Extraction Chemistry Research Articles

Chemical and mechanistic modelling of green solvent extraction of metallic species with 4-acylpyrazolones

Solvent extraction chemistry of metals needs the use of suitable organic ligands like 4-acylpyrazolones to coordinate the studied cation, to make it soluble in an organic phase and then allow its phase transfer from the aqueous phase. The competitive solvent extraction test of almost 25 metal ions by one powerful ligand, i.e. 3-methyl-1-phenyl-4-(4-trifluoromethylbenzoyl)-pyrazol-5-one diluted in one ionic liquid ([C1Cnim+][Tf2N−]) has been conducted to get a snapshot of its efficacy. Effect of diluents on the liquid–liquid extraction of 4f-ions with a series of chelating ligands of 4-acylpyrazolones family (∼5) is presented comparing ionic liquids and typical organic diluents: 14 in number. In addition, the solvent extraction of 12 refractory metals with a series of chelating extractants is investigated in five diluents: four 4-acylpyrazolones with different radicals. The solvent extraction stoichiometry of MoO42− and Zr4+ is studied in detail using molecular and ionic diluent for comparative purposes through slope analysis method. Ethylene glycol is used to develop a non-aqueous process for Gd3+ switchable extraction, i.e. boost of two immiscible organic phases. Furthermore, EPR, NMR, IR and DTA-TG-MS spectroscopies have been used to study the extracted d- and f-species in the obtained organic extracts in ionic liquid solutions.

Improving DNA recovery and sample throughput using the PrepFiler™ Automated Forensic DNA Extraction Kit on two customised Tecan Fluent® 1080 Automated Workstations

One of the primary goals of forensic laboratories performing DNA recovery and profiling is obtaining a high-quality DNA extract from crime scene samples. This is largely dependent on the sensitivity and reliability of the DNA extraction chemistry utilised, as well as the liquid handling and contamination minimisation techniques employed. Automation of DNA extraction methods on large liquid handling platforms allows high-throughput laboratories to apply sensitive chemistries to reliably process a large number of samples, while minimising manual processes and cross-contamination.This study describes the first known implementation of the PrepFiler™ Automated Forensic DNA Extraction Kit on a Tecan Fluent® Gx 1080 Automation Workstation. Two Workstations were customised with the addition of novel “Safe Pipetting Modules” to eliminate sample crossover between wells, which is important in a forensic biology setting to reduce inadvertent DNA transfer. A comparison of DNA extraction efficiency between an optimised PrepFiler™ method and the DNA IQ™ System performed on a Perkin Elmer Janus® Integrator platform showed the optimised PrepFiler™ method consistently extracted a higher yield of DNA from a range of blood inputs, as well as blood and buccal swabs. The PrepFiler™ chemistry also more efficiently removed humic acid and haematin, reducing subsequent PCR inhibition. The subsequent implementation of the optimised PrepFiler™ method onto the Tecan Fluent® Gx workstations showed a further increase in sensitivity, with no evidence of DNA cross-contamination observed. However, the optimised PrepFiler™ method encountered difficulties extracting DNA from fabric substrates, with the PrepFiler Express™ chemistry extracting higher yields on the cartridge-based AutoMate Express™ System.Overall, this study demonstrated the Tecan Fluent® Gx 1080 Automation Workstation is a sensitive, reliable and robust method for DNA extraction using the PrepFiler™ Automated Forensic DNA Extraction Kit, and the addition of the novel Safe Pipetting Module makes this platform an attractive option for forensic biology laboratories where minimising inadvertent DNA transfer is of paramount importance.

