Acid Function Research Articles

Kopi, Trend Minuman Kekinian Dengan Banyak Manfaat Komponen Bioaktif

Coffee is a widely enjoyed beverage in Indonesia and around the world, holding a significant role as a key commodity in Indonesia's plantation sector. This beverage is popular not only for its distinctive flavor but also for its various health benefits. This article reviews several main bioactive components in coffee, including caffeine, chlorogenic acid, ferulic acid, and caffeic acid, as well as the potential health benefits of each. Caffeine is known as a stimulant that can enhance alertness, reduce drowsiness, and acts as a potential antioxidant. Chlorogenic acid functions as an anti-inflammatory, antihypertensive, antidiabetic, and anti-obesity agent, helping to reduce the risk of cardiovascular diseases. Ferulic acid has strong antioxidant effects and is used as a diabetes therapy due to its ability to reduce oxidative stress, while caffeic acid is known for its anticancer, antioxidant, and antibacterial activities, supporting the prevention of atherosclerosis and cardiovascular diseases. This article also discusses the mechanisms of action for each bioactive component within the body, particularly on the nervous system, lipid metabolism, and antioxidant activity. Through this review, coffee is understood not only as a refreshing beverage but also as a potential agent in the therapy and prevention of various chronic diseases.

Organic Molecule Functionalization Enables Selective Electrochemical Reduction of Dilute CO2 Feedstock

AbstractThe electrochemical conversion of low‐concentration CO2 feedstock to value‐added chemicals and fuels is a promising pathway for achieving direct valorization of waste gas streams. However, this is challenging due to significant competition from the hydrogen evolution reaction (HER) and lowered CO2 reduction (CO2R) kinetics as compared to systems that employ pure CO2. Here we show that terephthalic acid (TPA) functionalization can boost selectivity towards CO2R and suppress HER over a range of catalysts including Bi, Cu and Zn. For instance, TPA functionalized Bi attained a formate Faradaic efficiency (FEHCOO‐) of 96.3 % at 300 mA cm−2 with pure CO2 feedstock. Density functional theory simulations indicate that this is because TPA functionalization modulates the binding energies of the key reaction intermediates *OCHO and *H. With low‐concentration feedstock (15 % CO2) at 100 mA cm−2, we achieved a high FEHCOO‐ of 85.8 %, which was double that of an unmodified Bi catalyst. Using an electrolyzer with a porous solid electrolyte layer, we successfully showcase 30 h of continuous high‐purity formic acid production with a 5 % CO2 feed. Taken together, our findings demonstrate that molecular tuning of a catalyst can be an effective strategy for enabling selective CO2R using low‐concentration feedstock.

2-Methylbutyric acid functions as a potential antifungal fumigant by inhibiting Botrytis cinerea and inducing resistance to gray mold in cherry tomatoes

Botrytis cinerea causes gray mold disease on postharvest fruit, resulting in serious economic losses. Fumigation with natural volatile organic compounds can replace artificially synthesized fungicides to control postharvest fungal decay of agricultural products. The antifungal effects and potential mechanisms of microbial volatile compound 2-methylbutyric acid (2-MBA) against B. cinerea were investigated in this study. Results showed that 2-MBA inhibited mycelial growth and spores germination, altered mycelial morphology and reduced metabolic vitality of B. cinerea. Moreover, 2-MBA induced oxidative damage by stimulating ROS accumulation, increasing malondialdehyde levels, and decreasing the ratio of reduced/oxidized glutathione. Further studies indicated that 2-MBA reduced mitochondrial membrane potential, interfered TCA cycle by decreasing succinate dehydrogenase activity and ATP content, ultimately leading to decreased mitochondrial activity. In addition, key genes involved in botrydial biosynthesis and mycelial growth were down-regulated. 2-MBA controlled postharvest gray mold by inducing resistance to B. cinerea in cherry tomatoes. Taken together, 2-MBA is an effective and promising fumigant to control gray mold caused by B. cinerea.

