Methyl Research Articles

Value-Added Products Derived from Poly(ethylene terephthalate) Glycolysis.

Among polymer wastes, poly(ethylene terephthalate) (PET) is the most important commercial thermoplastic polyester. Less than 30% of total PET production is recycled into new products. Therefore, large amounts of waste PET need to be recycled. We describe a feasible approach for the direct application of the glycolysis products of PET (GP-PET), without further purification, for the synthesis of value-added products. It was established that GP-PET is valorized via phosphorylation with phenylphosphonic dichloride (PPD), as well as with trimethyl phosphate (TMP). When PPD is used, a condensation reaction takes place with the evolution of hydrogen chloride. During the interaction between GP-PET and TMP, the following reactions take place simultaneously: a transesterification with the participation of the hydroxyl group of GP-PET and the methoxy group of TMP and an exchange reaction between the ester group of GP-PET and the methyl ester group of TMP. The occurrence of the exchange reaction was confirmed by 1H, 31P, 13C NMR, and GPC analysis. Thermogravimetric analysis (TGA) revealed that the percentage of a carbon residual (CR) implies the possibility of using the end products as flame retardant (FR) additives, especially for polyurethanes as well as thermal stabilizers of polymer materials or Li-ion cells.

Metabolomic Profiling and Biological Investigation of the Marine Sponge-Derived Fungus Aspergillus sp. SYPUF29 in Response to NO Condition.

Marine-derived fungi are assuming an increasingly central role in the search for natural leading compounds with unique chemical structures and diverse pharmacological properties. However, some gene clusters are not expressed under laboratory conditions. In this study, we have found that a marine-derived fungus Aspergillus sp. SYPUF29 would survive well by adding an exogenous nitric oxide donor (sodium nitroprusside, SNP) and nitric oxide synthetase inhibitor (L-NG-nitroarginine methyl ester, L-NAME) in culture conditions. Moreover, using the LC-MS/MS, we initially assessed and characterized the difference in metabolites of Aspergillus sp. SYPUF29 with or without an additional source of nitrogen. We have found that the metabolic pathway of Arginine and proline metabolism pathways was highly enriched, which was conducive to the accumulation of alkaloids and nitrogen-containing compounds after adding an additional source of nitrogen in the cultivated condition. Additionally, the in vitro anti-neuroinflammatory study showed that the extracts after SNP and L-NAME were administrated can potently inhibit LPS-induced NO-releasing of BV2 cells with lower IC50 value than without nitric oxide. Further Western blotting assays have demonstrated that the mechanism of these extracts was associated with the TLR4 signaling pathway. Additionally, the chemical investigation was conducted and led to nine compounds (SF1-SF9) from AS1; and six of them belonged to alkaloids and nitrogen-containing compounds (SF1-SF6), of which SF1, SF2, and SF8 exhibited stronger activities than the positive control, and showed potential to develop the inhibitors of neuroinflammation.

Evaluation of placental bed uterine in L-NAME-induced early-onset preeclampsia (EO-PE) like the rat model.

Preeclampsia (PE) is the leading cause of maternal death worldwide and is associated with long-term morbidity in both mothers and newborns. Animal modeling is considered a functional source for understanding PE pathogenesis, diagnostic standards, and therapeutic approaches. This study aimed to demonstrate and evaluate the use of N-nitro-L-arginine methyl ester (L-NAME) in a Wistar rat model under conditions similar to PE. A total of 12 rats were divided into 4 groups, each consisting of 3 members, including the pregnant control group and treatment groups administered low-dose (PE 25 mg/kg L-NAME/day), medium-dose (PE 50 mg/kg L-NAME/day), and high-dose L-NAME (PE 75 mg/kg L-NAME/day) L-NAME from gestational day 4 to 19. Measurements included blood pressure, creatinine, and proteinuria levels, placental histological changes, and placental tissue hypoxia-inducible factor 1-alpha, and plasma endothelial nitric oxide synthase levels. The results showed that intervention with L-NAME at 75 mg/kg body weight/day (PE3) induced PE earlier than that with 50 mg/kg body weight/day L-NAME. The model conditions also support further research into PE pathogenesis.