Micro-sample Nd isotopic measurement on reference rock powders via the thermal ionization mass spectrometer Nd+ mode

The Sm–Nd isotopic system has been broadly utilized for dating and tracing in earth and planetary sciences. However, low Nd+ ionization efficiency permanently hinders precise and accurate measurements on small amounts of Nd samples. So far, isotopic measurement of micro-amount Nd sample via thermal ionization mass spectrometry (TIMS) Nd+ mode was mostly performed on Nd reference solutions, but less on natural rock or mineral samples. In the present study, analytical procedures to measure isotopic composition via the TIMS Nd+ mode were designed for natural rock powders by using 1–5 ng pure Nd. The analytical technique was refined through low-blank sample digestion, small-column chemistry for Nd extraction from matrix elements, loading Nd using purified H3PO4 solution, and careful heating of filaments before data acquisition. Measurements on small Nd amounts (1 ng–5 ng) of either the JNdi-1 reference solution or four reference rock powders yielded satisfactory results of 143Nd/144Nd value with respect to precision and accuracy. The analytical results agree well with the recommendation values of the reference materials within analytical errors and the internal precision is better than ±0.005 % (2RSE). When using 1 ng or 2 ng Nd amounts, 144Nd ion flow can remain stable in a signal intensity of >100 mV, and without the assistance of an additional ionization enhancer. Therefore, the analytical procedure, featured by low procedural blank (about 10–22 pg), high Nd+ ionization efficiency, and easy operation, has broad prospects for the application of Nd isotope in single-grain minerals or micro-samples.

Chemical composition and bioactivity variability of two-step extracts derived from traditional and “QiNan” agarwood (Aquilaria spp.)

One of the primary applications for agarwood lies in the extracts, instead, there are obvious differences in the demands for agarwood components with different application fields. To obtain the rough separation and clarify each part's activity, four extracts of essential oil, hydrolat, extractum, and ethanol precipitation from traditional agarwood (TraA) and “Qinan” agarwood (QinA) were obtained by steam-solvent multistage extraction and ethanol precipitation. We investigated the chemistry and biological activity of multistage extracts using gas chromatography–mass spectrometry (GC–MS), high-performance liquid chromatography (HPLC), and in vitro activity testing. The results demonstrated that two kinds of agarwood essential oils contained mainly sesquiterpenoids, yet the sesquiterpene species were remarkably diverse in two kinds of agarwood essential oils. Then, the TraA and QinA hydrolat, all predominantly aromatic and sesquiterpene, but with differences from the essential oil ingredients. Additionally, the extractum chiefly contained chromones and the ethanol precipitation method worked well to separate the impurities in the TraA extract, however, it was ineffective for the QinA extract. Ultimately, essential oils and extractums all have antioxidant properties, with extractums outperforming essential oils. Moreover, both extractums and essential oils exhibited excellent broad-spectrum antimicrobial activity and anti-inflammatory activity. The findings pointed to the feasibility of separating the primary components from TraA and QinA using a multi-stage extraction technique, providing a scientific basis for the efficient utilization of all components of agarwood, as well as the functional product development and differentiated utilization of extract products in incense, fragrance, perfume, and daily chemicals.

Chemistry of plant extracts directs the silver nanostructures’ crystal structure into hexagonally close-packed: a comparative study using elecampane and blueberry extracts

In this study, silver nanostructures (AgNSs) were obtained using aqueous extracts of elecampane ( Inula viscosa) and blueberry ( Vaccinium arctostaphylos L.). The synthesized AgNSs were characterized using UV–visible spectrophotometers, Fourier-transformed infrared spectroscopy, scanning electron microscopy-energy dispersive X-ray analysis, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. The optimization studies revealed that pH and the extract/AgNO3 ratio played significant roles in the morphology and size of the AgNSs, while temperature did not show any significant role. Both the blueberry and elecampane extracts resulted in a mixture of spherical and aspherical silver nanoparticles (AgNPs). In contrast, utilization of a relatively high extract/AgNO3 ratio accompanied by an extended incubation period (i.e., 10 days) caused the formation of larger spherical (e.g., up to micron-sized) and large 1D AgNPs for the blueberry and elecampane extracts, respectively. The major difference related to the crystal structures was obtained, as the blueberry extracts resulted in face-centric cubic crystals, and the elecampane extracts allowed the formation of hexagonally close-packed (hcp) crystalline structures. The AgNPs were tested for their antibacterial activities using gram (−) and gram (+) bacterial species, where the elecampane-synthesized AgNPs possessed higher antibacterial activity that can be attributed to the hcp crystalline structure of the AgNPs.

