Unlocking bacterial defense: Exploring the potent inhibition of NorA efflux pump by coumarin derivatives in Staphylococcus aureus.

The occurrence of bacterial resistance has been increasing, compromising the treatment of various infections. The high virulence of Staphylococcus aureus allows for the maintenance of the infectious process, causing many deaths and hospitalizations. The MepA and NorA efflux pumps are transporter proteins responsible for expelling antimicrobial agents such as fluoroquinolones from the bacterial cell. Coumarins are phenolic compounds that have been studied for their diverse biological actions, including against bacteria. A pharmacokinetic in silico characterization of compounds C10, C11, C13, and C14 was carried out according to the principles of Lipinski's Rule of Five, in addition to searching for similarity in ChemBL and subsequent search for publications in CAS SciFinder. All compounds were evaluated for their in vitro antibacterial and modulatory activity against standard and multidrug-resistant Gram-positive and Gram-negative strains. The effect of coumarins C9, C10, C11, C13, and C14 as efflux pump inhibitors in Staphylococcus aureus strains was evaluated using the microdilution method (MepA or NorA) and fluorimetry (NorA). The behavior of coumarins regarding the efflux pump was determined from their interaction properties with the membrane and coumarin-protein using molecular docking and molecular dynamics simulations. Only the isolated coumarin compound C13 showed antibacterial activity against standard strains of Staphylococcus aureus and Escherichia coli. However, the other tested coumarins showed modulatory capacity for fluoroquinolone and aminoglycoside antibacterials. Compounds C10, C13, and C14 were effective in reducing the MIC of both antibiotics for both multidrug-resistant strains, while C11 potentiated the effect of norfloxacin and gentamicin for Gram-positive and Gram-negative bacteria and only norfloxacin for Gram-negative. Only coumarin C14 produced synergistic effects when associated with ciprofloxacin in MepA-carrying strains. All tested coumarins have the ability to inhibit the NorA efflux pump present in Staphylococcus aureus, both in reducing the MIC and inducing increased ethidium bromide fluorescence emission in fluorimetry. The findings of this study offer an atomistic perspective on the potential of coumarins as active inhibitors of the NorA pump, highlighting their specific mode of action mainly targeting protein inhibition. In molecular docking, it was observed that coumarins are capable of interacting with various amino acid residues of the NorA pump. The simulation showed that coumarin C10 can cross the bilayer; however, the other coumarins interacted with the membrane but were unable to cross it. Coumarins demonstrated their potentiating role in the effect of norfloxacin through a dual mechanism: efflux pump inhibition through direct interaction with the protein (C9, C10, C11, and C13) and increased interaction with the membrane (C10 and C13). In the context of pharmacokinetic prediction studies, the studied structures have a suitable chemical profile for possible oral use. We suggest that coumarin derivatives may be an interesting alternative in the future for the treatment of resistant bacterial infections, with the possibility of a synergistic effect with other antibacterials, although further studies are needed to characterize their therapeutic effects and toxicity.

In vitro and in silico evidences about the inhibition of MepA efflux pump by coumarin derivatives.

The discovery of antibiotics has significantly transformed the outcomes of bacterial infections in the last decades. However, the development of antibiotic resistance mechanisms has allowed an increasing number of bacterial strains to overcome the action of antibiotics, decreasing their effectiveness against infections they were developed to treat. This study aimed to evaluate the antibacterial activity of synthetic coumarins Staphylococcus aureus in vitro and analyze their interaction with the MepA efflux pump in silico. The Minimum Inhibitory Concentration (MIC) determination showed that none of the test compounds have antibacterial activity. However, all coumarin derivatives decreased the MIC of the standard efflux inhibitor ethidium bromide, indicating antibacterial synergism. On the other hand, the C14 derivative potentiated the antibacterial activity of ciprofloxacin against the resistant strain. In silico analysis showed that C9, C11, and C13 coumarins showed the most favorable interaction with the MepA efflux pump. Nevertheless, due to the present in silico and in vitro investigation limitations, further experimental research is required to confirm the therapeutic potential of these compounds in vivo.

In vitro and in silico antibacterial evaluation of coumarin derivatives against MDR strains of Staphylococcus aureus and Escherichia coli.

The increase in antibiotic resistance rates has attracted the interest of researchers for antibacterial compounds capable of potentiating the activity of conventional antibiotics. Coumarin derivatives have been reported to develop effective antibacterials with possible new mechanisms of action for treating infectious diseases caused by bacteria with a profile of drug resistance. In this context, the aim of the present study we have now prepared one variety of new synthetic coumarins evaluating the pharmacokinetic and chemical similarity in silico, their antimicrobial activity against Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922), and potential for the modulation of antibiotic resistance against Staphylococcus aureus (SA10) and Escherichia coli (EC06) clinical isolate bacteria by in vitro assay. The antibacterial activity and antibiotic-enhancing properties were evaluated by the broth microdilution method and pharmacokinetically characterized according to the Lipinsk rule of 5 and had their similarity analyzed in databases such as ChemBL and CAS SciFinder. The results demonstrated that only compound C13 showed significant antibacterial activity (MIC ≤256 µg/mL), and all other coumarins did not display relevant antibacterial activity (MIC ≥1024 µg/mL). However, they did modulate the antibiotics activities to norfloxacin and gentamicin, except, compound C11 to norfloxacin against Staphylococcus aureus (SA10). The in silico properties prediction and drug-likeness results demonstrated that all coumarins presented a good drug-likeness score with no violations and promising in silico pharmacokinetic profiles showing that they have the potential to be developed into an oral drug. The results indicate that the coumarin derivatives showed good in vitro antibacterial activity. These new coumarin derivatives also demonstrated the capacity to modulate antibiotic resistance with potential synergy action for current antimicrobials assayed, as antibiotic adjuvants, to reduce the emergence of antimicrobial resistance.

