Capillary electrophoresis-diode array detection--electrospray mass spectrometry for the analysis of selected tropane alkaloids in plant extracts

Capillary zone electrophoresis, coupled to UV and interfaced with electrospray ionization mass spectrometry (ESI-MS), is described for the simultaneous analysis of hyoscyamine and scopolamine. On-line UV detection occurred at 22 cm from the inlet of the capillary and ESI-MS monitoring was performed along the entire length of the capillary (85 cm). An alkaline solution of 40 mM ammonium acetate at pH 8.5 was suitable for the analysis of the alkaloids under consideration. Under the optimized conditions, including CE and ESI-MS parameters, the two alkaloids were resolved within a short time and with very high sensitivity. The differentiation of hyoscyamine and its positional isomer littorine, commonly encountered in plant material, is also presented using up-front collision-induced dissociation. Finally, the developed method was applied to the analysis of these alkaloids in Belladonna leaf extract and in Datura candida x D. aurea hairy root extract.     

Green and sustainable chemistry in Latin America: Which type of research is going on? And for what?

Green (and sustainable?) frame around ‘Inverted America’ (adapted from Torres García, 1943, Museo Juan Manuel Blanes, Montevideo, CC BY 4.0).

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A Sustainable Freeze‐Drying Route to Porous Polysaccharides with Tailored Hierarchical Meso‐ and Macroporosity

Bio‐derived polysaccharide aerogels are of interest for a broad range of applications. To date, these aerogels have been obtained through the time‐ and solvent‐intensive procedure of hydrogel fomation, solvent exchange, and scCO2 drying, which offers little control over meso/macropore distribution. A simpler and more versatile route is developed, using freeze drying to produce highly mesoporous polysaccharide aerogels with various degrees of macroporosity. The hierarchical pore distribution is controlled by addition of different quantities of t‐butanol (TBA) to hydrogels before drying. Through a systematic study an interesting relationship between the mesoporosity and t‐butanol/water phase diagram is found, linking mesoporosity maxima with eutectic points for all polysaccharides studied (pectin, starch, and alginic acid). Moreover, direct gelation of polysaccharides in aqueous TBA offers additional time savings and the potential for solvent reuse. This finding is a doorway to more accessible polysaccharide aerogels for research and industrial scale production, due to the widespread accessibility of the freeze drying technology and the simplicity of the method.

     

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.     

The harmonic inversion of the field-swept fixed-frequency resonance spectrum

When the spin Hamiltonian is a linear function of the magnetic field intensity the resonance fields can be determined, in principle, by an eigenfield equation. In this report, we show a new technical approach to the resonance field problem where the eigenfield equation leads to a dynamic equation or, more specifically, to a first order differential equation of a variable L(x), where x is associated with the magnetic field h. Such differential equation has the property that: its stationary solution is the eigenfield equation and the spectral information contained in L(x) is directly related to the resonance spectrum. Such procedure, known as the "harmonic inversion problem" (HIP), can be solved by the "filter diagonalization method" (FDM) providing sufficient precision and resolution for the spectral analysis of the dynamic signals. Some examples are shown where the resonance fields are precisely determined in a single procedure, without the need to solve eigenvalue equations.     

A Combined Experimental and Theoretical Study on the Formation of Ag Filaments on β‐Ag2MoO4 Induced by Electron Irradiation

A combined experimental and theoretical study is presented to understand the novel observed nucleation and early evolution of Ag filaments on β‐Ag₂MoO₄ crystals, driven by an accelerated electron beam from an electronic microscope under high vacuum. The growth process, chemical composition, and the element distribution in these filaments are analyzed in depth at the nanoscale level using field‐emission scanning electron microscopy (FE‐SEM) and transmission electron microscopy (TEM) with energy‐dispersive spectroscopy (EDS) characterization. To complement experimental results, chemical stability, structural and electronic aspects have been studied systematically using first‐principles electronic structure theory within a quantum theory of atoms in molecules (QTAIM) framework. The Ag nucleation and formation on β‐Ag₂MoO₄ are a result of structural and electronic changes of the AgO₄ tetrahedral cluster as a constituent building block of β‐Ag₂MoO₄, consistent with Ag metallic formation. The formation of Ag filament transforms the β‐Ag₂MoO₄ semiconductor from n‐ to p‐type concomitant with the appearance of Ag defects.     