Unraveling the “Gap‐Filling” Mechanism of Multiple Charge Carriers in Aqueous Zn‐MoS2 Batteries

AbstractThe utilization rate of active sites in cathode materials for Zn‐based batteries is a key factor determining the reversible capacities. However, a long‐neglected issue of the strong electrostatic repulsions among divalent Zn2+ in hosts inevitably causes the squander of some active sites (i.e., gap sites). Herein, we address this conundrum by unraveling the “gap‐filling” mechanism of multiple charge carriers in aqueous Zn‐MoS2 batteries. The tailored MoS2/(reduced graphene quantum dots) hybrid features an ultra‐large interlayer spacing (2.34 nm), superior electrical conductivity/hydrophilicity, and robust layered structure, demonstrating highly reversible NH4+/Zn2+/H+ co‐insertion/extraction chemistry in the 1 M ZnSO4+0.5 M (NH4)2SO4 aqueous electrolyte. The NH4+ and H+ ions can act as gap fillers to fully utilize the active sites and screen electrostatic interactions to accelerate the Zn2+ diffusion. Thus, unprecedentedly high rate capability (439.5 and 104.3 mAh g−1 at 0.1 and 30 A g−1, respectively) and ultra‐long cycling life (8000 cycles) are achieved.

Supramolecular chemistry of liquid-liquid extraction.

Liquid-Liquid Extraction (LLE) is a venerable and widely used method for the separation of a targeted solute between two immiscible liquids. In recent years, this method has gained popularity in the supramolecular chemistry community due to the development of various types of synthetic receptors that effectively and selectively bind specific guests in an aqueous medium through different supramolecular interactions. This has eventually led to the development of state-of-the-art extraction technologies for the removal and purification of anions, cations, ion pairs, and small molecules from one liquid phase to another liquid phase, which is an industrially viable method. The focus of this perspective is to furnish a vivid picture of the current understanding of supramolecular interaction-based LLE chemistry. This will not only help to improve separation technology in the chemical, mining, nuclear waste treatment, and medicinal chemistry sectors but is also useful to address the purity issue of the extractable species, which is otherwise difficult. Thus, up-to-date knowledge on this subject will eventually provide opportunities to develop large-scale waste remediation processes and metallurgy applications that can address important real-life problems.

Evaluation of solid-phase extraction sorbents for purification of oligosaccharides and glycans derivatized by positively charged labels followed by capillary electrophoretic analysis.

The sample preparation including labeling and clean-up represents a key analytical step in the analysis of oligosaccharides and glycans by either chromatographic or electrophoretic separation methods. Although the majority of labeling has been performed by neutral and/or negatively charged tags, the introduction of a positive charge into the saccharide molecule can significantly improve the analysis, especially with mass spectrometry detection. In this work, we present the evaluation of five solid-phase extraction sorbents differing in extraction chemistry for the clean-up and concentration of positively labeled maltooligosaccharides from the reaction mixtures. Maltooligosaccharides containing four to seven glucose units were labeled by cationic tags (2-aminoethyl)trimethylammonium chloride and (carboxymethyl)trimethylammonium chloride hydrazide and the extraction conditions were optimized followed by electrophoretic analysis with conductivity detection. The effects of the solid-phase extraction sorbent chemistry, extraction conditions, and sample composition are discussed. All tested sorbents were capable of cleaning up maltooligosaccharides from the reaction mixtures to some extent after optimization of the solid-phase extraction procedure (51.9%-98.9% recovery). The best-rated amide-based sorbent was used to process the sample of N-linked glycans enzymatically released from ribonuclease B.

