Nanoparticles based on biopolymers improved antioxidant activity of phenolic compounds from jambolan (Syzygium cumini (L.) skeels).

Jambolan (Syzygium cumini L.) is an underutilized fruit rich in bioactive phenolic compounds, specially anthocyanins, but the low stability of these substances and interaction with other compounds in the food matrix limit their application as food additives; nanoencapsulation is the best strategy to overcome these limitations. This study aimed to nanoencapsulate a phenolic-rich jambolan extract using whey proteins and pectin by nanoprecipitation in different antisolvent compositions. Two formulations were synthesized (7.33 % extract, 1.67 % pectin, and 5 % concentrated or isolated whey protein) precipitated in different acetone concentrations (50, 70, and 100 % v/v). SEM showed particles with spherical shape and smooth surface. DLS pointed diameters between 82 nm and 116 nm. FTIR indicated chemical interactions between the materials. Encapsulation efficiency showed high phenolic compounds entrapment in all systems [73.81-84.65 %, p > 0.05]. However, particles precipitated in 50 and 100 % acetone (v/v) showed greater anthocyanins retention [56.89-35.24 %, p < 0.05]. Nanoencapsulation potentiated the antioxidant activity up to 110 % more than the crude extract (p < 0.05). These results show the potential of nanoprecipitation as an effective encapsulation process and the biopolymers combination to produce nanoparticles containing jambolan phenolic compounds to promote their application in foods and health products.

A Newly Validated HPLC-DAD Method for the Determination of Ricinoleic Acid (RA) in PLGA Nanocapsules.

The assessment of ricinoleic acid (RA) incorporated into polymeric nanoparticles is a challenge that has not yet been explored. This bioactive compound, the main component of castor oil, has attracted attention in the pharmaceutical field for its valuable anti-inflammatory, antifungal, and antimicrobial properties. This work aims to develop a new and simple analytical method using high-performance liquid chromatography with diode-array detection (HPLC-DAD) for the identification and quantification of ricinoleic acid, with potential applicability in several other complex systems. The method was validated through analytical parameters, such as linearity, limit of detection and quantification, accuracy, precision, selectivity, and robustness. The physicochemical properties of the nanocapsules were characterized by dynamic light scattering (DLS) to determine their hydrodynamic mean diameter, polydispersity index (PDI), and zeta potential (ZP), via transmission electron microscopy (TEM) and quantifying the encapsulation efficiency. The proposed analytical method utilized a mobile phase consisting of a 65:35 ratio of acetonitrile to water, acidified with 1.5% phosphoric acid. It successfully depicted a symmetric peak of ricinoleic acid (retention time of 7.5 min) for both the standard and the RA present in the polymeric nanoparticles, enabling the quantification of the drug loaded into the nanocapsules. The nanocapsules containing ricinoleic acid (RA) exhibited an approximate size ranging from 309 nm to 441 nm, a PDI lower than 0.2, ζ values of approximately -30 mV, and high encapsulation efficiency (~99%). Overall, the developed HPLC-DAD procedure provides adequate confidence for the identification and quantification of ricinoleic acid in PLGA nanocapsules and other complex matrices.

Sustainable application of modified Luffa cylindrica biomass for removal of trimethoprim in water by adsorption with process optimization.