Inhibition of Staphylococcus aureus TetK and MsrA efflux pumps by hydroxyamines derived from lapachol and norlachol.

The present study aimed to evaluate the in vitro efflux pump inhibitory capacity of hydroxyamines derived from lapachol and norlachol, where compounds 3, 4, and 5 were tested against the S. aureus strains: RN4220 carrying the pUL5054 plasmid; and IS-58, endowed with the PT181 plasmid. The substances were synthesized from 2-hydroxy-quinones, lapachol and nor-lapachol obtaining the corresponding 2-methoxylated derivatives via dimethyl sulfate alkylation in a basic medium, which then reacted chemoselectively with 2-ethanolamine and 3-propanolamine to form the corresponding amino alcohols. The antibacterial action of the substances was quantified by determining the Minimum Inhibitory Concentration (MIC), while a microdilution assay was carried out to ascertain efflux pump inhibition of Staphylococcus aureus strains carrying the MsrA macrolide and the TetK tetracycline efflux pumps with the substances at a sub-inhibitory concentration. The results were subjected to statistical analysis by an ANOVA test and Bonferroni post hoc test. The MIC from the substances exhibited a value ≥ 1024 µg/mL. However, a significant reduction (p < 0.0001) of the erythromycin, tetracycline and ethidium bromide MIC was demonstrated when these were in combination with the substances, with this effect being due to a supposed efflux pump inhibition. The tested substances demonstrated effectiveness at decreasing the MIC of erythromycin, tetracycline and ethidium bromide, potentially by inhibiting the MsrA macrolide and the TetK tetracycline efflux pumps present in the tested S. aureus strains.

Effect of hydroxyamines derived from lapachol and norlachol against Staphylococcus aureus strains carrying the NorA efflux pump.

Isolated substances and those organically synthesized have stood out over the years for their therapeutic properties, including their antibacterial activity. These compounds may be an alternative to the production of new antibiotics or may have the ability to potentiate the action of preexisting ones. In this context, the objective of this study was to evaluate the in vitro antibacterial and efflux pump inhibitory activity of hydroxyamines derived from lapachol and norlachol, more specifically the compounds 2-(2-Hydroxyethylamino)-3-(3-methyl-2-butenyl)-1,4 dihydro-1,4-naphthalenedione, 2-(2-Hydroxyethylamino)-3-(2-methyl-propenyl)[1,4]naphthoquinone and 2-(3-Hydroxypropylamino)-3-(3-methyl-2-butenyl)-[1,4]naphthoquinone, against Staphylococcus aureus strains carrying the NorA efflux pump mechanism. The substances were synthesized from 2-hydroxy-quinones, lapachol and nor-lapachol, obtaining the corresponding 2-methoxylated derivatives via dimethyl sulfate alkylation in a basic medium, which then reacted chemoselectively with 2-ethanolamine and 3-propanolamine to form the corresponding amino alcohols. All three molecules underwent a virtual structure-based analysis (docking). The antibacterial activity of the substances was measured by determining their Minimum Inhibitory Concentration (MIC) and a microdilution assay was performed to verify efflux pump inhibition using the substances at a sub-inhibitory concentration. The results were subjected to statistical analysis using an analysis of variance (ANOVA) followed by Bonferroni's post hoc test. The substances obtained MIC values ≥1024 µg/mL, however, a significant reduction of their MICs was observed when the substances were associated with norfloxacin and ethidium bromide, with this effect being attributed to efflux pump inhibition. Following a virtual analysis based on its structure (docking), information regarding the affinity of new ligands for the ABC efflux pump were observed, thus contributing to the understanding of their mechanism of molecular interactions and the discovery of functional ligands associated with a reduction in bacterial resistance.

In silico evaluation of the antibacterial and modulatory activity of lapachol and nor-lapachol derivates.

The aim of this research was to investigate the pharmacological properties of 2-(2-hydroxyethylamine)-3-(3-methyl-2-butenyl)-1,4-dihydro-1,4-naphthalenedione, 2-(2-hydroxy-ethylamine)-3-(2-methyl-propenyl)-[1,4]naphthoquinone and 2-(3-hydroxy-propylamine)-3-(3-methyl-2-butenyl)-[1,4]naphthoquinone using computational prediction models, in addition to evaluating the in vitro antibacterial and modulatory activity of these compounds against bacterial ATCC strains and clinical isolates. The substances were synthesized from 2-hydroxy-quinones, lapachol and nor-lapachol obtaining the corresponding 2-methoxylated derivatives via dimethyl sulfate alkylation in a basic medium, these then reacted chemoselectively with 2-ethanolamine and 3-propanolamine to form the corresponding amino alcohols. The antibacterial activity and modulatory activity of the substances were assayed by broth microdilution method to determine the Minimum Inhibitory Concentration (MIC). The molecular structures were analyzed using the ChEMBL database to predict possible pharmacological targets, which pointed to the molecule 2- (2-hydroxy-ethylamine)-3-(2-methyl-propenyl)-[1,4]naphthoquinone as a probable antibacterial agent for the proteins Replicative DNA helicase and RecA. The compounds had a low molecular weight and a small number of rotatable bonds. The MICs of the substances were not clinically significant, however, the association with gentamicin and amikacin reduced the MICs of these antibiotics. In conclusion, the combination of these substances with aminoglycosides may be a therapeutic alternative to bacterial resistance and the reduction of side effects.

