Visible-light-mediated C-H amidation of imidazoheterocycles with N-amidopyridiniums.

C-3 amidated imidazoheterocycles were synthesized via a visible light-promoted reaction of imidazoheterocycles with N-amidopyridinium salts catalyzed by 4CzIPN under mild conditions. For imidazoheterocycles and N-amidopyridinium salts with various substituents, the reaction proceeded smoothly to give the corresponding products in moderate to good yields. The reaction provides a new strategy for the synthesis of secondary amides with the imidazo[1,2-a]pyridine core.

α7 Nicotinic acetylcholine receptor: a key receptor in the cholinergic anti-inflammatory pathway exerting an antidepressant effect.

Depression is a common mental illness, which is related to monoamine neurotransmitters and the dysfunction of the cholinergic, immune, glutamatergic, and neuroendocrine systems. The hypothesis of monoamine neurotransmitters is one of the commonly recognized pathogenic mechanisms of depression; however, the drugs designed based on this hypothesis have not achieved good clinical results. A recent study demonstrated that depression and inflammation were strongly correlated, and the activation of alpha7 nicotinic acetylcholine receptor (α7 nAChR)-mediated cholinergic anti-inflammatory pathway (CAP) in the cholinergic system exhibited good therapeutic effects against depression. Therefore, anti-inflammation might be a potential direction for the treatment of depression. Moreover, it is also necessary to further reveal the key role of inflammation and α7 nAChR in the pathogenesis of depression. This review focused on the correlations between inflammation and depression as well-discussed the crucial role of α7 nAChR in the CAP.

TBAI-Catalysed Formal [4+4]-Cycloaddition: Easy Access to Oxa-Bridged Eight-Membered Heterocycles.

TBAI-catalysed [4+4]-cyclization reaction of anthranils with hydrazones to deliver oxa-bridged eight-membered heterocycles in accepted yields was developed. Preliminary mechanistic studies indicated that the reaction involved the in situ generation of vinyldiazenes from readily available hydrazones followed by an aza-Michael addition of the anthranil substrates onto the vinyldiazenes and subsequent annulation. This transformation involved the formation of two new C-N bonds and C-O bond in one pot, overcoming the synthetic limitations of anthranils in organic chemistry. This strategy benefits from high efficiency and atomic economy with mild reaction conditions.

Molecular mechanisms of rapid-acting antidepressants: New perspectives for developing antidepressants.

Major depressive disorder (MDD) is a chronic relapsing psychiatric disorder. Conventional antidepressants usually require several weeks of continuous administration to exert clinically significant therapeutic effects, while about two-thirds of the patients are prone to relapse of symptoms or are completely ineffective in antidepressant treatment. The recent success of the N-methyl-D-aspartic acid (NMDA) receptor antagonist ketamine as a rapid-acting antidepressant has propelled extensive research on the action mechanism of antidepressants, especially in relation to its role in synaptic targets. Studies have revealed that the mechanism of antidepressant action of ketamine is not limited to antagonism of postsynaptic NMDA receptors or GABA interneurons. Ketamine produces powerful and rapid antidepressant effects by affecting α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptors, adenosine A1 receptors, and the L-type calcium channels, among others in the synapse. More interestingly, the 5-HT2A receptor agonist psilocybin has demonstrated potential for rapid antidepressant effects in depressed mouse models and clinical studies. This article focuses on a review of new pharmacological target studies of emerging rapid-acting antidepressant drugs such as ketamine and hallucinogens (e.g., psilocybin) and briefly discusses the possible strategies for new targets of antidepressants, with a view to shed light on the direction of future antidepressant research.

C-H functionalization of quinoline N-oxides catalyzed by Pd(II) complexes: a computational study.

