Influence of methanolic extracts from seeds and pulp of Annona squamosa L. on osmotic and morphological fragility in human erythrocytes.

Medicinal plants have been used for many years by communities to treat illnesses. The need for scientific proof of these vegetable's curative effects is as necessary as the proof of the inexistence of toxicity related to the use of extracts with therapeutic potential. Annona squamosa L. (Annonaceae), popularly known as "pinha", "ata" or "fruta do conde", has been used in traditional medicine for its analgesic and antitumor activities. The toxic effects attributed to this plant have also been explored as a pesticide and an insecticide. The aim of the present study was to investigate the toxicity of the methanolic extract of A. squamosa seeds and pulp against human erythrocytes. Blood samples were treated with methanolic extract at different concentrations, osmotic fragility was determined using saline tension assays and morphological analyzes were performed using optical microscopy. The extracts were analyzed using high performance liquid chromatography with diode array detection (HPLC-DAD) for phenolic quantification. The seed's methanolic extract showed toxicity above 50% from a concentration of 100 µg/mL, while also presenting echinocytes in the morphological analysis. The pulp's methanolic extract did not show toxicity to red blood cells or morphological changes at the concentrations tested. HPLC-DAD analysis revealed the presence of caffeic acid in the seed extract and gallic acid in the pulp extract. The seed's methanolic extract is toxic and the pulp's methanolic extract showed no toxicity against human erythrocytes.

Chemical Composition and Antimicrobial Potential of Essential Oil of Acritopappus confertus (Gardner) R.M.King & H.Rob. (Asteraceae).

Microbial resistance has become a worrying problem in recent decades after the abusive use of antibiotics causing the selection of resistant microorganisms. In order to circumvent such resistance, researchers have invested efforts in the search for promising natural substances, such as essential oils. Thus, the objective of this work was to determine the chemical composition of the essential oil of Acritopappus confertus leaves, to evaluate its intrinsic effect and its effects in combination with drugs against pathogenic fungi and bacteria, in addition to verifying the inhibition of virulence in Candida strains. To this end, the oil was verified by gas chromatography coupled with mass spectrometry (GC/MS). Candida strains were used for antifungal assays by means of the serial microdilution technique, in order to determine the average inhibitory concentration (IC50), and for the modification assays, sub-inhibitory concentrations (MIC/8) were used. Finally, the natural product's ability to inhibit the formation of filamentous structures was evaluated. In antibacterial tests, the MIC of the oil against strains of Staphylococcus aureus and Escherichia coli and its modifying effects in association with gentamicin, erythromycin, and norfloxacin were determined. The major constituent of the essential oil was the monoterpene myrcene (54.71%). The results show that the essential oil has an antifungal effect, with C. albicans strains being the most susceptible. Furthermore, the oil can potentiate the effect of fluconazole against strains of C. tropicalis and C. albicans. Regarding its effect on micromorphology, the oil was also able to inhibit the filaments in all strains. In combination with antibiotics, the oil potentiated the drug's action by reducing the MIC against E. coli and S. aureus. It can be concluded that the essential oil of A. confertus has potential against pathogenic fungi and bacteria, making it a target for the development of an antimicrobial drug.

Microbial resistance: The role of efflux pump superfamilies and their respective substrates.

The microorganism resistance to antibiotics has become one of the most worrying issues for science due to the difficulties related to clinical treatment and the rapid spread of diseases. Efflux pumps are classified into six groups of carrier proteins that are part of the different types of mechanisms that contribute to resistance in microorganisms, allowing their survival. The present study aimed to carry out a bibliographic review on the superfamilies of carriers in order to understand their compositions, expressions, substrates, and role in intrinsic resistance. At first, a search for manuscripts was carried out in the databases Medline, Pubmed, ScienceDirect, and Scielo, using as descriptors: efflux pump, expression, pump inhibitors and efflux superfamily. For article selection, two criteria were taken into account: for inclusion, those published between 2000 and 2020, including textbooks, and for exclusion, duplicates and academic collections. In this research, 139,615 published articles were obtained, with 312 selected articles and 7 book chapters that best met the aim. From the comprehensive analysis, it was possible to consider that the chromosomes and genetic elements can contain genes encoding efflux pumps and are responsible for multidrug resistance. Even though this is a well-explored topic in the scientific community, understanding the behavior of antibiotics as substrates that increase the expression of pump-encoding genes has challenged medicine. This review study succinctly summarizes the most relevant features of these systems, as well as their contribution to multidrug resistance.

