Antioxidative Activity Evaluation of High Purity and Micronized Tartary Buckwheat Flavonoids Prepared by Antisolvent Recrystallization.

Tartary buckwheat, a healthy food, is associated with a reduced risk of certain human chronic diseases. However, the bioactive component flavonoids in Tartary buckwheat have poor solubility and low absorption in vivo. To improve these points, 60.00% Tartary buckwheat total flavonoids (TFs) were obtained by ethanol refluxing method, which were purified and micronized by antisolvent recrystallization (ASR) using methanol as a solvent and deionized water as an antisolvent. By using High Performance Liquid Chromatography (HPLC) and electrospray ionized mass spectrometry (ESI-MS), the main flavonoid in pure flavonoids (PF) were rutin (RU), kaempferol-3-O-rutinoside (KA) and quercetin (QU); the content of TF is 99.81% after purification. It is more worthy of our attention that micronized flavonoids contribute more to antioxidant activity because of good solubility. These results provide a theoretical reference for the micronization of other flavonoids.

Study on the preparation and activity of intelligent response poly(lactic-co-glycolic acid)-ss-polyethylene glycol copolymer micelles.

Amphiphilic polymer micellar carriers are the most commonly used nanocarriers for oral delivery of hydrophobic drugs because their hydrophilic shell can avoid the recognition of the reticuloendothelial system (RES), has excellent drug-carrying capacity, and protect the drug from inactivation in the gastrointestinal fluid. The polymer micelle shell can enter cancer cells by endocytosis, and autophagy in cells, degradation by lysosomal pathway, so as to release drugs, prolong the circulation time of drugs in vivo, and then achieve the effect of drug sustained release. In this study, the glutathione-responsive PLGA-ss-PEG loaded paclitaxel (PTX) micelles (PLGA-ss-PEG-PTX) were developed for anticancer therapy. With its long-term circulation and EPR (enhanced permeability and retention) effect, and the micelle had disulfide bond, which could be used as the recognition group of tumor microenvironment, so that the PLGA-ss-PEG-PTX could specifically accumulate at the tumor site, so as to produce better anti-tumor effect. The PLGA-ss-PEG-PTX was formulated by the emulsification method in this study. The drug loading was about 21.54%, the entrapment efficiency was about 94.2%, and the particle size range was about 90 nm with narrow particle size distribution. Cytotoxicity and embryonic toxicity experiments were carried out using mouse lung cancer cells (LLC) and zebrafish fertilized eggs. It was proved that the low concentration of blank micelles had little cytotoxicity, but high concentration of blank micelles had adverse effects on zebrafish embryonic development, resulting in embryonic malformation. The uptake of drugs by cancer cells was studied by a high connotation cell imaging analysis system. The experiments showed that the drug molecules encapsulated in micelles could achieve higher uptake by cells compared with free drug molecules. In addition, in the in vivo evaluation experiment of drugs, the PLGA-ss-PEG-PTX could significantly enhance the therapeutic effect of the PTX, improve its water solubility, and improve its oral bioavailability.

Artemisinin hydroxypropyl-ß-cyclodextrin inclusion complex loaded with porous starch for enhanced bioavailability.

The current work aimed to enhance the oral bioavailability of water-insoluble drug Artemisinin (ART) by the inclusion of ART with hydroxypropyl-ß-cyclodextrin (HP-ß-CD) and then loaded with porous starch (PS). The preparation conditions of ART HP-ß-CD inclusion complex loaded with PS (AHPS) were optimized according to drug loading (DL) and entrapment efficiency (EE). The properties of AHPS were characterized by optical and thermodynamic methods. ART was linked by hydrogen bond to HP-ß-CD to form hydrophilic supramolecules, which are loaded into PS under the action of hydrogen bond. The maximum DL and EE of AHPS were about 16.51% and 67.26%, respectively. Then we investigated the physicochemical properties and antimalarial activity of AHPS. The solubility and bioavailability of AHPS at 48 h were higher than ART and market ART piperaquine tablets (APT), and showed better antimalarial activity in vitro and vivo. It provides a new idea for the development and application of fat-soluble drug.

Activating Surface Lattice Oxygen of a Cu/Zn1-xCuxO Catalyst through Interface Interactions for CO Oxidation.