Methyl esters production from Waste Cooking Oil catalysed by iron oxides supported on CaO: Cost and environmental impacts

It was the objective of this work, to assess the midpoint environmental impacts of the catalyst synthesis stage and biodiesel production from waste cooking oil (WCO) as feedstock, depending on the catalyst source, i.e. Fe2O3 or Fe(NO3)3⋅9H2O, lime or waste clam shells, to produce the applied bifunctional catalyst based on iron and CaO. The cost of biodiesel production depending on the catalyst was also established. In the catalyst synthesis stage, the use of clam shells contributed the most to the midpoint environmental categories, mainly terrestrial ecotoxicity, freshwater ecotoxicity, marine ecotoxicity and human non-carcinogenic toxicity. In the stage of biodiesel production (esterification-transesterification reaction), the scenario contributing the lowest (20.95–22.16 %) to the midpoint environmental impacts is when using Fe(NO3)3·9H2O and CaO as iron and lime precursors, respectively. Using waste clam shells increases the environmental impacts. Regarding costs, the clam shells lead to the most expensive process ($0.08 USD/MJ). The source of energy to conduct the biodiesel production was also assessed and it was found that the use of wind turbines leads to the lowest global warming potential (GWP), 11.6 g CO2 eq·MJ-1, with the catalyst prepared with the iron salt and with the CaO from lime. The presented results were obtained with the commercial software SimaPro® version 9.6 PhD. For the inventory, experimental data obtained at laboratory scale and previously published were used.It was concluded that based on environmental impacts and costs, it is recommended to use lime instead of clam shells waste as precursor of CaO and Fe(NO3)3·9H2O as precursor of iron.

Synthesis of functional derivatives of chlorine-substituted isothiazoles.

Optimal procedures have been developed for the synthesis of substituted isothiazoles containing an active chlorine atom in position 5 of the heterocycle and various functional groups in position 3: carboxyl, hydroxymethyl, aldehyde. Based on these methods, previously undescribed compounds were obtained: 5-morpholino-substituted 3-hydroxymethyl-4- chloroisothiazole, 4-chloroisothiazole-3-carboxylic acid and its methyl ester. The resulting substances are reactive building blocks for organic synthesis of compounds with a high potential for biological activity.