The present study describes a set of methodological procedures (seldom applied together), including (i) development of an alternative adsorbent derived from abundant low-cost plant biomass; (ii) use of simple low-cost biomass modification techniques based on physical processing and chemical activation; (iii) design of experiments (DoE) applied to optimize the removal of a pharmaceutical contaminant from water; (iv) at environmentally relevant concentrations, (v) that due to initial low concentrations required determination by ultra-performance liquid phase chromatography coupled to mass spectrometry (UPLC-MS/MS). A central composite rotational design (CCRD) was employed to investigate the performance of vegetable sponge biomass (Luffa cylindrica), physically processed (crushing and sieving) and chemically activated with phosphoric acid, in the adsorption of the antibiotic trimethoprim (TMP) from water. The optimized model identified pH as the most significant variable, with maximum drug removal (91.1 ± 5.7%) achieved at pH 7.5, a temperature of 22.5 °C, and an adsorbent/adsorbate ratio of 18.6 mg µg-1. The adsorption mechanisms and surface properties of the adsorbent were examined through characterization techniques such as scanning electron microscopy (SEM), point of zero charge (pHpzc) measurement, thermogravimetric analysis (TGA), specific surface area, and Fourier-transform infrared spectroscopy (FTIR). The best kinetic fit was obtained by the Avrami fractional-order model. The hypothesis of a hybrid behavior of the adsorbent was suggested by the equilibrium results presented by the Langmuir and Freundlich models and reinforced by the Redlich-Peterson model, which achieved the best fit (R2 = 0.982). The thermodynamic study indicated an exothermic, spontaneous, and favorable process. The maximum adsorption capacity of the material was 2.32 × 102 µg g-1 at an equilibrium time of 120 min. Finally, a sustainable and promising adsorbent for the polishing of aqueous matrices contaminated by contaminants of emerging concern (CECs) at environmentally relevant concentrations is available for future investigations.

Untargeted Liquid Chromatography-High-Resolution Mass Spectrometry Metabolomic Investigation Reveals Altered Lipid Content in Leishmania infantum Lacking Lipid Droplet Protein Kinase.

Leishmaniasis is a complex disease caused by different species of Leishmania. To date, no vaccine for humans or ideal therapy has been developed owing to the limited efficacy and toxicity of available drugs, as well as the emergence of resistant strains. Therefore, it is necessary to identify novel therapeutic targets and discover therapeutic options for leishmaniasis. In this study, we evaluated the impact of deleting the lipid droplet protein kinase (LDK) enzyme in Leishmania infantum using an untargeted metabolomics approach performed using liquid chromatography and high-resolution mass spectrometry. LDK is involved in lipid droplet biogenesis in trypanosomatids. Thirty-nine lipid metabolites altered in the stationary and logarithmic growth phases were noted and classified into five classes: (1) sterols, (2) fatty and conjugated acids, (3) ceramides, (4) glycerophosphocholine and its derivatives, and (5) glycerophosphoethanolamine and its derivatives. Our data demonstrated that glycerophosphocholine and its derivatives were the most affected after LDK deletion, suggesting that the absence of this enzyme promotes the remodeling of lipid composition in L. infantum, thus contributing to a better understanding of the function of LDK in this parasite.

A robust method for quantifying 42 phenolic compounds by RP-HPLC/DAD: Columns performance and characterization of Brazilian Citrus peels.

Reliable analytical methods are the basis for the elucidation of phenolic compounds in foods. This study aimed to optimize and validate a method for determining 42 phenolics using reverse-phase (RP) high-performance liquid chromatography (HPLC) coupled to diode-array-detector-DAD. The performance of two RP columns was evaluated. The 150x4.6 mm 3-µm column showed superior separation quality, whereas 35 of the 42 phenolics showed a separation resolution ≥1.5. The method's linearity, precision (coefficient variation< 3.09%), recovery (87.5-103.2%), specificity, limits of detection (0.04-0.25 mg/L), and quantification (0.06-0.25 mg/L) had acceptable ranges. Thirty phenolics were quantified in Citrus peels, mainly flavanones, flavanols, flavonols, and phenolic acids, highlighting the high values of hesperidin (535-35070 mg/kg) and naringin (26-36466 mg/kg). Lemon peels named 'Lisboa,' 'Thaiti,' 'Thaiti-2000', and 'Thaiti-2001' presented the main phenolics associated with antioxidant capacity. The presented method was robust for determining 42 phenolic compounds, offering a new approach for bioactive compound quantification in food matrices.

Hybrid organic monolithic column containing MIL-68(Al) for the separation of small molecules by capillary HPLC.

