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Valter M Barbosa-Filho,1,2 Emily P Waczuk,2 Nadghia F Leite,3 Irwin RA Menezes,1 José GM da Costa,1 Sírleis R Lacerda,1 Isaac A Adedara,2 Henrique Douglas Melo Coutinho,4 Thais Posser,5 Jean P Kamdem2,6 1Departamento de Ciências Biológicas, Centro de Ciências Biológicas e da Saúde (CCBS), Universidade Regional do Cariri (URCA), Crato, CE, Brazil; 2Programa de Pós-Graduação em Bioquímica Toxicológica, Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil; 3Departamento de Química Biológica, Centro de Ciências Biológicas e da Saúde (CCBS), 4Laboratory of Microbiology and Molecular Biology, Universidade Regional do Cariri (URCA), Crato, CE, Brazil; 5Campus São Gabriel, Universidade Federal do Pampa, São Gabriel, RS, Brazil; 6Departamento de Bioquímica, Instituto de Ciências Básica da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil Background: The challenge of antibiotic resistance and the emergence of new infections have generated considerable interest in the exploration of natural products from plant origins as combination therapy. In this context, crude ethanolic extract (CEE), ethyl acetate fraction (EAF), and methanolic fraction (MF) from Anacardium microcarpum were tested alone or in combination with antibiotics (amikacin, gentamicin, ciprofloxacin, and imipenem) against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Methods: Antibiotic resistance-modifying activity was performed using the microdilution method by determining the minimal inhibitory concentration (MIC). In addition, phytochemical prospecting analyses of tested samples were carried out. Results: Our results indicated that all the extracts showed low antibacterial activity against multidrug-resistant strains (MIC =512 µg/mL). However, addition of CEE, EAF, and MF to the growth medium at the subinhibitory concentration (MIC/8=64 µg/mL) significantly modulated amikacin- and gentamicin-resistant E. coli 06. CEE and EAF also demonstrated a significant (P

Context: Bismuth complexes with dithiocarbamate ligands have attracted attention because of their biological applications, such as antimicrobial, antileishmanial, and anticancer properties. These complexes have high cytotoxic activity against cancer cells, being more active than the standard drugs cisplatin, doxorubicin, and tamoxifen. In the present study, we investigated the ability of some DFT methods to reproduce the geometries and NMR spectra of the Bi(III) dithiocarbamate complexes, selected based on their proven antitumor activity. Our investigation revealed that the M06-L/def2-TZVP/ECP/CPCM method presented good accuracy in predicting geometries, while the TPSSh/def2-SVP/ECP/CPCM method proved effective in analyzing the 13 C NMR spectra of these molecules. In general, all examined methods exhibited comparable performance in predicting 1 H NMR signals., Methods: Calculations were performed with the Gaussian 09 program using the def2-SVP and def2-TZVP basis sets, employing relativistic effective core potential (ECP) for Bi and using the CPCM solvent model. The exchange-correlation functionals BP86, PBE, OLYP, M06-L, B3LYP, B3LYP-D3, M06-2X, TPSSh, CAM-B3LYP, and ωB97XD were used in the study. Geometry optimizations were started from crystallographic structures available at the Cambridge Structural Database. The theoretical results were compared with experimental data using the mean root-mean-square deviation (RMSD), mean absolute deviations (MAD), and linear correlation coefficient (R 2 )., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The aims of the study were: (i) evaluate the efficacy of using amphibian adipose tissue as a valid biomarker of water contaminated by pyriproxyfen; and (ii) verify the use of Lithobates catesbeianus in laboratory experiments as a potential bioindicator for bioaccumulation of pesticide in adipose tissue from amphibians. Adult frogs were exposed to different dilutions (0.002 g/L and 0.02 g/L) of Sumilarv® (pyriproxyfen) over 50 days. The average results of the fortified sample were 108%, indicating that the test method was effective. Adult frogs exposed to the standard dose recommended by the World Health Organization (WHO) showed bioaccumulation of pyriproxyfen in adipose tissue significantly higher than control animals. Lithobates catesbeianus proved to be an effective bioindicator and the adipose tissue was an efficient biomarker to bioaccumulation of pyriproxyfen. We conclude that high-performance liquid chromatography-mass spectrometry was effective measuring pyriproxyfen bioaccumulation in adult amphibians., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The 2,4,6-tribromophenol (TBP) is an environmental persistent pollutant widely used as flame retardant, antimicrobial and insecticide agent in wood preservation and plastic production. Currently, TBP is found in environmental compartments such as soil, freshwater, groundwater, sewage sludge and domestic dust, but the effects to biota and the risk of exposure to aquatic vertebrates are still scarce. In the present study, Rhamdia quelen fish embryos (8 h post-fertilization - hpf) were exposed to 0.3 and 3.0 μg L -1 of TBP until 96 hpf. Biochemical biomarkers, hatching, survival and larvae/embryo malformations were evaluated after exposure. Additionally, a mathematical model was proposed to evaluate the effects along further generations. The results showed that TBP decreased the survival level but did not cause significant difference in the hatching rates. After 72 and 96 hpf, individuals from the highest tested concentration group showed more severe malformations than individuals from control and the lower concentrations groups. The deformities were concentrated on the embryos facial region where the sensorial structures related to fish behavior are present. The biochemical biomarkers revealed both oxidative stress and neurotoxicity signs after exposure to the contaminant, while the application of the mathematical model showed a decrease of population in both tested TBP concentrations. In conclusion, the current results demonstrated that TBP is toxic to R. quelen embryos and represents a risk to population after early life stage exposure., (Copyright © 2019 Elsevier Inc. All rights reserved.)

