Homogeneous continuous flow nitration of -methylisouronium sulfate and its optimization by kinetic modeling.

Nitration of -methylisouronium sulfate under mixed acid conditions gives -methyl--nitroisourea, a key intermediate of neonicotinoid insecticides with high application value. The reaction is a fast and highly exothermic process with a high mass transfer resistance, making its control difficult and risky. In this paper, a homogeneous continuous flow microreactor system was developed for the nitration of -methylisouronium sulfate under high concentrations of mixed acids, with a homemade static mixer eliminating the mass transfer resistance.

Leukocyte-based delivery systems for enhanced nanotheranostics of inflammation and cancer.

As a part of the immune system, leukocytes (LEs) have the features of circumvention of immunogenicity as well as recruitment to sites of inflammation during infection and tumorigenesis. Utilizing LEs as vehicles to carry theranostic agents is a promising strategy for highly efficient targeted delivery and treatment for inflammation and cancer. Specifically, the LEs, similar to 'Trojan horses', can bypass the immune system and thus enhance the therapeutic effects on inflammation and cancer.

Recent progress in the extraction of terpenoids from essential oils and separation of the enantiomers by GC-MS.

Terpenoids possess significant physiological activities and are rich in essential oils. Some terpenoids have chiral centers and could form enantiomers with distinct physiological activities. Therefore, the extraction and separation of terpenoids enantiomers are very important and have attracted extensive attention in recent years.

Photodynamic anticancer activity evaluation of novel 5-aminolevulinic acid and 3-hydroxypyridinone conjugates.

5-Aminolevulinic acid (ALA) and its derivatives, serving as the endogenous precursor of the photosensitizer (PS) protoporphyrin IX (PpIX), successfully applied in tumor imaging and photodynamic therapy (PDT). ALA and its derivatives have been used to treat actinic keratosis (AK), basal cell carcinoma (BCC), and improve the detection of superficial bladder cancer. However, the high hydrophilicity of ALA and the conversion of PpIX to heme have limited the accumulation of PpIX, hindering the efficiency and potential application of ALA-PDT.

Study on the components changes of polysaccharides and saponins during nine steaming and drying of Polygonatum sibiricum.

Background: In this study, the content and structure of Polygonatum sibiricum polysaccharides and saponins during different processing stages were determined.

Results: After processing of Polygonatum, the content of polysaccharide and glucose decreased, and the content of galactose, glucuronic acid and sugar substitution gradually increased. The content of total saponins increased significantly.

NMR Study of Water-Soluble Carotenoid Crocin: Formation of Mixed Micelles, Interaction with Lipid Membrane and Antioxidant Activity.

Crocin is a unique water-soluble carotenoid found in crocus and gardenia flowers. Crocin has been shown to have a variety of pharmacological activities, such as antioxidant, anti-cancer, memory improvement, antidepressant, anti-ischemia, blood pressure lowering and aphrodisiac, gene protection and detoxification activities. Due to their amphiphilicity, crocin molecules form concentration-dependent self-associates (micelles) in a water solution.

Mechanochemical C-H Arylation and Alkylation of Indoles Using 3 d Transition Metal and Zero-Valent Magnesium.

Although the 3 d transition-metal catalyzed C-H functionalization have been extensively employed to promote the formation of valuable carbon-carbon bonds, the persistent problems, including the use of sensitive Grignard reagents and the rigorous operations (solvent-drying, inert gas protection, metal pre-activation and RMgX addition rate control), still leave great room for further development of sustainable methodologies. Herein, we report a mechanochemical technology toward in-situ preparation of highly sensitive organomagnesium reagents, and thus building two general 3 d transition-metal catalytic platforms that enables regioselective arylation and alkylation of indoles with a wide variety of halides (including those containing post transformable functionalities and heteroaromatic rings). This mechanochemical strategy also brings unique reactivity and high step-economy in producing functionalized N-free indole products.

Review of studies on polysaccharides, lignins and small molecular compounds from three Polygonatum Mill. (Asparagaceae) spp. in crude and processed states.

Since ancient times, Polygonatum Mill. (Asparagaceae) has been utilized as a medicinal and culinary resource in China. Its efficacy in treating various illnesses has been well documented.

A high activity mesoporous Pt@KIT-6 nanocomposite for selective hydrogenation of halogenated nitroarenes in a continuous-flow microreactor.