Inhibition of the MepA efflux pump by limonene demonstrated by in vitro and in silico methods.

Bacterial resistance is a natural process carried out by bacteria, which has been considered a public health problem in recent decades. This process can be triggered through the efflux mechanism, which has been extensively studied, mainly related to the use of natural products to inhibit this mechanism. To carry out the present study, the minimum inhibitory concentration (MIC) tests of the compound limonene were performed, through the microdilution methodology in sterile 96-well plates. Tests were also carried out with the association of the compound with ethidium bromide and ciprofloxacin, in addition to the ethidium bromide fluorimetry, and later the molecular docking. From the tests performed, it was possible to observe that the compound limonene presented significant results when associated with ethidium bromide and the antibiotic used. Through the fluorescence emission, it was observed that when associated with the compound limonene, a greater ethidium bromide fluorescence was emitted. Finally, when analyzing the in silico study, it demonstrated that limonene can efficiently fit into the MepA structure. In this way, it is possible to show that limonene can contribute to cases of bacterial resistance through an efflux pump, so that it is necessary to carry out more studies to prove its effects against bacteria carrying an efflux pump and assess the toxicity of the compound.

Chemical synthesis, molecular docking and MepA efflux pump inhibitory effect by 1,8-naphthyridines sulfonamides.

This study aimed to evaluate the antibacterial activity and to verify, in silico and in vitro, the inhibition of efflux mechanisms using a series of synthesized 1,8-naphthyridines sulfonamides against Staphylococcus aureus strains carrying MepA efflux pumps. The chemical synthesis occurred through the thermolysis of the Meldrum's acid adduct. The sulfonamide derivatives were obtained by the sulfonylation of 2-amino-5­chloro-1,8-naphthyridine with commercial benzenesulfonyl chloride. Antibacterial activity was assessed by the broth microdilution test. Efflux pump inhibitory capacity was evaluated in silico by molecular docking and in vitro by analyzing synergistic effects on ciprofloxacin and ethidium bromide (EtBr) and by EtBr fluorescence emission assays. The following 1,8-naphthyridines were synthesized: 4-methyl-N-(5­chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Compound 10a); 2,5-dichloro-N-(5­chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Compound 10b); 4-fluoro-N-(5­chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Compound 10c); 2,3,4-trifluoro-N-(5­chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Compound 10d); 3-trifluoromethyl-N-(5­chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Compound 10e); 4­bromo-2,5-difluoro-N-(5­chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Compound 10f). The 1,8-naphthyridines derivatives associated with sulfonamides did not show antibacterial activity. However, they showed a favorable pharmacokinetic profile with possible MepA efflux pump inhibitory action, demonstrated in molecular docking. In addition to the promising results in reducing the concentration of intracellular EtBr. 1,8-naphthyridines act as putative agents in the inhibitory action of the MepA efflux pump.

The 1,8-naphthyridines sulfonamides are NorA efflux pump inhibitors.

OBJECTIVE: Efflux pumps are transmembrane proteins associated with bacterial resistance mechanisms. Bacteria use these proteins to actively transport antibiotics to the extracellular medium, preventing the pharmacological action of these drugs. This study aimed to evaluate in vitro the antibacterial activity of 1,8-naphthyridines sulfonamides, as well as their ability to inhibit efflux systems of Staphylococcus aureus strains expressing different levels of the NorA efflux pump. METHODS: The broth microdilution test was performed to assess antibacterial activity. Efflux pump inhibition was evaluated in silico by molecular docking and in vitro by fluorometric tests, and the minimum inhibitory concentration (MIC) was determined. The MIC was determined in the association between 1,8-naphthyridine and norfloxacin or ethidium bromide. RESULTS: The 1,8-naphthyridines did not show direct antibacterial activity. However, they effectively reduced the MIC of multidrug-resistant bacteria by associating with norfloxacin and ethidium bromide, in addition to increasing the fluorescence emission. In silico analysis addressing the binding between NorA and 1,8-naphthyridines suggests that hydrogen bonds and hydrophilic interactions represent the interactions with the most favourable binding energy, corroborating the experimental data. CONCLUSION: Our data suggest that 1,8-naphthyridines sulfonamides inhibit bacterial resistance through molecular mechanisms associated with inhibition of the NorA efflux pump in S. aureus strains.

Influence of seasonal variation on phenolic content and in vitro antioxidant activity of Secondatia floribunda A. DC. (Apocynaceae).