This study aimed to verify the chelating, antioxidant and cytoprotective activities of Psidium brownianum Mart. Ex DC against mercury and aluminum. The ethanolic extract, as well as the tannic and flavonoid fractions, were prepared and subjected to liquid chromatography-mass spectrometry analysis. Ferric ion reduction and antioxidant activity measurement using the FRAP method were performed with P. brownianum. After determining the sub-allelopathic doses, germination tests using Lactuca sativa (lettuce) seeds were performed. The main compounds identified in the extract and fractions were: quercetin and its derivatives; myricetin and its derivatives; gallic acid; ellagic acid; quinic acid and gallocatechin. The Minimum Inhibitory Concentration (MIC) for all samples were ≥ 1024 μg/mL. The flavonoid fraction in association with mercury chloride demonstrated cytoprotection (p < 0.001). The sub-allelopathic concentration used was 64 μg/mL. The extract and fractions were cytoprotective for radicles and caulicles when assayed in association with mercury and against aluminum for radicles. This suggests that the P. brownianum extract and its fractions present cytoprotective activity, possibly related to the antioxidant effect of secondary metabolites, especially flavonoids., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The objective of this work was to evaluate the antioxidant, metal chelating and cytoprotective activity of the Eugenia jambolana Lam. extract, as well as of its flavonoid and tannic fractions, against the action of Mercury Chloride (HgCl 2 ). Flavonoids were quantified and an LC-MS chromatographic analysis was performed to identify secondary metabolites. Fe 2+ and Fe 3+ chelation tests and antioxidant activity were carried out using the FRAP method. Microbiological tests were performed by microdilution to determine the Minimum Inhibitory Concentration (MIC). From these results the Minimum Bactericidal (MBC) and Minimum Fungicide Concentration (MFC) were evaluated. The allelopathy and cytoprotection assays were performed using eukaryotic and prokaryotic models. The results revealed the presence of phenolic acids and flavonoids in the E. jambolana extract and fractions. The sub-allelopathic concentration (64 μg/mL) was used and the results demonstrated the E. jambolana potential cytoprotective effect against mercury chloride., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The present study had as its objective to verify the Psidium guajava var. Pomifera L. chelating, antioxidant and cytoprotective effects against mercury and aluminum. The ethanolic extract, tannic and flavonoid fractions were subjected to LC-MS analysis. The Ferric Reducing Antioxidant Power (FRAP) and ferric ion reduction demonstrated a present antioxidant activity. The fungicidal and bactericidal activity of these metals were established. After determining the sub-allelopathic doses, germination tests using Lactuca sativa were performed. Quercetin and its derivatives were the main compounds identified in the extract and the fractions. Mercury chloride significantly reduced the bactericidal effect of the flavonoid fraction (p < 0.001). None of the fractions were cytoprotective against mercury or aluminum in the fungal model assays. Using a sub-allelopathic concentration (64 μg/mL), the ethanolic extract, flavonoid and tannic fractions were found to be cytoprotective against aluminum for radicles, however only the tannic fraction was cytoprotective for caulicles. These data suggest that natural P. guajava products are promising cytoprotective compound sources. This activity may be related to the antioxidant effect of secondary metabolites, mainly flavonoids. Our results point to a potential for environmental intervention product and technique development aimed at mitigating contamination by toxic metals such as mercury and aluminum., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The recent increase of freshwater eutrophication has favored cyanobacteria blooms and consequently the increase of toxins such as microcystin-LR in aquatic environments, but few is know about the associated effect of toxin and other compounds. Pyriproxyfen is an insecticide indicated by WHO (World Health Organization) to control Aedes aegypti mosquito (vector of Dengue, Chikungunya and Zika diseases), however, the effects are not well described to non-target species, such as fish. The early life stages (ELS) of fish are more sensitive to chemical stress due to higher metabolic rate, immature immune system and high superficial area/volume ratio. In the current study, ELS of R. quelen a Neotropical fish were exposed to environmentally realistic concentrations of microcystin (1, 10 and 100 µg L -1 ; M1, M2 and M3 groups, respectively) from an algal extract, pyriproxyfen (1 and 10 µg L -1 , P1 and P2) and their association (co-exposure). The hatching, survival and larvae deformities were analyzed, and applied a mathematical model to evaluate the effects on the population size along further generations. Both compounds were toxic to embryos/larvae of fish, but the effects were more pronounced in M2, P1M2 and P2M1 for hatching and M2, P1M2, P2M1 and P1 for survival. Deformities prevailed in groups exposed to the chemicals at 48 hpf (hours post-fertilization) were suggestions of toxicological interaction in P1M2, P2M1 and P2M2 at 48 and 72 hpf. In 96 hpf, the levels of deformities were lower than in previous times. Model predicted population density over 100 years decreased to lower than 0.5 (50%) in all groups, except for P1M1, indicating risk of extinction. P1M2 had the worse results, followed by M2, P1M3 and P2M1. Cyanobacterial blooms can lead to microcystin-LR levels higher than M2 (10 µg L -1 ), and the suggestion of toxicological interaction with pyriproxyfen is relevant because both compounds may potentially coexist in aquatic environments. Finally, mathematical models may provide an ecological interpretation of the risk of exposure of fish., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The main objective of this study is to propose a new sorbent phase based on a commercial epoxy resin, for use as an alternative sorbent in the stir bar sorptive extraction (SBSE) technique. The analytes triclosan (TCS) and methyl-triclosan (MTCS) were selected in order to demonstrate the application of the bars, using some water samples as matrices. The extraction conditions of sample volume, stirring time, pH, temperature and ionic strength were evaluated, and for the back extraction, the bars were sonicated using 1.00 mL of acetonitrile for 10 min. The technique of liquid chromatography using a diode array detector was employed for the quantitation. Analytical curves of between 2.50 and 50.0 μg L -1 with r 2 of 0.9894 (TCS) and 0.9933 (MTCS), and limit of detection (LOD) values of 0.6 μg L -1 (TCS) and 2.0 μg L -1 (MTCS) were observed. Recovery values between 100.4% and 121.6% were verified for ultrapure water and between 50.3% and 93.8% for wastewater samples, thereby suggesting the possibility of employing the bars for quantitation of TCS and MTCS in aqueous samples. This is the first time that this resin has been applied without the need for the adhesion of any additional sorbent phase, thereby providing a simple and low-cost method. Another feature is that only eight bars were employed in the entire work, and each bar was used approximately 40 times with the same performance without memory effects.