Surface lattice oxygen in metal oxides is a common participant in many chemical reactions. Given this, the structural design of catalysts to activate lattice oxygen and moreover investigations into the effect of lattice oxygen on reaction pathways are hot topics. With this in mind, herein we prepare CuO-Zn1-xCuxO (ZCO) nanofibers akin to the Trojan horse legend and via an in situ reduction obtain activated Cu/Zn1-xCuxO (Cu/ZCO) nanofibers. X-ray absorption spectroscopy and X-ray photoelectron spectroscopy reveal that surface lattice oxygen of Cu/ZCO is effectively activated from inert O2- to reactive O2-x. This activation stems from the enhanced covalence of metal-oxygen bonds and the electron transfer between Cu and the support. Online mass spectrometry reveals that Cu/ZCO with activated lattice oxygen exhibits a higher Mars-van Krevelen reaction efficiency during the CO oxidation process. This study offers a new avenue to engineer interface interactions, given, as highlighted here, the importance of surface lattice oxygen in oxide supports during the catalytic process.

Crystal Structure, Solubility, and Pharmacokinetic Study on a Hesperetin Cocrystal with Piperine as Coformer.

Hesperetin (HES) is a key biological active ingredient in citrus peels, and is one of the natural flavonoids that attract the attention of researchers due to its numerous therapeutic bioactivities that have been identified in vitro. As a bioenhancer, piperine (PIP) can effectively improve the absorption of insoluble drugs in vivo. In the present study, a cocrystal of HES and PIP was successfully obtained through solution crystallization. The single-crystal structure was illustrated and comprehensive characterization of the cocrystal was conducted. The cocrystal was formed by two drug molecules at a molar ratio of 1:1, which contained O-H-O hydrogen bonds between the carbonyl and ether oxygen of PIP and the phenolic hydroxyl group of HES. In addition, a solubility experiment was performed on powder cocrystal in simulated gastrointestinal fluid, and the result revealed that the cocrystal improves the dissolution behavior of HES compared with that of the pure substance. Furthermore, HES's bioavailability in the cocrystal was six times higher than that of pristine drugs. These results may provide an efficient oral formulation for HES.

Synergistic Effects of a CeO2/SmMn2O5-H Diesel Oxidation Catalyst Induced by Acid-Selective Dissolution Drive the Catalytic Oxidation Reaction.

A diesel oxidation catalyst (DOC) is installed upstream of an exhaust after-treatment line to remove CO and hydrocarbons and generate NO2. The catalyst should possess both good oxidation ability and thermal stability because it sits after the engine. We present a novel high-performance DOC with high steam resistance and thermal stability. A selective dissolution method is adopted to modify the surface physicochemical environment of CeO2-SmMn2O5. The X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, Raman, electron paramagnetic resonance, hydrogen temperature-programmed reduction, and temperature-programmed desorption results reveal that surface Sm cations are partially removed with the exposure of more Mn4+ and Ce3+ cations and the presence of active surface oxygen species. This mechanism benefits the oxygen transformation from Ce to Mn and promotes the Ce3+ + Mn4+ ↔ Ce4+ + Mn3+ redox cycle according to the in situ near-ambient pressure X-ray photoelectron spectroscopy and in situ diffuse reflectance infrared Fourier transformation spectroscopy results. Under laboratory-simulated diesel combustion conditions, the catalyst demonstrates excellent low-temperature oxidation catalytic activity (CO and C3H6 conversion: T100 = 250 °C) compared to a Pt-based catalyst (CO and C3H6 conversion: T100 = 310 °C) with a WHSV of 120,000 mL g-1 h-1. Specifically, NO conversion reaches 68% when the temperature is approximately 300 °C.

Tunable metal-support interaction of Pt/CeO2 catalyst via surfactant-assisted strategy: Insight into the total oxidation of CO and toluene.

Catalytic oxidation is promising in removing atmospheric pollutants to address serious environmental concerns. Supported Pt-based catalysts (e.g., Pt/CeO2) are most effective for catalytic removal of atmospheric pollutants. However, the catalytic performance is largely affected by the oxidation state of Pt, oxygen vacancy and metal-support interaction (MSI). Herein, two different types of Pt/CeO2 catalyst were fabricated via surfactant-assisted strategy and treated in different annealing atmospheres, which was applied to carbon monoxide (CO) and toluene (C7H8) oxidation, respectively. The results reveal that the as-synthesized Pt/CeO2-NH catalyst is favorable to C7H8 oxidation, whereas the contrast Pt/CeO2-AH is favorable to CO oxidation. Meanwhile, Pt/CeO2-NH catalyst also has high thermal stability facing high temperature (e.g., 400 °C). Various characterizations, such as in-situ Raman, XPS, CO-DRIFTS and XANES, clarifies that the Pt/CeO2-NH catalyst has a higher surface Pt0 proportion, a weak MSI and more oxygen vacancies. The corresponding theoretical calculation also supports the experimental results. These results advance efficient regulation and fundamental understanding of MSI, and the design of heterogeneous catalysts.