A hybrid organic monolithic column made of poly(lauryl methacrylate-co-1,6-hexanediol dimethacrylate) and the metal-organic framework MIL-68(Al) was prepared for the first time. The column was used in capillary liquid chromatography, both in isocratic and gradient elution modes. Separation performance towards small molecules of different chemical nature (polycyclic aromatic hydrocarbons, alkylbenzenes, phenols, etc.) was studied. Monte Carlo simulations were made to both select the proper precursors to obtain empty metal-organic framework micropores in the monolithic polymer and also, to analyze the potential free access of the studied analytes into the micropores (necessary to improve mass transfer and column efficiency). The hereby synthesized metal-organic framework microcrystals allowed obtaining homogeneous hybrid monolithic columns. Adding of MIL-68(Al) (1030 m2 g-1 BET specific surface area) increased the surface area from 3.9 m2 g-1 for the parent monolith to 18.2 m2 g-1 for the hybrid column containing 8 mg mL-1 of the microcrystals. Chromatographic performance of this new column was evaluated by studying retention factors, resolution, and plate counts at room temperature. Different compounds, not completely resolved in the parent monolith, were partially or completely separated after metal-organic framework addition. Using the monolithic column with only 2 mg mL-1 of MIL-68(Al), five alkylbenzenes were completely separated with very symmetrical peak shapes, resolution factors up to 3.60 and plate counts of 4300 plates m-1 for n-hexylbenzene. This value is higher than those obtained by other authors who used organic monolithic columns with embedded metal-organic frameworks to perform separations at room temperature. Additionally, nine polycyclic aromatic hydrocarbons were partially or completely resolved in gradient elution mode. The hybrid monolithic columns exhibited very good intra-day (%RSD=1.9), inter-day (%RSD=2.6), and column-to-column (%RSD=4.3) reproducibility values. Easy and fast column preparation, and versatility to efficiently separate several compounds of different chemical nature in isocratic and gradient mode, makes this new hybrid column a very good option for the analysis of small molecules in capillary (or nano) HPLC.

Development and validation of a liquid chromatography coupled to a diode array detector (LC-DAD) method for measuring mitotane (DDD) in plasma samples.

INTRODUCTION: Mitotane (o,p'-DDD) is the drug of choice for Adrenocortical Carcinomas (ACC) and its measurement in plasma is essential to control drug administration. OBJECTIVE: To develop and validate a simple, reliable and straightforward method for mitotane determination in plasma samples. METHOD: Drug-free plasma samples were collected in potassium-ethylenediamine tetraacetate (K-EDTA) tubes and spiked with 1.0, 2.5, 10.0, 25.0 and 50.0 µg/mL of mitotane (DDD). The p,p'-DDD was used as an Internal Standard (IS) and was added at 25.0 µg/mL concentration to all samples, standards and controls. Samples were submitted to protein precipitation with acetonitrile and then centrifuged. 50 uL of the supernatant was injected into an HPLC system coupled to a Diode Array Detector (DAD). DDD and IS were detected at 230 nm in a 12 min isocratic mode with a solvent mixture of 60 % acetonitrile and 40 % formic acid in water with 0.1 % pump mixed, at 0.6 mL/min flow rate, in a reversed-phase (C18) chromatographic column kept at 28°C. The sensitivity, selectivity, precision, presence of carry-over, recovery and matrix-effect, linearity, and method accuracy were evaluated. RESULTS: The present study's method resulted in a symmetrical peak shape and good baseline resolution for DDD (mitotane) and 4,4'-DDD (internal standard) with retention times of 6.0 min, 6.4 mim, respectively, with resolutions higher than 1.0. Endogenous plasma compounds did not interfere with the evaluated peaks when blank plasma and spiked plasma with standards were compared. Linearity was assessed over the range of 1.00-50.00 µg/mL for mitotane (R2 > 0.9987 and a 97.80 %‒105.50 % of extraction efficiency). Analytical sensitivity was 0.98 µg/mL. Functional sensitivity (LOQ) was 1.00 µg/L, intra-assay and inter-assay coefficient of variations were less than 9.98 %, and carry-over was not observed for this method. Recovery ranged from 98.00 % to 117.00 %, linearity ranged from 95.00 % to 119.00 %, and high accuracy of 89.40 % to 105.90 % with no matrix effects or interference was observed for mitotane measurements. Patients' sample results were compared with previous measurements by the GC-MS method with a high correlation (r = 0.88 and bias = -10.20 %). CONCLUSION: DDD determination in plasma samples by the developed and validated method is simple, robust, efficient, and sensitive for therapeutic drug monitoring and dose management to achieve a therapeutic index of mitotane in patients with adrenocortical cancer.