Removal of <i>para</i>-Phenylenediamine (PPD) Dye from Its Aqueous Solution by Adsorption Using the Activated Carbon Nanoparticles

This study focused on the development of an efficient preparation method of activated carbon for the removal of para-phenylenediamine (PPD) dye in an aqueous solution. Walnut shells, a readily accessible biomass source in northern Iraq, were processed into activated carbon (AC). Several techniques, such as FTIR, XRD, and SEM, were applied to describe and study the surface of AC. According to XRD analysis, all the reflection peaks with the relative intensities of various planes indicate that the obtained particle size was around 7.63 nm. The influences of contact time, adsorbent, and other variables (the thermodynamic parameters for the influence of temperature) were calculated after studying the dosage and initial concentration. The effects of the change in the acidity functions and the increasing temperature were also studied. The results found that the best adsorption occurred in 120 min, with a 0.1 g adsorbent substance weight and pH 5. The adsorption rate was at its best at a temperature of 318 K. The best-recorded adsorption rate was obtained when applying the Langmuir and Freundlich isotherms, and the adsorption processes were of a physical nature.

Clinical characteristics of 30 children with severe acute SARS‐CoV‐2 infection

AbstractBackgroundTo describe the characteristics of pediatric patients with severe COVID‐19 in China and identify the clinical variables associated with cardiovascular involvement, severe neurological complications, and disease prognosis.MethodsA retrospective surveillance study were conducted from December 1 to 31, 2022, in Guangzhou Women and Children's Medical Center. Clinical and laboratory characteristics were abstracted by medical record review and were further analyzed according to different manifestations.ResultsA total of 30 children (median age, 27.5 months; 36.7% female) met the criteria for the diagnosis of severe COVID‐19. The top five presented symptoms were fever, convulsions, cough, polypnea, and fatigue. Compared with shock absent patients, the cardiovascular involved patients had different laboratory features, including elevated aspartate aminotransferase (AST), lactic acid levels, and abnormalities in coagulation parameters. Higher levels of alanine aminotransferase, AST, lactic dehydrogenase, creatinine, lactic acid, and abnormal coagulant function were more common in patients with severe neurological complications and patients who died during hospitalization. Higher lymphocyte counts and serum sodium concentrations were also observed in non‐survivors.ConclusionSevere COVID‐19 pediatric patients had varied clinical characteristics. Laboratory features associated with cardiovascular involvement, severe neurological complications, and adverse outcomes may facilitate early identification of the severe patients.

Tuned Manganese-Impregnated Mesoporous Silica Nanoparticles as a pH-Responsive Dual Imaging Probe.

The limitations of individual imaging modalities have led to significant interest in hybrid imaging methods that combine the advantages of multiple techniques. The development of diverse dual imaging agents, which offer the exceptional sensitivity of single-photon emission computed tomography (SPECT) and the high spatial resolution of magnetic resonance imaging (MRI), has been addressing the demand for more advanced diagnostic pharmaceuticals. In this study, 99mTc-labeled manganese oxide-loaded mesoporous silica nanoparticles (MSNs), conjugated with folic acid as the targeting moiety and the chelating agent H2pentapa-en-NH2 (99mTc-MnOx-MSN-FA-pa), were developed for targeted SPECT-MRI dual imaging. The toxicity of the nanoparticles was confirmed through an MTT assay, showing >90% viability in HEK-293 and MDA-MB-231 cells at concentrations up to 200 μg/mL, indicating nonsignificant toxicity. Cellular uptake studies showed that folic acid functionalization effectively accentuated tumor-specific intracellular uptake of nanoparticles in MDA-MB-231 cells through folate receptor-mediated endocytosis. Additionally, the radiolabeling yield of 99mTc-MnOx-MSN-FA-pa was found to be 99.6 ± 0.8% (n = 3), and the pH-responsive release of paramagnetic manganese ions increased the r1 relaxivity of the nanoprobe to 11.37 mM-1 s-1. In vivo SPECT imaging demonstrated rapid tracer accumulation in MDA-MB-231 xenografts, with a tumor-to-muscle ratio of 6.01 ± 0.51 at 2 h, and minimal uptake in nontargeted organs. In vivo MRI studies indicated the strongest tumor contrast at 2 h postinjection. Given its desirable contrast enhancement in T1 MRI and SPECT imaging, along with low toxicity, MnOx-MSN-FA-pa shows potential as an effective multifunctional nanoprobe for precise tumor imaging.

Metal Ion Sensing by Tetraloop-like RNA Fragment: Role of Compact Intermediates with Non-Native Metal Ion-RNA Inner-Shell Contacts.