The association of herbal products with standard antimicrobial drugs has recently gained more attention as a hope to overcome infectious diseases caused by multidrug-resistant microorganisms. Here, we investigated for the first time the antimicrobial (antifungal and antibacterial) activity of ethanolic and aqueous extracts of R. echinus against multiresistant strains of bacteria (E. coli, P. aeruginosa and S. aureus) and fungi (C. albicans, C. krusei and C. tropicalis), as well as potential to enhance the activity of antibiotics drugs. In addition, both extract were chemically characterized and their toxicity was assessed in Artemia salina. Our results demonstrate that aqueous extract of R. echinus caused a significant increase in the activity of antibiotics gentamicin and imipenem, while the ethanolic extract strongly enhanced the antibiotic activity of gentamicin, amikacin, imipenem and ciprofloxacin against P. aeruginosa. However, neither the ethanolic nor the aqueous extracts significantly affect the antibiotic activity of the drugs when tested against S. aureus. Phytochemical analysis of the extracts indicated ellagic acid, caffeic acid and chlorogenic acid as the major components which can be at least in part responsible for the enhanced activity of antibiotics. None of the extracts showed toxicity in A. salina even at the highest concentration tested (1000 μg/mL). All together, our results suggest that the leaf extract of R. echinus can be an effective source of modulating agents., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Mercury (Hg) is widely distributed in the environment and is known to produce several adverse effects in organisms. The aim of the present study was to examine the in vitro antioxidant activity and Hg chelating ability of the hydroalcoholic extract of Psidium guajava leaves (HEPG). In addition, the potential protective effects of HEPG against Hg(II) were evaluated using a yeast model (Saccharomyces cerevisiae). HEPG was found to exert significant antioxidant activity in 2,2-diphenyl-1-picrylhydrazyl scavenger and inhibition of lipid peroxidation induced by Fe(II) assays in a concentration-dependent manner. The extract also exhibited significant Hg(II) chelating activity. In yeast, Hg(II) induced a significant decrease in cell viability. In contrast, HEPG partially prevented the fall in cell viability induced by Hg(II). In conclusion, HEPG exhibited protective effects against Hg(II)-mediated toxicity, which may be related to both antioxidant and Hg(II)-chelating activities.

