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 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.

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.

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.

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.

Analysis of bioactivities and chemical composition of Ziziphus joazeiro Mart. using HPLC-DAD.

The aim of this study was to evaluate the chemical profile and antioxidant, antimicrobial and antiparasitic activities of the hydroalcoholic extract of the leaves of Ziziphus joazeiro Mart. (HELZJ). The antioxidant DPPH and FRAP assays and chemical profile were determined by colorimetric methods and HPLC/DAD. The antiparasitic, antibiotic and antibiotic-modifying activity were evaluated by microdilution assays. The HPLC-DAD assay showed the presence of mostly tannins and flavonoids, such as caffeic acid and quercetin. The levels of polyphenols and flavonoids were 183.136 mg/g extract and 7.37 mg/g extract, respectively. DPPH and FRAP showed low antioxidant activity for the extract. The antibacterial and antifungal activities were not of clinical relevance, showing MIC>1024 µg/mL. However, synergism was observed between HELZJ and the antibiotics amikacin and gentamicin, which resulted in decreased bacterial drug resistance. EHFZJ showed low toxicity in fibroblasts in vitro, while antiparasitic results against Trypnosoma cruzi, Leishmania braziliensis and Leishmania infantum were not clinically relevant. Thus, our results indicate that Z. joazeiro Mart. (HELZJ) could be a source of plant-derived natural products that could lead to the development of promising new antibiotic compounds for infectious diseases.

AVALIAÇÃO DA ATIVIDADE ANTIBACTERIANA E MODULADORA DE AMINOGLICOSÍDEOS DO ÓLEO ESSENCIAL DE Cymbopogon citratus (DC.) Stapf / Evaluación de la Actividad Antibacteriana y Moduladora de Aminoglucósidos de Aceite Escencial de Cymbopogon Citratus (DC.) Stapf / Evaluation of Antibacterial Activity of Aminoglycosides and Modulating the Essential Oil of Cymbopogon citratus (DC.) Stapf

Vários trabalhos vêm demonstrando a importância do estudo de produtos naturais como fonte alternativa para novos antimicrobianos ou que venham potencializar os já existentes. Neste contexto este trabalho teve como objetivo investigar a atividade antibacteriana e as possíveis interações entre o óleo essencial de Cymbopogon citratus combinados a aminoglicosídeos frente a linhagens padrões e multirresistentes de S. aureus, E. coli e de P. aeruginosa provenientes de isolados clínicos. Um ensaio de microdiluição foi realizado para verificar a atividade antibacteriana e as possíveis interacções entre o produto natural e os antibióticos, utilizando uma concentração sub-inibitória. Através dos resultados foi constatado a interferência sinérgica dos aminoglicosídeos quando associados com o óleo essencial em uma concentração de CIM/8, com redução das CIMs em até quatro pontos frente às linhagens de S. aureus 358, E. coli 27 e P. aeruginosa-143. Mas nenhuma atividade modificadora foi observada frente a P. aeruginosa 78 e P. aeruginosa 91. Através dos resultados pode-se concluir que o óleo essencial de Cymbopogon citratus pode ser uma fonte alternativa de produtos naturais com atividade antibacteriana.

Varios trabajos están demostrando la importancia del estudio de productos naturales como una fuente alternativa para nuevos antimicrobianos o que puedan mejorar los ya existentes. En este contexto, el objetivo de este trabajo fue investigar la actividad antibacteriana y las posibles interacciones entre el aceite esencial de Cymbopogon citratus aminoglucósido combinado frente de linajes y patrones de S. aureus multirresistente, E. coli y P. aeruginosa provenientes de aislamientos clínicos. Se realizó una prueba de microdilución para verificar la actividad antibacteriana y posibles interacciones entre el producto natural y antibióticos, usando una concentración sub-inibitória. A través de los resultados se observan interferencia sinérgica de los aminoglucósidos cuando se asocian con el aceite esencial en una concentración de CIM/8, con reducción de CIMs de hasta cuatro puntos contra las cepas de S. aureus 358, E. coli 27 y P. aeruginosa 143. Pero no se observó ninguna actividad modificadora contra P. aeruginosa 78 y P. aeruginosa 91. A través de los resultados se puede concluir que el aceite esencial de Cymbopogon citratus puede ser una fuente alternativa de productos naturales con actividad antibacteriana.

