Computational modelling of the antischistosomal activity for neolignan derivatives based on the MIA-SAR approach

Theoretical models for exploring the antischistosomal activity of a dataset of 18 synthetic neolignans are built using the multivariate image analysis applied to structure–activity relationships (MIA-SAR) approach. The obtained models were validated using the accuracy (Acc) in leave-one-out cross-validation, external validation and Y-randomization procedures, yielding correct classification superior to 80%, 70% and 60%, respectively. Additionally, a comparison was made of the models obtained from binary (black and white) and coloured images; the colours (pixel values) were selected to correspond to chemical properties. It was observed that the models obtained from coloured images with pixel values corresponding to electronegativity (known as the aug-MIA-SAR_colour approach) generally yielded superior statistical parameters compared with those obtained from binary images (MIA-SAR) and randomly coloured images (atoms are coloured according to their type) with atomic sizes corresponding to Van der Waals radius (aug-MIA-SAR), respectively. Mechanistic interpretation of the influence of different substituents on the antischistosomal activity revealed that methoxy substituents in the R1 (or R2) and R5 positions of the neolignan scaffold are indispensable for the antischistosomal activity. The obtained results provide knowledge of the possible structural modifications to yield novel neolignan compounds with antischistosomal activity.     

Assessment of dispersive liquid–liquid microextraction for the simultaneous extraction,preconcentration, and derivatization of Hg2+ and CH3Hg+ for further determination by GC–MS

This work reports the development of a dispersive liquid – liquid microextraction method for the simultaneous extraction, preconcentration, and derivatization of Hg²⁺ and CH₃Hg⁺ species from water samples for further determination by GC – MS. Some parameters of the proposed method, such as volume and type of disperser and extraction solvent, and Na[B(C₆H₅)₄] concentration were investigated using response surface methodology. Suitable recoveries were obtained using 80 μL C₂Cl₄ (as extraction solvent), 1000 μL ethanol (as disperser solvent), and 300 μL 2.1 mmol/L Na[B(C₆H₅)₄] (as derivatizing agent). Accuracy was evaluated in terms of recovery and ranged from 87 to 99% with RSD values <7%. In addition, a certified reference material of water (NIST 1641d) was analyzed and agreed with the certified value about 107% (for Hg²⁺), with RSD values <8.5%. LODs were 0.3 and 0.2 μg/L, with enrichment factors of 112 and 115 for Hg²⁺ and CH₃Hg⁺, respectively. The optimized method was applied for the determination of Hg²⁺ and CH₃Hg⁺ in tap, well, and lake water samples.     

Low‐level Laser Therapy Ameliorates CCl4‐induced Liver Cirrhosis in Rats

This study investigated the effects of low‐level laser therapy (LLLT) in the liver function, structure and inflammation in a experimental model of carbon tetrachloride (CCl₄)‐induced liver cirrhosis. Wistar rats were divided into Control, LLLT, CCl₄ and CCl₄+LLLT groups. CCl₄ groups received CCl₄ (0.4 g kg^?1; i.p.), three times a week, for 12 weeks. A 830 nm LLLT was performed with a continuous wave, 35 mW, 2.5 J cm^?2 per point, applied to four points of the liver (right and left upper and lower extremities, in the four lobes of the liver) for 2 weeks. Liver structure and inflammation (cirrhotic areas, collagen deposition, inflammation, density of Kupffer and hepatic stellate cells) and function (aspartate aminotransferase, alkaline phosphatase, gamma glutamyltransferase, lactate dehydrogenase, total proteins and globulins) were evaluated. LLLT significantly reduced CCl₄‐increased aspartate aminotransferase (P < 0.001), alkaline phosphatase (P < 0.001), gamma‐glutamyl transferase (P < 0.001) and lactate dehydrogenase (P < 0.01) activity, as well as total proteins (P < 0.05) and globulins (P < 0.01). LLLT also reduced the number of cirrhotic areas, the collagen accumulation and the hepatic inflammatory infiltrate. Of note, LLLT reduced CCl₄‐increased number of Kupffer cells (P < 0.05) and hepatic stellate cells (P < 0.05). We conclude that LLLT presents beneficial effects on liver function and structure in an experimental model of CCl₄‐induced cirrhosis.     

Single-drop microextraction for the determination of manganese in seafood and water samples

We describe a method for single drop microextraction of manganese from fish, mollusk, and from natural waters using the reagent 1-(2-pyridylazo)-2-naphthol as the complexing agent and chloroform as the fluid extractor. After extraction, the analyte was directly submitted to graphite furnace electrothermal atomic absorption spectrometry. Once optimized, the method has a detection limit of 30 ng L^?1, a limit of quantification of 100 ng L^?1, and an enrichment factor of 16. Its accuracy was verified by applying the procedure to the following certified reference materials: apple leaves, spinach leaves, bovine liver, and mussel tissue. The procedure was also successfully applied to the determination of manganese in seafood and natural waters.

