Antibacterial Activity of the Essential Oil of Piper tuberculatum Jacq. Fruits against Multidrug-Resistant Strains: Inhibition of Efflux Pumps and ß-Lactamase.

Antimicrobial resistance has become a growing public health concern in recent decades, demanding a search for new effective treatments. Therefore, this study aimed to elucidate the phytochemical composition and evaluate the antibacterial activity of the essential oil obtained from the fruits of Piper tuberculatum Jacq. (EOPT) against strains carrying different mechanisms of antibiotic resistance. Phytochemical analysis was performed using gas chromatography-mass spectrometry (GC/MS). The antibacterial activity of EOPT and its ability to inhibit antibiotic resistance was evaluated through the broth microdilution method. The GC-MS analysis identified 99.59% of the constituents, with ß-pinene (31.51%), α-pinene (28.38%), and ß-cis-ocimene (20.22%) being identified as major constituents. The minimum inhibitory concentration (MIC) of EOPT was determined to assess its antibacterial activity against multidrug-resistant strains of Staphylococcus aureus (IS-58, 1199B, K2068, and K4100). The compound showed a MIC of ≥ 1024 µg/mL, suggesting a lack of intrinsic antibacterial activity. However, when the EOPT was associated with antibiotics and EtBr, a significant decrease in antibiotic resistance was observed, indicating the modulation of efflux pump activity. This evidence was corroborated with the observation of increased fluorescent light emission by the bacterial strains, indicating the involvement of the NorA and MepA efflux pumps. Additionally, the significant potentiation of ampicillin activity against the S. aureus strain K4414 suggests the ß-lactamase inhibitory activity of EOPT. These results suggest that the essential oil from P. tuberculatum fruits has antibiotic-enhancing properties, with a mechanism involving the inhibition of efflux pumps and ß-lactamase in MDR S. aureus strains. These findings provide new perspectives on the potential use of EOPT against antibiotic resistance and highlight the importance of Piper species as sources of bioactive compounds with promising therapeutic activities against MDR bacteria. Nevertheless, further preclinical (in vivo) studies remain necessary to confirm these in vitro-observed results.

Antibacterial Activity and Anxiolytic Effect in Adult Zebrafish of Genus Lippia L. Species.

Species belonging to the genus Lippia are used worldwide as foods, beverages, and seasonings. Studies have demonstrated that these species have antioxidant, sedative, analgesic, anti-inflammatory, and antipyretic activities. This work aimed to evaluate the antibacterial activity and anxiolytic effect by different pathways of essential oils and ethanolic extracts of three species of Lippia (Lippia alba, Lippia sidoides, and Lippia gracilis). The ethanolic extracts were characterized by HPLC-DAD-ESI-MSn and their phenolics were quantified. The antibacterial activity was evaluated by determining the minimal inhibitory concentration and modulation of antibiotic activity, and toxic and anxiolytic effects were evaluated in the zebrafish model. The extracts showed compositions with a low ratio and shared compounds. L. alba and L. gracilis showed higher amounts of phenols and flavonoids, respectively. All extracts and essential oils presented antibacterial activity, especially those obtained from L. sidoides. On the other hand, L. alba extract presented the most significant antibiotic-enhancing effect. The samples were not toxic after 96 h of exposure, but showed an anxiolytic effect through modulation of the GABAA receptor, while L. alba extract acted via modulation of the 5-HT receptor. This new pharmacological evidence opens horizons for therapeutic approaches targeting anxiolytic and antibacterial therapies and food conservation using these species and their constituents.

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.

13C NMR spectroscopic data of aporphine alkaloids.

This study involves aporphine alkaloids identified through 13C Nuclear Magnetic Resonance (NMR) spectroscopic data. For the present publication, articles were selected from several databases on aporphine alkaloids from 1994 to 2021. In this class, more than 700 compounds have been registered, with 221 were included in this section, among which 122 were characterized for the first time in the investigated period. The study also addresses their biosynthetic pathways, classifying substances according to their structural characteristics based on established literature. Furthermore, pharmacological activities related to the aporphine alkaloids highlighted in this section are also presented, giving an overview of the various applications of these compounds.

LC-MS Analysis and Antifungal Activity of Turnera subulata Sm.