In this study, we designed a Pt@KIT-6 nanocomposite prepared by impregnating platinum nanoparticles on the nanopores of the KIT-6 mesoporous material. This Pt@KIT-6 nanocomposite was used as a catalyst in a micro fixed bed reactor (MFBR) for the continuous-flow hydrogenation of halogenated nitroarenes, which demonstrates three advantages. First, the Pt@KIT-6 nanocomposite has a stable mesoporous nanostructure, which effectively enhances the active site and hydrogen adsorption capacity.

Mechanochemical synthesis of cysteine-gum acacia intermolecular complex for multiple metal(loid) sequestration from herbal extracts.

The ubiquitous heavy metal(loid)s (HMs) contamination has triggered great concern about food safety, while sequestration and separation of trace HMs from herbal extracts still calls for appropriate sorbent materials. In this work, gum acacia was modified by cysteine to form a cysteine-acacia intermolecular complex (Cys-GA complex) via facile mechanochemical synthesis, aiming at capturing multiple HMs simultaneously. Preliminary screening confirms the superiority of Cys-CA complex for both cationic and anionic HMs, and determines an optimum Cys/GA mass ratio of 9:1 to achieve high removal capacities for Pb(II) (938 mg g), Cd(II) (834 mg g), As(V) (496 mg g), and Cr(VI) (647 mg g) in simulated aqueous solution.

Universal response method for the quantitative analysis of photodegradation impurities in lomefloxacin hydrochloride ear drops by liquid chromatography coupled with charged aerosol detector.

In terms of risk assessment especially for the impurities with different ultraviolet responses, quantitative analysis without the availability of corresponding reference substances currently poses a challenge. In this study, a universal response method was established for the quantitative analysis of photodegradable impurities in lomefloxacin hydrochloride ear drops by high performance liquid chromatography-charged aerosol detector (HPLC-CAD) for the first time. The chromatographic conditions and CAD parameters were optimized for a good separation and sensitivity.

Study on the impurity profile and influencing factors of photodegradation in non-aqueous ofloxacin ear drops using liquid chromatography combined with ion trap/time-of-flight mass spectrometry.

Ofloxacin ear drops contain a large proportion of organic solvents, which have a great effect on the photodegradation of ofloxacin. The photodegradation impurities of ofloxacin in aqueous solution has been studied, however, the photodegradation of ofloxacin in non-aqueous solution with a high proportion of organic solvents has not been reported. In this article, the impurity profile in non-aqueous ofloxacin ear drops was studied for further improvement of official monograph in pharmacopoeia and quality control of drug.

NMR-Based Metabolomics to Analyze the Effects of a Series of Monoamine Oxidases-B Inhibitors on U251 Cells.

Alzheimer's disease (AD) is a typical progressive neurodegenerative disorder, and with multiple possible pathogenesis. Among them, coumarin derivatives could be used as potential drugs as monoamine oxidase-B (MAO-B) inhibitors. Our lab has designed and synthesized coumarin derivatives based on MAO-B.

Improving the Treatment Effect of Carotenoids on Alzheimer's Disease through Various Nano-Delivery Systems.

Natural bioactive compounds have recently emerged as a current strategy for Alzheimer's disease treatment. Carotenoids, including astaxanthin, lycopene, lutein, fucoxanthin, crocin and others are natural pigments and antioxidants, and can be used to treat a variety of diseases, including Alzheimer's disease. However, carotenoids, as oil-soluble substances with additional unsaturated groups, suffer from low solubility, poor stability and poor bioavailability.

An Efficient Continuous Flow Synthesis for the Preparation of -Arylhydroxylamines: Via a DMAP-Mediated Hydrogenation Process.

The selective hydrogenation of nitroarenes to -arylhydroxylamines is an important synthetic process in the chemical industry. It is commonly accomplished by using heterogeneous catalytic systems that contain inhibitors, such as DMSO. Herein, DMAP has been identified as a unique additive for increasing hydrogenation activity and product selectivity (up to >99%) under mild conditions in the Pt/C-catalyzed process.

C-4 Regioselective Alkylation of Pyridines Driven by Mechanochemically Activated Magnesium Metal.

Mechanochemically activated magnesium(0) metal as a highly active mediator driving direct C-4-H alkylation of pyridines with alkyl halides has been developed. Excellent regioselectivity and substrate scope, including those containing reducible functionalities, free amines, and alcohols, as well as biologically relevant molecules were achieved to access 4-alkylpyridine products. Preliminary mechanistic studies suggested a radical-radical coupling pathway.

Study on Absorption, Distribution and Excretion of a New Candidate Compound XYY-CP1106 against Alzheimer's Disease in Rats by LC-MS/MS.