Potencial antibacteriano e modulador de antibióticos das folhas de Allamanda puberula A.DC. (quatro-patacas) / Antibacterial and modulatory potential of antibiotics from leaves of Allamanda puberula A.DC. (quatro-patacas)

Introdução: Extratos de plantas têm sido testados com o intuito de descobrir novos compostos com atividade antibacteriana reconhecida. Objetivos: Explorar o extrato etanólico das folhas de A. puberula, quanto à presença de compostos químicos, atividade antibacteriana e como um agente modificador da resistência aos antibióticos das classes dos aminoglicosídeos e lincosamidas. Métodos: O extrato etanólico foi obtido a partir das folhas frescas de A. puberula e submetido à análise fitoquímica, pelo método colorimétrico. A atividade antibacteriana in vitro frente cepas padrões de Staphylococcus aureus, Pseudomonas aeruginosa e Escherichia coli foi avaliada pela microdiluição em caldo, determinando a Concentração Inibitória Mínima. A modulação da atividade antibiótica foi testada em concentração subinibitória. Resultados: O produto natural apresentou em sua constituição, metabólitos secundários com reconhecida atividade biológica, no entanto, não foi constatada atividade antibacteriana clinicamente relevante do extrato isolado frente às linhagens trabalhadas. Houve melhora na resposta quando associado o produto natural com aminoglicosídeos, tendo a atividade da amicacina concomitante ao extrato frente à S. aureus e E. Coli, uma redução significativa da CIM de 182,29 µg/ml para 32,55 µg/ml e de 42,315 µg/ml para 26,04 µg/ml, respectivamente. A gentamicina associada ao extrato frente à P. aeruginosa obteve redução da CIM de 104,17 µg/ml para 15,46 µg/ml. Conclusões: A associação do antibiótico com o produto natural diminuiu a dose terapêutica, esta atividade pode ser justificada pela presença de metabolitos secundários no extrato que possui reconhecida atividade antibacteriana.

Introduction: Some plant extracts have been tested for new compounds with recognized antibacterial activity. Objectives: Explore the ethanolic extract of A. puberula leaves for the presence of chemical compounds, antibacterial activity and as modifier of resistance to antibiotics in classes of aminoglycosides and lincosamides. Methods: The ethanolic extract was obtained from fresh leaves of Allamanda puberula and subjected to phytochemical analysis by the colorimetric method. In vitro antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli pattern strains was evaluated by broth microdilution to determine the minimum inhibitory concentration. Modulation of antibiotic activity was tested at a subinhibitory concentration. Results: The natural product analyzed was found to contain secondary metabolites of recognized biological activity. However, clinically relevant antibacterial activity of the isolated extract against the lineages studied was not observed. The response was found to improve when the natural product was associated to aminoglycosides. The activity of the amikacin concomitant to the extract against S. aureus and E. Coli causes a significant minimum inhibitory concentration reduction of 182.29 µg/ml to 32.55 µg/ml and 42.315 µg/ml to 26.04 µg/ml, respectively. Association of gentamicin to the extract against P. aeruginosa caused a minimum inhibitory concentration reduction of 104.17 µg/ml to 15.46 µg/ml. Conclusions: Association of the antibiotic to the natural product reduced the therapeutic dose. This activity may be due to the presence of secondary metabolites in the extract with recognized antibacterial activity.

Inhibition of the essential oil from Chenopodium ambrosioides L. and α-terpinene on the NorA efflux-pump of Staphylococcus aureus.

This study was carried out to test the essential oil from C. ambrosioides leaves and its main constituent, α-Terpinene, in an antibacterial activity assay. As well, it was evaluated ability reduce resistance to norfloxacin and ethidium bromide was compared the Staphylococcus aureus 1199B whith 1199 wild type strain. The MIC of the C. ambrosioides essential oil and α-Terpinene were determined by microdilution method. The MIC of the essential oil and α-Terpinene presented a value ≥ 1024 µg/mL. However, when associated with antibacterials, the essential oil from C. ambrosioides leaves significantly reduced the MIC of antibiotics and ethidium bromide, characterizing an efflux pump inhibition. The C. ambrosioides essential oil, despite having no direct antibacterial activity against the S. aureus 1199B strain, showed a potentiating action when associated with antibacterial agents, this being attributed to an inhibition of efflux pumps.

Potentiation of antibiotic activity by Passiflora cincinnata Mast. front of strains Staphylococcus aureus and Escherichia coli.

The development of new drugs from plants is an interesting alternative approach to overcoming microbial resistance. Passiflora cincinnata shows resistance to diseases and pests and a higher concentration of chemical components that may be useful in the pharmaceutical industry. We investigated the potential antimicrobial and antibiotic-modifying activity of hydroalcoholic extracts of leaves, stems, bark, pulp and seeds of P. cincinnata. The extracts were prepared by homogenization of material in 50% ethanol. Minimum inhibitory concentration (MIC) was determined by the broth dilution method, and the bacterial strains tested were Staphylococcus aureus and Escherichia coli. Antibiotic-modifying activity was evaluated against the strains S. aureus 03 and E. coli 08, using a subinhibitory concentration of extract. The antibiotics tested were: amikacin, gentamicin, ampicillin, potassium benzylpenicillin and oxacillin. The extracts did not show antimicrobial activity of clinical relevance, where the MIC was equal to or greater than 1024 µg/mL. S. aureus showed 13 events, while E. coli showed only 4 events. Among these events, 14 involved synergistic activity, potentiating the effect of the antibiotics, and only 3 events demonstrated antagonistic activity toward ampicillin. Hydroalcoholic extracts are potential antimicrobial agents when combined with conventional drugs little utilized in in vivo treatment.