Several works demonstrated the importance of the study of natural products as an alternative source for new antimicrobial drugs or for modulators for these ones. In this point, the aim of this was to investigate the antibacterial activity and the possible interactions between the essential oil of Cymbopogon citratus alone and in association with aminoglycosides against standard and clinically isolated strains of multidrug-resistant bacteria such as S. aureus, E. coli and P. aeruginosa by microdilution method. The results indicated a synergism between the antibiotics and the essential oil with a subinhibitory concentration (MIC/8), reducing the minimal inhibitory concentration (MIC) sixteen times against the multidrug-resistant strains of S. aureus 358, E. coli 27 and P. aeruginosa 143, but none modulatory activity was observed against P. aeruginosa 78 and P. aeruginosa 91 strains. By our results, can be concluded that the essential oil of Cymbopogon citratus can be an interesting source of natural products with antibacterial and/or modulatory antibiotic activities.

Evaluation of antibacterial, antifungal and modulatory activity of methanol and ethanol extracts of Padina sanctae-crucis.

BACKGROUND: Multi-resistantmicroorganisms such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida tropicalis e Candida krusei are the main causes of microbial infections. Padina sanctae-crucis is a seaweed often used to check the contamination of ecosystems by materials such as heavy metals, but studies of the antimicrobial activity of the same seaweed were not found. METHODS: The tests for the minimum inhibitory concentration and modulation of microbial resistance, with the use of ethanolic and methanolic extracts of Padina Sanctae-cruces combined with drugs of the class of aminoglycosides and antifungal were used to evaluate the activity against the cited microorganisms. RESULTS: Was observed a modulation of antibiotic activity between the natural products and the E. coli and S. aureus strains, indicating a synergism and antagonism respectively. CONCLUSIONS: The results showed a moderate modulatory effect against some microorganisms studied.

Composição química e estudo da atividade antibacteriana de Bowdichiavirgilioides Kunth (Sucupira) – Fabaceae – Papilonoidae / Study on the chemical composition and antibacterial activity of Bowdichia virgilioides kunth (Sucupira) - Fabaceae - Papilonoidae

Bowdichia virgilioides (Fabaceae - Papilionoidea), popularly known as Sucupira-preta, is a Brazilian native tree used in the traditional medicine against throat infections. Due this fact and due the interest to validate the traditional use, the objective of this work was evaluates the in vitro antibacterial activity of extracts and fractions of the stem and heartwood of the plant. The phytochemical profile revealed the presence of tannins and flavonoids in the stem and heartwood, and only alkaloids in the stem.The HPLC analysis revealed the presence of flavonoids and phenolic acids, natural products with several biological activities, including the modifying antibiotic activity. All microrganisms were inhibited only with MIC > 1024 microgramo/mL. However, when associated with aminoglycosides, was demonstrated a potentiation of these antibiotics when associated with almost all products assayed and against one bacterium at least.

Bowdichia virgilioides (Fabaceae - Papilionoidea), popularmente conhecida como Sucupira-preta, é uma espécie arbórea nativa do Brasil utilizadas na medicina popular para infecções de garganta. Com base nessas evidências, e com o interesse para justificar o uso popular, este trabalho teve como objetivo verificar a atividade antibacteriana in vitro de extratos brutos e fracionados de cascas e cerne da planta. Observou-se pela conclusão do levantamento fitoquímico a presença de taninos e flavonóides nas cascas e no cerne, e alcalóides apenas encontrados na casca. A análise por HPLC revelou a presença de flavonóides e ácidos fenólicos, produtos naturais, com diversas atividades biológicas, incluindo a atividade modificadora antibiótica. Todos os microorganismos foram inibidos apenas com o CIM > 1024 ug/mL. No entanto, quando associado a antibióticos aminoglicosídeos, foi demonstrada potenciação destes em quase todos os produtos testados e em pelo menos uma bactéria foi observada uma atividade moduladora significativa.