Divalent metal ions influence the folding and function of ribonucleic acid (RNA) in the cells. The mechanism of how RNA structural elements in riboswitches sense specific metal ions is unclear. RNA interacts with ions through two distinct binding modes: direct interaction between the ion and RNA (inner-shell (IS) coordination) and indirect interaction between the ion and RNA mediated through water molecules (outer-shell (OS) coordination). To understand how RNA senses metal ions such as Mg2+ and Ca2+, we studied the folding of a small RNA segment from the Mg2+ sensing M-Box riboswitch using computer simulations. This RNA segment has the characteristics of a GNRA tetraloop motif and interestingly requires the binding of a single Mg2+ ion. The folding free energy surface of this simple tetraloop system is multidimensional, with a population of multiple intermediates where the tetraloop and cation interact through IS and OS coordination. The partially folded compact tetraloop intermediates form multiple non-native IS contacts with the metal ion. Thermal fluctuations should break these strong non-native IS contacts so that the tetraloop can fold to the native state, resulting in higher folding free energy barriers. Ca2+ undergoes rapid OS to IS transitions and vice versa due to its lower charge density than Mg2+. However, the ability of Ca2+ to stabilize the native tetraloop state is weaker, as it could not hold the loop-closing nucleotides together due to its weaker interactions with the nucleotides. These insights are critical to understanding the specific ion sensing mechanisms in riboswitches, and the predictions are amenable for verification by nuclear magnetic resonance (NMR) experiments.

Photocatalytic degradation of organic dyes under sunlight using a mononuclear Zn complex-embedded-functionalized porous material.

In this study, mesoporous materials (MCM-41 and MCM-48) were synthesized and functionalized with an acid group through a post-synthetic modification method. A mononuclear Zn complex [Zn(dmp)Cl2] (dmp = neocuprine) was also prepared and incorporated into a functionalized mesoporous material. Extensive characterization of the material married was carried out using techniques such as X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), and Fourier-transform infrared spectroscopy (FT-IR) to evaluate the characteristics of modified materials. The characterization results revealed that the post-synthetic modification did not alter the phase purity, crystallinity, or morphology of the mesoporous materials while confirming the successful grafting of the desired sulphonic acid functionality and Zn complex. The Zn complex-grafted-functionalized mesoporous materials were then assessed for their photo-degradation using methylene blue (MB) and rhodamine B (RB). The results demonstrated exceptional photo-degradation efficiency of the modified materials under sunlight. Within 15min, 10mg/ml of dye concentration, and adsorbent dosage 0.15mg/ml and 0.1mg/ml, degradation efficiencies of 99% and 92%, were achieved for MB using M-48-S-Zn1 and M-41-S-Zn1, respectively. Similarly, 91% and 78% degradation rates were achieved within 30min for RB using the same materials. The modified mesoporous materials exhibited a remarkable degradation performance even in challenging environments, including highly acidic, basic, and salt-concentrated conditions. This highlights the versatility and robustness of the modified materials in different environmental scenarios.

Electron Donor-Acceptor Complex-Assisted Photochemical Conversion of O-2-Nitrobenzyl Protected Hydroxamates to Amides.

The hydroxamic acid functionality is present in various medicinal agents and has attracted special interest for synthetic transformations in both organic and medicinal chemistry. The N-O bond cleavage of hydroxamic acid derivatives provides an interesting transformation for the generation of various products. We demonstrate, herein, that O-benzyl-type protected hydroxamic acids may undergo photochemical N-O bond cleavage, in the presence or absence of a catalyst, leading to amides. Although some O-benzyl protected aromatic hydroxamates may be photochemically converted to amides in the presence of a base and anthracene as the catalyst, employing O-2-nitrobenzyl group allowed the smooth conversion of both aliphatic and aromatic hydroxamates to primary or secondary amides in good to excellent yields in the presence of an amine, bypassing the need of a catalyst. DFT and UV-Vis studies supported the effective generation of an electron donor-acceptor (EDA) complex between O-2-nitrobenzyl hydroxamates and amines, which enabled the successful product formation under these photochemical conditions. An extensive substrate scope was demonstrated, showcasing that both aliphatic and aromatic hydroxamates are compatible with this protocol, affording a wide variety of primary and secondary amides.