Pd(II) catalysts, particularly the acetate salt in acetic acid, tended to favor regioselective C-H activation of quinoline N-oxides (QOs) at the C2 position. However, Pd(II)Cl2 was shown to catalyze their C-H activation at C8 and, in the presence of water, C8-H activation was accompanied by the formation of 2-quinolinones. The aim of the DFT study described in this work was to shed light on the complete mechanism of these competing catalytic reactions, when PdCl2 reacts with QO and benzaldehyde in dichloroethane. C-H activation of QO was the first step of the reaction and involved either a metallacycle, with a CQO-Pd(II) σ-bond and a C(8)-H-Pd(II) agostic bond, or an η3-QO complex, with three carbon atoms of the heteroring of QO binding PdCl2. The first situation led to the unusual C8 activation and the second to C2 activation. The σ-metallacycle undergoes C8-H activation and the energy of the TOF determining the transition state to form the product is ∼17 kcal mol-1, while for the reaction through the π-metallacycle (C2-H activation) the corresponding energy is higher (∼29 kcal mol-1) and thus is not competitive under the same conditions. The reaction proceeding through the σ-complex, activating the C8 position, is preferred, in agreement with experimental results. Both reactions involve oxidation of Pd(II) to Pd(IV) and the catalyst is regenerated. When small amounts of water are added to the reaction mixture, C8-H activation (acylation) results from the same σ-metallacycle with the same barrier, but the simultaneous formation of 2-quinolinones is more complicated. It starts with OH- attack at the C2 position, and is followed by the migration of two hydrogen atoms, and the final reductive elimination step ends with Pd(0). The higher barriers for the migration and reoxidation of Pd(0) are associated with the more demanding reaction conditions. The different reactivity of Pd(II)(OAc)2 under analogous conditions is clarified, as it is only capable of forming the above mentioned π-complex and thus of activating the C2 position of QO. This catalyst can preferentially activate the C8-H bond under rather different conditions, including in particular acetic acid medium, as shown by other authors.

The application of extracellular vesicles in colorectal cancer metastasis and drug resistance: recent advances and trends.

Colorectal cancer (CRC) has high incidence and mortality rates and is one of the most common cancers of the digestive tract worldwide. Metastasis and drug resistance are the main causes of cancer treatment failure. Studies have recently suggested extracellular vesicles (EVs) as a novel mechanism for intercellular communication. They are vesicular particles, which are secreted and released into biological fluids, such as blood, urine, milk, etc., by a variety of cells and carry numerous biologically active molecules, including proteins, nucleic acids, lipids, metabolites, etc. EVs play a crucial part in the metastasis and drug resistance of CRC by delivering cargo to recipient cells and modulating their behavior. An in-depth exploration of EVs might facilitate a comprehensive understanding of the biological behavior of CRC metastasis and drug resistance, which might provide a basis for developing therapeutic strategies. Therefore, considering the specific biological properties of EVs, researchers have attempted to explore their potential as next-generation delivery systems. On the other hand, EVs have also been demonstrated as biomarkers for the prediction, diagnosis, and presumed prognosis of CRC. This review focuses on the role of EVs in regulating the metastasis and chemoresistance of CRC. Moreover, the clinical applications of EVs are also discussed.

Directing group migration strategy in transition-metal-catalysed direct C-H functionalization.

Very recently, directing group (DG) migration has emerged as a practical strategy for transition-metal-catalysed direct C-H activation, resulting in a highly atom-economical process and enabling the reusage of DG. Therefore, great progress has been made in developing multitasking DGs. In this tutorial review, we present the rapid advances of this novel strategy by analyzing and comparing the different types of migratable DGs (including N-O, N-C, N-N or O-C bond cleavage to trigger DG migration). The related mechanisms, as well as synthetic applications, are also mentioned.

Solid lipid nanoparticle as an effective drug delivery system of a novel curcumin derivative: formulation, release in vitro and pharmacokinetics in vivo.

CONTEXT: Curcumin (Cur) has a short duration of action which limits its therapeutic efficacy. Carbonic acid 17-(1,5-dimethyl-hexyl)-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-3-yl ester 4-[7-(4-hydroxy-3-methoxy-phenyl)-3,5-dioxo-hepta-1,6-dienyl]-2-methoxy-phenyl ester (CUD), as a small molecule derivative of Cur with superior stability, has been developed in our laboratory. OBJECTIVE: CUD-loaded solid lipid nanoparticles (CUD-SLN) were prepared to prolong the duration of the drug action of Cur. MATERIALS AND METHODS: CUD-SLN were prepared with Poloxamer 188 (F68) and hydrogenated soybean phospholipids (HSPC) as carriers, and the prescription was optimized. The in vitro release of CUD and CUD-SLN was investigated. CUD-SLN (5 mg/kg) was injected into Sprague Dawley (SD) rats to investigate its pharmacokinetic behaviour. RESULTS: CUD-SLN features high entrapment efficiency (96.8 ± 0.4%), uniform particle size (113.0 ± 0.8 nm), polydispersity index (PDI) (0.177 ± 0.007) and an appropriate drug loading capacity (6.2 ± 0.1%). Optimized CUD-SLN exhibited sustained release of CUD for about 48 h. Moreover, the results of the pharmacokinetic studies showed that, compared to Cur, CUD-SLN had a considerably prolonged half-life of 14.7 h, slowed its metabolism in vivo by 35.6-fold, and had an improved area under the curve (AUC0-t) of 37.0-fold. CONCLUSIONS: CUD-SLN is a promising preparation for the development of a small molecule derivative of Cur.