Fungi of the Candida genus are responsible for invasive candidiasis, which affects people all over the world and has high mortality rates. This is due to their virulence factors, which give them great resistance and pathogenicity. In addition, the emergence of multidrug-resistant strains makes it difficult to treat these infections. In this way, natural products have emerged as an alternative to standard drugs, where plants known for their medicinal properties such as Turnera subulata become attractive to research. The present work aimed to analyze the ethanol extract of Turnera subulata leaves against standard strains of Candida albicans, Candida krusei and Candida tropicalis using broth microdilution techniques. The identification of the compounds in T. subulata leaves by LC-MS revealed the presence of a wide variety of substances such as carboxylic acids and terpenes, with flavonoids and fatty acids being more evident. The antifungal assays showed that the extract was not able to inhibit the growth of the tested strains at concentrations with a clinical relevance. However, at higher concentrations, it was able to inhibit the fungal dimorphism of C. albicans and C. tropicalis. It is possible that the T. subulata extract has potential as an inhibitor of fungal virulence factors without affecting the cell viability. Further research should be carried out in order to assess its inhibitory potential for other fungal virulence factors.

Anti-inflammatory effects of α-humulene and ß-caryophyllene on pterygium fibroblasts.

AIM: To investigate the anti-inflammatory effects of the sesquiterpenes α-humulene and ß-caryophyllene on pterygium fibroblasts. METHODS: Primary cultures of pterygium fibroblasts were established. Third passage pterygium fibroblasts were exposed to α-humulene and ß-caryophyllene separately and together. The cell viability was assessed by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay at 12, 24, 48, and 72h after exposure. The levels of the inflammatory cytokines interleukin (IL)-1ß, IL-6, IL-8, tumor necrosis factor (TNF)-α and IL-10 in the conditioned culture medium were assessed by enzyme-linked immunosorbent assay (ELISA) at 12, 24 and 48h after exposure. Data were statistically analyzed using Friedman repeated measures analysis of variances on ranks. RESULTS: The 25 µmol/L ß-caryophyllene induced significant decrease in the IL-6 production by pterygium fibroblasts 48h after the exposure (P=0.041). The levels of IL-1ß, IL-8, IL-10, and TNF-α were very low and had no statistically significant variations after exposure to α-humulene, ß-caryophyllene, or both compounds together. CONCLUSION: The exposure to 25 µmol/L of ß-caryophyllene significantly reduce the production of IL-6 by pterygium fibroblasts after 48h. This sesquiterpene may be a potential alternative adjuvant agent for the treatment of pterygium.

Analysis toxicity by different methods and anxiolytic effect of the aqueous extract Lippia sidoides Cham.

Lippia sidoides Cham. (Verbenaceae) is a species often mentioned in traditional medicine due to the medicinal properties attributed to its leaves, which include antibacterial, antifungal, acaricidal and antioxidant. Several of these actions have been scientifically proven, according to reports in the literature; however, little is known about toxicological aspects of this plant. This work included studies to determine the chemical composition and toxicity tests, using several methods aiming to evaluate the safety for use of the aqueous extract of L. sidoides leaves, in addition, the anxiolytic effect on adult zebrafish was investigated, thus contributing to the pharmacological knowledge and traditional medicine concerning the specie under study. The chemical profile was determined by liquid chromatography coupled to mass spectrometry-HPLC/MS with electrospray ionization. Toxicity was evaluated by zebrafish, Drosophila melanogaster, blood cells, and Artemia salina models. 12 compounds belonging to the flavonoid class were identified. In the toxicity assays, the observed results showed low toxicity of the aqueous extract in all tests performed. In the analysis with zebrafish, the highest doses of the extract were anxiolytic, neuromodulating the GABAa receptor. The obtained results support the safe use of the aqueous extract of L. sidoides leaves for the development of new drugs and for the use by populations in traditional medicine.

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.

Advances in Evaluation of Antioxidant and Toxicological Properties of Stryphnodendron rotundifolium Mart. in Drosophila melanogaster Model.

This study investigated the flavonoid content, antioxidant activity, and toxicological properties of the acetone-water fraction of stem bark of Stryphnodendron rotundifolium Mart. (TFSR). The total flavonoid content and antioxidant activity were determined, as typified by DPPH● and ABTS●+ radical scavenging abilities, Fe3+ reducing antioxidant power (FRAP), relative antioxidant capacity (RAC), and the inhibition of thiobarbituric acid reactive species (TBARs) in Drosophila melanogaster tissue. Toxicity and locomotor functions were evaluated in adult D. melanogaster flies through aging and survival assays, startle-induced negative geotaxis, and centrophobic responses with video-assisted open field motion tracking. The flavonoid content of dry TFSR (DF) was 3.36 mg quercetin/g. Furthermore, the significant antioxidant activity of TFSR was revealed through scavenging 95.3% of the ABTS●+ radical and 82.4% of the DPPH● radical, as well reducing 74.7% of Fe3+ in the FRAP assay and 80% Mo6+ in the RAC assay. TFSR conferred 70.25% protection against lipid peroxidation in Drosophila tissue. Survival rates ranged from 84.65 to 103.98% in comparison to the non-supplemented control and no evident deterioration of locomotor functions and centrophobia responses was observed. These results revealed that TFSR has potent antioxidant activity and low toxicity in vivo, profiling TFSR as a promising natural product in the treatment/management of iron overload and associated conditions.