DNA Hydrogels for Cancer Diagnosis and Therapy.

Nucleic acids, because of their precise pairing and simple composition, have emerged as excellent materials for the formation of gels. The application of DNA hydrogels in the diagnosis and therapy of cancer has expanded significantly through research on the properties and functions of nucleic acids. Functional nucleic acids (FNAs) such as aptamers, Small interfering RNA (siRNA), and DNAzymes have been incorporated into DNA hydrogels to enhance their diagnostic and therapeutic capabilities. This review discusses various methods for forming DNA hydrogels, with a focus on pure DNA hydrogels. We then explore the innovative applications of DNA hydrogels in cancer diagnosis and therapy. DNA hydrogels have become essential biomedical materials, and this review provides an overview of current research findings and the status of DNA hydrogels in the diagnosis and therapy of cancer, while also exploring future research directions.

Arachidonic acid promotes ovarian development by modulating lipid metabolism and steroid hormone secretion in Chinese mitten crab (Eriocheir sinensis)

In this study, two animal experiments were designed to assess the function of arachidonic acid (ARA) on the ovarian development of Chinese mitten crab (Eriocheir sinensis). In experiment 1, female crabs (35.55 ± 0.02 g) were fed seven experimental diets, each containing varying levels of ARA (0.01 %, 0.28 %, 0.48 %, 0.67 %, 0.86 %, 1.02 %, and 1.21 %) for 120 d. Dietary 0.48 %–0.86 % ARA significantly improved the growth performance of crabs, and more than dietary 0.67 % ARA significantly increased the gonadosomatic index (GSI), ovarian vitellogenin (VTG) and vitellin (Vn) contents (P < 0.05). The egg diameter was largest when dietary 0.86 % ARA. Moreover, dietary ARA also significantly affected the hepatopancreatic and ovarian fatty acid compositions and ARA content by increasing the relative expressions of phospholipase A2 (pla2), cyclooxygenase-1(cox-1), cyclooxygenase-2 (cox-2) and 5-lipoxygenase (5-lox), while decreasing the relative expressions of fatty acid synthase (fas), fatty acid desaturase (fad6), lipoprotein lipase (lpl) and fatty acid elongase (elo) (P < 0.05). Based on the GSI and egg diameter, the amount of 0.86 % ARA was selected to further investigate the mechanisms involved in ovarian development. In experiment 2, female crabs (73.34 ± 0.07 g) were fed ARA diets (0.01 % and 0.86 %) for 60 d. Results demonstrated that a diet supplemented with 0.86 % ARA notably increased the progesterone (PROG) and prostaglandins (PGs) contents in hepatopancreas, as well as the thromboxane A2 (TXA2), estradiol (E2), and estriol (E3) contents in ovaries of E. sinensis (P < 0.05). Immunohistochemical analyses showed that 0.86 % ARA significantly promoted the expression of E2 receptor. Moreover, transcriptome sequencing revealed that 15 KEGG pathways, including the mTOR and FoxO signalling pathways and steroid biosynthesis, were enriched in the differentially expressed genes (DEGs) of crabs fed 0.86 % ARA. In conclusion, dietary 0.86 % ARA accelerated the deposition of ARA in the hepatopancreas and ovaries by regulating ARA synthesis and metabolism-related genes, then subsequently providing energy for ovarian development. Meanwhile, ARA promoted steroid hormone secretion and ovarian development-related pathways by facilitating the generation of PGs and ultimately promoted ovarian development in Chinese mitten crabs.

Valorization of carbonaceous co-product obtained from iron ore-catalyzed methane cracking as support for Pd catalysts in toluene hydrogenation reaction

Iron ore has been proven as an abundant and sustainable catalyst in the production of hydrogen by catalytic cracking of methane. One of the main challenges is the identification of suitable market niches for the utilization of the resulting iron-carbon hybrid in order to make this process economically viable. This study examines the feasibility of using the iron-carbon hybrid obtained from methane cracking as support of Pd catalysts for the hydrogenation of toluene (350 ºC, 35 bar of H2 at room temperature and 90 min). Before supporting Pd, Fe-C hybrid was subjected to different acid functionalization treatments (nitric and/or phosphoric acids). The results indicate that sequential oxidation with nitric acid, followed by phosphoric acid, is the most effective strategy for achieving the highest catalytic activity (1294 mmolToluene gPd⁻¹) and conversion (27 %). Toluene conversion was 1.8 and 14.2 times higher than with the catalysts treated with nitric and phosphoric acid separately. Therefore, this work proves the possibility of employing carbon/Fe hybrid materials obtained in iron ore catalyzed methane cracking as catalytic supports in industrial relevant reactions.