Hydrophobic natural deep eutectic solvents for marine lipid extraction

Abstract‘Type V' natural deep eutectic solvents (TV NADES) are a novel class of solvent media with many potential ‘green chemistry’ applications. Here, we assess the potential of two TV NADES: menthol:carvacrol (M:C) and menthol:thymol (M:T), and a single terpenoid extraction media carvacrol (C), as media from total lipid extraction of three compositionally diverse, freeze‐dried marine tissues: hoki (Macruronus novaezelandaiae), jack mackerel (Trachurus declivis) and green‐lipped mussel (kuku, Perna canaliculus). Room temperature extraction yields into these media were benchmarked relative to lipid yields from chloroform‐methanol‐water extractions. Relative extraction yields using the M:C and M:T media were (both) 87% for jack mackerel, 85%–87% for hoki, and 43%–47% for green‐lipped mussels. Comprehensive chemical analyses of TV NADES lipid extracts suggested that neutral lipids were extracted in greater yield than phospholipids, and that phosphatidylinositol, lysophospholipids and (in the case of mussels) ceramideaminoethylphosphonates were particularly resistant to extraction into C, M:C and M:T. C—a thymol isomer that, unlike menthol and thymol is a liquid at room temperature—appeared to perform (marginally) better than M:C and M:T systems, implying there may be no advantage to using the TV NADES over a single terpenoid with similar chemistry for total lipid extraction.

Altitudinal variability in chemical profile and pesticidal properties of Zingiber roseum (Roxb.) Roscoe extracts

Plant extracts are considered as a promising alternative to chemical pest control agents. The chemistry of plant extracts varies with several environmental as well as geographical factors. Zingiber roseum (Roxb.) Roscoe also known as “Rosy Ginger” and “Jangli Adrak” is one of the most important aromatic and medicinal plant of family Zingiberaceae. The present study aimed to investigate the impact of altitude on the chemical composition, nematicidal and herbicidal activity of Z. roseum rhizome and seed extracts. The plants were collected from three different altitudes of Kumaun, Uttarakhand representing different environmental conditions. The extracts were prepared in acetone using cold percolation method. The compositional variation in chemical constituents of the extracts was determined by gas chromatography-mass spectrometry (GC–MS) analysis. The yield and chemical composition of extracts showed a significant altitudinal impact. Nematicidal activity of extracts was performed against Meloidogyneincognita. Results showed that the extracts exhibited significant nematode mortality irrespective of the altitudinal gradients. A significant correlation of altitudinal gradient was observed for the nematode egg hatchability reduction for the rhizome extracts. It was observed that plants growing at higher altitudes had better egg hatchability reduction (86.42 ± 2.30% at 1000 μg/mL after 96 h), compared with those growing at lower elevations. The herbicidal activity of rhizome and seed extracts was performed against radish and chicory seeds and the extracts showed different level of intensity of germination percentage, root and shoot length inhibition. In silico molecular docking was conducted to screen the nematicidal activity of major and potent compounds with the crystalline structure of Glutathione S-transferases (GSTs) of Caenorhabditis elegans and Wuchereria bancrofti, and Glutathione S-transferase-1 (GST-1) of M. incognita. Based on the current study, extract of Z. roseum may be regarded as potential nematicidal and herbicidal agents and may have potential application as botanicals.

Microbial pigments: Eco-friendly extraction techniques and some industrial applications

Since ancient times, natural coloring agents have been produced from plants, insects, animals, and ores. Although they have a dangerous impact on mammals and the environment, synthetic dyes replace natural colors because of their limited availability throughout the year; instability in light, heat, and pH; increased global demand; and low water solubility. Therefore, pigments from microbial sources are considered the best alternatives to natural pigments. The potential of microbial pigments for easy mass production, diversified coloring properties, and inexpensive production is now receiving the attention of researchers and industries. Most industrial extraction processes are based on traditional liquid-liquid systems that use organic solvents for the extraction of pigments. The environmental pollution generated by these chemicals has become a central issue in societal and political decisions. This has led to a growing demand for efficient eco- friendly extraction technologies. In the last two decades, significant advances have been made in the green chemistry of pigment extraction and separation techniques. Methods such as ultrasound-assisted extraction, microwave-assisted extraction, pressurized liquid extraction, enzyme-assisted extraction, and more recently, ionic liquid-assisted extraction have been developed. This review summarizes the methods for the simple and eco -friendly extraction of microbial pigments for applications in the food and textile sectors.

