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The traditional knowledge associated with the use of medicinal plants has significantly contributed to drug development research. In this context, Aloysia gratissima, commonly known as bee-brush or white-brush, has been widely used in Brazilian folk medicine as an analgesic and antimicrobial species. Phytochemical analysis of A. gratissima essential oil has identified sesquiterpene β-caryophyllene (17.3%) as a major component with significant antibacterial activity. Thus, this study aimed to characterize the antibacterial effects of the essential oil obtained from A. gratissima (EOAG) and its major compound β-caryophyllene, as well as to evaluate their potential to act as efflux pumps inhibitors in association with conventional antibiotics. The phytochemical characterization of EOAG was performed by gas chromatography coupled to mass spectrometry (GC-MS), while the antibacterial activity against the strains Pseudomonas aeruginosa 24, Staphylococcus aureus 10, and Escherichia coli 06 was assessed using the broth microdilution method. The antibiotic potentiating activity was investigated by analyzing the ability of the natural products to decrease the minimum inhibitory concentration (MIC) of norfloxacin and ciprofloxacin against S. aureus strains 1199B and K2068. A reduction in the MIC of ethidium bromide in the presence of essential oil components was interpreted as efflux pump inhibition. The GC-MS analysis identified 30 compounds, including β-caryophyllene as the major component. The antibacterial activity analysis demonstrated that both EOAG and β-caryophyllene both EOAG and β-caryophyllene presented antibacterial effects against S. aureus 10 (MIC = 32 μg/mL), in addition to potentiating the activity of norfloxacin against [S. aureus 10], [P. aeruginosa 24], and [E. coli 06]. The isolated compound also reversed the degree of antibiotic resistance observed in strains carrying efflux pumps. In conclusion, the essential oil of A. gratissima and β-caryophyllene have the potential to increase the effectiveness of antibiotics and as such can be used in the development of new therapies against bacterial resistance.

Infectious diseases caused by multidrug-resistant microorganisms has increased in the last years. Piper species have been reported as a natural source of phytochemicals that can help in combating fungal and bacterial infections. This study had as objectives characterize the chemical composition of the essential oil from Piper caldense (EOPC), evaluate its potential antimicrobial activity, and investigate the synergistic effect with Norfloxacin against multidrug-resistant S. aureus overproducing efflux pumps, as well as, verify the EOPC ability to inhibit the Candida albicans filamentation. EOPC was extracted by hydrodistillation, and the chemical constituents were identified by gas chromatography, allowing the identification of 24 compounds (91.9%) classified as hydrocarbon sesquiterpenes (49.6%) and oxygenated sesquiterpenes (39.5%). Antimicrobial tests were performed using a 96-well plate microdilution method against C. albicans ATCC 10231, Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923 standard strains, as well as against multidrug-resistant strains S. aureus SA1199B (overexpressing norA gene), S. aureus K2068 (overexpressing mepA gene) and S. aureus K4100 (overexpressing qacC gene). The oil showed activity against C. albicans ATCC 10231 (≥ 512 µg/mL) and was able to inhibit hyphae formation, an important mechanism of virulence of C. albicans. On the other hand, EOPC was inactive against all bacterial strains tested (≤ 1,024 µg mL). However, when combined with Norfloxacin at subinhibitory concentration EOPC reduced the Norfloxacin and Ethidium bromide MIC values against S. aureus strains SA1199B, K2068 and K4100. These results indicate that EOPC is a source of phytochemicals acting as NorA, MepA and QacC inhibitors.

This study aimed to investigate the chemical composition and antifungal potential of the essential oil of Baccharis trimera (Less.) DC. against Candida strains. The half maximal inhibitory concentration (IC50) was assessed by the microdilution method using the essential oil at a concentration range of 8192 to 8 μg/mL. The minimum fungicide concentration (MFC) was determined by subculture in solid medium. The ability of the essential oil to modulate the activity of antifungals was determined in wells treated simultaneously with the oil at a subinhibitory concentration (MFC/16) and fluconazole (FCZ). The fungal morphology was analyzed by microscopy. Gas chromatography coupled with mass spectrometry (GC/MS) was used to identify the chemical composition. The essential oil presented an CI50 of 11.24 and 1.45 μg/mL, which was found to potentiate the effect of FCZ against Candida albicans. On the other hand, this combined treatment resulted in antagonism against Candida tropicalis and no evident modulation against Candida krusei was observed. The essential oil significantly inhibited hyphae growth. However, with a MFC ≥ 16,384 μg/mL, it is assumed that it has a fungistatic action. The antifungal properties demonstrated in this study might be related to the presence of sesquiterpenes and monoterpenes, and the interaction between them. In conclusion, Baccharis trimera showed promising anti-Candida effects, in addition to potentiating the activity of FCZ against Candida albicans, affecting its morphological transition. Therefore, this species constitutes a source of chemical compounds with the potential to be used in the combat of fungal infections.

This study aimed to evaluate the intrinsic antibacterial activity and antibiotic-enhancing effect of an arylamino methylene derivative (MAD) in association with fluoroquinolones. The antibacterial activity against multiresistant Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli was analyzed by determining the minimum inhibitory concentration (MIC) using the broth micro dilution method. A reduction in the MIC of the fluoroquinolones against strains treated simultaneously with the MAD was interpreted as an enhanced antibiotic activity. While the MAD exhibited no clinically effective action (MIC ≥ 1.024 µg/mL), it was found to significantly potentiate the activity of norfloxacin, ofloxacin and lomefloxacin against all the strains, which may be related to structural similarities between the MAD and quinolones. Our findings suggest that Meldrum’s acid arylamino derivatives may represent promising molecules in the elaboration of new drugs to reverse resistance to fluoroquinolones.