This study reports the effects of seasonal variation on the total polyphenol and flavonoid content and the in vitro antioxidant activity of Secondatia floribunda A. DC. The extracts were prepared from the inner bark and heartwood of samples harvested in the 2015 to 2016. The total phenolic and flavonoid content was determined by specific qualitative tests. The in vitro antioxidant capacity was analyzed using the following tests: 1-1-diphenyl-2-picrylhydrazyl radical (DPPH), 2,2'-azinobis-3-ethylbenzenothiazoline-6-sulfonic acid (ABTS+), ferric reducing antioxidant power (FRAP) and iron (Fe2+) chelating activity. The total polyphenol and total flavonoid content varied over the harvest period. The DPPH and ABTS tests revealed that in the dry season had the most potent in vitro antioxidant activity, although the extracts obtained during the rainy season presented the higher Fe2+ chelating and Ferric reducing activities. In conclusion, the phenolic content and in vitro antioxidant activity are correlated, and both are influenced by seasonality.

Caracterización química y evaluación de las propiedades antioxidantes y antimicrobianas del aceite de pulpa de frutas de Mauritia flexuosa L. f. / Chemical characterization and evaluation of antioxidant and antimicrobial properties of the pulp oil of fruits of Mauritia flexuosa L. f

Este estudio tuvo como objetivo caracterizar las propiedades químicas, antioxidantes y antimicrobianas del aceite de pulpa de Mauritia flexuosa L. f. (Arecaceae). La identificación química se realizó por cromatografía de gases acoplada a espectrometría de masas. Se caracterizaron las propiedades fisicoquímicas. La capacidad antioxidante se ha verificado eliminando los radicales libres, reduciendo y quelando el hierro. La actividad antimicrobiana se evaluó mediante la concentración inhibitoria mínima y la acción moduladora de los antibióticos. Los principales ácidos grasos identificados fueron ácido esteárico, ácido palmítico y ácido oleico. La acidez y el índice de saponificación están dentro de los límites establecidos por la Agencia Nacional de Vigilancia Sanitaria. El aceite mostró actividad antioxidante moderada y actividad antimicrobiana contra las cepas de Candida. También mostró efectos sinérgicos, especialmente acerca de cefotaxima contra Bacillus cereus. Los resultados sugieren el potencial de la especie como antioxidante y en terapia antimicrobiana.

This study aimed to characterize the chemical, antioxidant and antimicrobial properties of the pulp oil of Mauritia flexuosa L. f. (Arecaceae). Chemical identification was performed by gas chromatography coupled to mass spectrometry. The physicochemical properties were characterized. Antioxidant capacity has been verified by eliminating of free radicals, reducing and chelation of iron. The antimicrobial activity was evaluated by the minimum inhibitory concentration and the modulatory action of antibiotics. The major fatty acids identified were stearic acid, palmitic acid and oleic acid. The acidity and the saponification index are within the limits established by the National Sanitary Surveillance Agency. The oil showed moderate antioxidant activity and antimicrobial activity against Candida strains. It also showed synergistic effects, especially on cefotaxime against Bacillus cereus. The results suggest the potential of the species as an antioxidant and in antimicrobial therapy.

In vitro antimicrobial activity of the essential oil from Vanillosmopsis arborea Barker (Asteraceae) and its major constituent, α-bisabolol.

Vanillosmopsis arborea Barker (Asteraceae), commonly known as "candeeiro" is an endemic tree to the Caatinga biome, in northeast Brazil. The major component of its essential oil is α-bisabolol, a monocyclic sesquiterpene alcohol with several biological activities reported. In this study, the antimicrobial activity of the essential oil of V. arborea was investigated in comparison with its major component α-bisabol. The antimicrobial activity was performed against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 12692, Candida albicans (CA) INCQS 40006, Candida krusei (CK) INCQS 40095, Candida tropicalis (CT) INCQS 40042, and multiresistant bacterial strains Staphylococcus aureus 03 and Escherichia coli 08 by the microdilution method and direct contact modulation. The results showed that all strains were sensitive to the samples, except E. coli against the essential oil. Both the essential oil and the α-bisabolol had a synergistic effect against all strains, except for ampicillin against S. aureus 03, which did not show any modifications when combined with the oil. These data show the potential of V. arborea essential oil as an antibiotic modulator as well as a source of bioactive compounds with potential for the development of antimicrobial drugs as well as adjuvant to therapy against these pathogens.