Improved water dispersion and bioavailability of coenzyme Q10 by bacterial cellulose nanofibers.

The purpose of this study was to investigate the potential of bacterial cellulose nanofiber suspension (BCNs) as stabilizer in anti-solvent precipitation and its effect on improving bioavailability of coenzyme Q10. Bacterial cellulose (BC) was hydrolyzed by sulfuric acid followed by the oxidation with hydrogen peroxide to prepare BCNs. The suspension of BCNs-loaded CoQ10 (CoQ10-BCNs) were prepared by antisolvent precipitation. The zeta potential of CoQ10-BCNs was about -36.01 mV. The properties of CoQ10, BCNs and CoQ10-BCNs were studied by scanning electron microscopy, transmission electron microscope, Fourier-transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and thermo gravimetric analysis. The crystallinity of CoQ10 decreased in CoQ10-BCNs compared with the raw CoQ10, and CoQ10-BCNs have good physicochemical stability. In oral bioavailability studies, the area under curve (AUC) of CoQ10-BCNs was about 3.62 times higher than the raw CoQ10 in rats.

Preparation and evaluation of paclitaxel-loaded reactive oxygen species and glutathione redox-responsive poly(lactic-co-glycolic acid) nanoparticles for controlled release in tumor cells.

Aim: To formulate and assess the anticancer effect of the poly(lactic-co-glycolic acid) (PLGA) copolymer with the thioether groups (diethyl sulfide [Des]) and disulfide bond (cystamine containing disulfide [Cys]), which encapsulated the anticancer drug paclitaxel (PTX) and triggered PTX release in cancer cell H2O2-rich or glutathione-rich surroundings. Methods: PLGA-b-P (Des@Cys) and PLGA-b-P nanoparticles loaded with PTX were prepared and characterized in vitro. The delivery ability of the PLGA-b-P nanoparticles and PLGA-b-P-PTX nanoparticles was assessed on a CT26 (mouse colon cancer cell line) and mouse lung cancer LLC model. Results: The nanoparticles were successfully prepared. Compared with free PTX, the formulated PLGA-b-P nanoparticles loaded with PTX exhibited greater accumulation at the tumor site in the mouse model. Conclusion: PLGA-b-P nanoparticles promote drug accumulation at tumor sites, providing an effective strategy for an intelligent, responsive drug-delivery system.

Improving the antioxidant activity of natural antioxidant honokiol by introducing the amino group.

Exploring and synthesizing the compounds with stronger antioxidant activity have always been the goal of researchers. Herein, the substitution effects of the amino (NH2-) group with the excellent electron-donating ability in different positions on the antioxidant activity of Honokiol (Hon) were systematically explored by using the quantum chemistry calculation based on the density functional theory method. The three possible antioxidant mechanisms of Hon and its four NH2-substituted derivatives (Hon1-Hon4), containing the hydrogen atom transfer (HAT), single electron transfer followed by proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET), were explored in depth considering the gas and solvent phases. In addition, the frontier molecular orbital energies, natural bond orbital (NBO) charge population, and global descriptive parameters were used to study their antioxidant activity. The results indicate that compared with the original molecule Hon, the NH2 substituents would have the stronger antioxidant activity. Moreover, the radical scavenging process of Hon and its derivatives has a disposition to the HAT and SPLET mechanisms in the gas and solvent phases, respectively. Meaningfully, owing to the lowest bond dissociation enthalpy and proton affinity values, Hon4 would show the most prominent antioxidant activity by comparison with the other compounds. In conclusion, this work will provide the purposeful reference for designing and synthesizing the antioxidants with more outstanding performance.

Phloretin loaded porous starch (Ph-PS): Preparation, characterization, in vitro release and protective effect against oxidative stress in vivo zebrafish model.