Osteogenic citric acid linked chitosan coating of 3D-printed PLA scaffolds for preventing implant-associated infections

>25 % of the patients who receive orthopedic implants have been reported with implant-associated osteomyelitis, which can result in inflammation, osteolysis, and aseptic loosening of implants. Current treatment methods doesn't ensure defect healing and prevention from reinfection. Thermoplastic-based 3D-printed scaffolds offer a bioresorbable, biocompatible, and mechanical strong implant system. However, the hydrophobicity and bio-inertness of these polymers prevent their use in clinics. In this study, we developed dual functionalized scaffolds with osteogenic and antibacterial properties by immobilizing citric acid-linked chitosan on oxygen plasma etched 3D-printed PLA scaffolds through an EDC-NHS coupling reaction. Acellular mineralization of these scaffolds in DMEM demonstrated the deposition of crystalline hydroxyapatite. In addition, the antibacterial properties of these surface-modified scaffolds have been determined against E. coli and S. aureus, where the citric-linked chitosan biofunctionalized 3D-printed PLA scaffolds showed significantly higher antibacterial activity in comparison to oxygen-etched PLA and PLA scaffolds due to the synergistic effect of citric acid and chitosan functionalities. MG-63 cells exhibited increased proliferation and osteogenic activity on the modified scaffolds compared to the PLA and OP-PLA. These 3D-printed scaffolds, coated with citric-linked chitosan, can be a potential solution to orthopedic complications such as critical-sized bone defects and implant-associated osteomyelitis.

Adsorption of l-Cysteine and Cysteamine on Zinc Oxide Nanoparticles.

The reaction of l-cysteine and cysteamine hydrochloride with zinc oxide nanoparticles (ZnO NPs), by stirring excess reactant with the NPs in ethanol, has been studied by thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman spectroscopy. l-Cysteine adsorption occurs via the thiol functional group, and there is no evidence for bonding via the carboxylic acid or amine functionalities. However, Raman spectroscopy and XPS reveal some protonated thiol, suggesting unbound l-cysteine is also present, as confirmed by XRD that shows the presence of l-cysteine crystallites. In the case of cysteamine/ZnO, TGA indicates that a large fraction of the sample is organic, and Raman spectroscopy reveals a dramatic shift in the C-S stretch from 796 cm-1 for unreacted cysteamine to 837 cm-1 for the reacted cysteamine. It is postulated that the acidic and chelating nature of the reaction causes dissolution of some Zn2+ ions that form a Zn(II) coordination complex with cysteamine. These studies have implications for biomolecular applications in which ZnO nanoparticles are used for biosensors, bioimaging, and drug delivery.

The host tropism of current zoonotic H7N9 viruses depends mainly on an acid-labile hemagglutinin with a single amino acid mutation in the stalk region.

The incidence of human infection by zoonotic avian influenza viruses, especially H5N1 and H7N9 viruses, has increased. Current zoonotic H7N9 avian influenza viruses (identified since 2013) emerged during reassortment of viruses belonging to different subtypes. Despite analyses of their genetic background, we do not know why current H7N9 viruses are zoonotic. Therefore, there is a need to identify the factor(s) responsible for the extended host tropism that enables these viruses to infect humans as well as birds. To identify H7N9-specific amino acids that confer zoonotic properties on H7N9 viruses, we performed multiple alignment of the hemagglutinin (HA) amino acid sequences of A/Shanghai/1/2013 (H7N9) and A/duck/Zhejiang/12/2011(H7N3) (a putative, non- or less zoonotic HA donor to the zoonotic H7N9 virus). We also analyze the function of an H7N9 HA-specific amino acid with respect to HA acid stability, and evaluated the effect of acid stability on viral infectivity and virulence in a mouse model. HA2-116D, preserved in current zoonotic H7N9 viruses, was crucial for loss of HA acid stability. The acid-labile HA protein in H7 viruses played an important role in infection of human airway epithelial cells; HA2-116D contributed to infection and replication of H7 viruses. Finally, HA2-116D served as a H7 virulence factor in mice. These results suggest that acid-labile HA harboring HA2-116D confers zoonotic characteristics on H7N9 virus and that future novel zoonotic avian viruses could emerge from non-zoonotic H7 viruses via acquisition of mutations that remove HA acid stability.