Inhibition of the TetK efflux-pump by the essential oil of Chenopodium ambrosioides L. and α-terpinene against Staphylococcus aureus IS-58.

The use of natural products is crucial to suppress the development of these micro-organisms and to reduce the concentration necessary to inhibit these microrganisms, reducing the toxicity risks also. In this study, the essential oil from Chenopodium ambrosioides Leaves and its main constituent α-Terpinene were used in the antibacterial and potentiating activity of antibiotics and ethidium bromide assays, against the bacterial strains Staphylococcus aureus IS-58, carriers of efflux pumps. The Minimum Inhibitory Concentration (MIC) was determined using a microdilution method. The capacity of the aforementioned was also tested in combination with tetracycline and ethidium bromide, with the aim of improving the activity of the antibacterials. The MIC of the C. ambrosioides L. essential oil and of α-Terpinene were above 1024 µg/mL, comprising a clinically irrelevant value. However, when associated with the antibiotics, the C. ambrosioides L. essential oil, significantly decreased the MIC of tetracycline and ethidium bromide. The efflux pump is the only mechanism the bacteria possesses to reduce the toxicity of ethidium bromide, and thus this reduction in the MIC demonstrates that the C. ambrosioides L. essential oil is an effective option in the inhibition of the efflux pump present in these micro-organisms.

Psidium guajava L., from ethnobiology to scientific evaluation: Elucidating bioactivity against pathogenic microorganisms.

ETHNOPHARMACOLOGICAL RELEVANCE: The use of popular plants has guided pharmaceutical research aimed at combating pathogenic microorganisms. Psidium guajava L. is a plant of great versatility and it has been used both as food and as a therapeutic agent. Root, bark, leaves, fruits, flowers and seeds are used for medicinal purposes, especially in infusions and decoctions for oral and topical use. P. guajava is utilized in symptomatology treatment related to organ malfunction and of diseases caused by the action of pathogenic and/or opportunistic microorganisms. Many pharmacological studies have been conducted to scientifically assess its therapeutic potential. AIMS OF STUDY: The aim of the current study is to relate the popular use of this plant and its bioscientific assessment as a therapeutic agent in the treatment of diseases and symptoms caused by the action of protozoa, fungi, bacteria and viruses, and also evaluate the safety for the usage and the interaction with drugs. MATERIALS AND METHODS: A bibliographic database the ethnobiology of Psidium guajava (2005-2015) and the pharmacological infections and parasitic diseases (2010-2015). Searches were done in scientific disclosure databases such as PubMed, Web of Science, and Scopus. RESULTS: P. guajava leaf extracts were scientifically investigated for the treatment of diseases caused by protozoa (leishmaniasis, malaria, giardiasis, amoebiasis and trichomoniasis), fungi (dermatosis, systemic and mucocutaneous diseases), bacteria (respiratory, mucocutaneous and gastrointestinal infections, cholera, gastritis and stomach ulcers, oral and periodontal infections, venereal diseases and urinary infections) and viruses (herpes, influenza, rotavirus disease and AIDS). The toxicity assays indicates the safet for usage. CONCLUSIONS: Highlight and elucidate the therapeutic potential and versatility of P. guajava. They also justify using ethnobiology efficiency to guide pharmacological studies. Some limitations can be observed in this kind of study, as the lack for ethnobiological informations and the absence of some controls in the assays.

Avaliação da atividade antibacteriana e moduladora dos extratos metanólico e hexânico da folha de Allium cepa / Evaluation of the Antibacterial and Modulating Activity of Methanolic and Hexanic Extracts of the Allium Cepa / Evaluación de la actividad antibacteriana y moduladora de los extractos metanol y hexano de la hoja de Allium cepa

Introdução: A resistência bacteriana tem crescido significativamente nos últimos tempos, tornando-se imprescindível a busca por novos alvos terapêuticos. Nesse contexto, compostos bioativos presentes em algumas plantas medicinais podem apresentar várias atividades biológicas, como ação antimicrobiana. Allium cepa conhecida popularmente como cebola é utilizada de maneira etnofarmacológica há muito tempo para o tratamento de diversas enfermidades: tuberculose, diabetes, hipertensão, reumatismo e assim por diante. Objetivo: O principal objetivo deste trabalho foi avaliar a atividade antimicrobiana e modulatória dos extratos metanólico e hexânicoda das folhas A. cepa frente às cepas de bactérias padrões e multirresistentes. Materiais e métodos: Pelos métodos e microdiluição e modulação com antibióticos. Resultados: Os resultados deste estudo demonstraram uma variação no CMI (Concentração Inibitória Mínima) de 128 a ≥ 1024 μg/mL dos extratos metanólico de A. cepa (EMAC) e hexânico de A. cepa (EHAC). Na modulação com os aminoglicosídeos (amicacina e gentamicina) observaram-se efeitos sinérgicos e antagônicos dos extratos EHAC e EMAC frente às cepas Escherichia coli e Staphylococcus aureus de linhagem multirresistente. Novas pesquisas são necessárias para uma possível utilização das plantas medicinais combinadas com os antimicrobianos frente às linhagens patogênicas. Conclusão: Através desses resultados sugere-se que os produtos naturais representam fontes promissoras no combate à resistência bacteriana.