Monoaromatic Compounds Biodegradation by Hydrocarbon-Oxidizing Actinobacteria

Monoaromatic substances belong to the most widespread and dangerous environmental pollutants. They are components of wastewater from oil refineries and the coal and chemical industries and are often found in soil, groundwater, and surface water. The use of actinobacteria for bioremediation of natural and industrial objects contaminated by these substances is an environmentally and economically advantageous alternative to physicochemical cleaning methods. Therefore, it is actual to search for new actinobacteria strains capable to assimilate of monoaromatic compounds for their further use in biotechnologies of purification of the environment polluted by these substances. Aim. To determine the ability of hydrocarbon-oxidizing strains of actinobacteria of the Ukrainian Collection of Microorganisms to assimilate monoaromatic compounds − derivatives of benzene and phenol. Methods. The strain cultivation was carried out in a liquid mineral medium at an initial concentration of monoaromatic compounds of 500 mg/L as the only source of carbon and energy. The expression activity of the catA gene encoding catechol 1,2-dioxygenase, the key enzyme at the initial stage of the monoaromatic compounds biodegradation, was assessed under culture growth conditions with phenol and glucose. Relative expression of the catA gene was evaluated using RT-qPCR. Fatty acid methyl esters were obtained by hydrolysis of cells in a 5 % solution of acetyl chloride in methanol, followed by extraction with an ether-hexane mixture. Methyl esters were identified using an Agilent 6800N/5973 inert GC/MS system (Agilent Technologies, US). Fatty acid content was determined by AgilentChemStation software. Results. It was established that the studied strains of actinobacteria belonging to the species Dietzia maris, Gordonia rubripertincta, Rhodococcus aetherivorans, and Rhodococcus erythropolis differ in their ability to assimilate monocyclic aromatic compounds − benzene and phenol derivatives. Most strains grew better in media with benzene and its derivatives. All strains well grew on a mixture of ethylbenzene, ortho-, meta-, and para-xylene (EX), most of them grew with different intensities on a mixture of benzene, toluene, and ortho-xylene (BTX), and on monosubstrates – benzene, benzotriazole, and benzoate. Toluene was used by 50 % of the studied strains, and only one of them (R. aetherivorans UCM Ac-602) grew on ortho-xylene. A smaller amount of strains grew in media with phenol derivatives. They did not assimilate ortho-cresol and hydroquinone but grew with different intensities on phenol, paranitrophenol, resorcinol, and catechol. Only a few strains grew in the presence of meta- and para-cresols. The widest range of monoaromatic substances was used by R. aetherivorans UCM Ac-602. It was shown that in the process of phenol assimilation by strain R. aetherivorans UCM Ac-602, the level of transcriptional activity of the catA gene encoding the key enzyme of an ortho-pathway of aromatic ring cleavage, catechol 1,2-dioxygenase, increased almost 2-fold after 48 h compared to 24 h of strain growth on this substrate and 3-fold compared to glucose. The obtained data indicate the ability of R. aetherivorans UCM Ac-602 strains to assimilate monoaromatic substances through theortho-cleavage way. During growth on benzene, toluene, BTX and EX substances, the fatty acid pool of cells of this strain was dominated by hexadecanoic C16:0 (32.73-39.81 %), hexadecenoic C16:1 cis-9 (5.66-15.11 %), and octadecenoic C18:1 cis-9 (7.09-11.83 %) acids, as well as 10-methyloctadecanoic 10-Me-C18:0 (29.88-34.76 %) acid. The composition of fatty acids of cells grown on aromatic compounds, unlike those grown on glucose, contained 2.4-4.0 times less unsaturated C18:1 cis-9 acid and 2.8-3.2 times more methyl-branched acid 10Me-C18:0. Conclusions. Assimilation of monoaromatic compounds − derivatives of benzene and phenol - is a strain-specific characteristic of the actinobacteria species. Using strain R. aetherivorans UCM Ac-602 as an example, it was shown that the assimilation of monoaromatic substances in studied actinobacteria occurs through the ortho-cleavage pathway. One of the adaptation mechanisms of strain R. aetherivorans UCM Ac-602 to the assimilation of these substances is a significant decrease in unsaturated fatty acids and an increase in methyl branched acids, which contributes to an increase in membrane rigidity and cell resistance to the toxic effect of these substrates. The data obtained indicate a high level of adaptation of actinobacteria to the assimilation of monoaromatic compounds and the prospects for their further study to be used in biotechnologies for environmental purification from these pollutants.

Upconversion-nanoparticle-assisting near-infrared photosensitive effect at 1550 nm in organic photorefractive devices

The near-infrared (NIR) photosensitive photorefractive device is a promising optoelectronic unit in the optical signal/information processing and telecommunication. In this work, the upconversion-assisting NIR photosensitive device is presented by adding the upconversion nanoparticles (UCNPs) to the photorefractive composite with (Vlieg et al., 2022; Vlieg et al., 2022) [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) as visible photosensitizer. The XRD and TEM results indicated the hexagonal β-phase nanoparticles of UCNPs. The PL measurement under the 1550-nm excitation showed the upconversion emission peaks of NaYF4:Er@NaYF4 nanocrystals at the visible lights of 525 nm, 545 nm and 650 nm. The SEM images revealed that the CRA-DR1 photorefractive composite takes on a good morphology due to the uniform distribution of UCNPs. The two-beam coupling (TBC) experiment without external electric filed indicated the coupling gain coefficient of 77.4 cm−1 at 1550 nm in the CRA-DR1/ECZ/PC61BM/(5 %)UCNPs composite. This upconversion-assisting photosensitive effect will open up the novel approaches for organic NIR photorefractive devices.

Comparative Study of Immobilized Biolipasa-R for Second Generation Biodiesel Production from an Acid Oil.