The objective of this study was to determine the chemical profile and to evaluate the antibacterial activity of the essential oils of Piper species and modulation of the antibiotic activity, using the microdilution method to determine the minimum inhibitory concentration. The chemical components were characterized by gas chromatography coupled to mass spectrometry, which revealed β-copaen-4-α-ol (31.38%), spathulenol (25.92%), and germacrene B (21.53%) as major constituents of the essential oils of Piper arboreum, Piper aduncum, and Piper gaudichaudianum, respectively. The essential oils analyzed in this study did not present a clinically relevant activity against standard and multiresistant Escherichia coli. However, in the case of multiresistant Staphylococcus aureus, there was a significant activity, corroborating with reports in the literature, where Gram-positive bacteria are more susceptible to antimicrobial activity. The essential oils modulated the effect of the antibiotics norfloxacin and gentamicin, having on the latter greater modulating effect; however, for erythromycin, no statistically significant effect was observed. In conclusion, the results obtained in this study demonstrated that the essential oils of the analyzed Piper species present an inhibitory effect against S. aureus and modulate antibiotic activity, most of which presents synergistic activity.

In a recent study, our research group demonstrated that the essential oil of Ocotea odorifera (EOOO) and its major compound safrole potentiated the action fluoroquinolones, modulating bacterial resistance possibly due to direct inhibition of efflux pumps. Thus, in the present study, we investigated whether these treatments could enhance the activity of gentamicin and erythromycin against multidrug-resistant (MDR) bacteria. The EOOO was extracted by hydrodistillation, and the phytochemical analysis was performed by gas chromatography coupled to mass spectrometry (GC–MS). The antibiotic-enhancing effect of the EOOO and safrole against MDR strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa was analyzed by the broth microdilution method. The chemical analysis confirmed the presence of safrole as a major component among the 16 compounds identified in the EOOO. Both the essential oil and the isolated compound showed clinically relevant antibacterial activities against S. aureus. Regarding the modulation of antibiotic resistance, the EOOO was found to enhance the activity of erythromycin against the strains of P. aeruginosa and S. aureus, as well as improving the action of gentamicin against S. aureus. On the other hand, safrole potentiated the activity of gentamicin against the S. aureus strain alone. It is concluded, therefore, that the EOOO and safrole can enhance the activity of macrolides and aminoglycosides, and as such are useful in the development of therapeutic tools to combat bacterial resistance against these classes of antibiotics.

The Atlantic Forest is regarded a rich source of aromatic plants with a broad spectrum of biological properties. The leaves of seven Piper species were collected from the Atlantic Forest domain in the coastal region of Paraná state in winter (W) and spring (S). The volatile oils were extracted from the leaves through hydrodistillation method. The volatile oils were characterized by means of GC-FID and GC-MS. Sesquiterpenes were among the major compounds in all species studied, with many dozens of representatives. However, very low concentrations of monoterpenes were observed; α-pinene in Piper mosenii and P. cernuum, δ-3-carene in P. rivinoides, camphene and β-pinene in P. cernuum are exceptions. The arylpropanoides myristicine and elemicin were found in considerable amount in P. diospyrifolium (26.2%/S) and P. mosenii (16.4%/W), respectively. These oils were also screened for inhibitory activities against acetylcholinesterase (AChE) and α-glucosidase (AG). For AChE the most active samples were P. diospyrifolium, P. aduncum and P. cernuum, with inhibiting level > 93%. For the less sensitive AG, the most promising candidates were P. diospyrifolium and P. mosenii, with inhibiting level > 65%. These results highlight the importance of native plants as renewable source of new inhibitors for AChE and AG. Further investigation is required to identify the most active constituents or fractions from the selected volatile oils. Resumo A Floresta Atlântica é considerada uma rica fonte de plantas aromáticas com amplo espectro de propriedades biológicas. Na busca de novos inibidores da acetilcolinesterase (AChE) e α-glicosidase (AG), folhas de diferentes espécies de Piper localizadas na Floresta Atlântica no litoral do Paraná - Brasil, foram submetidas a hidrodestilação e seus óleos voláteis caracterizados por CG-DIC e CG-EM. A coleta ocorreu em duas estações distintas, inverno (I) e primavera (P), de 7 diferentes espécies. Sesquiterpenos foram identificados entre os compostos majoritários em todas as espécies estudadas, com dezenas de representantes. No entanto, foram observadas baixas concentrações de monoterpenos; α-pinene in Piper mosenii and P. cernuum, δ-3-carene in P. rivinoides, camphene and β-pinene in P. cernuum são exceções. Os arilpropanoides miristicina e elemicina foram identificadas em quantidades significativas em P. diospyrifolium (26.2%/P) e P. mosenii (16.4%/I), respectivamente. Para a AChE as amostras mais ativas foram P. diospyrifolium, P. aduncum e P. cernuum, com níveis de inibição > 93%. Para a AG, que se mostrou menos sensível às amostras, os candidatos mais promissores foram P. diospyrifolium e P. mosenii, ambos com níveis de inibição > 65%. Esses resultados destacam a importância das plantas nativas como fontes renováveis de novos inibidores para AChE e AG. Estudos adicionais se fazem necessários para identificar os constituintes ou frações mais ativas dos óleos voláteis selecionados.