Introduction: Bacterial resistance has grown significantly in recent years, making the search for new antibiotics imperative. Bioactive compounds in some medicinal plants may exhibit various biological activities as antimicrobial activity. Allium cepa, popularly known as onion, is ethnopharmacologically used for treating various diseases, such as tuberculosis, diabetes, hypertension and rheumatism; it is also considered a powerful bactericide. Objective: The main objective of this study was to evaluate the antimicrobial and modulating activity of methanol and hexane extracts of A. cepa against the strains of multiresistant bacteria. Materials and methods: Microdilution and modulation of antibiotics. Results: The results showed a variation in the MIC (Minimum Inhibitory Concentration) from 128 to ≥ 1024μg / mL between A. cepa methanol (EMAC) and A. cepa hexane (EHAC) extracts. Modulation with aminoglycosides (gentamicin and amikacin) have proved to have antagonistic effects of the extracts sinérgicose EHAC and EMAC against strains of multiresistant Escherichia coli and Staphylococcus aureus. Further research is needed related to the use of medicinal plants combined with antimicrobials against pathogenic strains. Conclusion: Through these results it can be inferred that natural products could constitute a promising source for combating bacterial resistance.

Introducción: la resistencia bacteriana ha crecido significativamente en los últimos años, por lo que es necesaria la búsqueda de nuevas dianas terapéuticas. En este contexto, los compuestos bioactivos presentes en algunas plantas medicinales pueden tener diversas actividades biológicas, tales como la acción antimicrobiana. Allium cepa, conocida como la cebolla, es utilizada, popularmente de forma etnofarmacológica para el tratamiento de diversas enfermedades tales como la tuberculosis, la diabetes, la hipertensión, el reumatismo y así sucesivamente. Objetivo: el objetivo de este estudio fue evaluar la actividad antimicrobiana y moduladora de extractos de metanol y hexano de Allium cepa frente a las cepas de bacterias y normas multirresistentes. Materiales y métodos: por los métodos microdilución y modulación con antibióticos. Resultados: los resultados mostraron una variación de MIC(concentración mínima inhibitoria) de 128 a ≥ 1024μg / mL dos extractos metanólicos A. cepa (EMAC) y hexano de A. cepa (EHAC). En la modulación con aminoglucósidos (amikacina y gentamicina), se observaron efectos sinérgicos y antagónicos de EHAC y EMAC, frente a las cepas de Escherichia coli y Staphylococcus aureus multirresistente. Se necesitan nuevas investigaciones para un posible uso de plantas medicinales combinadas con la cara antimicrobiana de las cepas patógenas. Conclusión: a partir de estos resultados, se sugiere que los productos naturales son fuentes prometedoras en la lucha contra la resistencia bacteriana.

Potentiation of antibiotic activity of aminoglycosides by natural products from Cordia verbenacea DC.

Medicinal plants are often the only therapeutic resource for many communities and ethnic groups. Cordia verbenacea DC., "Erva-baleeira," is one of the species of plants currently used to produce a phytotherapeutic product extracted from its leaves. The present study aimed to establish its chemical profile, antibacterial activity and resistance-modulating potential. The C. verbenacea extracts were prepared from fresh leaves using solvents as methanol and hexane. Ethyl Acetate was used for the preparation of the fraction. Phytochemical screening was carried out using HPLC-DAD for determination and quantification of the secondary metabolites present in the fractions. Antibacterial and resistance-modulation assays were performed to determine minimum inhibitory concentration (MIC) using a microdilution assay. The data were subjected to statistical analysis with two-way ANOVA and Bonferroni posttests. Results of phytochemical prospecting and HPLC analysis of the fractions were in agreement with the literature. The natural products presented moderate antibacterial activity when considering the clinical relevance of a MIC of 256 µg/mL against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, and 512 µg/mL against P. aeruginosa. However, when the fractions were combined with antibiotics we observed a synergic effect, as natural products enhanced the antibacterial effect of aminoglycosides, significantly decreasing the MIC of antibiotics at 12.5%-98.4%. We believe that the data obtained from phytochemical analysis and from antibacterial and resistance modulation assays of C. verbenacea extracts new can open perspectives in the search for new alternatives for the treatment of bacterial infections and stimulate the renewed use of antibiotics with reduced effectiveness due to resistance.

Cytoprotective Effect of Lygodium venustum Sw. (Lygodiaceae) against Mercurium Chloride Toxicity.

Mercury is a very dangerous metal when humans come into contact with it, whether through the air or skin or by ingestion. The aim of this work was to investigate the possible effects of the ethanol extract and fractions of Lygodium venustum Sw. against mercurium chloride toxicity towards Escherichia coli strain ATCC25922. The polyphenols and flavonoids present in the extract and fractions were quantified in mg equivalent of gallic acid/g sample and mg equivalent of quercetin/g sample, respectively. The in vitro FRAP method demonstrated the antioxidant activity of the samples. The antibacterial activity of the natural products was evaluated by microdilution method and by assays to elucidate the possible cytoprotective action when combining the natural products samples and mercurium chloride, utilizing the extract and fractions at a subinhibitory concentration. The results obtained in this work indicate that the ethanol extract and fractions of L. venustum are an alternative source of natural products with cytoprotective action, where this protection is correlated with antioxidant and chelating activity, due to the presence of total phenols and flavonoids.

