6 research outputs found

    Bioactive compounds: a goldmine for defining new strategies against pathogenic bacterial biofilms?

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    Most human infectious diseases are caused by microorganisms growing as biofilms. These three-dimensional self-organized communities are embedded in a dense matrix allowing microorganisms to persistently inhabit abiotic and biotic surfaces due to increased resistance to both antibiotics and effectors of the immune system. Consequently, there is an urgent need for novel strategies to control biofilm-associated infections. Natural products offer a vast array of chemical structures and possess a wide variety of biological properties; therefore, they have been and continue to be exploited in the search for potential biofilm inhibitors with a specific or multi-locus mechanism of action. This review provides an updated discussion of the major bioactive compounds isolated from several natural sources - such as plants, lichens, algae, microorganisms, animals, and humans - with the potential to inhibit biofilm formation and/or to disperse established biofilms by bacterial pathogens. Despite the very large number of bioactive products, their exact mechanism of action often remains to be clarified and, in some cases, the identity of the active molecule is still unknown. This knowledge gap should be filled thus allowing development of these products not only as novel drugs to combat bacterial biofilms, but also as antibiotic adjuvants to restore the therapeutic efficacy of current antibiotics

    Metabolic profiling and antibacterial activity of Eryngium pristis Cham. & Schltdl. - prospecting for its use in the treatment of bacterial infections

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    Morbidity and mortality of the infected patients by multidrug-resistant bacteria have increased, emphasizing the urgency of fi ght for the discovery of new innovative antibiotics. In this sense, natural products emerge as valuable sources of bioactive compounds. Among the biodiversity, Eryngium pristis Cham. & Schltdl. (Apiaceae Lindl.) is traditionally used to treat thrush and ulcers of throat and mouth, as diuretic and emmenagogue, but scarcely known as an antimicrobial agent. With this context in mind, the goals of this study were to investigate the metabolic profi le and the antibacterial activity of ethanolic extract (EE-Ep) and hexane (HF-Ep), dichloromethane (DF-Ep), ethyl acetate (EAF-Ep) and butanol (BF-Ep) fractions from E. pristis leaves. Gas Chromatography-Mass Spectrometry (GC-MS) was performed to stablish the metabolic profi le and revealed the presence of 12 and 14 compounds in EAF-Ep and HF-Ep, respectively. β-selinene, spathulenol, globulol, 2-methoxy-4-vinylphenol, α-amyrin, β-amyrin, and lupeol derivative were some of phytochemicals identifi ed. The antibacterial activity was determined by Minimal Inhibitory Concentration (MIC) using the broth micro-dilution against eight ATCC® and fi ve methicillin-resistant Staphylococcus aureus (MRSA) clinical strains. HF-Ep was the most eff ective (MIC ≤ 5,000 μg/μL), being active against the largest part of tested Gram-positive and Gram-negative bacterial strains, including MRSA, with exception of Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 9027) and (ATCC 27853). These results suggest that E. pristis is a natural source of bioactive compounds for the search of new antibiotics which can be an interesting therapeutic approach to recover patients mainly infected by MRSA strains.info:eu-repo/semantics/publishedVersio

    Polygonum hydropiperoides Michx. (Polygonaceae Juss.): perfil metabolômico e potenciais antibacteriano e antibiofilme in vitro frente espécies de Salmonella