Considering the evidence that essential oils, as well as safrole, could modulate bacterial growth in different resistant strains, this study aims to characterize the phytochemical profile and evaluate the antibacterial and antibiotic-modulating properties of the essential oil Ocotea odor&iacute, fera (EOOO) and safrole against efflux pump (EP)-carrying strains. The EOOO was extracted by hydrodistillation, and the phytochemical analysis was performed by gas chromatography coupled to mass spectrometry (GC-MS). The antibacterial and antibiotic-modulating activities of the EOOO and safrole against resistant strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were analyzed through the broth microdilution method. The EP-inhibiting potential of safrole in association with ethidium bromide or antibiotics was evaluated using the S. aureus 1199B and K2068 strains, which carry genes encoding efflux proteins associated with antibiotic resistance to norfloxacin and ciprofloxacin, respectively. A reduction in the MIC of ethidium bromide or antibiotics was used as a parameter of EP inhibition. The phytochemical analysis identified 16 different compounds in the EOOO including safrole as the principal constituent. While the EOOO and safrole exerted clinically relevant antibacterial effects against S. aureus only, they potentiated the antibacterial activity of norfloxacin against all strains evaluated by our study. The ethidium bromide and antibiotic assays using the strains of S. aureus SA1119B and K2068, as well as molecular docking analysis, indicated that safrole inhibits the NorA and MepA efflux pumps in S. aureus. In conclusion, Ocotea odorifera and safrole presented promising antibacterial and antibiotic-enhancing properties, which should be explored in the development of drugs to combat antibacterial resistance, especially in strains bearing genes encoding efflux proteins.

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.

Essential oils are secondary metabolites with immense pharmacological potential.These substances are abundantly produced by plants of the family Asteraceae, such as Baccharis coridifolia. Previous studies have demonstrated that this species has pharmacological properties that make it a promising source of new antibacterial agents. Therefore, the present study aimed to evaluate the antibacterial and antibiotic-modulating activity of Baccharis coridifolia essential oil against multidrug-resistant (MDR) strains. The phytochemical analysis was carried out by gas chromatography coupled to Mass Spectroscopy (GC/MS), and realized the Minimum Inhibitory Concentation (MIC) and antibiotic-modulation from the microdilution method in 96-well plates. It was revealed the presence of germacrene D (23.7%), bicyclogermacrene (17.1%), and (E)-caryophyllene (8.4%) as major components. The minimum inhibitory concentration of essential oil against strains of Pseudomonas aeruginosa (512 μg/mL) and Staphylococcus aureus (128 μg/mL) demonstrated clinically relevant antibacterial activity. In addition, the combination of subinhibitory doses of the oil with conventional antibiotics showed synergism, indicating potentiation of the antibacterial effect. In conclusion, the essential oil of Baccharis coridifolia (EOBc) presented antibacterial and antibiotic-modulating activities that place this species as a source of molecules useful in the fight against bacterial resistance.

Presently, results from a study carried out in this area using the essential oil from the Calyptranthes concinna species, a representative from the Myrtaceae family, are reported. The essential oil was obtained by hydrodistillation and gas chromatography coupled to mass spectrometry was used to identify its chemical constituents. Antibacterial activity was determined using the broth microdilution method, thus obtaining the Minimal Inhibitory Concentration (MIC) value, from which the subinhibitory concentration (MIC/8) was derived. The C. concinna essential oil presented antibacterial activity against both standard and multiresistant bacteria. In addition, the oil demonstrated an antibiotic activity potentiation against Staphylococcus aureus and Escherichia coli when in combination with the antibiotic gentamicin, reducing the MIC from 141.38 &mu, g/mL and 208.63 &mu, g/mL to 64 &mu, g/mL and 128 &mu, g/mL, respectively. Conclusions: Findings from the present study suggest this oil is promising in terms of its antimicrobial activity.

The present study had as its objective to evaluate the antibacterial and antibiotic modulatory activity of the Baccharis dracunculifolia (DC) essential oil (EOBD), a species commonly known as “Alecrim do campo”. The essential oil chemical composition analysis and the direct in vitro antibiotic activity evaluation, as well as in combination with the antibiotics Ampicillin, Gentamicin, and Norfloxacin against standard Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 9027, and Staphylococcus aureus ATCC 25923 strains, as well as E. coli 06, P. aeruginosa 24, and S. aureus 10 resistant strains, were performed. Gas chromatography-mass spectrometry (GC–MS) revealed the major terpenoids: Germacrene D (18.4%), (E)-Nerolidol (14.0%), Mustacone (11.2%), Spathulenol (11%), β-pinene (9.5%) and Bicyclogermacrene (8.4%). A direct B. dracunculifolia essential oil antibacterial activity against S. aureus 25923 with a MIC of 102 μg/mL and one of 512 μg/mL against S. aureus 10 were observed. The EOBD synergistically modulated the Norfloxacin antibiotic against P. aeruginosa 24, with a MIC reduction from 50.8 to 6.35 μg/mL, a Gentamicin MIC reduction from 20.16 to 4 μg/mL, and an Ampicillin MIC reduction from 645.1 to 512 μg/mL. The essential oil synergistically modified Norfloxacin activity against E. coli 06 with a MIC reduction from 40.32 to 3.17 μg/mL, and a Gentamicin MIC reduction from 50.8 to 25.4 μg/mL. The essential oil also showed synergism against S. aureus 10 when associated with Norfloxacin, with a MIC reduction from 322.54 to 203.2 μg/mL, whilst when associated with Ampicillin, it demonstrated synergism by reducing the MIC from 80.6 to 20.16 μg/ml. Results from this research revealed that the EOBD is a promising natural product with antimicrobial potential, both directly and in combination with antibiotics, for clinical use against Gram-positive and Gram-negative bacteria.