Development and validation of a rapid RP-HPLC-DAD analysis method for the quantification of pilocarpine in Pilocarpus microphyllus (Rutaceae).

A method using high performance liquid chromatography with diode array detector (HPLC-DAD) for identification and quantification of pilocarpine in the extract of Pilocarpus microphyllus, popularly known as jaborandi. The analysis was conducted using RP-18 column (250 mm × 4.6 mm x 5 µm id) and a buffer solution composed of acidified water, phosphoric acid and triethylamine and methanol as a mobile phase in a flow rate of 1.0 mL/min and detection at 215  nm at 25 °C. Excellent linearity with r2 equal to 0.9999 was obtained. The recovery percentage was very satisfactory with values within the specifications. It is correct to affirm that the method has optimal intracurrent and intercurrent precision values with relative standard deviations of 0.1852% and 0.1932%, respectively. The robustness of the method, assessed through the Youden test, showed no significant influence of any of the evaluated parameters. In general, the method proved to be suitable for the intended purpose.

Chemical composition and synergistic interaction between aminoglycosides antibiotics and essential oil of Lantana montevidensis Briq.

The chemical composition of the essential oil from Lantana montevidensis Briq. and its antibiotic resistance modifying activity were investigated by gas chromatography/mass spectrometry (GC/MS) and microdilution assay, respectively. ß-Caryophyllene (31.50%), germacrene D (27.50%) and bicyclogermacrene (13.93%) were the main constituents. The essential oil was examined for antibiotic activity alone in association with aminoglycosides against Escherichia coli Ec27 and Staphylococcus aureus Sa358. The results showed antibacterial activities of the oil and synergistic effects combined with aminoglycosides. The most expressive effect was the potentiating of amikacin on E. coli with minimal inhibitory concentration decrease (512-5 µg mL(-1)). The data obtained are indicative of the antibacterial activity of the essential oil of L. montevidensis and its potential in modifying the resistance of aminoglycosides analysed.

Antiulcerogenic activity of the essential oil of Hyptis martiusii Benth. (Lamiaceae).

ETHNOPHARMACOLOGICAL RELEVANCE: Hyptis martiusii (Lamiaceae), popularly known as "cidreira-do-mato" or "cidreira-brava", grows in abundance in the Northeast region of Brazil, where its leaves are traditionally used in folk medicine in the treatment of intestinal and stomach diseases. The aim of this study was to characterize the chemical constituents and to evaluate the anti-ulcerogenic activity of the essential oil of the leaves of Hyptis martiusii (EOHM) in in vivo models of experimental ulcers in rodents. MATERIALS AND METHODS: EOHM was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS). Acute gastric ulcer was induced using absolute ethanol, HCl/ethanol and indomethacin. The volume, pH and total acidity of gastric secretion were determined by the pyloric ligature method and gastrointestinal motility using gastric emptying and intestinal transit. RESULTS: Chemical analysis revealed the presence of 24 components that account for 92.13% of the essential oil of dried leaves, indicating the occurrence of mono and sesquiterpenes. Oral administration of EOHM (100, 200 and 400mg/kg) inhibited ethanol-, HCl/ethanol- and indomethacin-induced ulcers. In the case of pylorus ligature, the oil reduced the volume of gastric juices and total acidity, and increased gastric pH. The EOHM reduced the rate of gastric emptying with only the highest doses, but did not show any effect on intestinal transit at any of the three doses. CONCLUSIONS: The results indicate that the essential oil of leaves of Hyptis martiusii has an antiulcerogenic activity, as evidenced by its significant inhibition of the formation of ulcers in various models. This effect could be related to an increase of gastric mucosal defensive factors. Further pharmacological studies are being undertaken in order to provide more precise elucidation of the action mechanism involved in this activity.

Antibacterial activity and chemical composition of essential oil of Lippia microphylla Cham / Atividade antibacteriana e composição química do óleo essencial de Lippia microphylla Cham

The essential oil from the fresh leaves of Lippia microphylla Cham. was obtained by hydrodistillation and characterized by gas chromatography-mass spectrometry (GC-MS). Major constituents of the oil were 1.8-cineole (18.12%), -ocimene (15.20%), bicyclogermacrene (11.63%) and caryophyllene oxide (8.32%). Antimicrobial activity of the oil against Gram-positive and Gram-negative bacteria was determined by gel diffusion method. The oil showed good antibacterial activity against Shigella flexneri, Escherichia coli and Streptococcus pyogenes and very good antibacterial activity against Staphylococcus aureus.