The primary objective of this work is to develop a sustainable biocatalytic transesterification process for low-grade oils, aligning with EU green technology requirements for the shift to second generation biodiesel. Thus, we investigated the immobilization and subsequent application of the lipase Biolipasa-R on transesterification processes to produce fatty acid methyl esters (FAMEs) from both a sunflower oil and an acid oil which is a bioproduct of the biodiesel industry. The lipase was immobilized on biomaterials, such as diatomaceous earth, with a yield of 60 %, and commercial carriers such as methacrylic resins with a yield of 100 %. The enzyme demonstrated superior activity when immobilized on diatomaceous earth, particularly in reactions involving the acid oil, outperforming the benchmark enzyme Novozym® 435 (95.1 % and 35 % conversion respectively). This work highlights the potential of Biolipasa-R as a cost-effective and efficient biocatalyst for biodiesel production and emphasizes the environmental benefits of utilizing industrial byproducts and eco-friendly immobilization techniques. The findings suggest that Biolipasa-R is a promising candidate for industrial applications in biodiesel production, offering a sustainable solution for waste management and energy generation.

Characterization of a GDS(L)-like hydrolase from Pleurotus sapidus with an unusual SGNH motif

The GDS(L)-like lipase from the Basidiomycota Pleurotus sapidus (PSA_Lip) was heterologously expressed using Trichoderma reesei with an activity of 350 U L−1. The isoelectric point of 5.0 was determined by isoelectric focusing. The novel PSA_Lip showed only 23.8–25.1%, 25.5%, 26.6% and 28.4% identity to the previously characterized GDSL-like enzymes phospholipase, plant lipase, acetylcholinesterase and acetylxylan esterase, from the carbohydrate esterase family 16, respectively. Therefore, the enzyme was purified from the culture supernatant and the catalytic properties and the substrate specificity of the enzyme were investigated using different assays to reveal its potential function. While no phospholipase, acetylcholinesterase and acetylxylan esterase activities were detected, studies on the hydrolysis of ferulic acid methyl ester (~ 8.3%) and feruloylated carbohydrate 5-O-transferuloyl-arabino-furanose (~ 0.8%) showed low conversions of these substrates. By investigating the hydrolytic activity towards p-nitrophenyl-(pNP)-esters with various chain-lengths, the highest activity was determined for medium chain-length pNP-octanoate at 65 °C and a pH value of 8, while almost no activity was detected for pNP-hexanoate. The enzyme is highly stable when stored at pH 10 and 4 °C for at least 7 days. Moreover, using consensus sequence analysis and homology modeling, we could demonstrate that the PSA_Lip does not contain the usual SGNH residues in the actives site, which are usually present in GDS(L)-like enzymes.

Utilization of opium poppy seed oil for biodiesel production: A parametric characterization and statistical optimization

Consuming traditional petroleum-derived diesel fuel has long been associated with issues such as the depletion of natural energy resources. To solve these challenges, an alternate source like as biodiesel is an appealing option. Seed oils have long been recognized as an abundant and diverse source of biodiesel. In this study, poppy seed oil from the poppy (Papaver somniferum) was investigated for biodiesel production. Poppy seed biodiesel was generated and refined using acid-pretreated esterification with sulphuric acid prior to transesterification, as well as single-step alkaline catalyzed transesterification with methanol and potassium hydroxide. Finally, the percentage yield was compared. Using Statistica, the Box-Behnken design was applied to optimize process variables like time, temperature, catalyst concentration, and methanol-oil ratio to produce maximum yield. The relationship of process variables was also shown with the help of the Response Surface Methodology. A maximum yield of 94.87 % was obtained at optimized conditions, i.e., 90min reaction time, 60 °C of temperature, 0.25 mg of catalyst concentration, and 3v/v% alcohol-oil ratio. The fuel properties of biodiesel produced, such as acid value, moisture content, saponification value, iodine value, specific gravity, percentage of free fatty acids, refractive index, viscosity, boiling point, and peroxide value, were measured and compared with the American Society for Testing and Materials (ASTM) D6751 and European Standards (EN) 14214. Further results were studied and discussed using Fourier Transfer Infrared (FTIR) analysis, which showed maximum similarity of raw material to formed biodiesel. Gas Chromatography-Mass Spectrometry (GC-MS) analysis was performed to identify and quantify various fatty acid methyl esters. The results obtained were in accordance with various international standards for biodiesel fuel. Thus, poppy seeds can be used to obtain biodiesel.