The objective of this work was to evaluate the phytochemical composition and the antibacterial and antibiotic-modulating activities of the essential oils of Eugenia brasiliensis Lam (OEEb) and Piper mosenii C. DC (OEPm) singly or in association with blue LED (Light-emitting diode) light. The antibacterial and antibiotic-modulatory activities of the essential oils on the activity of aminoglycosides were evaluated to determine the minimum inhibitory concentration (MIC, &mu, g/mL) in the presence or absence of exposure to blue LED light. The chemical analysis showed &alpha, pinene and bicyclogermacrene as major constituents of OEPm, whereas &alpha, muurolol was the main compound of OEEb. Both OEEb and OEPm showed MIC &ge, 512 &mu, g/mL against the strains under study. However, the association of these oils with the blue LED light enhanced the action of the aminoglycosides amikacin and gentamicin. In conclusion, the association of aminoglycosides with the blue LED light and essential oils was effective against resistant bacteria.

The secular use of plants in popular medicine has emerged as a source for the discovery of new compounds capable of curing infections. Among microbial resistance to commercial drugs, species such as Piper diospyrifolium Kunth, which are used in popular therapy, are targets for pharmacological studies. With this in mind, antimicrobial experiments with the essential oil from the P. diospyrifolium (PDEO) species were performed and its constituents were elucidated. The oil compounds were identified by gas chromatography coupled to mass spectrometry (GC/MS). The broth microdilution method with colorimetric readings for bacterial tests (Escherichia coli and Staphylococcus aureus) and spectrophotometric readings for fungal tests (Candida albicans and Candida tropicalis), whose data were used to create a cell viability curve and calculate its IC50 against fungal cells, were used to determine the minimum inhibitory concentration of the oil and its combined action with commercial drugs. The oil's minimal fungicidal concentration and its action over fungal morphological transition were analyzed by subculture and microculture, respectively. Chemical analysis revealed Z-Carpacin, Pogostol and E-Caryophyllene as the most abundant compounds. Results from the intrinsic analysis were considered clinically irrelevant, however the oil presented a synergistic effect against multiresistant E. coli and S. aureus strains when associated with gentamicin, and against the standard and isolated C. tropicalis strains with fluconazole. A fungicidal effect was observed against the C. albicans isolate. Candida spp. hyphae inhibition was verified for all strains at the highest tested concentrations. The P. diospyrifolium essential oil presented a promising effect when associated with commercial drugs and against a fungal virulence factor. Thus, the oil presented active compounds which may help the development of new drugs, however, new studies are needed in order to clarify the oil's mechanism of action, as well as to identify its active constituents.

Arctium species are known for a variety of pharmacological effects due to their diverse volatile and non-volatile secondary metabolites. Representatives of Arctium species contain non-volatile compounds including lignans, fatty acids, acetylenic compounds, phytosterols, polysaccharides, caffeoylquinic acid derivatives, flavonoids, terpenes/terpenoids and volatile compounds such as hydrocarbons, aldehydes, methoxypyrazines, carboxylic and fatty acids, monoterpenes and sesquiterpenes. Arctium species also possess bioactive properties such as anti-cancer, anti-diabetic, anti-oxidant, hepatoprotective, gastroprotective, antibacterial, antiviral, antimicrobial, anti-allergic, and anti-inflammatory effects. This review aims to provide a complete overview of the chemistry and biological activities of the secondary metabolites found in therapeutically used Arctium species. Summary of pharmacopeias and monographs contents indicating the relevant phytochemicals and therapeutic effects are also discussed, along with possible safety considerations.

The family Piperaceae is known for presenting in its species flavoring, healing and antimicrobial properties among others. The objective of the present study was: to study the chemical profile of the essential oil of Piper rivinoides (EOPR); to analyze its anti-bacterial and antifungal potential, as well as to evaluate the antifungal and antibiotic-modifying capacity. The chemical constituents were identified by gas chromatography with flame ionization detector (GC-FID), allowing the identification of 7 constituents of a total of 86.99%. E-Isoelemicin was identified as the main constituent of petroleum (40.81%). Clinically relevant MIC results were obtained against fungi in which the inhibitory concentration remained

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-5‑chloro-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-(5‑chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Compound 10a); 2,5-dichloro-N-(5‑chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Compound 10b); 4-fluoro-N-(5‑chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Compound 10c); 2,3,4-trifluoro-N-(5‑chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Compound 10d); 3-trifluoromethyl-N-(5‑chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Compound 10e); 4‑bromo-2,5-difluoro-N-(5‑chloro-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.

Naphthyridines represent a class of heterocyclic compounds formed by two condensed aromatic rings. This study aimed to evaluate the antibacterial activity and in vitro inhibition of efflux resistance mechanisms of a series of 1,8-naphthyridine sulfonamides against strains carrying Tet(K) and MsrA efflux pumps. The efflux pump inhibitory capacity was evaluated by analyzing synergistic effects between 1,8-naphthyridine sulfonamides and standard antibiotics, as well as ethidium bromide. The following 1,8-naphthyridines were used: 4-methyl-N-(5-chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Naph 1); 2,5-Dichloro-N-(5-chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Naph 2); 2,3,4-trifluoro-N-(5-chloro-1,8-naphthyridin-2-yl)benzenesulfonamide (Naph 7); 3-trifluoromethyl-N-(5-chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Naph 9). The 1,8-naphthyridine sulfonamide derivatives possessed a potential Tet(K) and MsrA efflux pump inhibitory action.