Changes in Soil Sulphur Fractions as Influenced by Nutrient Management Practices in Mulberry

Sulphur (S) plays a vital role in improving the quality of mulberry leaves because of its involvement in protein synthesis. The knowledge of different pools of S in soils and its bioavailability for mulberry nutrition is thus, required for optimizing S fertilization. Hence, the present study was designed to ascertain the influence of chemical fertilizer and farmyard manure (both are S sources) on S fractions and its bioavailability in soils. In this regard, four nutrient management practices viz., control (without any chemical fertilizers and organic manures), recommended doses of N, P and K fertilizers (100% RDF), 80% RDF, 60% RDF with four mulberry varieties viz., V-1, G-4, AGB-8 and MSG-2 besides a fallow were considered for the study. Furthermore, the bioavailability of S in soils was tested using four commonly used chemical extractants viz., CaCl2, NaHCO3, AB-DTPA and Mehlich-3 (with different modes and chemistry of extraction). Organic S was the dominant fraction in the experimental soils accounting for 94.7% of total soil S while the inorganic fraction constituted only 5.3% that includes water soluble, sorbed and carbonate occluded S. Lowest amount of organic S content in soils of unmanured control (579.6 mg kg−1) was observed while the 100% RDF treatment (673.2 mg kg−1) maintained a higher content of soil organic S. High amount of sorbed and occluded S was observed in control plot compared to other fertilizer treatments (100% RDF, 80% RDF and 60% RDF). There was a gradual decline in soil S fractions when the fertilizer inputs were reduced to 60% suggesting that recommended doses of fertilizer inputs could maintain the soil S fractions. In addition, the extractable fractions of S were influenced by the fertilizer application rates and the extractability of all four extractants decreased with the reduction in fertilizer inputs. The amount of S extracted by all four chemical extractants followed the order of NaHCO3 > Mehlich-3 > AB-DTPA > CaCl2 across the tested soils. Dynamic relationships among the extractants indicated that they could extract the S from the same pools in soil. Of the four extractants tested for evaluating plant available S, Mehlich-3 showed a higher degree of correlations with plant tissue S concentration and applied S through chemical fertilizers and farmyard manure. Furthermore, it could maintain strong correlations with water soluble and organic S fractions which were found to contribute significantly to plant S concentration. Thus, Mehlich-3 can be recommended for the assessment of bioavailable S for the nutrition of mulberry.

Willow bark proanthocyanidins with potential for water treatment: Chemical characterization and zinc/bisphenol A removal

This study investigates the chemical structure of proanthocyanidin-rich crude extracts from willow bark and these materials were tested initially as adsorbents for artificial (waste)water treatment. The crude extracts were obtained through mild water extraction and the colorant fractions were further chromatographically fractionated to understand the chemical structure of the willow bark proanthocyanidins. The chemistry of crude extracts and purified fractions were investigated using nuclear magnetic resonance (NMR) and ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Both NMR (liquid and solid-state) and UPLC-MS/MS suggest that the crude extracts constitute of interflavan linked flavan-3-ols, i.e. proanthocyanidins with both procyanidin (PC)-type and prodelphinidin (PD)-type subunits, with the PC/PD ratio of approximately 2.3–2.5. PD-type proanthocyanidins were detected from the purified colorant fractions only with UPLC-MS/MS. Both the UPLC-MS/MS and size exclusion chromatography suggest that the crude extracts have an average oligomerization degree of roughly 5–6 flavan-3-ol units. Adsorption experiments showed that the activated foams made of crude extracts were effective in removing both zinc and Bisphenol A (BPA) with removal efficiencies of roughly 80–90% and thus these willow bark-derived proanthocyanidins are promising in water treatment. The significance of this study suggests the upgrading use of crude extracts for water treatment could significantly improve the value of willow bark.