Proteomic changes of the bovine blood plasma in response to heat stress in a tropically adapted cattle breed.

Background: Identifying molecular mechanisms responsible for the response to heat stress is essential to increase production, reproduction, health, and welfare. This study aimed to identify early biological responses and potential biomarkers involved in the response to heat stress and animal's recovery in tropically adapted beef cattle through proteomic analysis of blood plasma. Methods: Blood samples were collected from 14 Caracu males during the heat stress peak (HSP) and 16 h after it (heat stress recovery-HSR) assessed based on wet bulb globe temperature index and rectal temperature. Proteome was investigated by liquid chromatography-tandem mass spectrometry from plasma samples, and the differentially regulated proteins were evaluated by functional enrichment analysis using DAVID tool. The protein-protein interaction network was evaluated by STRING tool. Results: A total of 1,550 proteins were detected in both time points, of which 84 and 65 were downregulated and upregulated during HSR, respectively. Among the differentially regulated proteins with the highest absolute log-fold change values, those encoded by the GABBR1, EPHA2, DUSP5, MUC2, DGCR8, MAP2K7, ADRA1A, CXADR, TOPBP1, and NEB genes were highlighted as potential biomarkers because of their roles in response to heat stress. The functional enrichment analysis revealed that 65 Gene Ontology terms and 34 pathways were significant (P < 0.05). We highlighted those that could be associated with the response to heat stress, such as those related to the immune system, complement system, hemostasis, calcium, ECM-receptor interaction, and PI3K-Akt and MAPK signaling pathways. In addition, the protein-protein interaction network analysis revealed several complement and coagulation proteins and acute-phase proteins as important nodes based on their centrality and edges. Conclusion: Identifying differentially regulated proteins and their relationship, as well as their roles in key pathways contribute to improve the knowledge of the mechanisms behind the response to heat stress in naturally adapted cattle breeds. In addition, proteins highlighted herein are potential biomarkers involved in the early response and recovery from heat stress in tropically adapted beef cattle.

Bilirubin Molecular Species Play an Important Role in the Pathophysiology of Acute-on-Chronic Liver Failure.

Bilirubin plays a key role in early diagnosis, prognosis, and prevention of liver diseases. Unconjugated bilirubin (UCB) requires conversion to a water-soluble form through liver glucuronidation, producing monoglucuronide (BMG) or diglucuronide bilirubin (BDG) for bile excretion. This study aimed to assess the roles of bilirubin's molecular species-UCB, BMG, and BDG-in diagnosing and understanding the pathogenesis of liver cirrhosis in patients with acute-on-chronic liver failure (ACLF), compensated liver cirrhosis (LC) patients, and healthy individuals. The study included patients with ACLF and compensated LC of diverse etiologies, along with healthy controls. We collected laboratory and clinical data to determine the severity and assess mortality. We extracted bilirubin from serum samples to measure UCB, BMG, and BDG using liquid chromatography-mass spectrometry (LC-MS). The quantification of bilirubin was performed by monitoring the mass charge (m/z) ratio. Of the 74 patients assessed, 45 had ACLF, 11 had LC, and 18 were healthy individuals. Among ACLF patients, the levels of molecular species of bilirubin were UCB 19.69 µmol/L, BMG 47.71 µmol/L, and BDG 2.120 µmol/L. For compensated cirrhosis patients, the levels were UCB 11.29 µmol/L, BMG 1.49 µmol/L, and BDG 0.055 µmol/L, and in healthy individuals, the levels were UCB 6.42 µmol/L, BMG 0.52 µmol/L, and BDG 0.028 µmol/L. The study revealed marked elevations in the bilirubin species in individuals with ACLF compared to those with compensated cirrhosis and healthy controls, underscoring the progression of liver dysfunction. The correlation of BMG and BDG levels with commonly used inflammatory markers suggests a relationship between bilirubin metabolism and systemic inflammation in ACLF.