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    Polygonum hydropiperoides Michx. (Polygonaceae Juss.), popularly known in Brazil as "erva-de-bicho", is an Asian native plant species also widely distributed in the Americas. Traditionally, it is used as an astringent, antidisenteric, anti-hemorrhagic, anti-hemorrhoids, diuretic, vermicide, against varicose veins, erysipelas, rheumatism and in the treatment of wounds. With this context in mind, the present study aimed to chemically characterize, deeply investigate the antibacterial potential and evaluate the antibiofilm potential, as well as to screening the in vitro toxicity of hexane (EH), ethyl acetate (EAE) and ethanolic (EE) extracts from aerial parts of P. hydropiperoides. The chemical characterization was performed through High Performance Liquid Chromatography with a Diode Array Detector and an ion trap Mass Spectrometer with an Electrospray Interface (HPLC-DAD-ESI/MSn ). The antibacterial potential was determined by the Minimal Inhibitory Concentration (MIC) using the broth microdilution method and the Minimal Bactericidal Concentration (MBC) followed by the classification of the antibacterial effect. For this purpose, five human clinical strains of methicillin-resistant Staphylococcus aureus (MRSA) and five Salmonella spp. strains were tested, making a total of ten strains. In addition, the antibacterial potential was also be assessed through bacterial death kinetics and the effect of the extract combined with antibiotics used in clinical practice (combinatory effect) against Salmonella spp. strains. The antibiofilm potential against Salmonella spp. strains in polystyrene surface was evaluated. The acute in vitro toxicity screening was determined through the Artemia salina bioassay. Chemical characterization revealed the presence of phenolic acids and flavonoids in EAE. Regarding antibacterial activity, EAE proved to be the most effective extract among the tested, being active against all the ten strains with MIC values ranging from 625 to 2500 µg/mL and bacteriostatic effect. EAE also revealed the ability to interfere in the bacterial death kinetics, isolated and in partially sinergy association with chloramphenicol, being able to drastically reduce the population density of Salmonella spp. at levels more accentuated than ampicillin, chloramphenicol and levofloxacin used isolated. The evaluation of antibiofilm potential against Salmonella spp. strains revealed that EAE was the most efective extract, being able to inhibity the bacterial cells adhesion in the polystyrene surface. In relation to the acute toxicity screening, EAE was unable to make the microcrustacean A. salina unfeasible in concentrations ranging from 500 to 5000 µg/mL, showing low toxicity. Together, these results suggest that P. hydropiperoides is a natural source of active substances with antibacterial potential, which add scientific support for its popular use, mainly as antidisenteric, due to its effect on the Salmonella strains tested.Polygonum hydropiperoides Michx. (Polygonaceae Juss.), popularmente conhecida no Brasil como erva-de-bicho, é uma planta nativa da Ásia com ampla distribuição nas Américas. Tradicionalmente, é utilizada como adstringente, antidisentérica, anti-hemorrágica, antihemorroidas, diurética, vermicida, contra varizes, erisipela, reumatismo e no tratamento de feridas. Com base no exposto, o presente estudo teve por objetivos caracterizar quimicamente, aprofundar a investigação do potencial antibacteriano e avaliar o potencial antibiofilme, bem como efetuar uma triagem da toxicidade in vitro dos extratos hexânico (EH), acetato de etila (EAE) e etanólico (EE) das partes aéreas de P. hydropiperoides. A caracterização química foi realizada através de Cromatografia Líquida de Alta Eficiência acoplada a Detector de Arranjo de Diodos e a Espectrômetro de Massas com Ionização por Electrospray (CLAE-DADESI/EMn ). O potencial antibacteriano foi avaliado por meio das determinações da Concentração Inibitória Mínima (CIM) pelo método de microdiluição em caldo e da Concentração Bactericida Mínima (CBM) seguida pela classificação do efeito antibacteriano. Para tanto, foram testadas cinco cepas clínicas humanas de Staphylococcus aureus resistente à meticilina (MRSA) e cinco de Salmonella spp., perfazendo um total de dez cepas. Além disso, o potencial antibacteriano também foi avaliado através da cinética de morte bacteriana e do efeito do extrato combinado com antibióticos utilizados na prática clínica (efeito combinatório) frente às cepas de Salmonella spp. O potencial de inibição da formação de biofilmes em superfícies de poliestireno foi avaliado frente às cepas de Salmonella spp. A triagem da toxicidade aguda in vitro foi determinada através de bioensaio com Artemia salina. A caracterização química revelou a presença de ácidos fenólicos e flavonoides em EAE. Quanto à atividade antibacteriana, EAE mostrou-se o mais efetivo entre os extratos estudados, sendo ativo contra as dez cepas testadas, com valores de CIM variando de 625 a 2500 µg/mL e efeito bacteriostático. EAE também revelou a capacidade de interferir na cinética de morte bacteriana, de forma isolada e em combinação parcialmente sinérgica com cloranfenicol, sendo capaz de reduzir drasticamente a densidade populacional de Salmonella spp. em níveis mais acentuados que ampicilina, cloranfenicol e levofloxacina utilizados isoladamente. A avaliação do potencial de inibição de formação de biofilmes de Salmonella spp. revelou que EAE foi o mais efetivo, sendo capaz de impedir a adesão das células bacterianas na superfície de poliestireno. Em relação à triagem da toxicidade aguda, EAE não foi capaz de inviabilizar o microcrustáceo A. salina em concentrações variando de 500 a 5000 µg/mL, mostrando-se de baixa toxicidade. Somados, estes resultados sugerem que P. hydropiperoides é uma fonte natural de substâncias com potencial antibacteriano, que agregam subsídio científico para seu uso popular, principalmente como antidisentérica, em virtude de seu efeito sobre as cepas de Salmonella testadas.CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

    Metabolic profiling and antibacterial activity of Eryngium pristis Cham. & Schltdl. - prospecting for its use in the treatment of bacterial infections

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    Morbidity and mortality of the infected patients by multidrug-resistant bacteria have increased, emphasizing the urgency of fight for the discovery of new innovative antibiotics. In this sense, natural products emerge as valuable sources of bioactive compounds. Among the biodiversity, Eryngium pristis Cham. & Schltdl. (Apiaceae Lindl.) is traditionally used to treat thrush and ulcers of throat and mouth, as diuretic and emmenagogue, but scarcely known as an antimicrobial agent. With this context in mind, the goals of this study were to investigate the metabolic profile and the antibacterial activity of ethanolic extract (EE-Ep) and hexane (HF-Ep), dichloromethane (DF-Ep), ethyl acetate (EAF-Ep) and butanol (BF-Ep) fractions from E. pristis leaves. Gas Chromatography-Mass Spectrometry (GC-MS) was performed to stablish the metabolic profile and revealed the presence of 12 and 14 compounds in EAF-Ep and HF-Ep, respectively. β-selinene, spathulenol, globulol, 2-methoxy-4-vinylphenol, α-amyrin, β-amyrin, and lupeol derivative were some of phytochemicals identified. The antibacterial activity was determined by Minimal Inhibitory Concentration (MIC) using the broth micro-dilution against eight ATCC® and five methicillin-resistant Staphylococcus aureus (MRSA) clinical strains. HF-Ep was the most effective (MIC ≤ 5,000 µg/µL), being active against the largest part of tested Gram-positive and Gram-negative bacterial strains, including MRSA, with exception of Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 9027) and (ATCC 27853). These results suggest that E. pristis is a natural source of bioactive compounds for the search of new antibiotics which can be an interesting therapeutic approach to recover patients mainly infected by MRSA strains
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