The genus Baccharis (Asteraceae) demonstrated the presence of compounds with antibacterial, antifungal and antioxidant activities. Because of the increasing rates of antimicrobial resistance, adequate treatment of infections caused by Gram-negative bacteria has become challenging. The objective of the present study was evaluate the antibacterial and antibiotic-modifying activity of the essential oil obtained from Baccharis reticulata (Ruiz & Pav.) Pers. and the compound α-pinene against Pseudomonas aeruginosa and other multiresistant bacteria. An analysis by gas chromatography associated with mass spectrometry (GC/MS) revealed the presence of dilapiol (33.8 %), α-pinene (31.7 %) and β-pinene (9.4 %) as major components of the oil. The determination of the Minimum Inhibitory Concentration (MIC) revealed that the oil has antibacterial activity against S. aureus only. However, the oil potentiated the norfloxacin and gentamicin against all strains evaluated. Also, α-pinene increased the activity of norfloxacin against E. coli, as well as potentiated the activity of norfloxacin and gentamicin against S. aureus. Therefore, the authors conclude that the essential oil of B. reticulata, as well as the compound α-pinene, have antibacterial and antibiotic-modulating activities that make them useful in the development of new weapons against bacterial resistance.

Infections by multiresistant microorganisms have led to a continuous investigation of substances acting as modifiers of this resistance. By following this approach, the chemical composition of the essential oil from Piper caldense leaf and its antimicrobial potential were investigated. The antimicrobial activity was determined by broth microdilution method providing values for minimum inhibitory concentration (MIC), IC50, and minimum fungicidal concentration (MFC). The essential oil was tested as a modulator for several antibiotics, and its effect on the morphology of Candida albicans (CA) strains was also investigated. The chemical characterization revealed an oil composed mainly of sesquiterpenes. Among them are caryophyllene oxide (13.9%), spathulenol (9.1%), &delta, cadinene (7.6%) and bicyclogermacrene (6.7%) with the highest concentrations. The essential oil showed very low activity against the strains of CA with the lowest values for IC50 and MFC of 1790 &mu, g/mL and 8192 &mu, g/mL, respectively. The essential oil modulated the activity of fluconazole against CA URM 4387 strain, which was demonstrated by the lower IC50 obtained, 2.7 &mu, g/mL, whereas fluconazole itself presented an IC50 of 7.76 &mu, g/mL. No modulating effect was observed in the MFC bioassays. The effect on fungal morphology was observed for both CA INCQS 40006 and URM 4387 strains. The hyphae projection was completely inhibited at 4096 &mu, g/mL and 2048 &mu, g/mL, respectively. Thus, the oil has potential as an adjuvant in antimicrobial formulations.

The Piper mikanianum species were investigated by the antimicrobial potential and chemical composition. Chemical analysis was performed by gas chromatography coupled to mass spectrometry (GC/MS). The Minimum Inhibitory Concentration (MIC) as well as the 50% Inhibitory Concentration against Candida strains were determined by microdilution. The effect of the drug-oil combination was also evaluated to verify possible synergism. The Minimum Fungicidal Concentration (MFC) was evaluated by subculturing the microdilution in Petri dishes and the anti-pleomorphism potential of the oil was tested in humid chambers. Chemical analysis revealed safrol as the major compound. The results from the intrinsic activity evaluation of the oil did not reveal a clinical importance, however, it presented a synergistic effect when associated with gentamicin against the multidrug resistant E. coli strain and when associated with fluconazole against fungal strains. Moreover, the oil possessed a fungistatic effect. Total inhibition of filamentous structures occurred in both Candida species in the anti-virulence test. The P. mikanianum essential oil showed a potentiating activity of drugs for which resistance exists and an inhibitory effect of one of the main virulence factors of the Candida genus, morphological transition, which has been previously shown to be responsible for causing invasive infections in human tissues.

1 recurso en línea (páginas 491-499), Las especies nativas de Piper presentan importantes actividades biológicas repelentes, antimicrobianos, insecticidas, antitumoral y anti-protozoario. Los estudios sobre nuevas especies representan potenciales descubrimientos sin publicar y la propagación vegetativa es necesario para el desarrollo del protocolo de cultivo; además, reduce la extracción natural. El objetivo de esta investigación fue evaluar el enraizamiento de esquejes de P. arboreum, P. cernuum y P. diospyrifolium con diferentes tratamientos que contienen dosis del ácido indolbutirico (0, 500, 1.000, 1.500, 2.000 y 3.000 mg L-1). Ramas fueran colectadas en la Reserva Biológica Bom Jesus, estado de Paraná, Brasil. Los cortes con una longitud de 12 cm y el diámetro promedio de 6 mm se instalaron en tubos de plástico de 53 cm3 usando el sustrato comercial Tropstrato HP® y riego por nebulización intermitente. Después de 90 días se evaluaron las tasas de supervivencia, mortalidad y esquejes con nuevos brotes, número y longitud de las tres raíces principales. Los porcentajes de enraizamiento alcanzaron un promedio de 67,5% para P. arboreum, 51,6% para P. cernuum y 50,4% para P. diospyrifolium. Se encontró respuesta positiva de los tratamientos que contienen el regulador vegetal para las variables de enraizamiento, porcentaje de esquejes con brotes y número de raíces por estaca, pero hubo variaciones en las respuestas de cada especie. La permanencia de hojas fue un factor importante para el proceso de enraizamiento adventicio en las especies evaluadas., biological activities. Studies on new species can discover unpublished potentialities and vegetative propagation for the development of cultivation protocols and reduce the natural extraction. The objective of this study was to evaluate the rooting of P. arboreum, P. cernuum and P. diospyrifolium stem cuttings with different treatments containing doses of indole butyric acid (0, 500; 1,000; 1,500; 2,000 and 3,000 mg L-1). Branches were collected in the “Bom Jesus Biological Reserve”, Parana state, Brazil. The cuttings, with a length of 12 cm and average diameter of 6 mm, were placed in 53 cm3 plastic tubes with the commercial substrate Tropstrato HP® and intermittent misting. After 90 days, the survival, mortality, cuttings with new shoots, number and length of the three main roots were evaluated. The percentages of rooting reached an average of 67.5% for P. arboreum, 51.6% for P. cernuum and 50.4% for P. diospyrifolium. A positive effect in the treatments containing the plant regulator was observed for rooting development, percentage of cuttings with shoots and number of roots per propagule, but there were variations in the responses of each species. Leaf retention was an important factor for the adventitious rooting formation in all evaluated species., Bibliografía y webgrafía: páginas 498-499