Oxygen-Controlled Electrocatalysis for Selective Dechlorination of 2-Chloro-5-Trichloromethyl Pyridine on Activated Ag Electrode

Electrochemical selective dechlorination can be regarded as one of the most promising strategies for generating high-valued chemicals. In the electrochemical dechlorination process of 2-chloro-5-trichloromethylpyridine (TCMP), except the anticipated dechlorination products involving 2-chloro-5-dichloromethylpyridine (DCMP), 2-chloro-5-chloromethylpyridine (CCMP), and 2-chloro-5-methylpyridine (CMP), some unexpected oxygen-incorporated products (6-chloronicotinic acid (CNA) and 6-chloronicotinoyl methyl ester (MCN)) can be obtained. Consequently, understanding the electrochemical dechlorination behavior of TCMP is crucial. Our research revealed that the activated Ag electrodes in halide ion solution exhibit enhanced electrochemical activities for electrochemical dechlorination of TCMP, compared with the pure Ag owing to the increased active specific surface areas and charge transfer. Second, oxygen participation in the reaction is a necessary condition for the formation of oxygen-incorporated products. A 100% selectivity of oxygen-incorporated products can be obtained at the potential of −0.6 V vs Ag/AgCl. Conversely, insufficient oxygen may lead to the potential becoming the determining condition that affects the reaction pathways. A more negative potential (−1.2 V vs Ag/AgCl) is conducive to the formation of dechlorination products with 94.2% conversion and 100% selectivity. This study, for the first time, elucidates the electrocatalyst, atmosphere, and potential-dependent activity and selectivity for the two dechlorination pathways of TCMP.

Role of l -arginine/nitric oxide/cyclic GMP/K ATP channel signaling pathway and opioid receptors in the antinociceptive effect of rutin in mice.

The l -arginine ( l -Arg)/nitric oxide/cyclic GMP/potassium channel (K ATP ) pathway and opioid receptors are known to play critical roles in pain perception and the antinociceptive effects of various compounds. While there is evidence suggesting that the analgesic effects of rutin may involve nitric oxide modulation, the direct link between rutin and the l -Arg/nitric oxide/cyclic GMP/K ATP pathway in the context of pain modulation requires further investigation. The antinociceptive effect of rutin was studied in male NMRI mice using the formalin test. To investigate the role of the l -Arg/nitric oxide/cyclic GMP/K ATP pathway and opioid receptors, the mice were pretreated intraperitoneally with different substances. These substances included l -Arg (a precursor of nitric oxide), S-nitroso- N -acetylpenicillamine (SNAP, a nitric oxide donor), N(gamma)-nitro- l -arginine methyl ester (L-NAME, an inhibitor of nitric oxide synthase), sildenafil (an inhibitor of phosphodiesterase enzyme), glibenclamide (a K ATP channel blocker), and naloxone (an opioid receptor antagonist). All pretreatments were administered 20 min before the administration of the most effective dose of rutin. Based on our investigation, it was found that rutin exhibited a dose-dependent antinociceptive effect. The administration of SNAP enhanced the analgesic effects of rutin during both the initial and secondary phases. Moreover, L-NAME, naloxone, and glibenclamide reduced the analgesic effects of rutin in both the primary and secondary phases. In conclusion, rutin holds significant value as a flavonoid with analgesic properties, and its analgesic effect is directly mediated through the nitric oxide/cyclic GMP/K ATP channel pathway.