Insights into the adsorption mechanism of chlorpyrifos on activated carbon derived from prickly pear seeds waste: An experimental and DFT modeling study

The removal of chlorpyrifos (CPF) from water was achieved using activated carbon (AC) derived from prickly pear seeds (PPS) wastes, developed through chemical activation with phosphoric acid. Several physico-chemical characterization methods were employed. The determination of surface functions using the Boehm assay indicated that the processed AC predominantly possesses acidic functions. The results obtained from the Boehm assay were corroborated by the pH value of the point of zero charge (pHpzc), which was equal to 2.5. Specific area calculation by the BET (Brunauer Emmett Teller) method revealed a large specific area (SBET) of 1077.66 m2 g⁻1. Adsorption experiments of CPF on AC demonstrated that the pseudo-second order (PSO) model and the Freundlich model were the most suitable for kinetic and isothermal modeling, respectively. The maximum CPF adsorption capacity of the PPS AC was found to be approximately 35 mg g⁻1. A theoretical study employing the density functional theory (DFT) was conducted using the B3LYP/6-311G (d, p) method. The most reliable adsorption energy (Eads) and Gibbs free energy (ΔGads) values between CPF and the functional groups on the AC surface were calculated. Results indicated a strong interaction between the lactone group of AC and CPF (ΔGads = −7.15 kcal mol⁻1, ΔEads = −21.55 kcal mol⁻1) and the hydroxyl group (ΔGads = −6.61 kcal mol⁻1, ΔEads = −20.66 kcal mol⁻1). This study demonstrates that activated carbon possesses significant adsorption power, making it highly effective for depolluting water contaminated by pesticides. The application of the theoretical DFT method enhances the understanding of the adsorption phenomenon of CPF on AC.

Improvement of tetracycline removal using amino acid ionic liquid modified magnetic biochar based on theoretical design

In current research, biochar is widely used to remove antibiotic contamination from the environment. However, original biochar produced through direct pyrolysis has significant limitations in removing antibiotics. In this paper, response surface methodology provided the laudable choice for magnetic poplar biochar (MPBC) considering the synergistic effect of multi-factors as well as the restrictions abundance experiments during the preparation of MPBC. Amino acid ionic liquids (AAILs) are a class of ionic liquids in which amino acids act as the anionic component, combining the tunable properties of ionic liquids with the biocompatibility and functionality of amino acids. To ameliorate adsorption capacity of MPBC, tetra-ethylammonium glycinate ([TEA][Gly]) with the best affinity for tetracycline (TC) were screened from 600 AAILs based on theoretical predictions using the conductor-like screening model for real solvents (COSMO-RS) without extensive experimental. Furthermore, AAILs-modified magnetic biochar (MPBC-AAIL) was synthesized chemically for the first time. Adsorption kinetics, isotherms, and thermodynamic analyses revealed that TC adsorption by both MPBC and MPBC-AAIL is a monolayer, spontaneous, and exothermic chemical process. Moreover, MPBC-AAIL exhibited a maximum adsorption capacity of 305.9 mg·g−1. Meanwhile, MPBC-AAIL maintains superior adsorption performance for TC in different impurity solutions as well as in real water samples. The excellent reusability and selective adsorption capacity of the material demonstrate the superiority of the theoretical based design. The characterization reveals that the adsorption mechanisms include pore filling, π-π interactions, surface complexation, hydrogen bonding, and electrostatic interactions. In addition, theoretical calculations showed that ionic liquid modification altered the adsorption sites between TC and MPBC-AAIL, leading to enhanced adsorption. This comprehensive study introduces an innovative modification of biochar, providing a novel approach to designing biochar composites and promoting their application in the remediation of complex environmental pollution.