Background: Rhaphiodon echinus is a weed plant used in the Brazilian folk medicinal for the treatment of infectious diseases. In this study, the essential oil of R. echinus leaf was investigated for its antimicrobial properties., Methods: The chemical constituents of the essential oil were characterized by GC-MS. The antimicrobial properties were determined by studying by the microdilution method the effect of the oil alone, and in combination with antifungal or antibiotic drugs against the fungi Candida albicans, Candida krusei and Candida tropicalis and the microbes Escherichia coli, Staphylococcus aureus and Pseudomonas. In addition, the iron (II) chelation potential of the oil was determined., Results: The results showed the presence of β-caryophyllene and bicyclogermacrene in major compounds, and revealed a low antifungal and antibacterial activity of the essential oil, but a strong modulatory effect on antimicrobial drugs when associated with the oil. The essential oil showed iron (II) chelation activity., Conclusions: The GC-MS characterization revealed the presence of monoterpenes and sesquiterpenes in the essential oil and metal chelation potential, which may be responsible in part for the modulatory effect of the oil. These findings suggest that essential oil of R. echinus is a natural product capable of enhancing the antibacterial and antifungal activity of antimicrobial drugs.

The therapeutic combinations have been increasingly used against fungal resistance. Natural products have been evaluated in combination with pharmaceutical drugs in the search for new components able to work together in order to neutralize the multiple resistance mechanisms found in yeasts from the genus Candida. The aqueous and hydroethanolic extracts from Psidium brownianum Mart ex DC. and Psidium guajava L. species were evaluated for their potential to change the effect of commercial pharmaceutical drugs against Candida albicans and Candida tropicalis strains. The tests were performed according to the broth microdilution method. Plate readings were carried out by spectrophotometry, and the data generated the cell viability curve and IC50 of the extracts against the yeasts. A chemical analysis of all the extracts was performed for detection and characterization of the secondary metabolites. The total phenols were quantified in gallic acid eq/g of extract (GAE/g) and the phenolic composition of the extracts was determined by HPLC. Fluconazole and all extracts presented high Minimum Inhibitories Concentrations (MICs). However, when associated with the extracts at sub-inhibitory concentrations (MIC/16), fluconazole had its effect potentiated. A synergistic effect was observed in the combination of fluconazole with Psidium brownianum extracts against all Candida strains. However, for Psidium guajava extracts the synergistic effect was produced mainly against the Candida albicans LM77 and Candida tropicalis INCQS 400042 strains. The IC50 values of fluconazole ranged from 19.22 to 68.1 μg/mL when it was used alone, but from 2.2 to 45.4 μg/mL in the presence of the extracts. The qualitative chemical characterization demonstrated the presence of phenols, flavonoids and tannins among the secondary metabolites. The concentration of total phenols ranged from 49.25 to 80.77 GAE/g in the P. brownianum extracts and from 68.06 to 82.18 GAE/g in the P. guajava extracts. Our results indicated that both P. brownianum and P. guajava extracts are effective on potentiating the effect of fluconazole, and therefore, these plants have the potential for development of new effective drugs for treating fungal infections., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Drug resistance in the treatment of neglected parasitic diseases, such as leishmaniasis and trypanosomiasis, has led to the search and development of alternative drugs from plant origins. In this context, the essential oil extracted by hydro-distillation from Lantana camara leaves was tested against Leishmania braziliensis and Trypanosoma cruzi. The results demonstrated that L. camara essential oil inhibited T. cruzi and L. braziliensis with IC50 of 201.94 μg/mL and 72.31 μg/mL, respectively. L. camara essential oil was found to be toxic to NCTC929 fibroblasts at 500 μg/mL (IC50 = 301.42 μg/mL). The composition of L. camara essential oil analyzed by gas chromatography-mass spectrometry (GC/MS) revealed large amounts of (E)-caryophyllene (23.75%), biciclogermacrene (15.80%), germacrene D (11.73%), terpinolene (6.1%), and sabinene (5.92%), which might be, at least in part, responsible for its activity. Taken together, our results suggest that L. camara essential oil may be an important source of therapeutic agents for the development of alternative drugs against parasitic diseases.