XYY-CP1106, a candidate compound synthesized from a hybrid of hydroxypyridinone and coumarin, has been shown to be remarkably effective in treating Alzheimer's disease. A simple, rapid and accurate high-performance liquid chromatography coupled with the triple quadrupole mass spectrometer (LC-MS/MS) method was established in this study to elucidate the pharmacokinetics of XYY-CP1106 after oral and intravenous administration in rats. XYY-CP1106 was shown to be rapidly absorbed into the blood (, 0.

Metal-free regioselective mono- and poly-halogenation of 2-substituted indazoles.

An unprecedented metal-free regioselective halogenation of 2-indazoles has been revealed, which not only realized the highly selective synthesis of mono-halogenated products, but also completed poly-halogenations by fine tuning the reaction conditions. Various mono-/poly-/hetero-halogenated indazoles were obtained in moderate to excellent yields. Notably, this approach features environmentally friendly solvents, mild reaction conditions, simple execution and short reaction time.

Efficacy and safety of native type II collagen in modulating knee osteoarthritis symptoms: a randomised, double-blind, placebo-controlled trial.

Purpose: Knee osteoarthritis (OA) is the most common form of clinical arthritis in middle-aged and older individuals. Undenatured or native type II (TII) collagen derived from the chicken sternum has a good therapeutic effect on relieving severe pain of OA. Hence, the present study aimed to investigate the efficacy and safety of TII collagen (Native CT-II®) in individuals with knee OA.

Differentiation of tetracyclines and their 4-epimers by mass spectrometry of the alkali metal adduct ions.

Tetracyclines (TCs) are a family of broad-spectrum antibiotics. During the manufacturing process or storage, epimerization of tetracyclines could occur, leading to 4-epimers which are nearly inactive. From an analytical point of view, isomers are often difficult to distinguish.

Design and biological features of platinum (II) complexes with 3-hydroxy-3-(Trifluoromethyl)cyclobutane-1,1-Dicarboxylate as a leaving ligand.

A series of platinum compounds 2a-5a and 2b-5b with fluoro-functional groups are designed and synthesized. Among them, complex 2b is the most effective agent with 3-hydroxy-3-(trifluoromethyl)cyclobutane-1,1-dicarboxylate as a leaving ligand, which showed better cytotoxic activity than compounds containing only CF or OH group at 3-position of cyclobutane-1,1-dicarboxylate. The water solubility of 2a is better than that of carboplatin (32 mg/mL vs.

Modular reconstruction and optimization of the trans-4-hydroxy-L-proline synthesis pathway in Escherichia coli.

Background: In recent years, there has been a growing demand for microbial production of trans-4-hydroxy-L-proline (t4Hyp), which is a value-added amino acid and has been widely used in the fields of medicine, food, and cosmetics. In this study, a multivariate modular metabolic engineering approach was used to remove the bottleneck in the synthesis pathway of t4Hyp.

Results: Escherichia coli t4Hyp synthesis was performed using two modules: a α-ketoglutarate (α-KG) synthesis module (K module) and L-proline synthesis with hydroxylation module (H module).

Preparation of protamine-hyaluronic acid coated core-shell nanoparticles for enhanced solubility, permeability, and oral bioavailability of decoquinate.

Decoquinate (DQ) has low oral bioavailability owing to its poor water solubility. In this study, a DQ solid dispersion (DQ-SD) was fabricated using mechanochemical technology to encapsulate DQ and improve its oral bioavailability. DQ-SD is easily generated via self-assembly in the aqueous phase to form micelles consisting of disodium glycyrrhizinate (NaGA) nanoparticles with a protamine (PRM) and anionic hyaluronic acid (HA) layers.

Preparation of DNC Solid Dispersion by a Mechanochemical Method with Glycyrrhizic Acid and Polyvinylpyrrolidone to Enhance Bioavailability and Activity.

To exploit aqueous-soluble formulation and improve the anticoccidial activity of 4,4'-dinitrocarbanilide (DNC, active component of nicarbazin), this paper prepared DNC/GA/PVP K30 solid dispersion (SD) with glycyrrhizic acid (GA) and polyvinylpyrrolidone (PVP) K30 by a mechanical ball milling method without using any organic solvent. Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and scanning electron microscopy were used for the solid state characterization. High performance liquid chromatography, critical micelle concentration, particle characterization, and transmission electron microscopy were used to evaluate the behavior in aqueous solution.