Catalytic behavior, electronic structure and spectroscopic (FT-IR, Raman, UV–vis) properties for the new ionic liquid imidazolium hydrogen sulfate

Catalytic performance, chemical reactivity, vibrational modes and electronic transitions of the ion pair [H–Im]+[HSO4]– were investigated in the current paper. Hence, a combined experimental (Hammett acidity function, infrared, Raman and ultraviolet-visible spectroscopies) and theoretical (molecular electrostatic potential surface, reduced density gradient, frontier molecular orbital analysis, quantum theory of atoms in molecules, net atomic charges, global and local reactivity descriptors) study was conducted. In terms of the catalytic performance, the acetic acid esterification with butanol was evaluated. Important kinetic (rate constant, activation energy, pre-exponential factor) and thermodynamic (enthalpy, entropy, Gibbs free energy barrier) factors for ester production as a function of the temperature and catalyst loading have been determined. Results revealed intensive electron density distribution in [H–Im]+[HSO4]– due to chemical interactions between the cationic and anionic moieties. These bonds were established as electrostatic in nature. The pronounced charge transfers within [H–Im]+[HSO4]– managed the title compound acidity (H0) and its catalytic behavior towards butyl acetate synthesis. Using the thermodynamic and kinetic measurements, a mechanism for acetic acid esterification with butanol in the presence of imidazolium hydrogen sulfate ionic liquid was offered.

Discovery and Biosynthesis of Sulfenicin and Its New-to-Nature Acylsulfenic Acid Functional Group.

Life's organic molecules are built with diverse functional groups that enable biology by fine tuning intimate connections through time and space. As such, the discovery of new-to-nature functional groups can expand our understanding of the natural world and motivate new applications in biotechnology and biomedicine. Herein we report the genome-aided discovery of sulfenicin, a novel polyketide-nonribosomal peptide hybrid natural product from a marine Streptomyces bacterium bearing a unique acylsulfenic acid functionality. Through a series of heterologous biosynthesis, functional genetics, and enzymatic reconstitution experiments, we show that this previously described synthetic functional group is biologically assembled by a set of enzymes from both primary and secondary metabolism, including a novel flavin-dependent S -hydroxylase that hydroxylates a thiocarboxylic acid's sulfur atom. While the sulfenicin biosynthetic gene cluster is presently without parallel in public databases, acylsulfenic acid-encoding enzymes are widely distributed in bacterial genomes, implying that this labile functional group may similarly have a broad distribution among specialized metabolites.

α-Mangostin Attenuates Blood Pressure and Reverses Vascular Remodeling by Balancing ACE/AT1R and ACE2/Ang-(1-7)/MasR Axes in Ang II-Infused Hypertensive Mice.

Hyperuricemia is a common comorbidity of hypertension and probably has a causal relationship with hypertension. Alpha-mangostin (α-MG) has been reported to have uric acid lowering effect. This study aimed to investigate the dual effects of α-MG on blood pressure (BP) and uric acid levels in angiotensin II (Ang II)-infused hypertensive mice. Male C57BL/6 mice were randomized into five groups: control, Ang II infusion (500 ng/kg/min for 2 weeks), Ang II infusion with gavage administration of α-MG 4.0 and 8.0 mg/kg and benzbromarone (25 mg/kg) respectively. BP, uric acid levels, vascular structure and function, and renin-Ang II system expressions in the aorta were assessed. Treatment with α-MG reduced BP, improved endothelial relaxation, and reversed aortic wall thickening and collagen deposition in Ang II-induced hypertensive mice. It also downregulated Ang II receptor 1 (AT1R) and angiotensin converting enzyme (ACE) expression, while upregulating ACE2, Mas receptor (MasR), and angiotensin (1-7) in the aorta. Moreover, α-MG demonstrated a significant enhancement in uric acid clearance and reduction in serum uric acid levels. Conversely, benzbromarone did not result in a decrease in BP, indicating that the hypotensive effect of α-MG may not be necessarily dependent on its urate-lowering properties. α-MG can attenuate Ang II-induced hypertension and reverse vascular remodeling, potentially by balancing the ACE/Ang II/AT1R axis and the ACE2/Ang-(1-7)/MasR axis. Our findings provide insights into α-MG as a novel anti-hypertensive drug especially in patients with hyperuricemia.