Avaliação da atividade antimicrobiana e moduladora do extrato etanólico de Libidibia ferrea (Mart. ex Tul.) L.P. Queiroz / Evaluación de la actividad antimicrobiana y modulatória del extracto etanólico de Libidibia ferrea (Mart. ex Tul.) L.P. Queiroz / Evaluation of antimicrobial and modulatory activity of the ethanol extract of Libidibia ferrea (Mart. ex Tul.) L.P. Queiroz

Introdução: Staphylococcus aureus é mencionada na literatura como um importante patógeno, algumas espécimes acarretam infecções oportunistas em muitos animais e homens. Escherichia coli é uma das principais causas de doenças infecciosas humanas. Pertencente à família das Enterobacteriaceae, compartilham diversos fatores de virulência descrita por sua resistência a vários antibióticos, as contaminações são provavelmente iniciadas por modificações de defesas do hospedeiro. Pseudomonas aeruginosaé conhecida por causar infecção aguda pela produção de toxinas. Objetivo: avaliar o efeito antimicrobiano do extrato etanólico de Libidibia ferrea (Mart. ex Tul.) L.P. Queiroz, e modulação da atividade antibiótica. Métodos: o material botânico de Libidibia ferrea foi coletado no município de Penaforte, Ceará, Brasil. Para a obtenção dos extratos foram coletadas entrecasca e vagem frescas, submersos em etanol separadamente por 72 h, sendo após esse período, filtrado e concentrado em condensador rotativo a vácuo. Foram realizados testes de atividade antimicrobiana e modulação da atividade antimicrobiana com cepas padrões e multirresistentes de bactérias. Resultados: o extrato demonstrou atividade moduladora quando combinados com alguns antimicrobianos contra algumas linhagens testadas. Conclusões: portanto, é sugerido que o extrato de L. ferrea pode ser utilizada como uma fonte de produtos naturais na terapêutica antimicrobiana e no combate a multirresistência bacteriana(AU)

Introducción: Staphylococcus aureus se menciona en la literatura como un patógeno importante, algunos provocan infecciones oportunistas en animales y hombres. Escherichia coli es una de las principales causas de enfermedades infecciosas humanas. Ambas pertenecen a la familia Enterobacteriaceae, comparten muchos factores de virulencia y se caracterizan por su resistencia a múltiples antibióticos, su contaminación tal vez iniciada por la modificación de las defensas del hospedero. Pseudomonas aeruginosa causa de infección aguda mediante la producción de toxinas. Objetivo: evaluar el efecto antimicrobiano del extracto de etanol de Libidibia ferrea (Mart ex Tul.) LP Queiroz, y la modulación de la actividad antibiótica. Métodos: L. ferrea fue recopilada en el municipio de Penaforte, Ceará, Brasil. Para obtener los extractos se recogieron corteza y frutos frescos, sumergidos en etanol por separado durante 72 h, después se filtraron y se concentraron en un condensador rotatorio. Se realizaron pruebas de actividad antimicrobiana y la modulación de la actividad antimicrobiana con cepas multirresistentes de bacterias. Resultados: los extractos mostraron actividad moduladora cuando se combina con algunos antibióticos contra algunas cepas ensayadas. Conclusión: por lo tanto, se sugiere que el extracto de L. ferrea puede ser utilizado como una fuente de productos naturales en la terapia antimicrobiana y en la resistencia a múltiples fármacos bacteriana combate(AU)

Introduction: Staphylococcus aureus is mentioned in the literature as an important pathogen, some opportunistic bacteria may cause several problems in many animals and humans. Escherichia coli is a leading cause of human infectious diseases. Belonging to the family Enterobacteriaceae, share many virulence factors described by their resistance to multiple antibiotics, the contamination is probably initiated by modifications in the host defenses. Pseudomonas aeruginosa is known to cause acute infection by producing toxins. Objective: evaluate the antimicrobial effect of the ethanol extract of Libidibia ferrea (Mart ex Tul.) LP Queiroz, and modulation of antibiotic activity. Methods: L. ferrea was collected in the municipality of Penaforte, Ceará, Brazil. To obtain the extracts were collected bark and fruits, submerged in ethanol separately for 72 h, after this period, filtered and concentrated in a rotary vacuum condenser. Antimicrobial activity tests were performed and modulation of antimicrobial activity with standards and multiresistant strains of bacteria. Results: the extract showed antibacterial activity when combined with some antibiotics against the assayed strains, demonstrating a modulatory potential. Conclusion: therefore, it is suggested that L. ferrea extract can be used as a source of natural products in the antimicrobial therapy and in the combat bacterial multidrug resistance(AU)

Modulation of the antibiotic activity against multidrug resistant strains of 4-(phenylsulfonyl) morpholine.

The compound 4-(Phenylsulfonyl) morpholine belongs to the class of sulfonamides, which are widely used in the treatment of a large number of diseases caused by microorganisms. This compound has a morpholine group, which is also known for its antimicrobial properties. The aim of the present study was to investigate the antimicrobial and modulating activity of 4-(Phenylsulfonyl) morpholine against standard and multi-resistant strains of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and strains of the fungi Candida albicans, C. tropicalis and C. krusei. Antimicrobial activity was assessed based on the minimum inhibitory concentration (MIC) using the microdilution method. MIC was ⩾1024 µg/mL for all microorganisms. Regarding modulating activity, the most representative effect occurred with the combination of 4-(Phenylsulfonyl) morpholine at a concentration of 128 µg/mL (MIC 1/8) and amikacin against P. aeruginosa 03, with a reduction in MIC from 312.5 to 39.06 µg/mL.

HPLC-DAD phenolic profile, cytotoxic and anti-kinetoplastidae activity of Melissa officinalis.