Characterizing lipid constituents of B. moojeni snake venom: a comparative approach for chemical and biological investigations.

Snake venoms are complex mixtures majorly composed of proteins with well-studied biological effects. However, the exploration of non-protein components, especially lipids, remains limited despite their potential for discovering bioactive molecules. This study compares three liquid-liquid lipid extraction methods for both chemical and biological analyses of Bothrops moojeni snake venom. The methods evaluated include the Bligh and Dyer method (methanol, chloroform, water), considered standard; the Acunha method, a modification of the Bligh and Dyer protocol; and the Matyash method (MTBE/methanol/water), featuring an organic phase less dense than the aqueous phase. Lipidomic analysis using liquid chromatography with high-resolution mass spectrometry (LC-HRMS) system revealed comparable values of lipid constituents' peak intensity across different extraction methods. Our results show that all methods effectively extracted a similar quantity of lipid species, yielding approximately 17-18 subclasses per method. However, the Matyash and Acunha methods exhibited notably higher proportions of biologically active lipids compared to the Bligh and Dyer method, particularly in extracting lipid species crucial for cellular structure and function, such as sphingomyelins and phosphatidylinositol-phosphate. In conclusion, when selecting a lipid extraction method, it is essential to consider the study's objectives. For a biological approach, it is crucial to evaluate not only the total quantity of extracted lipids but also their quality and biological activity. The Matyash and Acunha methods show promise in this regard, potentially offering a superior option for extracting biologically active lipids compared to the Bligh and Dyer method.

Basal release of 6-cyanodopamine from rat isolated vas deferens and its role on the tissue contractility.

6-Cyanodopamine is a novel catecholamine released from rabbit isolated heart. However, it is not known whether this catecholamine presents any biological activity. Here, it was evaluated whether 6-cyanodopamine (6-CYD) is released from rat vas deferens and its effect on this tissue contractility. Basal release of 6-CYD, 6-nitrodopamine (6-ND), 6-bromodopamine, 6-nitrodopa, and 6-nitroadrenaline from vas deferens were quantified by LC-MS/MS. Electric-field stimulation (EFS) and concentration-response curves to noradrenaline, adrenaline, and dopamine of the rat isolated epididymal vas deferens (RIEVD) were performed in the absence and presence of 6-CYD and /or 6-ND. Expression of tyrosine hydroxylase was assessed by immunohistochemistry. The rat isolated vas deferens released significant amounts of both 6-CYD and 6-ND. The voltage-gated sodium channel blocker tetrodotoxin had no effect on the release of 6-CYD, but it virtually abolished 6-ND release. 6-CYD alone exhibited a negligible RIEVD contractile activity; however, at 10 nM, 6-CYD significantly potentiated the noradrenaline- and EFS-induced RIEVD contractions, whereas at 10 and 100 nM, it also significantly potentiated the adrenaline- and dopamine-induced contractions. The potentiation of noradrenaline- and adrenaline-induced contractions by 6-CYD was unaffected by tetrodotoxin. Co-incubation of 6-CYD (100 pM) with 6-ND (10 pM) caused a significant leftward shift and increased the maximal contractile responses to noradrenaline, even in the presence of tetrodotoxin. Immunohistochemistry revealed the presence of tyrosine hydroxylase in both epithelial cell cytoplasm of the mucosae and nerve fibers of RIEVD. The identification of epithelium-derived 6-CYD and its remarkable synergism with catecholamines indicate that epithelial cells may regulate vas deferens smooth muscle contractility.