In this study, the Piper cernuum Essential Oil (EOPC) was tested against bacterial and fungal strains using the microdilution method to evaluate its minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC), as well as its antibiotic modifying effect, in addition to observing the oils ability to cause fungal dimorphism and to generate an IC50 cell viability curve. The EO was obtained through hydrodistillation using a Clevenger-type apparatus with the dry leaves and analyzed by GC-FID, allowing the identification of 14 compounds, with the main compound being 4-epi-cis-dihydromarofuran (28.97%). An EOPC intrinsic activity was identified only against Candida albicans 4127 (IC50 56.851 μg/mL). Given the MIC results from the EOPC intrinsic activity against Staphylococcus aureus 10 at the concentration of 406 μg/mL, its association with fluconazole potentiated it’s antifungal action. The action of gentamicin was potentiated by the addition of the EOPC to Staphylococcus aureus 10 and Escherichia coli 06 strains, both with MIC

In this work we present a study of the vibrational spectra of 2,2-dimethyl-5-(4H-1,2,4-triazol-4-ylaminomethylene)-1,3-dioxane-4,6-dione monohydrate, C 9 H 10 N 4 O 4 ⋅H 2 O. The FT-IR and FT-Raman spectra of the crystal were recorded at room temperature in the regions 400–4000 cm −1 and 50–4000 cm −1 , respectively. Vibrational wavenumbers and wave vector were predicted using density functional theory calculations with the B3LYP functional and 6-31G(d,p) basis set. The descriptions of the normal modes were made after considering the Potential Energy Distribution (PED). A comparison with experimental spectra allowed us to assign all of the normal modes of the crystal.

The Schiff base 4-{[(1E)-(2-Hydroxyphenyl)methylidene]amino}-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (C 18 H 17 N 3 O 2 ) is a synthetic compound with a variety of scientific and technological applications, such as clinic, analytic and pharmacologic. In this work FT-Raman spectrum and FT-infrared spectrum of C 18 H 17 N 3 O 2 were investigated at 300 K. Vibrational wavenumber and wave vector have been predicted using Density Functional Theory (B3LYP) calculations with the 6-31 G(d,p) basis set. The description of the normal modes was performed by means of the potential energy distribution. A comparison with experiment allowed us to assign most of the normal modes of the crystal.

This work presents through the X-ray diffraction method the crystal structure of ((4E)-4-((E)-3-phenyl-allylideneamino)-1,2-dihydro-2,3-dimethyl-1-phenylpirazol-5-one (C20H19N3O) as well as its vibrational properties and DFT calculations. The crystal is monoclinic with a = 13.487 A, b = 9.788 A, c = 13.836 A and the space group P21/n ( C 2 2 ). The equilibrium geometries, harmonic frequencies, infrared intensities and Raman scattering activities were calculated by density functional B3LYP method with the 6-31 G(d,p) basis set. The comparison between the calculated and experimental results covering molecular structure and, assignments of fundamental vibrational modes were investigated. The optimized molecular geometries have been compared with the experimental data obtained from XRD data, which indicates that the theoretical results agree well with the corresponding experimental values. For the compound, comparisons and assignments of the vibrational frequencies indicate that the calculated frequencies are close to the experimental data.

SUMMARYLeishmaniasis is one of the neglected diseases. High cost, systemic toxicity, and diminished efficacy due to development of resistance by the parasites has a negative impact on the current treatment options. Thus, the search for a new, effective and safer anti-leishmanial drug becomes of paramount importance. Compounds derived from natural products may be a better and cheaper source in this regard. This study evaluated the in vitro anti-leishmanial activity of Spiranthera odoratíssima (Rutaceae) fractions and isolated compounds, using promastigote and amastigote forms of different Leishmania species. J774 A.1 macrophage was used as the parasite host cell for the in vitro assays. Evaluations of cytoxicity, nitric oxide (NO), interleukin-10 and in silico analysis were carried out. In vitro experiments showed that the fruit hexanic fraction (Fhf) and its alkaloid skimmianine (Skm) have a significant (PL. braziliensis. This anti-L. braziliensis activity of Fhf and Skm was due to increased production of NO and attenuation of IL-10 production in the macrophages at concentrations ranging from 1·6 to 40·0 μg/ml. The in silico assay demonstrated significant interaction between Skm and amino acid residues of NOS2. Skm is thus a promising drug candidate for L. braziliensis due to its potent immunomodulatory activity.