Possibility of culturing the early developing kidney cells by utilizing simulated microgravity environment.

In recent years, the successful construction of tissues derived from established iPSCs has been disclosed, but it has been reported that the constructed tissues encounter problems of internal necrosis when their size increases. To solve this problem, a simulated microgravity device is used. However, the culture of early developing kidney cells using this device has not yet been reported. This study investigated whether developing kidney cells cultured in a simulated microgravity environment can differentiate into glomerular cells and renal epithelial cells. The results showed that both mouse developing kidney cells cultured in simulated microgravity and static environment formed kidney spheroids. In static culture, ureteric bud and glomerular structures were not found. While ureteric buds, podocytes, PECAM-1 positive cell aggregates, and primordial vascular plexus were formed in the kidney spheroids in simulated microgravity culture. Moreover, the expression level of the PECAM-1 gene was significant in simulated microgravity culture as compared to that of static culture. These results indicate that simulated microgravity is effective for the differentiation of developing kidney cells.

Novel Ferrocene Derivatives Induce G0/G1 Cell Cycle Arrest and Apoptosis through the Mitochondrial Pathway in Human Hepatocellular Carcinoma.

In this study, detailed information on hepatocellular carcinoma (HCC) cells (HepG-2, SMMC-7721, and HuH-7) and normal human liver cell L02 treated by ferrocene derivatives (compounds 1, 2 and 3) is provided. The cell viability assay showed that compound 1 presented the most potent and selective anti-HCC activity. Further mechanism study indicated that the proliferation inhibition effect of compound 1 was associated with the cycle arrest at the G0/G1 phase and downregulation of cyclin D1/CDK4. Moreover, compound 1 could induce apoptosis in HCC cells by loss of mitochondrial membrane potential (ΔΨm), accumulation of reactive oxygen species (ROS), decrease in Bcl-2, increase in BAX and Bad, translocation of Cytochrome c, activation of Caspase-9, -3, and cleavage of PARP. These results indicated that compound 1 would be a promising candidate against HCC through G0/G1 cell cycle arrest-related proliferation inhibition and mitochondrial pathway-dependent apoptosis.

Application of curcumin and its derivatives in tumor multidrug resistance.

Malignant tumor endangers seriously the health of all mankind. Multidrug resistance (MDR) is one of the main causes of clinical tumor chemotherapy failure. Curcumin (CUR) has not only antitumor activity but also reversing tumor MDR effect. CUR reverses tumor MDR via regulating related signal pathways or corresponding expressed proteins or gene. When combined with chemotherapeutic agents, CUR can be a chemotherapeutic sensitive agent to enhance chemotherapy efficacy and weaken tumor MDR. On the other hand, to improve the MDR reversal effect of CUR, its derivatives have been extensively studied. Therefore, this article mainly focuses on reviewing the application of CUR and its derivatives in MDR and its mechanism of reversing MDR.

Enhanced Oral Bioavailability of Felodipine from Solid Lipid Nanoparticles Prepared Through Effervescent Dispersion Technique.

Felodipine (FLD), a dihydropyridine calcium channel blocker with excellent antihypertensive effect, is poorly soluble and undergoes extensive hepatic metabolism, which lead to poor oral bioavailability (about 15%) and limit its clinic application. The goal of this study was to develop solid lipid nanoparticles (SLNs) loading FLD to improve the oral bioavailability. The FLD loaded solid lipid nanoparticles (FLD-SLNs) were prepared by the effervescent dispersion technique developed by our laboratory, which might have some advantages over traditional methods. The FLD-SLNs showed desired particle characteristics with particle size (198.15 ± 1.82 nm), poly dispersity index (0.26 ± 0.02), zeta-potential (- 25.53 ± 0.60 mV), entrapment efficiency (95.65 ± 0.70%), drug loading (2.33 ± 0.10%), and a spherical appearance. Pharmacokinetic results showed that the FLD-SLNs presented 3.17-fold increase in area under the curve (AUC(0-t)) compared with free FLD after oral administration in beagle dogs, which indicated that SLNs prepared using the effervescent dispersion technique can improve the bioavailability of lipophilic drugs like felodipine by enhancement of absorption and reduction first-pass metabolism.