Ferulic acid derivatives inhibiting Staphylococcus aureus tetK and MsrA efflux pumps.

Background: Bacterial resistance to multiple drugs has recently emerged as a serious health problem. Concomitantly, the characterization of new substances with potential antimicrobial activity has been less frequent in the drug development industry. The overexpression of genes encoding efflux pumps that expel antimicrobial drugs from the intracellular environment, lowering these to subinhibitory concentrations, are among the resistance mechanisms predisposing microorganisms to high drug resistance. Staphylococcus aureus is a bacterium found in the normal microbiota of the skin and mucous membranes, and is an opportunistic microorganism capable of causing infections with high rates of morbidity and mortality. TetK is an efflux pump characterized by its ability to provide bacterial resistance to antibiotics from the tetracycline class. This study aimed to evaluate the inhibitory effect of ferulic acid and four of its esterified derivatives against resistant Staphylococcus aureus strains. Method: Ferulic acid derivatives were obtained by esterification and then characterized by hydrogen and carbon-13 nuclear magnetic resonance analysis. The minimum inhibitory concentrations (MIC) of ferulic acid and its esterified derivatives, ethidium bromide, and antibiotics were obtained using the microdilution test, while the efflux pump inhibition test was conducted by examining reduction in the MICs. Results: Propylferulate was seen to reduce the minimum inhibitory concentration (MIC) of both the control substance ethidium bromide and the tested antibiotic, indicating that this compound is promising for the use of efflux pump inhibition of IS-58 strains. Conclusions: This study provides strong evidence that the molecular basis for this activity is potentially due to the MsrA and TetK efflux pumps. However, further investigations are necessary to prove this hypothesis and elucidate the potentiating mechanism of the modulatory effect.

HPLC-DAD analysis and antimicrobial activities of Spondias mombin L. (Anacardiaceae).

Spondias mombin is used in the folk medicine for the treatment of diarrhea and dysentery, indicating that extracts obtained from this species may present pharmacological activities against pathogenic microorganisms. The purpose of this work was to investigate the chemical composition and evaluate the antimicrobial activity of extracts obtained from the leaves (aqueous) and bark (hydroethanolic) of S. mombin both as single treatments and in combination with conventional drugs. Following a qualitative chemical prospection, the extracts were analyzed by HPLC-DAD. The antimicrobial activities were evaluated by microdilution. The combined activity of drugs and extracts was verified by adding a subinhibitory concentration of the extract in the presence of variable drug concentrations. The Minimum Fungicidal Concentration (MFC) was determined by a subculture of the microdilution test, while the effect of the in vitro treatments on morphological transition was analyzed by subculture in moist chambers. While the qualitative analysis detected the presence of phenols and flavonoids, the HPLC analysis identified quercetin, caffeic acid, and catechin as major components in the leaf extract, whereas kaempferol and quercetin were found as major compounds in the bark extract. The extracts showed effective antibacterial activities only against the Gram-negative strains. With regard to the combined activity, the leaf extract potentiated the action of gentamicin and imipenem (against Staphylococcus aureus), while the bark extract potentiated the effect of norfloxacin (against S. aureus), imipenem (against Escherichia coli), and norfloxacin (against Pseudomonas aeruginosa). A more significant antifungal (fungistatic) effect was achieved with the bark extract (even though at high concentrations), which further enhanced the activity of fluconazole. The extracts also inhibited the emission of filaments by Candida albicans and Candida tropicalis. Together, these findings suggest that that the extract constituents may act by favoring the permeability of microbial cells to conventional drugs, as well as by affecting virulence mechanisms in Candida strains.

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.

Antioxidant Activity of Stryphnodendron rotundifolium Mart. Stem Bark Fraction in an Iron Overload Model.