Ionization by pH and Anionic Surfactant Binding Gives the Same Thickening Effects of Crosslinked Polyacrylic Acid Derivatives

Physical properties of aqueous solutions of hydrophobically modified crosslinked polyacrylic acids change quite extensively as the polymer is charged up. A study is carried out concerning the similarities between two polymer ionization processes, that is, by pH increment and anionic surfactant addition. The two processes charge the polymer by distinctly different mechanisms. At sufficiently high pH the carboxylic groups of the polymer are virtually all ionized and the polymer is, therefore, fully charged. The effective repulsion among the charged groups due to the entropy of the counterions promotes an increased stiffness as well as an expansion of the polymer particles. We investigate here how the ionization and swelling will be if, instead of high pH, the polymer is at low pH conditions but associated to ionic surfactants. Surfactants associate to the polymer both in a noncooperative way by the binding of individual surfactant molecules and in a cooperative way as micelles since the polymer promotes surfactant self-assembly. This binding leads to a highly charged polymer-surfactant complex and leads to an osmotic swelling as well. The swelling and the gelation were monitored by rheology and dynamic light scattering, of polymer solutions by varying the pHs and adding ionic surfactants at low pH. The results show that ionization by surfactants and by pH lead to approximately the same gelation degree, as can be seen by similar viscosity values. Both processes result in dramatic viscosity increases, up to 8 orders of magnitude. More hydrophobic surfactants, with longer alkyl chain, are shown to be more efficient as enhancers of swelling and gelation. The network that is formed at high pH or at sufficiently high concentration of surfactant can be weakened or even disrupted if monovalent or divalent salts are added, demonstrating the role of counterion entropy.     

The Redox‐Neutral Approach to C?H Functionalization

The direct functionalization of C? H bonds is an attractive strategy in organic synthesis. Although several advances have been made in this area, the selective activation of inert sp³ C? H bonds remains a daunting challenge. Recently, a new type of sp³ C? H activation mode through internal hydride transfer has demonstrated the potential to activate remote sp³ C? H linkages in an atom‐economic manner. This Minireview attempts to classify recent advances in this area including the transition to non‐activated sp³ C? H bonds and asymmetric hydride transfers.     

Preparation and characterization of microcapsules loaded with polyphenols-enriched Uncaria tomentosa extract using spray-dryer technique

Journal of Thermal Analysis and Calorimetry - This work prepared and characterized microcapsule of Uncaria tomentosa (UT) in order to standardize a spray-dryer Uncaria tomentosa extract. The UT...     

Using Design of Experiments to Optimize a Screening Analytical Methodology Based on Solid-Phase Microextraction/Gas Chromatography for the Determination of Volatile Methylsiloxanes in Water

Volatile methylsiloxanes (VMSs) constitute a group of compounds used in a great variety of products, particularly personal care products. Due to their massive use, they are continually discharged into wastewater treatment plants and are increasingly being detected in wastewater and in the environment at low concentrations. The aim of this work was to develop and validate a fast and reliable methodology to screen seven VMSs in water samples, by headspace solid-phase microextraction (HS-SPME) followed by gas chromatography with flame ionization detection (GC-FID). The influence of several factors affecting the extraction efficiency was investigated using a design of experiments approach. The main factors were selected (fiber type, sample volume, ionic strength, extraction and desorption time, extraction and desorption temperature) and optimized, employing a central composite design. The optimal conditions were: 65 µm PDMS/Divinylbenzene fiber, 10 mL sample, 19.5% NaCl, 39 min extraction time, 10 min desorption time, and 33 °C and 240 °C as extraction and desorption temperature, respectively. The methodology was successfully validated, showing low detection limits (up to 24 ng/L), good precision (relative standard deviations below 15%), and accuracy ranging from 62% to 104% in wastewater, tap, and river water samples.     

Antimicrobial Activity of Pyrazinamide Coordination Frameworks Synthesized by Mechanochemistry

The urge for the development of a more efficient antibiotic crystalline forms led us to the disclosure of new antibiotic coordination frameworks of pyrazinamide, a well-known drug used for the treatment of tuberculosis, with some of the novel compounds unravelling improved antimycobacterial activity. Mechanochemistry was the preferred synthetic technique to yield novel compounds, allowing the reproduction of a 1D zinc framework, the synthesis of a novel hydrogen bonding manganese framework, and three new compounds with silver. The structural characterization of the novel forms is presented along with stability studies. The increased antimicrobial activity of the new silver-based frameworks against Escherichia coli, Staphylococcus aureus, and Mycobacterium smegmatis is particularly relevant.     

Metabolomics Insights of the Immunomodulatory Activities of Phlorizin and Phloretin on Human THP-1 Macrophages

Dihydrochalcones, phlorizin (PZ) and its aglycone phloretin (PT), have evidenced immunomodulatory effects through several mechanisms. However, the differential metabolic signatures that lead to these properties are largely unknown. Since macrophages play an important role in the immune response, our study aimed to characterise human THP-1 macrophages under PZ and PT exposure. A multiplatform-based untargeted metabolomics approach was used to reveal metabolites associated with the anti-inflammatory mechanisms triggered by the dihydrochalcones in LPS-stimulated macrophages, for the first time. Results showed differential phenotypic response in macrophages for all treatments. Dihydrochalcone treatment in LPS-stimulated macrophages mimics the response under normal conditions, suggesting inhibition of LPS response. Antagonistic effects of dihydrochalcones against LPS was mainly observed in glycerophospholipid and sphingolipid metabolism besides promoting amino acid biosynthesis. Moreover, PT showed greater metabolic activity than PZ. Overall, the findings of this study yielded knowledge about the mechanisms of action PZ and PT at metabolic level in modulating inflammatory response in human cells.