O óleo essencial das folhas frescas de Lippia microphylla Cham. foi obtido por hidrodestilação e caracterizado por cromatografia gasosa acoplada a espectrometria de massas (CG-EM). O constituinte majoritário do óleo foi 1.8-cineol (18,12%), -ocimeno (15,20%), bicyclogermacreno (11,63%) e óxido de caryophylleno (8,32%). A atividade antimicrobiana do óleo frente às bactérias Gram-positivas e Gram-negativas foi determinada pelo método de difusão em gel. O óleo apresentou uma boa atividade antibacteriana frente a Shigella flexneri, Escherichia coli e Streptococcus pyogenes sendo o melhor resultado frente a Staphylococcus aureus.

Antibacterial activity and chemical composition of essential oil of Lippia microphylla Cham - doi: 10.4025/actascibiolsci.v33i2.5792 / Antibacterial activity and chemical composition of essential oil of Lippia microphylla Cham - doi: 10.4025/actascibiolsci.v33i2.5792

The essential oil from the fresh leaves of Lippia microphylla Cham. was obtained by hydrodistillation and characterized by gas chromatography-mass spectrometry (GC-MS). Major constituents of the oil were 1.8-cineole (18.12%), β-ocimene (15.20%), bicyclogermacrene (11.63%) and caryophyllene oxide (8.32%). Antimicrobial activity of the oil against Gram-positive and Gram-negative bacteria was determined by gel diffusion method. The oil showed good antibacterial activity against Shigella flexneri, Escherichia coli and Streptococcus pyogenes and very good antibacterial activity against Staphylococcus aureus.

The essential oil from the fresh leaves of Lippia microphylla Cham. was obtained by hydrodistillation and characterized by gas chromatography-mass spectrometry (GC-MS). Major constituents of the oil were 1.8-cineole (18.12%), β-ocimene (15.20%), bicyclogermacrene (11.63%) and caryophyllene oxide (8.32%). Antimicrobial activity of the oil against Gram-positive and Gram-negative bacteria was determined by gel diffusion method. The oil showed good antibacterial activity against Shigella flexneri, Escherichia coli and Streptococcus pyogenes and very good antibacterial activity against Staphylococcus aureus.

Abordagem fitoquímica, composição bromatológica e atividade antibacteriana de Mimosa tenuiflora (Wild) Poiret E Piptadenia stipulacea (Benth) Ducke / Phytochemical approach, bromatologic composition and antibacterial activity of Mimosa tenuiflora (Wild) Poiret and Piptadenia stipulacea (Benth) Ducke

A necessidade de encontrar novas drogas eficazes no combate microbiano tem aumentado a cada dia e estimulado a busca de novos compostos naturais com atividades biológicas. Neste trabalho, realizaram-se estudo fitoquímico e análises microbiológicas com os extratos etanólicos das espécies (jurema-preta) Mimosa tenuiflora (Wild) Poiret e (jurema-branca) Piptadenia stipulacea (Benth) Ducke, frente a linhagens de bactérias patogênicas. O pó da casca do caule de ambas as espécies foi submetido à avaliação bromatológica e determinados os teores de Matéria Seca, Matéria Mineral, Proteína Bruta, Fibra em Detergente Neutro e Energia Bruta. Os resultados para a prospecção química indicaram a presença de taninos e outros compostos fenólicos, bem como a presença de saponinas em ambos os extratos. Os extratos das duas espécies demonstraram que mais de uma parte das plantas possui atividade antimicrobiana. A composição bromatológica da casca do caule de jurema-preta e jurema-branca apresentou teores diferenciados para as variáveis avaliadas.

The need to find new efficient drugs to combat microbes has increased the search for new natural compounds with biological activities. In this work, phytochemical studies and microbiological analysis were carried out with the ethanol extracts of Mimosa tenuiflora (Wild) Poiret and Piptadenia stipulacea (Benth) Ducke on pathogenic bacteria strains. The bark powders of both species were submitted to bromatologic evaluation and the levels of dry matter, mineral matter, crude protein, neutral detergent fiber (NDF) and crude energy were determined. The results of the chemical search chemical showed the presence of tannins and other phenolic compounds as well as the presence of saponins in both extracts. The microbiologic evaluation of the extracts of both species showed that more than one part of the plants had antimicrobial activity. The bromatologic composition of the bark powder of Mimosa tenuiflora (Wild) Poiret and Piptadenia stipulacea (Benth) Ducke showed different contents for analyzed variables.