LC-MS metabolomics analysis of serum metabolites during neoadjuvant chemoradiotherapy in locally advanced rectal cancer.

BACKGROUND: This study aimed to investigate the serum metabolite profiles during neoadjuvant chemoradiotherapy (NCRT) in locally advanced rectal cancer (LARC) using liquid chromatography-mass spectrometry (LC-MS) metabolomics analysis. METHODS: 60 serum samples were collected from 20 patients with LARC before, during, and after radiotherapy. LC-MS metabolomics analysis was performed to identify the metabolite variations. Functional annotation was applied to discover altered metabolic pathways. The key metabolites were screened and their ability to predict sensitivity to radiotherapy was calculated using random forests and ROC curves. RESULTS: The results showed that NCRT led to significant changes in the serum metabolite profiles. The serum metabolic profiles showed an apparent separation between different time points and different sensitivity groups. Moreover, the functional annotation showed that the differential metabolites were associated with a series of important metabolic pathways. Pre-radiotherapy (3Z,6Z)-3,6-Nonadiena and pro-radiotherapy 1-Hydroxyibuprofen showed good predictive performance in discriminating the sensitive and non-sensitive group to NCRT, with an AUC of 0.812 and 0.75, respectively. Importantly, the combination of different metabolites significantly increased the predictive ability. CONCLUSION: This study demonstrated the potential of LC-MS metabolomics for revealing the serum metabolite profiles during NCRT in LARC. The identified metabolites may serve as potential biomarkers and therapeutic targets for the management of this disease. Furthermore, the understanding of the affected metabolic pathways may help design more personalized therapeutic strategies for LARC patients.

Unveiling complex interaction of sickle cell hemoglobin with another hemoglobinopathy - A Rare Entity

ABSTRACT Hemoglobinopathies constitute one of the most common inherited hematological disorders in the world with an increasing global disease burden each year. One among them is sickle cell disease with diverse genotypes and wide phenotypic heterogenity. Many subgroups exist within the umbrella of sickle cell disease. Hb S/DPunjab, a rare hemoglobinopathy, is one of them, mimics sickle cell disease, and is discussed in the present study. We describe one such unusual clinical case of a young child who presented with intermittent fever and joint problems. The study case was found to have Hb S/DPunjab by high performance liquid chromatography. Clinical and hematological details of this rare condition is only briefly discussed in the literature. Precise diagnosis can be made using high performance liquid chromatography in conjunction with family studies.

Optimization of resolution as a simultaneous function of solvent composition, pH and temperature in reversed-phase liquid chromatography.

BACKGROUND: The latest chromatographic retention models are capable of accurately describe the dependencies of retention over a wide range of experimental conditions. By using a suitable conversion, these models can be transformed into equations expressing the optimization criteria as function of multiples variables. Even though that theoretical models significantly reduce the experimental requirements for optimizations, these models have been barely used. Instead, most optimizations rely on empirical exploration of the relationships between criterions and variables. There is a need for a strategy to reduce the required number of experiments in multivariated optimization of separations, and Fundamental Models offer a clear opportunity for addressing it. RESULTS: A Fundamental Model is used to give the simultaneous dependence of chromatographic retention of seven ionizable pesticides on the three variables: solvent composition, temperature and pH (w, T, pH). Based on few experiments, the 10 parameters required to predict the chromatographic retention of those compounds, taken as model analytes, can be obtained. Two mathematical treatments to convert retentions into resolutions between pairs are used: one considering extracolumn dispersions and other neglecting these contributions. Using the Overlapped Resolutions Maps, extended to four dimensions, two optimal conditions can be found for the two different mathematical conversions. Chromatographic conditions were empirically evaluated obtaining the best results for the optimization considering extracolumn dispersions, proving that this condition is a true optimal. It was demonstrated that any small shift in any of the variables from this true optimal leads to a loss in resolution. SIGNIFICANCE: Fundamental Models describing chromatographic retention as a simultaneous function of multiple variables are nowadays very accurate. In this work is demonstrated that these models are useful not only to predict retentions, but also to optimize separations, even in the more challenging mode: isocratic, isothermal and iso-pH. However, the success in the optimization procedure depends also on the proper definition of the mathematical conversion of the Fundamental Models into optimization criteria.