Phloretin loaded porous starch (Ph-PS) were prepared for its application in food. The effects of Ph-PS in vitro release and its ability against AAPH-induced oxidative stress in vivo zebrafish model were investigated. Ph-PS was prepared by absorption method, the physical and chemical characterization showed that PS decreased the crystallinity of Ph obviously. Ph-PS exhibited higher release amount and faster release rate of Ph compared to free Ph in vitro release study. What's more, the effect of Ph-PS reduced ROS generation and lipid peroxidation was better than that of free Ph in zebrafish model. These findings suggest Ph-PS is a new and simple strategy to improve dissolution rate and antioxidant ability of Ph.

Fabrication of Nanohybrid Spinel@CuO Catalysts for Propane Oxidation: Modified Spinel and Enhanced Activity by Temperature-Dependent Acid Sites.

Modulating the catalyst electronic structure is a promising direction to enhance the catalytic oxidation performance. Herein, we report an innovative synthesis of the nanohybrid spinel@CuO catalyst with a broad biphasic interface for propane oxidation. The reaction rate of spinel@CuO catalyst was significantly increased compared to the physically mixed spinel+CuO catalyst. Lattice distortions and severe blurring of lattice fringes adjacent to the interface (between the spinel and CuO) comes with the spinel@CuO system, which enhanced interfacial interaction to form defect structures. The cobalt cations were selectively doped into the spinel lattice and occupied both the A and the B sites, while the CuO was not affected. At lower temperatures (∼200 °C), the enrichment of Brønsted acid sites increased the adsorption energy of propane. At higher temperatures (∼350 °C), the A and B sites cobalt weakened the Cu-O bond to make the oxygen vacancies form more readily, thereby enriching the Lewis acid sites. The substitution doping also resulted in lattice distortion in the spinel species, promoting the formation of a defect structure. The broad interface and temperature-dependent acid sites were conducive to propane oxidation.

Synthesis of α-MnO2-like rod catalyst using YMn2O5 A-site sacrificial strategy for efficient benzene oxidation.

The elimination of benzene, a typical volatile organic pollutant, is one of the most challenging topics for environmental scientists. Catalytic oxidation technology is considered the most efficient approach for its elimination. Herein, we report the successful preparation of a novel α-MnO2-like rod catalyst via an acid etching route and propose YMn2O5 mullite as a novel precursor. The optimized α-MnO2-like rod catalyst showed significantly improved benzene oxidation activity compared to the raw YMn2O5 and commercial MnO2 catalysts, resulting in 100 % benzene conversion at 200 °C at a GHSV of 60,000 mL g-1 h-1. Notably, the α-MnO2-like rod catalyst performance at lower temperatures (100-175 ℃) exceeded that of a commercial Pt/Al2O3 catalyst. The excellent catalytic performance of the α-MnO2-like rod catalyst is associated with its low-temperature reducibility and abundant surface-active oxygen species. During the acid etching process, more Mn3+ is oxidized to Mn4+, and more surface oxygen vacancies are generated on the α-MnO2-like rod catalyst, which provides more adsorption sites for oxygen molecules to promote the benzene oxidation reaction. The α-MnO2-like rod catalyst should be a great alternative to commercial noble metal catalysts for the elimination of volatile organic pollutants, especially at lower temperatures.

Enhanced Water Solubility and Oral Bioavailability of Paclitaxel Crystal Powders through an Innovative Antisolvent Precipitation Process: Antisolvent Crystallization Using Ionic Liquids as Solvent.

Paclitaxel (PTX) is a poor water-soluble antineoplastic drug with significant antitumor activity. However, its low bioavailability is a major obstacle for its biomedical applications. Thus, this experiment is designed to prepare PTX crystal powders through an antisolvent precipitation process using 1-hexyl-3-methylimidazolium bromide (HMImBr) as solvent and water as an antisolvent. The factors influencing saturation solubility of PTX crystal powders in water in water were optimized using a single-factor design. The optimum conditions for the antisolvent precipitation process were as follows: 50 mg/mL concentration of the PTX solution, 25 °C temperature, and 1:7 solvent-to-antisolvent ratio. The PTX crystal powders were characterized via scanning electron microscopy, Fourier transform infrared spectroscopy, high-performance liquid chromatography-mass spectrometry, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Raman spectroscopy, solid-state nuclear magnetic resonance, and dissolution and oral bioavailability studies. Results showed that the chemical structure of PTX crystal powders were unchanged; however, precipitation of the crystalline structure changed. The dissolution test showed that the dissolution rate and solubility of PTX crystal powders were nearly 3.21-folds higher compared to raw PTX in water, and 1.27 times higher in artificial gastric juice. Meanwhile, the bioavailability of PTX crystal increased 10.88 times than raw PTX. These results suggested that PTX crystal powders might have potential value to become a new oral PTX formulation with high bioavailability.