Context Melissa officinalis subsp. inodora Bornm. (Lamiaceae) has been used since ancient times in folk medicine against various diseases, but it has not been investigated against protozoa. Objective To evaluate the activities of M. officinalis against Leishmania braziliensis, Leishmania infantum and Trypanosoma cruzi as well as its cytotoxicity in fibroblast cell line. Materials and methods The fresh leaves were chopped into 1 cm(2) pieces, washed and macerated with 99.9% of ethanol for 72 h at room temperature. Antiparasitic activity of M. officinalis was accessed by direct counting of cells after serial dilution, while the cytotoxicity of M. officinalis was evaluated in fibroblast cell line (NCTC929) by measuring the reduction of resazurin. The test duration was 24 h. High-performance liquid chromatography (HPLC) was used to characterise the extract. Results The extract at concentrations of 250 and 125 µg/mL inhibited 80.39 and 54.27% of promastigote (LC50 value = 105.78 µg/mL) form of L. infantum, 80.59 and 68.61% of L. brasiliensis (LC50 value = 110.69 µg/mL) and against epimastigote (LC50 value = 245.23 µg/mL) forms of T. cruzi with an inhibition of 54.45 and 22.26%, respectively, was observed. The maximum toxicity was noted at 500 µg/mL with 95.41% (LC50 value = 141.01 µg/mL). The HPLC analysis identified caffeic acid and rutin as the major compounds. Discussion The inhibition of the parasites is considered clinically relevant (< 500 µg/mL). Rutin and caffeic acids may be responsible for the antiprotozoal effect of the extract. Conclusion The ethanol extract of M. officinalis can be considered a potential alternative source of natural products with antileishmania and antitrypanosoma activities.

AVALIAÇÃO DA ATIVIDADE ANTI-INFLAMATÓRIA TÓPICA E ANTIBACTERIANA DO EXTRATO METANÓLICO DAS FOLHAS DE Sideroxylon obtusifolium / Evaluation of the Topical Anti-inflammatory Activity and Antibacterial Activity of Methanol Extract in the Sideroxylon obtusifolium Leaves / Evaluación de la actividad antiedematogenic tópica y antibacteriana del extracto metanólico de hojas de Sideroxylon obtusifolium

Sideroxylon obtusifolium, conhecida como quixaba, é utilizada para diversos fins medicinais, dentre eles em casos de inflamações e infecções bacterianas, com isso, o estudo teve por objetivo investigar a atividade anti-inflamatória tópica e antibacteriana do extrato metanólico obtido das folhas de S. obtusifolium. A prospecção fitoquímica do extrato revelou a presença de diversas classes, entre eles: Fenóis; Taninos Pirogálicos, Flavonoides, Catequinas e alcaloides. Os polifenóis e flavonóides presentes neste extrato foram quantificados em 150,3 mg equivalentes de ácido gálico/g de extrato e 98,5 mg equivalentes de quercetina/g de extrato, respectivamente. Os resultados obtidos através dos testes de microdiluição e modulação mostraram potencial atividade antibacteriana quando associados a gentamicina e amicacina para cepas multirresistentes de Staphylococcus aureus. Para cepas de Escherichia coli, houve sinergismo frente ao antibiótico amicacina havendo antagonismo para gentamicina, o mesmo efeito foi observado para Pseudomonas aeruginosas em ambos antibióticos. Nos testes para inflamação aguda através dos modelos de edema de orelha induzido por óleo de cróton e fenol, o extrato apresentou um potente efeito antiedematogênico significativo (p < 0,05). Diante dos resultados, podem-se observar atividades biológicas de S. obtusifolium, o que condiz com seu uso na terapia popular.

Sideroxylon obtusifolium, known as "quixaba", is used for various medicinal purposes, including in cases of inflammation and bacterial infections, therefore, the study aimed to investigate the topical antibacterial and anti-inflammatory activity of the methanol extract obtained from the leaves of S. obtusifolium. The phytochemical screening of the extract revealed the presence of several classes, including Phenols; Tannins, Flavonoids, catechins and alkaloids. Polyphenols and flavonoids present in this extract were quantified in 150.3 mg of gallic acid equivalents / g extract and 98.5 mg of quercetin equivalents / g extract, respectively. The results obtained by the microdilution tests have shown potential and modulation antibacterial activity when associated gentamicin, and amikacin for multidrug-resistant strains of Staphylococcus aureus. For Escherichia coli, there was synergism for amikacin, gentamicin having antagonism, the same effect was observed for Pseudomonas aeruginosa on both antibiotics. In tests for acute models of inflammation by ear edema induced by croton oil, and phenol, the extract had a potent antiedematogenic significant effect (p < 0.05). Therefore, the results can be observed biological activities of S. obtusifolium, which is consistent with its use in popular therapy.

Sideroxylon obtusifolium conocida como quixaba, se utiliza para diversos fines medicinales, incluso en los casos de infecciones bacterianas y la inflamación, por lo tanto, este estudio tuvo como objetivo investigar la actividad antiinflamatoria tópica y antibacteriana del extracto de metanol obtenido de las hojas de S. obtusifolium. El tamizaje fitoquímico del extracto reveló la presencia de varias clases, incluyendo: fenoles; taninos pirogálicos, flavonoides, catequinas y alcaloides. Los polifenoles y flavonoides presentes en este extracto se cuantificaron en 150,3 mg de equivalentes de ácido/g de extracto gálico y 98,5 mg de extracto de quercetina equivalentes/g, respectivamente. Los resultados obtenidos por los ensayos de microdilución han mostrado actividad potencial y la modulación antibacteriana cuando se asocia gentamicina, amikacina y para las cepas resistentes a múltiples fármacos de Staphylococcus aureus. Para Escherichia coli, solo se obtuvo sinergismo con amikacina, y se observo antagonismo para gentamicina, este mismo efecto fue observado para Pseudomonas aeruginosa en ambos antibióticos. En las pruebas de modelos agudos de inflamación por edema de la oreja inducido por aceite de crotón, y el fenol, el extracto tuvo un efecto significativo antiedematogenic potente (p <0,05). Por lo tanto, los resultados muestran actividad biológica de S. obtusifolium, que es coherente con su uso en terapia popular.