The present paper reports the synthesis and antiprotozoal activity of N-quinolin-8-yl-arylsulfonamides and their copper and zinc complexes. Sulfonamides 2-5 were synthesized by reacting 8-aminoquinoline with several commercial arylsulfonyl chlorides. The corresponding complexes 6-13 were obtained using copper (II) acetate or zinc chloride in methanol. In vitro activity was carried out against promastigote forms of Leishmania braziliensis and L. chagasi, and epimastigote forms of Trypanosoma cruzi. Selected compounds were tested against axenic amastigote forms of L. braziliensis. The new 2,5-dichlorobenzenesulfonamide ligand was found to be inactive under the selected bioassays, however its copper complex 8 was active with the highest selective indexes (SI) against L. braziliensis promastigote and amastigote forms, with IC50 values of 2.59 and 0.35 μM, respectively. Difluorinated copper 10 and zinc 11 complexes were most active against L. braziliensis, with IC50 of 1.11 μM and 1.25 μM, respectively. However, the SI values were about 12 for both compounds. In general, the complexation of sulfonamides increases the antiprotozoal activity, as well as the cytotoxicity on Vero cells. These results confirm the antiprotozoal potential of sulfonamides and metal-based sulfonamides.

Plant secondary metabolites have attracted considerable attention from the industry as consumers are increasing their interest for natural products over chemically synthesized reagents to be used as additives in food, cosmetics or pharmaceuticals. Some plant essential oils show significant antimicrobial properties and this could be exploited to produce new food preservatives or novel antimicrobial formulations. Here we describe the extraction, chemical analysis and antimicrobial properties of grass lemon Cymbopogon citratus and Cymbopogon flexuosus essential oils. Essential oils were extracted from dried leaves using hydrodestilation and their composition was established by gas chromatography coupled to mass spectrometry. Agar diffusion assays indicated that C. citratus and C. flexuosus essential oils act as antimicrobial agents against both gram negative and gram positive model organisms. These data support that lemon grass essential oils can be used as an alternative for microbiological control.

The reactions of 2-amino-8-hydroxyquinoline and 2-amino-4(1H)quinolone with different sulfonyl chlorides have been investigated. The chemoselectivity was observed to afford exclusively the arylsulfonate ester derivatives. The mechanism of the reaction is also discussed.

The phytochemical investigation of the methanol crude extract obtained from Acosmium dasycarpum (Vog.) Yakovlev root bark led to the isolation of the quinolizidine alkaloids lupanine, acosmine, acosminine and lupanacosmine, as well as the diaza-adamantane alkaloids panacosmine and dasycarpumine. Lupanacosmine (4) and dasycarpumine (6) have been described for the first time herein.

Sulfonamides obtained by reaction of 8-aminoquinoline with 4-nitrobenzenesulfonylchloride and 2,4,6-triisopropylbenzenesulfonyl chloride were used to synthesize coordination compounds with CuII and ZnII with a ML2 composition. Determination of the crystal structures of the resulting zinc and copper complexes by X-ray diffraction show a distorted tetrahedral environment for the [Cu(qnbsa)2], [Cu(qibsa)2] and [Zn(qibsa)2] complexes in which the sulfonamide group acts as a bidentate ligand through the nitrogen atoms from the sulfonamidate and quinoline groups. The complex [Zn(qnbsa)2] crystallizes with a water molecule from the solvent and the Zn is five-coordinated and shows a bipyramidal-trigonal geometry. The electrochemical and electronic spectroscopy properties of the copper complexes are also discussed.

An efficient synthesis of 1,8‐naphthyridine‐4(1H)‐one sulfonamide derivatives by thermolysis of 2‐pyridylaminomethylene (Meldrum's acid derivative) starting from 4,6‐dimethyl‐2‐aminopyridine (1) is described.

The thermocyclisation of phenylenediamine-bis(methylene Meldrum's acid) derivatives has been investigated. Those of o-phenylenediamines give 1,10-phenanthroline derivatives, while those of m- and p-phenylenediamines lead to the preferential formation of angular diazatricycles. Thus, for example, the di-Meldrum's acid derivative of 2,5-dichloro-1,4-phenylenediamine gives, via ipso-substitution, the unexpected angular product 19.

In this work we present a study of the vibrational spectra of 4,5,6,8,9-pentachloropyrimido-[1,2-a][1,8]naphthyridin-10-one, C 11 H 2 Cl 5 N 3 O, a substance belonging to the important pharmacological class of 1,8-naphthyridine derivatives. The Fourier transform infrared and the Fourier transform Raman spectra of the crystal were recorded at room temperature in the regions 400–4000 and 50–4000 cm −1 , respectively. Vibrational wavenumbers were predicted using Density Functional Theory calculations with the B3LYP functional on 6-31G(d,p) and 6-311++G(d,p) basis sets. The descriptions of the normal modes were made after calculating the potential energy distribution. Additionally, potential reaction sites were evaluated through Mulliken population and Frontier Orbital analysis.