Direct application of tungstosilicic acid hydrate for the treatment of high free fatty acid in acidic crude palm oil and for biodiesel production

AbstractThis study explored the use of industrial acidic crude palm oil (ACPO) for biodiesel production, facing a significant obstacle due to its high free fatty acid (FFA) content, which complicates the biodiesel production process. Typically, esterification is employed to convert FFAs into fatty acid methyl ester (FAME). Herein, the effectiveness of tungstosilicic acid hydrate (TSAH) as an unsupported heteropoly acid (HPA) catalyst for FFA esterification in ACPO was investigated. The FFA content was reduced from 8.43% to 0.95% under optimum conditions (4 wt% catalyst dosage, a methanol to oil molar ratio of 10:1, 150 min and a temperature of 60°C). Noteworthy, the TSAH catalyst showed stability over 7 cycles. The kinetic analysis revealed that the FFA esterification process closely followed pseudo first‐order kinetics, with an R2 value of 0.94. Furthermore, the biodiesel produced from TSAH‐treated ACPO meets the standard specifications outlined by ASTM D6751 and EN 14214. This research highlights the effectiveness of TSAH in catalyzing FFA esterification without the need for additional support materials or modifications.

Controlled Release Simvastatine from Molecularly Imprinted Cryogel Membranes

AbstractIn this study, poly(2‐hydroxyethyl methacrylate‐N‐methacryloyl‐L‐tryptophan methyl ester) cryogel membranes were synthesized in different concentrations by using molecular imprinting technique, for controlled release of simvastatin. The cryogel membranes were prepared in various compositions and thus the releases of cryogels containing 0.5, 0.75 and 1 mg hydrophilic simvstatin were compared. The chemical and morphological properties of the poly(HEMA‐MATrp) cryogel membranes were evaluated through a series of characterization techniques. The membranes were subjected to swelling tests to assess their ability to absorb water and their degree of crosslinking. Fourier‐transform infrared spectroscopy was applied to determine the functional groups present in the cryogel matrix and to evaluate the degree of chemical modification that occurred during synthesis. Additionally, scanning electron microscopy was employed to visualize the cryogel at high resolution, providing insights into the pore structure and overall architecture of the matrix. Then, cryogel membranes were evaluated for cell proliferation abilities by 3‐(4,5‐dimethyl/thiazol‐2‐yl) 2,5‐diphenyltetra zolium bromide thiazolyl blue (MTT) assay for cell viability. The prepared cryogel membranes have a diameter and thickness of about 10 mm and 1.0 mm, respectively. The increasing attention towards the use of cryogel membranes in tissue‐engineering has resulted in demonstrating the dependency of release profiles of simvastatin cryogel membranes on their composition.

House cricket protein hydrolysates alleviate hypertension, vascular dysfunction, and oxidative stress in nitric oxide-deficient hypertensive rats.

Edible insects with high protein content and bioactive peptides with health promotion against chronic disease. Deficiency of nitric oxide (NO) contributes to hypertension, a leading cause of cardiovascular diseases and death worldwide. This study assessed the antihypertensive effects of house cricket protein hydrolysates (HCPH) in NO-deficient hypertensive rats. Male Sprague-Dawley rats (n = 12/group) were hypertensive after the administration of Nω-nitro-L-arginine methyl ester (L-NAME) at a dose of 50 mg/kg body weight (BW)/day in drinking water for 7 weeks. The animals were then treated with HCPH (250 or 500 mg/kg BW/day) or lisinopril (Lis) (1 mg/kg BW/day) for the last 4 weeks of L-NAME administration. Blood pressure (BP), vascular function, and structural changes, endothelial NO synthase (eNOS), and p47phox nicotinamide adenine dinucleotide phosphate (NADPH) oxidase protein expression in aortic tissues, plasma nitrate/nitrite, plasma angiotensin-converting enzyme (ACE) activity, and oxidative stress markers in blood and tissues were evaluated. Induction of hypertension resulted in significantly elevated BP, decreased plasma nitrate/nitrite concentration, abolished vascular function, and increased vascular wall thickness. Overproduction of carotid and mesenteric superoxide, increased plasma, heart, and kidney malondialdehyde, and protein carbonyl levels, and increased plasma ACE activity were observed. Down-expression of eNOS with overexpression of p47phox NADPH oxidase subunit was also found in L-NAME hypertensive rats. Oral treatment with HCPH, particularly at a dose of 500 mg/kg BW/day, significantly alleviated these alterations in a manner comparable to that of Lis. HCPH improved vascular function and exerted antihypertensive effects, mainly due to the improvement of NO bioavailability, reduction of oxidative stress, and inhibition of ACE.