Chemical composition and evaluation of modulatory of the antibiotic activity from extract and essential oil of Myracrodruon urundeuva.

CONTEXT: The combination of antibiotics with natural products has demonstrated promising synergistic effects in several therapeutic studies. OBJECTIVE: The aim of this study was to determine the effect of a combination of an ethanol extract of Myracrodruon urundeuva Fr. All. (Anacardiaceae) (aroeira plant) and its essential oil with six antimicrobial drugs against multiresistant strains of Staphylococcus aureus and Escherichia coli from clinical isolates. MATERIALS AND METHODS: After identification of the chemical components by GC-MS, the antibacterial activity of the natural products and antibiotics was assessed by determining the minimal inhibitory concentration (MIC) using the microdilution method and concentrations ranging 8-512 µg/mL and 0.0012-2.5 mg/mL, respectively. Assays were performed to test for a possible synergistic action between the plant products and the antimicrobials, using the extract and the oil at a sub-inhibitory concentration (128 µg/mL) and antibiotic at concentrations varying between 8 and 512 µg/mL. RESULTS: The GC-MS analysis identified the main compound as δ-carene (80.41%). The MIC of the natural products was >1024 µg/mL, except against S. aureus ATCC25923. Only the combinations of the natural products with gentamicin, amikacin and clindamycin were effective against S. aureus 358, enhancing the antibiotic activity by reducing the MIC. CONCLUSIONS: The extract from aroeira showed a higher antibacterial activity and the oil was more effective in potentiating the activity of conventional antibiotics.

Atividade antiparasitária in vitro e citotóxica de cariofileno e eugenol contra Trypanossoma cruzi e Leishmania brasiliensis / Actividad antiparasitaria in vitro citotóxica de cariofileno y eugenol contra Trypanosoma cruzi y Leishmania brasiliensis / In vitro cytotoxic and antiparasitic activity of caryophyllene and eugenol against Trypanosoma cruzi and Leishmania brasiliensis

Introdução: as doenças negligenciadas persistem por conta de falhas da ciência e acometem principalmente países em desenvolvimento, como exemplos podemos citar a doença de Chagas e a leishmaniose. Objetivo: avaliar o potencial antiparasitário in vitro de um terpenóide componente de óleo essencial, o cariofileno e o eugenol, contra as formas epimastigota e promastigota de T. cruzi e L. brasiliensis, respectivamente, bem como verificar sua citotoxicidade em células de mamíferos. Métodos: para os estudos in vitro de T. cruzi, foi usado o clone B5-CL, estavelmente transfectadas com o gene de Escherichia coli ß-galactosidase (lacZ). Os ensaios de inibição de promastigotas foram realizadas utilizando a estirpe de L. braziliensis, cultivadas a 22 ºC em meio de Schneider de Drosophila suplementado com FBS a 20 %. Para os testes de atividade antiepimastigota, antipromastigota foram utilizados placas de 96 poços com culturas que não tinham atingido a fase estacionária. Os ensaios de citotoxicidade utilizado estirpe de fibroblastos NCTC929 cultivadas em Meio Essencial Mínimo (Sigma). A viabilidade dessas linhagens através da utilização de resazurina como um método colorimétrico. Resultados: as substâncias cariofileno e eugenol foram testadas quanto à atividade antiepimastigota, antipromastigota e quanto à citotoxidade. Foi visto um efeito clinicamente relevante do cariofileno contra os parasitas T. cruzi e L. brasiliensi. Conclusões: os resultados mostram que o cariofileno obteve um melhor resultado quando comparado ao eugenol, sendo capaz de inibir o crescimento dos parasitas testados mostrando uma alternativa contra T. cruzi e L. brasiliensi. Em relação à citotoxidade novos testes deverão ser realizados para futuros testes in vivo.