Made available in DSpace on 2016-01-28T16:56:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2015. Added 1 bitstream(s) on 2016-01-28T17:02:34Z : No. of bitstreams: 1 ISSN2146-8397-2015-04-01-57-63.pdf: 297158 bytes, checksum: 30b8521cabfb3c72af3e3fa6e79061b7 (MD5) Fundação de Amparo à Pesquisa do Estado de Mato Grosso (FAPEMAT) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Aim: The present study was undertaken to evaluate the acute and subchronic antihyperglycemic effects of methanolic extract of B. virgilioides root bark of B. virgilioides in streptozotocin-induced diabetic rats.Materials and Methods: The extract (100, 250 or 500 mg/kg) was orally administered to male Wistar diabetic (streptozotocin, 42 mg/kg i.v.) and non-diabetic rats into two main protocols: i) subchronic experiments, where animals were treated for 21 days with B. virgilioides extract and the following parameters were evaluated: body weight, fluid and food intake (determined daily), urinary glucose and urea (every 3 days) and glycemia (every 5 days). At the end of the experimental period, skeletal muscles (extensor digitorum longus and soleus), retroperitoneal and epididymal white adipose tissues were collected and weighed; liver samples were used for the determination of the lipid and glycogen contents; ii) acute experiments, which evaluated the alterations on fasting and post-prandial glycemia and on glucose tolerance using the oral glucose tolerance test (OGTT).Results: In subchronic experiments, the treatment with B. virgilioides extract did not change any parameter evaluated in diabetic and non-diabetic animals. On fasting and post-prandial glycemia, the extract treatment did not promote changes in the glycemia values in diabetic or non-diabetic animals. In OGTT, the treatment with 500 mg/kg B. virgilioides extract reduced the hyperglycemia peak after a glucose overload, when compared with non-treated diabetic animals, resulting in a lower area under curve (AUC). Conclusion: The results of our work indicate that B. virgilioides root extract promotes an acute antihyperglycemic effect in STZ-diabetic rats; this effect probably occurs through an inhibition of the intestinal glucose absorption. The continuity of the research is necessary to elucidate these possibilities. Universidade Estadual Paulista Júlio de Mesquita Filho, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas de Araraquara, Araraquara, Rua Expedicionários do Brasil, 1621, Centro, CEP 14801902, SP, Brasil Department of Chemistry, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil Department of Science Education, Federal University of Paraná, Coastal Sector, Matinhos, Paraná, Brazil Universidade Estadual Paulista Júlio de Mesquita Filho, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas de Araraquara, Araraquara, Rua Expedicionários do Brasil, 1621, Centro, CEP 14801902, SP, Brasil

The nearly planar amino­quinoline fragment and the aromatic ring of the triisopropyl­benzene­sulfonate group of the title compound, C24H30N2O3S, form a dihedral angle of 47.9 (2)°. Both H atoms of the amino group are involved in inter­molecular hydrogen bonds of types N—H⋯O (2.56 A) and N—H⋯N (2.26 A), linking the mol­ecules into dimers.

The title mol­ecule, [Zn(C10H8NO)2(H2O)], lies on a crystallographic twofold axis. The ZnII atom is in a trigonal–bipyramidal coordination geometry formed by two N atoms of two quinoline groups, two O atoms and a water mol­ecule. In the crystal structure, inter­molecular hydrogen bonds link mol­ecules into a two-dimensional network.

The essentially planar quinoline fragment and the aromatic ring of the toluene­sulfonate group of the title compound, C16H14N2O3S, form a dihedral angle of 52.2 (1)°; the torsion angle about the central bridge C—O—S—C is −69.3 (2)°. The N—H⋯N and N—H⋯O hydrogen bonds, involving the H atoms of the amino group and the quinoline and sulfonyl N and O atoms [N⋯N = 3.055 (3) A and N⋯O = 3.058 (2) A], link the mol­ecules into dimers; a C—H⋯O inter­action formed by the CH group in position 4 of the quinoline group [C⋯O = 3.293 (3) A] further links the dimers into infinite chains running along the diagonal of the ab plane.

In the title compound, [Zn(C17H7Br2F6N2O2S)2], the zinc(II) ion has a distorted tetra­hedral geometry formed by the N atoms of the quinoline and the sulfonamide groups. One inter­molecular C—H⋯O hydrogen bond to a sulfonyl O atom is observed.

In the title compound, [Zn(C15H10N3O4S)2(H2O)], the asymmetric unit contains one half-mol­ecule. The coordination of the ZnII ion, which occupies a special position on a twofold axis, is distorted trigonal bipyramidal.

In the title compound, [Zn(C15H10FN2O2 S)2]·0.5H2O, the Zn atom has a distorted tetrahedral geometry, formed by the N atoms of the quinoline and the sulfonamide groups. The water molecule occupies a special position on a twofold axis. Intermolecular C—H...O hydrogen bonds to the sulfonyl O atoms link the molecules into a three-dimensional network.

In the title compound, [Cu(C30H20F2N4O4S2)]·0.5CH2Cl2, the CuII atom is four-coordinated by the N atoms of quinoline and sulfonamide groups in a distorted tetrahedral geometry. The solvent molecule lies on a twofold axis. Intermolecular C—H...O hydrogen bonds link the molecules into a three-dimensional network.

In the title compound, [Zn(C18H17N2O2S)2]·C3H7NO, the Zn atom is four-coordinated by the N atoms of sulfonamide and quinoline groups. Two intermolecular C—H...O hydrogen bonds connect the molecules into a three-dimensional network.

In the crystal structure of the title compound, C26H34N2O3S, the quinoline ring system, with meth­oxy and methyl substituents, is nearly planar. An intra­molecular hydrogen bond [N—H⋯N = 2.16 (2) A] is observed.

This work describes the volatile composition obtained by hidrodistillation of fresh leaves of Siparuna guianensis Aublet collected from Cuiaba (MT), Brazil. The composition of DCM extract of hydrolate was determined by GC-MS analysis and the results showed that the specie present a range of components according to their phenology and period of the leaves were collects. The highest volatile components yield was obtained during the reproductive period and the principal compound was the siparunone.

The reactions of 2-amino-8-hydroxyquinoline and 2-amino-4(1H)quinolone with different sulfonyl chlorides have been investigated. The chemoselectivity was observed to afford exclusively the arylsulfonate ester derivatives. The mechanism of the reaction is also discussed.