Dereplication Tools for Rhizophora mangle Extracts from Different Mangrove Areas and their Potential Against Staphylococcus aureus.

Rhizophora extracts have several potential biological activities, and their metabolites can be used in the pharmaceutical industry. Extracts of Rhizophora species obtained from mangroves have shown prospective activity against Staphylococcus aureus. This study aimed to investigate the chemical profile of Rhizophora mangle leaves from fringe, basin, and transition mangrove zones and their bactericidal/bacteriostatic potential against S. aureus. R. mangle leaves were collected monthly in 2018 from litterfall in three different zones of the mangrove of Guaratiba State Reserve: fringe, basin, and transition. Extracts were prepared from the material collected in October and December for LC-HRMS/MS analysis, and dereplication was performed using a molecular library search and the classical molecular networking GNPS platform. The minimum inhibitory concentrations (MICs) of the aqueous extract of R. mangle against S. aureus were determined. No S. aureus growth was observed compared to the control for extracts collected from September to December. Different compounds were annotated in each region, yet a marked presence of phenolic compounds was noted, among them glycosylated flavonoid derivatives of quercetin and kaempferol. The results suggest bactericidal/bacteriostatic activity for extracts of R. mangle leaves collected in 2018 from three mangrove forest zones.

Assessing antibiotic residues in sediments from mangrove ecosystems: A review.

Antibiotics' widespread and abusive use in aquaculture and livestock leads to extensive environmental dissemination and dispersion, consequently increasing antibiotic-resistant bacteria in marine ecosystems. Hence, there is an increased need for efficient methods for identifying and quantifying antibiotic residues in soils and sediments. From a review of the last 20 years, we propose and compare different chromatographic techniques for detecting and quantifying antibiotics in sediment samples from marine ecosystems, particularly in mangrove forest sediments. The methods typically include three stages: extraction of antibiotics from the solid matrix, cleaning, and concentration of samples before quantification. We address the leading causes of the occurrence of antibiotics in marine ecosystem sediments and analyze the most appropriate methods for each analytical stage. Ultimately, selecting a method for identifying antibiotic residues depends on multiple factors, ranging from the nature and physicochemical properties of the analytes to the availability of the necessary equipment and the available resources.

Identification and Characterization of Rotigotine Degradation Products by HPLC Coupled DAD and CAD Detectors and HRMS Through Q-Orbitrap and Electrospray Ionization.

Rotigotine (RTG) is a dopamine agonist used in the treatment of Parkinson's disease. As it is susceptible to oxidation, stability studies must be carefully designed for the identification and characterization of all possible degradation products. Here, RTG degradation was evaluated according to the International Conference on Harmonization guidelines under various stress conditions, including acidic and basic hydrolysis, oxidative, metallic, photolytic, and thermal conditions. Additionally, more severe stress conditions were applied to induce RTG degradation. Significant degradation was only observed under oxidative and photolytic conditions. The samples were analyzed by high performance liquid chromatography coupled to photodiode array detectors, charged aerosol, and high-resolution mass spectrometry. Chromatographic analyses revealed the presence of eight substances related to RTG, four of which were already described and were qualified impurities (impurities B, C, K and E) and four new degradation products (DP-1 - DP-4), whose structures were characterized by high-resolution mass spectrometry through Q-Orbitrap and electrospray ionization. In the stress testing of the active pharmaceutical ingredient in solid form, significant RTG degradation was observed in the presence of the oxidative matrix. The results corroborate the literature that confirm the high susceptibility of RTG to oxidation and the importance of using different detectors to detect degradation products in forced degradation studies.