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

The guava fruit, Psidium guajava var. pomifera (Myrtaceae family), is a native plant from South America. Its leaves and fruits are widely used in popular medicine in tropical and subtropical countries. Drosophila melanogaster has been used as one of the main model organisms in genetic studies since the 1900s. The extensive knowledge about this species makes it one of the most suitable organisms to study many aspects of toxic compound effects. Due to the lack of studies on the effects of the bioactive compounds present in the P. guajava var. pomifera essential oil, we performed a phytochemical characterization by CG-MS and evaluated the toxicity induced by the essential oil in the D. melanogaster insect model. In order to understand the biochemical mechanisms of toxicity, changes on the Nrf2 signaling as well as hallmarks of oxidative stress response were followed in the exposed flies. Our results showed that exposure of insects to the P. guajava oil increased mortality and locomotor deficits in parallel with an oxidative stress response signaling. Therefore, it suggested a bioinsecticidal activity for P. guajava volatile compounds by means of oxidative stress. Further studies are ongoing to identify which oil compounds are responsible for such effect.

The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were determined in surface sediment samples from nine sites located at the Iguaçu River Basin in the Metropolitan Region of Curitiba, Brazil to evaluate their distribution and sources. The total concentration of the PAHs was greater for sediments from highly urbanized areas, while the sediments from the Iraí Environmental Protection Area (Iraí EPA) showed significantly low concentrations. The sediments from the Iguaçu and Barigui rivers were classified as highly contaminated, while those from the Cercado and Curralinho rivers were classified as moderately contaminated. The predominance of PAHs containing two to four aromatic rings in most of the samples suggested the direct input of raw sewage into the water resources evaluated. Benzo[g,h,i]perylene, dibenzo[a,h]anthracene and indeno[1,2,3-cd]pyrene were predominant in sediments from the areas under the greatest urban and industrial development. The correlation between thermodynamic stability and the kinetics of evolution presented by the isomeric pairs indicated that combustion is the predominant source of PAHs in the sediments because the combustion of fossil fuels affected most of the points evaluated, followed by combustion of biomass and eventually combustion of oil product inputs. In general, the results showed that areas under strong urban influence, as well as the Iraí EPA, receive contributions of PAHs from similar sources.

A procedure for the determination of very low polycyclic aromatic hydrocarbons (PAHs) concentrations in sediment samples has been developed by gas chromatography-quadrupole ion trap mass spectrometry (GC-QIT MS) after extraction with dichloromethane and purification by using silica gel cleanup. Identification and quantification of analytes were based on the selected ion storage (SIS) strategy using deuterated PAHs as internal standards. In order to search out the main factors affecting the SIS mass spectrometry efficiency, four MS parameters, including target total ion count (TTIC), waveform amplitude (WA), transfer line (XLT) and ion trap temperatures (ITT) were subjected to a complete multifactorial design. The most relevant parameters obtained (TTIC and WA) were optimized by a rotatable and orthogonal composite design. Optimum values for these parameters were selected for the development of the method involving PAH determination in sediment samples. The optimized method exhibited a range of 111-760% higher signal-to-noise (S/N) ratios for PAHs in comparison with the method operated by the default conditions, demonstrating that the multifactorial optimization contributed to substantially improve the sensitivity of the GC-QIT MS determination. The accuracy of the method was verified by analyzing NWRI EC-3 certified reference material (Lake Ontario sediment). The selectivity, sensitivity (limits of quantification were in the range of 0.02-11.0 ng g(-1)), accuracy (recoveries >or=77%) and precision (RSD

Significant amounts of pinocembrin (>10%), a dihydroxy-flavanone, was found in the composition of an unusual brand of a subtropical Brazilian propolis. Incidentally, this sealing material was obtained from hives surrounding a large forestry site based on a single exotic flora, namely poplar (Populus sp.). Examination of the different botanical parts of poplar revealed the buds as the main source of the flavanone. Techniques used for the establishment of the chemical correlation between the propolis brand and the poplar buds were TLC/densitometry, capillary GC-MS in the e.i. mode, and CZE with DAD monitoring. Since color enhancement after Al3+ complexation applies just for more hydroxylated flavonoids, the alternative techniques herein applied were of value for pinocembrin detection and estimation. Analytical data indicated the dominance of the main phenolic pinocembrin biomarker as well as the presence of other related flavonoids in the botanical source and in the propolis derived thereof.