Sequential hydrothermal extraction chemistry for recovering bioactives from potato peels

Sequential Hydrothermal Extraction (SeqHTE) provides a versatile platform to produce phytochemicals from potato peels. However, there is a lack of understanding of the SeqHTE reaction mechanisms and pathways. In this study, the chemistry of SeqHTE for the recovery of valuable bioactives from peels was investigated. The slightly more polar conditions of the first stage of SeqHTE favored the retrieval of free form polyphenols and extraction of polysaccharides and glycoalkaloids. In contrast, the second stage displayed preferential recovery of bound-type polyphenols and extraction of solanidine. The acid-catalyzed acyl bimolecular and the unimolecular nucleophilic substitution reaction mechanisms were identified. Additionally, the kinetics indicated that the ideal conditions to enhance bioactive recovery while reducing degradation were a temperature range from 140 ℃ to 160 ℃ and 170–190 ℃ for the first and second stage, respectively. The results demonstrated that SeqHTE offers a suitable environment to break down the peels for the recovery of structurally diverse bioactives.

Phytochemical Composition and Antibacterial Properties of Surface Extracts of Six Salvia Species

The chemistry and biological activity of cuticular waxes and the secondary metabolites produced in the indumentum of different plant organs has been attracting the interest of botanists. This work was aimed to investigate the chemistry and antibacterial activity of the surface extracts (SE) of different organs of six Salvia species. The cuticles and indumenta of the leaves, calyxes, and stems of Salvia atropatana Bunge., S. lachnocalyx Hedge., S. ceratophylla L., S. palaestina Benth., S. persepolitana Boiss., and S. hydrangea DC. ex Benth. were extracted with dichloromethane. The SEs were analyzed using gas chromatography-mass spectrometry (GC/MS). The antibacterial activity of each extract was assessed against Escherichia coli, Staphylococcus epidermidis, and Bacillus subtilis strains using the agar disc diffusion bioassay. The yields of extracts were in the range from 1.1- 2.3% w/w, while the detected compounds constituted 59.3-95.4% of the total extract composition. All species except S. persepolitana contained the sesquiterpenes, including β-caryophyllene (0.5-19.5%) and germacrene D (0.4-12.9%), while sclareol (2.1-75.6%) was the major labdane diterpenoid in the examined Salvia species excepting S. hydrangea. In addition to terpenoids, the analyzed SEs contained long-chain n-alkanes, fatty acids, alcohols, and aldehydes in the range from 4.8-78.5%. E. coli was the most susceptible microorganism to the tested extracts of S. persepolitana calyxes and stems (20 and 18 mm) and the S. lachnocalyx stems (17 mm), respectively. The antibacterial properties of the SEs of the plants suggested their protective role against pathogenic microorganisms, which can be attributed to their major phytochemicals such as sclareol and abienol.