Biofilm-producing Escherichia coli O104:H4 overcomes bile salts toxicity by expressing virulence and resistance proteins.

We investigated bile salts' ability to induce phenotypic changes in biofilm production and protein expression of pathogenic Escherichia coli strains. For this purpose, 82 pathogenic E. coli strains isolated from humans (n = 70), and animals (n = 12), were examined for their ability to form biofilms in the presence or absence of bile salts. We also identified bacterial proteins expressed in response to bile salts using sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-electrophoresis) and liquid chromatography-mass spectrometry (LC-MS/MS). Lastly, we evaluated the ability of these strains to adhere to Caco-2 epithelial cells in the presence of bile salts. Regarding biofilm formation, two strains isolated from an outbreak in Republic of Georgia in 2009 were the only ones that showed a high and moderate capacity to form biofilm in the presence of bile salts. Further, we observed that those isolates, when in the presence of bile salts, expressed different proteins identified as outer membrane proteins (i.e. OmpC), and resistance to adverse growth conditions (i.e. F0F1, HN-S, and L7/L12). We also found that these isolates exhibited high adhesion to epithelial cells in the presence of bile salts. Together, these results contribute to the phenotypic characterization of E. coli O104: H4 strains.

Bisphenol A released and ultrastructural changes in dental composite resins

Dental composite resins may release bisphenol-A or similar molecules affecting patient health and the environment. This study measured bisphenol-A release from three commonly used in patients composite resins (Filtek™ Z350 XT, Filtek™ P60, Filtek™ Bulk Fill) immersed in three liquid mediums (artificial saliva, 0.001 M lactic acid and 15% ethanol) and assessed the changes in the surface micromorphology.The released BPA was measured by HPLC at basal time (t=0), 1 h, 1 d, 7 d and 30 d. Topographic analysis of specimens was performed by scanning electron microscopy (SEM). The data were analyzed using one-way ANOVA and Tukey post-hoc test (P < 0.05). BPA in solution increased significantly in the three DCRs immersed in 0.001 M lactic acid at all times. SEM micrographs of the specimen in 0.001 M lactic acid disclosed more structural defects than others. The surface of the three composite resins was morphologically affected by their immersion in all solutions. SEM evidenced that the dental materials underwent erosion and cracks with filler particles protruding from the surface. The morphological changes in tested dental materials produced by exposure to these solutions are potentially dangerous to patients by causing caries, infections, and partial loss of dental material.

Seasonal and Circadian Variation of Non-Volatile Metabolites in Lippia alba Leaves.

The present study describes the seasonal and circadian variations of the major compounds from Lippia alba leaves. SPSS was used to identify, quantify, and associate the variations in the secondary metabolites of this species through HPLC/DAD analysis of the leaves hydroethanolic extracts of six selected L. alba specimens. For the circadian study, the samples were collected at four different daily hours in each year's season. For the seasonal study, the samples were collected monthly from the same individuals for two consecutive years (2018 and 2019). These samples were analyzed and quantified using a validated HPLC method for flavonoids, iridoids, and phenyl ethanoid glycoside. Mussaenoside, acteoside, and tricin-7-O-diglucuronide showed a moderate positive correlation between their biosynthesis and the precipitation index, while epi-loganin had a moderate negative correlation. Acteoside showed a moderate positive correlation between the minimum registered temperature and its production. Compared with previous studies, a drastic reduction (about 95 %) in the production of tricin-7-O-diglucuronide compared with previous study and this difference could be attributed to the plant's aging. Thus, the data demonstrated that lower temperatures and high rainfall could favor the production of the major L. alba active compounds (acteoside and tricin-7-O-diglucuronide) and that older plants harm their production.