Caracterização química e avaliação da atividade antioxidante, antifúngica e moduladora do extrato etanólico de Anadenanthera macrocarpa (BERTH) BRENAN / Caracterización química y actividad antioxidante, antifúngica y moduladora del extracto alcohólico de Anadenantera macrocarpa (Berth) Brenan / Chemical characterization and antioxidant, antifungal and modulating activity of the alcohol extract from Anadenantera macrocarpa (Berth) Brenan

Introdução: o estudo com plantas medicinais tem sido usado para assistência médica e farmacêutica, mais principalmente utilizadas como forma alternativa ou complementar ao tratamento terapêutico. Objetivo: este trabalho teve como objetivo elucidar os principais metabólitos secundários e atividade antioxidante, bem como avaliar a atividade antifúngica e moduladora do extrato etanólico de folhas de Anadenanthera macrocarpa frente às linhagens do gênero Candida. Métodos: na elucidação dos constituintes químicos foi utilizado o método de Cromatografia Líquida de Alta Eficiência, sendo que a verificação da atividade antioxidante foi realizada por método de FRAP. A atividade antifúngica do extrato foi mensurada através da determinação da Concentração Inibitória Mínima, sendo a modulação realizada por ensaio de microdiluição, realizado para verificar as interações entre o produto natural e o antifúngico utilizando a amostra em uma concentração subinibitória. Resultados: demonstrou-se pela análise do Cromatografia Líquida de Alta Eficiência a presença de metabólitos secundários, como a: quercitrina, quercetina, isoquercitrina, apigenina, ácido gálico e ácido caféico. No ensaio FRAP, a redução ocorreu em uma equivalência de 2,72 mg de FeSO4 por g de extrato. Na avaliação da concentração inibitória mínima foram obtidos resultados ≥512 µg/mL e na avaliação dos ensaios para efeito modulador, o extrato etanólico não potencializou o efeito do antifúngico, não havendo nem sinergismo nem antagonismo. Conclusão: através dos resultados podemos concluir que o presente extrato pode ser uma alternativa terapêutica uma vez que possui constituintes químicos com reconhecidas atividades biológicas e antioxidantes com baixo potencial tóxico(AU)

Introduction: the study of medicinal plants has been used for medical and pharmaceutical services, but mainly used as an alternative or in addition to therapeutic treatment. Objective: this study aimed to elucidate the main secondary metabolites and antioxidant activity and to evaluate the antifungal and modulating activity of the ethanol extract from Anadenanthera macrocarpa leaves against genus Candida strains. Methods: the chemical component clearance was made by using high-performance liquid chromatography, and checking of the antioxidant activity was performed by FRAP method. The antifungal activity of the extract was measured by determining the minimum inhibitory concentration, the modulation performed by microdilution test, carried out to verify the interactions between the natural product and the antifungal product using the sample at a subinhibitory concentration. Results: high-performance liquid chromatography showed the presence of secondary metabolites, such as: quercitrin, quercetin, isoquercitrin, apigenin, caffeic acid and gallic acid. In the FRAP assay, the reduction was 2,72 mg per equivalence grams of FeSO4 extract. The results of the assessment of minimum inhibitory concentration were ?512 µg/mL and in the evaluation of tests for modulating effect, the extract ethanol did not potentiate the antifungal effect, with neither synergism nor antagonism. Conclusions: from the results we can conclude that this extract can be an alternative since it has chemical constituents with known biological activities and antioxidants with low toxic potential(AU)

Introducción: el estudio de las plantas medicinales se han utilizado para la asistencia médica y farmacéutica, la mayoría utiliza principalmente como una alternativa o complemento al tratamiento terapéutico. Objetivo: el objetivo del estudio para dilucidar los principales metabolitos secundarios y la actividad antioxidante, así como evaluar la actividad antifúngica modulando el extracto de etanol de Anadenanthera macrocarpa frente las cepas del género Candida. Métodos: el esclarecimiento de los componentes químicos se utilizó cromatografía líquida de alta eficiencia y la comprobación de la actividad antioxidante se realizó por el método FRAP. La actividad antifúngica del extracto se midió mediante la determinación de la concentración mínima inhibitoria, y la modulación realizó por la prueba de microdilución, llevado a cabo para comprobar las interacciones entre el producto natural y el antifúngico utilizando la muestra a una concentración subinibitória. Resultados: se demostró mediante análisis por cromatografía líquida de alta eficiencia, de la presencia de metabolitos secundarios, tales como: quercitrina, quercetina, isoquercitrina, apigenina, ácido gálico y ácido cafeico. El ensayo FRAP, la reducción fue de 2,72 mg por equivalencia g de FeSO4 extrato. Na evaluación de la concentración inhibitoria mínima se obtuvieron resultados ≥512 µg/mL y la evaluación de las pruebas para el efecto de modulación, el extracto etanol no potenció el efecto de antifúngico, ni con sinergismo o antagonismo. Conclusión: de los resultados se puede concluir que el extracto puede ser una terapia alternativa, ya que tiene componentes químicos con actividades biológicas reconocidas y antioxidantes con bajo potencial tóxico(AU)