetSAR e para a avaliação da biodisponibilidade por via oral teórica in silico utilizou-se o programa Molinspiration Cheminformatics. O estudo in silico demonstrou que o flavonoide apresentou uma grande probabilidade de ser ativo, frente a vários micro-organismos, incluindo bactérias. Os experimentos de atividade antibacteriana revelaram que o flavonoide apresentou um efeito bacteriano frente espécies gram-positivas e gramnegativas, com CIM50 de 64 μg/mL para algumas cepas de Pseudomonas aeruginosa, sobre diferentes cepas de Staphylococcus aureus o flavonoide apresentou CIM50 de 256 μg/mL e sobre uma das cepas testadas de Escherichia coli a CIM50 foi de 512 μg/mL. O flavonoide demonstrou ser bacteriostático para todas as espécies de bactérias testadas e também apresentou um efeito sinérgico. Nos estudos da atividade antioxidante, o flavonoide apresentou um efeito quelante sobre o íon ferroso. O flavonoide demonstrou uma baixa toxicidade teórica, bem como uma boa biodisponibilidade oral através da análise in silico. Estes resultados sugerem que o flavonoide apresenta efeito antibacteriano e antioxidante, com baixo efeito toxicológico

Toxicity and antitumor potential of Mesosphaerum sidifolium (Lamiaceae) oil and fenchone, its major component

Abstract Background The essential oil from Mesosphaerum sidifolium (L’Hérit.) Harley & J.F.B.Pastore (syn. Hyptis umbrosa), Lamiaceae (EOM), and its major component, have been tested for toxicity and antitumor activity. Methods EOM was obtained from aerial parts of M. sidifolium subjected to hydro distillation, and gas chromatography-mass spectrometry was used to characterize the EOM chemical composition. The toxicity was evaluated using haemolysis assay, and acute toxicity and micronucleus tests. Ehrlich ascites carcinoma model was used to evaluate the in vivo antitumor activity and toxicity of EOM (50, 100 and 150 mg/kg), and fenchone (30 and 60 mg/kg) after 9 d of treatment. Results The EOM major components were fenchone (24.8%), cubebol (6.9%), limonene (5.4%), spathulenol (4.5%), β-caryophyllene (4.6%) and α-cadinol (4.7%). The HC50 (concentration producing 50% haemolysis) was 494.9 μg/mL for EOM and higher than 3000 μg/mL for fenchone. The LD50 for EOM was approximately 500 mg/kg in mice. The essential oil induced increase of micronucleated erythrocytes only at 300 mg/kg, suggesting moderate genotoxicity. EOM (100 or 150 mg/kg) and fenchone (60 mg/kg) reduced all analyzed parameters (tumor volume and mass, and total viable cancer cells). Survival also increased for the treated animals with EOM and fenchone. For EOM 150 mg/kg and 5-FU treatment, most cells were arrested in the G0/G1 phase, whereas for fenchone, cells arrested in the S phase, which represents a blockage in cell cycle progression. Regarding the toxicological evaluation, EOM induced weight loss, but did not induce hematological, biochemical or histological (liver and kidneys) toxicity. Fenchone induced decrease of AST and ALT, suggesting liver damage. Conclusions The data showed EOM caused in vivo cell growth inhibition on Ehrlich ascites carcinoma model by inducing cell cycle arrest, without major changes in the toxicity parameters evaluated. In addition, this activity was associated with the presence of fenchone, its major component