Deactivation Mechanism of Multipoisons in Cement Furnace Flue Gas on Selective Catalytic Reduction Catalysts.

Increasing numbers of cement furnaces have applied selective catalytic reduction (SCR) units for advanced treatment of NO in the flue gas. However, the SCR catalysts may face various poisons, such as acidic, alkaline, and heavy metal species, in the fly ash. In this work, we studied the deactivation mechanisms of multipoisons (Ca, Pb, and S) on the CeO2-WO3/TiO2 catalyst, using the in situ diffuse reflectance infrared Fourier transform spectroscopy method. Calcium promoted the conversion of Ce(III) to Ce(IV) and, thus, (i) suppressed the redox cycle, (ii) decreased the NO adsorption (monodentate NO3- and bridged NO2-), and (iii) enriched the Lewis acid sites. Pb(IV) blocked Ce2(WO4)3, aggravating the electronegativity of W6+, which inhibited (i) the binding stability of tungsten and ammonia species, (ii) bridged NO3- (bonded to tungsten), and (iii) the Brønsted acid sites. The multipoisoning processes enriched O2- by repairing partial surface oxygen defects, which suppressed O22- and O-. Sulfur occupied the surface base sites and formed PbSO4 after Ce2(WO4)3 was saturated.

Melatonin loaded with bacterial cellulose nanofiber by Pickering-emulsion solvent evaporation for enhanced dissolution and bioavailability.

The objective of the present work aimed to explore the potential of bacterial cellulose (BC) for oral delivery of melatonin (MLT), a natural hormone that faces problems of low solubility and oral bioavailability. BC was hydrolyzed by sulfuric acid followed by the oxidation to prepare bacterial cellulose nanofiber suspension (BCNs). Melatonin-loaded bacterial cellulose nanofiber suspension (MLT-BCNs) was prepared by emulsion solvent evaporation method. The properties of freeze-dried BCs and MLT-BCNs were studied by Fluorescence microscopy (FM), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermo gravimetric (TG). The results indicated that the fibers in BCNs became short and thin compared with BC, MLT in MLT-BCNs was uniformly distributed, both BCNs and MLT-BCNs have good thermodynamic stability. The MLT-BCNs showed more rapid dissolution MLT rates compared to the commercially available MLT in SGF and SIF, the dissolution of the cumulative release rate was about 2.1 times of the commercially available MLT. The oral bioavailability of MLT-BCNs in rat was about 2.4 times higher than the commercially available MLT. Thus, MLT-BCNs could act as promising delivery with enhanced dissolution and bioavailability for MLT after oral administration.

Performance of Modified La xSr1- xMnO3 Perovskite Catalysts for NH3 Oxidation: TPD, DFT, and Kinetic Studies.

The modified perovskites (La xSr1- xMnO3) were prepared using the selective dissolution method for the selective catalytic oxidation (SCO) of NH3. We found that more Mn4+ cations and active surface oxygen species formed on the catalyst's surface with increasing the dissolution time (dis). The 1h-dis catalyst exhibited excellent NH3 conversion, and it performed well in the presence of SO2 and H2O. The 10h-dis and 72h-dis catalysts produced considerable N2O and NO at high temperatures, while they were not detected from the fresh catalyst. Both temperature-programmed experiments and density functional theory calculations proved that NH3 strongly and mostly bonded to the B-site cations of the perovskite framework rather than A-site cations: this framework limited the bonding of SO2 to the surface. The reducibility increased superfluously after more than 10 h of immersion. The adsorptions of NH3 on Mn4+ exposed surface were stronger than that on La3+ or Sr4+ exposed surfaces. The selective catalytic reduction, nonselective catalytic reduction, and catalytic oxidation reactions all contributed to NH3 conversion. The formed NO from catalytic oxidation preferred to react with -NH2/-NH to form N2/N2O.