1248. Relationship Between ALT and New HBV Biomarkers in HBV/HIV Coinfected Persons Started on Antiviral Therapy

Abstract Background While HBV DNA has served as a primary biomarker of HBV infection, newer biomarkers including pre-genomic HBV RNA (pgRNA) and quantitative HBV surface antigen (qHBsAg) may prognosticate treatment responses better. We analyzed the changes in these biomarkers over time following initiation of antiviral therapy in persons living with HIV (PLWH) to determine the relationship to ALT, a key marker of liver injury. FigureBiomarker changes Methods NIH AIDS Clinical Trials Group Study 5127 enrolled HBV/HIV PLWH into a Phase 2 treatment trial that randomized them to receive 48 weeks of either tenofovir (TDF) or adefovir (ADV). ALT and HBV DNA were evaluated as measures of treatment response. Stored samples were tested for HBV pgRNA and qHBsAg at baseline, 4, 12, 24, 36, and 48 weeks. HBV pgRNA was isolated using RNA-selective extraction chemistry followed by a multiplex RT-qPCR that targets the HBV X and core targets on the m2000 system (Abbott Molecular, Des Plaines, Illinois). A sensitive second-generation assay with a lower limit of quantification (LLOQ) of 10 copies/mL was utilized. Quantitative HBsAg was determined by Abbott ARCHITECT (List# 6C36) with a LLOQ of 0.05 IU/mL. Data were analyzed using SAS® version 9.4. Results Overall, 47 study participants had sufficient samples for biomarker testing. Participants were predominantly male (93.6%) and identified as white, non-Hispanic (55.3%) or black (34%). Groups were evenly randomized to receive either TDF (n=23) or ADV (n=24). Baseline ALT mean was 64.9 U/L, and HBV DNA was 9.1 (+1.6) copies/mL. Pre-treatment pgRNA serum concentration was 7.0 (+1.3) log U/mL, and qHBsAg was 195,574 (+272,190) IU/mL. Over the course of treatment, pgRNA was significantly correlated with the change in serum ALT levels (r=0.48; p=0.0035) but not HBV DNA (r=0.21; p=0.226). ALT was negatively correlated with qHBsAg (r=-0.52; p=0.02). pgRNA was also highly negatively correlated with qHBsAg (r=-0.49l; p=0.03) but not HBV DNA (r=0.13; p=0.59). (Figure). Conclusion HBV pgRNA is a better predictor of ALT change – a key measure of hepatocyte injury – than HBV DNA in PLWH who are initiated on nucleotide/nucleoside therapy. Quantitative HBsAg is inversely associated with ALT levels, supporting the hypothesis that HBsAg inhibits immune mediated injury to hepatocytes. Disclosures Michael E. Stec, MSc, Abbott Laboratories: Employee of Abbott|Abbott Laboratories: Stocks/Bonds mark C. Anderson, PhD, Abbott Laboratories: Employment|Abbott Laboratories: Stocks/Bonds Marion G. Peters, MD, Aligos: Advisor/Consultant|antios: Advisor/Consultant|Excision Biotherapeutics: DSMB Gavin Cloherty, PhD, Abbott: Employee|Abbott: Stocks/Bonds|Abbott Labs: Employee.

Caucasian Blueberry: Comparative Study of Phenolic Compounds and Neuroprotective and Antioxidant Potential of Vaccinium myrtillus and Vaccinium arctostaphylos Leaves

(1) Background: Two Caucasian blueberries Vaccinium myrtillus L. and Vaccinium arctostaphylos L. are famous berry bushes growing in the Caucasus region and used to treat neurological diseases, but the chemistry and bioactivity of leaf extracts are still poorly studied. (2) Methods: Phenolic compounds of V. myrtillus and V. arctostaphylos leaf extracts were profiled and quantified by HPLC-PDA-ESI-tQ-MS. The neurotropic potential of Vaccinium extracts was studied using the model of middle cerebral artery permanent occlusion to determine cerebral blood flow, the area of the brain tissue necrosis, and antioxidant enzyme activity (including superoxide dismutase, succinate dehydrogenase, and cytochrome C oxidase), as well as the concentration of TBARS. (3) Results: Hydroxycinnamates and flavonoids were identified in the leaves of V. myrtillus and V. arctostaphylos, and the dominant metabolite of both extracts was 5-O-caffeoylquinic acid in the amount of 105-226 mg/g. The studied extracts enhanced the cerebral hemodynamics and decreased the frequency of necrotic and lipooxidative processes in the brain tissue, accompanied by an increase in the activity of antioxidant enzymes. The positive effect of V. arctostaphylos was stronger and exceeded the effectiveness of Ginkgo biloba standardized extract. (4) Conclusion: The leaf extracts of Caucasian blueberries V. myrtillus and V. arctostaphylos as a new source of hydroxycinnamates demonstrated a protective effect of the brain ischemia pathology and can be used as therapeutic agents to treat neurological diseases.