Photodynamic Activity on Biofilm in Endotracheal Tubes of Patients Admitted to an Intensive Care Unit

Ventilator-associated pneumonia (VAP) is an infection that arises after endotracheal intubation affecting patients under intensive care. The presence of the endotracheal tube (ETT) is a risk factor since it is colonized by multispecies biofilm. Antimicrobial photodynamic therapy (aPDT) could be a strategy to decontaminate ETTs. We verify if methylene blue (MB) associated with external illumination of the ETT could be an alternative to destroy biofilm. We performed an in vitro and ex vivo study. In vitro study was performed with P. aeruginosa biofilm grew over ETT for 7 days. After treatment, the surviving cells were cultured for 3 days and the biofilm was analyzed by crystal violet absorbance. Ex vivo study employed ETT obtained from extubated patients. aPDT was performed with MB (100 µm ) and red LED (λ = 640±20 nm). We quantified the biofilm thickness and used scanning electron microscopy and fluorescence technique to verify morphological and functional changes after aPDT. Our results showed that bacteria remain susceptible to aPDT after sequential treatments. We also attested that aPDT can reduce biofilm thickness, disrupt biofilm attachment from ETT surface and kill microbial cells. These data suggest that aPDT should be investigated to decrease VAP incidence via ETT decontamination.     

Potential Anti-Inflammatory Effect of Rosmarinus officinalis in Preclinical In Vivo Models of Inflammation

This systematic review aimed to evaluate the potential anti-inflammatory effect of Rosmarinus officinalis in preclinical in vivo models of inflammation. A search was conducted in the databases PubMed, Scopus, and Web of Science, with related keywords. The inclusion criteria were inflammation, plant, and studies on rats or mice; while, the exclusion criteria were reviews, studies with in vitro models, and associated plants. The predominant animal models were paw edema, acute liver injury, and asthma. Rosemary was more commonly used in its entirety than in compounds, and the prevalent methods of extraction were maceration and hydrodistillation. The most common routes of administration reported were gavage, intraperitoneal, and oral, on a route-dependent dosage. Treatment took place daily, or was single-dose, on average for 21 days, and it more often started before the induction. The most evaluated biomarkers were tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-10, myeloperoxidase (MPO), catalase (CAT), glutathione (GSH), glutathione peroxidase (GPx), malondialdehyde (MDA), and superoxide dismutase (SOD). The best results emerged at a dose of 60 mg/kg, via IP of carnosic acid, a dose of 400 mg/kg via gavage of Rosmarinus officinalis, and a dose of 10 mg/kg via IP of rosmarinic acid. Rosmarinus officinalis L. showed anti-inflammatory activity before and after induction of treatments.     

Oral fluid/plasma cannabinoid ratios following controlled oral THC and smoked cannabis administration

Oral fluid (OF) is a valuable biological alternative for clinical and forensic drug testing. Evaluating OF to plasma (OF/P) cannabinoid ratios provides important pharmacokinetic data on the disposition of drug and factors influencing partition between matrices. Eleven chronic cannabis smokers resided on a closed research unit for 51 days. There were four 5-day sessions of 0, 30, 60, and 120 mg oral ?⁹-tetrahydrocannabinol (THC)/day followed by a five-puff smoked cannabis challenge on Day 5. Each session was separated by 9 days ad libitum cannabis smoking. OF and plasma specimens were analyzed for THC and metabolites. During ad libitum smoking, OF/P THC ratios were high (median, 6.1; range, 0.2–348.5) within 1 h after last smoking, decreasing to 0.1–20.7 (median, 2.1) by 13.0–17.1 h. OF/P THC ratios also decreased during 5-days oral THC dosing, and after the smoked cannabis challenge, median OF/P THC ratios decreased from 1.4 to 5.5 (0.04–245.6) at 0.25 h to 0.12 to 0.17 (0.04–5.1) at 10.5 h post-smoking. In other studies, longer exposure to more potent cannabis smoke and oromucosal cannabis spray was associated with increased OF/P THC peak ratios. Median OF/P 11-nor-9-carboxy-THC (THCCOOH) ratios were 0.3–2.5 (range, 0.1–14.7) ng/μg, much more consistent in various dosing conditions over time. OF/P THC, but not THCCOOH, ratios were significantly influenced by oral cavity contamination after smoking or oromucosal spray of cannabinoid products, followed by time-dependent decreases. Establishing relationships between OF and plasma cannabinoid concentrations is essential for making inferences of impairment or other clinical outcomes from OF concentrations.     

On the structure of inner ideals of nest algebras

IfA is a nest algebra andA _s=A ∩ A* , whereA* is the set of the adjoints of the operators lying inA, then the pair (A, A _s) forms a partial Jordan *-triple. Important tools when investigating the structure of a partial Jordan *-triple are its tripotents. In particular, given an orthogonal family of tripotents of the partial Jordan *-triple (A, A _s), the nest algebraA splits into a direct sum of subspaces known as the Peirce decomposition relative to that family. In this paper, the Peirce decomposition relative to an orthogonal family of minimal tripotents is used to investigate the structure of the inner ideals of (A, A _s), whereA is a nest algebra associated with an atomic nest. A property enjoyed by inner ideals of the partial Jordan *-triple (A, A _s) is presented as the main theorem. This result is then applied in the final part of the paper to provide examples of inner ideals. A characterization of the minimal tripotents as a certain class of rank one operators is also obtained as a means to deduce the principal theorem.