Stryphnodendron rotundifolium Mart., popularly known as "barbatimão", is a plant species traditionally used by topical and oral routes for the treatment of infectious and inflammatory diseases. Considering the well-described antioxidant properties of this species, this study investigated the protective effects of its keto-aqueous extract using an in vitro model of iron overload. Phenolic compounds were quantified and identified by Ultra-Performance Liquid Chromatography coupled with quadrupole Time-Of-Flight Electrospray Ionization Mass Spectrometry (UPLC-ESI-qTOF-MS/MS) in positive and negative ions mode analysis. Antioxidant activity was analyzed following the iron-chelating-reducing capacity and deoxyribose degradation (2-DR) protection methods. The analysis identified condensed tannins (54.8 mg catechin/g dry fraction (DF), polyphenols (25 mg gallic acid/g DF), and hydrolyzable tannins (28.8 mg tannic acid/g DF). Among the constituents, prodelphinidin, procyanidin, and prorobinetinidine were isolated and identified. The extract significantly protected 2-DR degradation induced by Fe2+ (72% protection) or •OH (43% protection). The ortho-phenanthroline test revealed Fe2+-chelating and Fe3+-reducing activities of 93% and 84%, respectively. A preliminary toxicological analysis using Artemia salina revealed mortality below 10%, at a concentration of 0.25 mg/mL, indicating low toxicity under the present experimental conditions. In conclusion, the findings of the present study indicate that Stryphnodendron rotundifolium is a source of antioxidant compounds with the potential to be used in drug development in the context of iron overload disorders, which remains to be further investigated in vivo.

Myorelaxant Effect of the Dysphania ambrosioides Essential Oil on Sus scrofa domesticus Coronary Artery and Its Toxicity in the Drosophila melanogaster Model.

PURPOSE: Alternative methods for the use of animals in research have gained increasing importance, due to assessments evaluating the real need for their use and the development of legislation that regulates the subject. The principle of the 3R's (replacement, reduction and refinement) has been an important reference, such that in vitro, ex vivo and cord replacement methods have achieved a prominent place in research. METHODS: Therefore, due to successful results from studies developed with these methods, the present study aimed to evaluate the myorelaxant effect of the Dysphania ambrosioides essential oil (EODa) using a Sus scrofa domesticus coronary artery model, and the toxicity of both the Dysphania ambrosioides essential oil and its major constituent, α-terpinene, against Drosophila melanogaster in toxicity and negative geotaxis assays. RESULTS: The EODa relaxed the smooth muscle of swine coronary arteries precontracted with K+ and 5-HT in assays using Sus scrofa domesticus coronary arteries. The toxicity results presented LC50 values of 1.546 mg/mL and 2.282 mg/mL for the EODa and α-terpinene, respectively, thus showing the EODa and α-terpinene presented toxicity to these dipterans, with the EODa being more toxic. CONCLUSIONS: Moreover, the results reveal the possibility of using the EODa in vascular disease studies since it promoted the relaxation of the Sus scrofa domesticus coronary smooth muscle.

Phytochemical characterization and inhibition of Candida sp. by the essential oil of Baccharis trimera (Less.) DC.

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.

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.

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.

Removal of copper(II) ions and lead(II) from aqueous solutions using seeds of Azadirachta indica A. Juss as bioadsorvent.

In recent decades, aquatic environment pollution has become a global challenge due to a rapid industrial growth. In this context, adsorption has become one of the most used methods, gaining importance especially in the last decades, given the growing concern over environmental damages caused by these pollutants. Additionally, its low cost and bioavailability are attractive. Therefore, the present study proposed to investigate the adsorption potential of A. indica seeds for Cu(II) and Pb(II) removal in synthetic solutions. Equilibrium studies were carried out via isothermal adsorption in batch systems. Kinetic studies were used to evaluate the lowest equilibrium time. The two evaluated ions were better suited to the Langmuir model and Freundlich model. When applying Langmuir's model on Neem seed powder adsorption, maximum adsorption capacities of 11.54 mg g-1 and 17.96 mg g-1, in the crude form and 11.41 mg g-1 and 19.80 mg g-1 in the alkaline form were obtained for Cu(II) and Pb(II) ions, respectively. The equilibrium time was approximately 80 and 100 min for both ions. The kinetic model best adjusted to the phenomena was the pseudo-second order (Ho Model), suggesting adsorption mainly has a chemical nature for both the studied metals. The results showed Neem seed powder may be a sustainable, efficient and low cost alternative for the removal of Cu(II) and Pb(II) metal cations present in effluents.

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.

Piper diospyrifolium Kunth.: Chemical analysis and antimicrobial (intrinsic and combined) activities.

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.