Vasorelaxant Effects of Ethanolic Extract from Cydonia oblonga Mill. Leaves on Isolated Rat Thoracic Aorta and Potential Mechanism of Action

Objective: Cydonia oblonga Mill . leaves ethanolic extract (CydOL-EE) has shown different cardioprotective effects. However, no previous studies investigated its direct effect on the vascular smooth muscle tone. Therefore, the study aimed to test the potential vasodilator activity of CydOL-EE in ex-vivo rat thoracic aorta preparations with an additional investigation of its mechanistic effects. Methods: CydOL-EE phytochemical profile was first investigated by HPLC-DAD-ESI-MS/MS and then tested for the vasorelaxation/vasoreactivity effects in rat aortic rings. The NO synthase inhibitor N(ω)-nitro-L-arginine methyl ester (L-NAME) and cyclic guanosine monophosphate inhibitor 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) were used to explore of the involvement of NO-dependent pathways. Results: Chromatographic analysis of CydOL-EE revealed the presence of six flavonols and seven hydroxycinnamic acids. Moreover, CydOL-EE showed a decrease in vasoreactivity caused by dose-dependent phenylephrine (PE) (Control, Emax = 104.29 ± 3.67 vs CydOL-EE, Emax = 70.73 ± 3.67, P < .0001) and a direct relaxing activity to precontraction with PE (Emax = 79.63 ± 3.67%). These responses were abolished during e-NOS inhibition, demonstrating that the mechanism of action was predominately controlled by the participation of an endothelium-dependent system. Conclusion: The results of our study show that CydO-EE demonstrates vasorelaxation and reduction of vasoreactivity through a NO-dependent pathway. These findings provide scientific evidence for further understanding of CydOL-EE use in the treatment of cardiovascular disease.

Mechanism regulation over dual-atom catalyst enables high-performance oxidative alcohol esterification

The development of heterogeneous catalysts with well-defined uniform isolated or multiple active sites is of great importance for understanding catalytic performances and studying reaction mechanisms. Herein, we present a CoCu dual-atom catalyst (CoCu-DAC) where bonded Co–Cu dual-atom sites are embedded in N-doped carbon matrix with a well-defined Co(OH)CuN6 structure. The CoCu-DAC exhibits higher catalytic activity and selectivity than the Co single-atom catalyst (Co-SAC) and Cu single-atom catalyst (Cu-SAC) counterparts in the catalytic oxidative esterification of alcohols and a variety of methyl and alkyl esters have been successfully synthesized. Kinetic studies reveal that the activation energy (29.7 kJ mol−1) over CoCu-DAC is much lower than that over Co-SAC (38.4 kJ mol−1) and density functional theory (DFT) studies disclose that two different mechanisms are regulated over CoCu-DAC and Co-SAC/Cu-SAC in three-step esterification of alcohols. The bonded Co–Cu and adjacent N species efficiently catalyze the elementary reactions of alcohol dehydrogenation, O2 activation and ester formation, respectively. The stepwise alkoxy pathway (O–H and C–H scissions) is preferred for both alcohol dehydrogenation and ester formation over CoCu-DAC, while the progressive hydroxylalkyl pathway (C–H and O–H scissions) for alcohol dehydrogenation and simultaneous hemiacetal dehydrogenation are favored over Co-SAC and Cu-SAC. Characteristic peaks in the Fourier transform infrared spectroscopy analysis may confirm the formation of the metal-C intermediate and the hydroxylalkyl pathway over Co-SAC.