Assessment of the Equilibrium Constants of Mixed Complexes of Rare Earth Elements with Acidic (Chelating) and Organophosphorus Ligands

A survey of the experimental equilibrium constants in solution for the mixed complexes of 4f ions with acidic (chelating) and O-donor organophosphorus ligands published in the period between 1954 and 2022 is presented. These data are widely used in both analytical and solvent extraction chemistry. Important data evaluation criteria involved the specification of the essential reactions, process conditions and the correctness of techniques and calculations used, as well as appropriate equilibrium analysis of experimental data. Higher-quality data have been evaluated, compiled and presented herein, providing a synoptic view of the unifying theme in this area of research, i.e., synergism.

Essential Oil from Hibiscus Flowers through Advanced Microwave-Assisted Hydrodistillation and Conventional Hydrodistillation

Due to the increased demand and importance of essential oils in medicinal applications, advanced essential oil extraction techniques have been employed. Both conventional hydrodistillation (HD) and microwave-assisted hydrodistillation (MAHD) were employed to extract the essential oils from the hibiscus flower. Extraction time and solvent polarity were the most critical factors. Scanning electron microscopy (SEM) was used to investigate the surface morphologies of raw powdered hibiscus flowers (not exposed to any pretreatment) and pretreated powdered hibiscus flowers (exposed to methanol absorption for 60 minutes prior to extraction). Extractive chemistry analysis utilizing Fourier transform infrared (FTIR) spectroscopy was performed on the volatile oil obtained by MAHD. Different peaks in the gas chromatography/mass spectrometry (GC/MS) analysis indicated the presence of thirty-seven different compositions. MAHD was more energy efficient, had higher yield production, and was environmentally friendly, reducing HD’s overall carbon footprint by 40%. Oxygenated monoterpene, sesquiterpene, and sesquiterpene hydrocarbons were found in the hibiscus flower’s crude extract. Moreover, the methanolic extract of Hibiscus rosa-sinensis has potent antioxidant properties. A hibiscus flower extract had scavenging activities of 51.2% at 0.2 mg/mL, 0.3% at 0.6 mg/mL, 0.8% at 1.0 mg/mL, and 68.5% at 1.2 mg/mL against DPPH free radicals. Therefore, the MAHD method is well-suited to extracting essential oils from hibiscus flowers, and the resulting oil has the potential to provide significant therapeutic advantages.

Machine Learning Quantitative Structure-Property Relationships as a Function of Ionic Liquid Cations for the Gas-Ionic Liquid Partition Coefficient of Hydrocarbons.

Ionic liquids (ILs) are known for their unique characteristics as solvents and electrolytes. Therefore, new ILs are being developed and adapted as innovative chemical environments for different applications in which their properties need to be understood on a molecular level. Computational data-driven methods provide means for understanding of properties at molecular level, and quantitative structure–property relationships (QSPRs) provide the framework for this. This framework is commonly used to study the properties of molecules in ILs as an environment. The opposite situation where the property is considered as a function of the ionic liquid does not exist. The aim of the present study was to supplement this perspective with new knowledge and to develop QSPRs that would allow the understanding of molecular interactions in ionic liquids based on the structure of the cationic moiety. A wide range of applications in electrochemistry, separation and extraction chemistry depends on the partitioning of solutes between the ionic liquid and the surrounding environment that is characterized by the gas-ionic liquid partition coefficient. To model this property as a function of the structure of a cationic counterpart, a series of ionic liquids was selected with a common bis-(trifluoromethylsulfonyl)-imide anion, [Tf2N]−, for benzene, hexane and cyclohexane. MLR, SVR and GPR machine learning approaches were used to derive data-driven models and their performance was compared. The cross-validation coefficients of determination in the range 0.71–0.93 along with other performance statistics indicated a strong accuracy of models for all data series and machine learning methods. The analysis and interpretation of descriptors revealed that generally higher lipophilicity and dispersion interaction capability, and lower polarity in the cations induces a higher partition coefficient for benzene, hexane, cyclohexane and hydrocarbons in general. The applicability domain analysis of models concluded that there were no highly influential outliers and the models are applicable to a wide selection of cation families with variable size, polarity and aliphatic or aromatic nature.