Introducción: las enfermedades desatendidas persisten debido a los fracasos de la ciencia y afectan principalmente a los países en desarrollo, como ejemplos se pueden citar la enfermedad de Chagas y la leishmaniasis. Objetivo: evaluar el potencial de un componente in vitro terpenoide antiparasitario aceite esencial, el cariofileno y eugenol contra epimastigotes y promastigotes de Trypanosoma cruzi y Leishmania brasiliensis, respectivamente, así como comprobar su citotoxicidad en células de mamífero. Métodos: para los estudios in vitro de Trypanosoma cruzi, se utilizó el clon B5-CL, transfectadas establemente con el gen de la ß galactosidasa de Escherichia coli-(lacZ). Los ensayos de inhibición se realizaron con la cepa promastigotes de Leishmania braziliensis, se cultivó a 22 °C en medio de Schneider de Drosophila suplementado con FBS 20 %. Para la actividad de las pruebas antiepimastigota y antipromastigota, se utilizaron placas de 96 pocillos con cultivos que no habían alcanzado la fase estacionaria. En los ensayos de citotoxicidad se utilizó NCTC929, cepa de fibroblastos cultivados en medio esencial mínimo (Sigma). La viabilidad de estas cepas se evaluó mediante el uso de la resazurina como un método colorimétrico. Resultados: las sustancias cariofileno y eugenol se ensayaron para determinar la actividad antiepimastigota y antipromastigota, respecto a citotoxicidad. Se observó un efecto clínicamente relevante de cariofileno contra los parásitos Trypanosoma cruzi y Leishmania brasiliensis. Conclusiones: los resultados muestran que con el cariofileno se ha obtenido un mejor resultado en comparación con eugenol, siendo capaz de inhibir el crecimiento de parásitos que presentan una alternativa probada contra Trypanosoma cruzi y Leishmania brasiliensis. En cuanto a las pruebas de citotoxicidad, nuevos estudios deben llevarse a cabo para realizar más pruebas in vivo.

Introduction: neglected diseases continue to exist due to failures in science. They mainly affect developing countries. Two examples of neglected diseases are Chagas' disease and leishmaniasis. Objective: evaluate the potential of an in vitro antiparasitic terpenoid essential oil component, caryophyllene and eugenol, against epimastigotes and promastigotes of Trypanosoma cruzi and Leishmania brasiliensis, respectively, and verify their cytotoxicity in mammal cells. Methods: for in vitro studies of Trypanosoma cruzi, the B5-CL clone was used, stably transfected with the beta-galactosidase gene of Escherichia coli-(lacZ). Inhibition assays were performed on the promastigote strain of Leishmania braziliensis, cultured at 22°C in a Schneider's medium of Drosophila supplemented with 20% FBS. For anti-epimastigote and anti-promastigote activity tests, 96-well plates were used with cultures which had not reached their stationary stage. NCTC929 was used in cytotoxicity tests, a strain of fibroblasts cultured in minimum essential medium (Sigma). The viability of these strains was evaluated using resazurine as colorimetric method. Results: the substances caryophyllene and eugenol were assayed to determine their anti-epimastigote and anti-promastigote activity with respect to cytotoxicity. it was found that caryophyllene has a clinically relevant effect against the parasites Trypanosoma cruzi and Leishmania brasiliensis. Conclusions: results show that caryophyllene was more effective than eugenol, inhibiting the growth of parasites and thus constituting a proven alternative against Trypanosoma cruzi and Leishmania brasiliensis. As to cytotoxicity testing, new studies should be conducted in which more in vivo tests are performed.

Modulation of the antibiotic activity by extracts from Amburana cearensis A. C. Smith and Anadenanthera macrocarpa (Benth.) Brenan.

The aim of this study was to verify the possible interactions between ethanol extracts of Amburana cearensis A. C. Smith and Anadenanthera macrocarpa (Benth.) Brenan, combined with six antimicrobial drugs against multiresistant strains of Staphylococcus aureus and Escherichia coli isolated from humans. The antibacterial activity of the extracts was determined using the minimum inhibitory concentration (MIC). The microdilution assay was performed to verify the interactions between the natural products and the antibiotics using a subinhibitory concentration. The activity of amikacin associated with the extract of Anadenanthera macrocarpa against EC 27 was enhanced, demonstrating an MIC reduction from 128 to 4 µg/mL. Among the ß-lactams, no potentiation on its activity was observed, with exception to the antagonism of the natural products with ampicillin against S. aureus 358.