Changes in bioenergetic characteristics of the murine lymphoma cells under the action of a thiazole derivative in complex with polymeric nanoparticles

Background. Mitochondria can influence cancer cells both indirectly via reactive oxygen species mediation and directly through mitochondrial biogenesis. Energy production in mitochondria is crucial as it facilitates the synthesis of essential molecules needed for cellular biosynthesis, growth, and proliferation. The development of new anticancer drugs that target the energy metabolism of tumor cells shows promise in cancer treatment. Our study aimed to investigate how the thiazole derivative N-(5-benzyl-1,3-thiazol-2-yl)-3,5-dimethyl-1-benzofuran-2-carboxamide (BF1), the polymeric nanoparticles based on the polyethylene glycol (PEG-PN, Th5), and their complex with BF1 (Th6) affect respiration and mitochondrial membrane potential in murine NK/Ly tumor cells. Materials and Methods. The study was performed on white wild-type male mice with grafted NK/Ly lymphoma. The test substances were added to the cell suspension at a final concentration of 10 μM and incubated for 15 min at 37 °C. Oxygen uptake rates in NK/Ly cells were measured using a polarographic method with Clark electrode. Changes in mitochondrial membrane potential were assessed using the tetramethylrhodamine methyl ester fluorescence dye. The fluorescence intensity was evaluated using the ImageJ computer program. Results. After incubating NK/Ly cells with BF1 (10 µM), Th5, or the BF1 + PEG-PN complex (Th6) for 15 min, no changes were observed in glucose-fueled basal respiration. However, the Th6 complex significantly activated FCCP-stimulated respiratory processes in NK/Ly lymphoma cells. Fluorescent microscopy data indicated that BF1 or Th5 alone did not affect mitochondrial membrane potential values. However, the Th6 complex significantly decreased mitochondrial membrane potential, suggesting a reduction in NK/Ly cell viability. Conclusions The investigated complex of thiazole derivative BF1 with PEG-based polymeric nanoparticles may realize its cytotoxic effect by depolarization of mitochondrial membrane in NK/Ly lymphoma cells.

In-situ construction of solid electrolyte interphase for stable zinc anode via synergy of electrochemical reduction and chemical precipitation

Aqueous zinc ion batteries (ZIBs) feature high theoretical capacity, low cost, and high safety, but they suffer from moderate reversibility arising from electrolyte decomposition, Zn corrosion/passivation, and dendrite growth. To address this issue, an effective strategy is to construct a functional solid electrolyte interface (SEI) in situ. However, this is substantially challenging owing to the severe hydrogen evolution reaction (HER) and a lack of substances that can be decomposed to form SEI in the aqueous electrolytes. Herein, we propose the fabrication of a stable SEI in situ via a synergistic electrochemical reduction-chemical precipitation approach. By chemically capturing the hydroxide ions (OH−) from HER, fatty acid methyl ester ethoxylate (FMEE), as an aqueous electrolyte additive, undergoes ester group hydrolysis following by a combination with Zn2+ to form insoluble fatty acid-zinc, enabling intelligent growth of a SEI on the Zn anode surface. As a result, the enhanced Zn anode exhibits a prolonged cycling life of up to 2700 h at 1 mA/cm2 and 1 mAh/cm2. The Zn-V2O5 full cell with the designed electrolyte demonstrates excellent rate capability and significantly improved cycling stability. This study presents a simple and practical strategy for in-situ formation of SEI in aqueous electrolytes, advancing the development of high-performance aqueous batteries.

Mild and Efficient Synthesis of Para-Substituted 2-Hydroxymethyl Piperazine

Abstract: 2-Hydroxymethyl piperazine is a crucial structural unit and essential intermediate in the drug development process. However, there are few reported methods for synthesizing 2- hydroxymethyl piperazine substituted at position 5. Herein, the 2-hydroxymethyl piperazines are synthesized from serine methyl ester hydrochloride and N-Boc-L-amino acids through a four-step reaction of condensation, deprotection, cyclisation, and reduction. This synthetic route has several advantages, including mild reaction conditions, availability of reagents, non-racemic composition, and the potential for gram-scale synthesis. In this study, we present a mild and effective synthetic method for preparing para-substituted 2-hydroxymethyl piperazine.