Iridium(III)-Catalyzed C-H Amidation of Nitrones with Dioxazolones.

Various amidated nitrones were efficiently achieved through Ir(III)-catalyzed direct C-H amidation of nitrones with good to excellent yields and tolerance of broad functional groups. This reaction smoothly proceeded at room temperature in the absence of acid or base in a short reaction time. Carbon dioxide was generated as the sole byproduct, thus providing an environmentally benign amidation process. The title products could be efficiently transformed to substituted benzisoxazoline.

Change in Renal Glomerular Collagens and Glomerular Filtration Barrier-Related Proteins in a Dextran Sulfate Sodium-Induced Colitis Mouse Model.

Renal disease is not rare among patients with inflammatory bowel disease (IBD) and is gaining interest as a target of research. However, related changes in glomerular structural have rarely been investigated. This study was aimed at clarifying the changes in collagens and glomerular filtration barrier (GFB)-related proteins of glomeruli in a dextran sulfate sodium (DSS)-induced colitis mouse model. Acute colitis was induced by administering 3.5% DSS in Slc:ICR strain mice for eight days. Histological changes to glomeruli were examined by periodic acid-Schiff (PAS) and Masson's trichrome staining. Expressions of glomerular collagens and GFB-related proteins were analyzed by immunofluorescent staining and Western blot analysis. DSS-colitis mice showed an elevated disease activity index (DAI), colon shortening, massive cellular infiltration and colon damage, confirming that DSS-colitis mice can be used as an IBD animal model. DSS-colitis mice showed increased glycoprotein and collagen deposition in glomeruli. Interestingly, we observed significant changes in glomerular collagens, including a decrease in type IV collagen, and an increment in type I and type V collagens. Moreover, declined GFB-related proteins expressions were detected, including synaptopodin, podocalyxin, nephrin and VE-cadherin. These results suggest that renal disease in DSS-colitis mice might be associated with changes in glomerular collagens and GFB-related proteins. These findings are important for further elucidation of the clinical pathological mechanisms underlying IBD-associated renal disease.

Gastric floating sustained-release tablet for dihydromyricetin: Development, characterization, and pharmacokinetics study.

Dihydromyricetin (DHM) is a natural dihydroflavonol compound with quite a number of important pharmacological properties. However, its low solubility in water and poor stability in aqueous environment, have compromised drug efficacy of DHM, thus hindering its clinical use. The present study was to develop DHM-loaded gastric floating sustained-release tablet (DHM-GFT) to improve the bioavailability of DHM. DHM-GFT was prepared via powder direct compression. The formulation of tablet was optimized in terms of the floating ability and drug release rate. The optimized DHM-GFT exhibited short floating lag time of less than 10 s and long floating duration of over 12 h in acidic medium. It had a 12-hour sustained release of DHM, which proved its potential to develop as a twice-a-day dosing preparation. The physicochemical properties of DHM-GFT well satisfied the pharmacopoeial requirements. In addition, the results from pharmacokinetic studies demonstrated that, DHM-GFT could considerably prolong the in vivo residence time of drug and improve the bioavailability via good gastric floating ability and sustained drug release when compared to DHM powder. Therefore, DHM-GFT is promising to promote the application of DHM and merits studies for further development.

Rhodium-catalyzed regioselective C8-H amination of quinoline N-oxides with trifluoroacetamide at room temperature.

A facile and efficient protocol for rhodium-catalyzed amination of quinoline N-oxides at the C-8 position using simple and commercially available trifluoroacetamide as the amino source has been developed, which proceeds with perfect regioselectivity at room temperature and short reaction times. This catalytic system is highly convenient on a gram scale. The desired products feature diverse functional group tolerance with good to excellent yields.

[The Relationship Among Physical Activity During the Third Trimester, Maternal Pre-Pregnancy Body Mass Index, Gestational Weight Gain, and Pregnancy Outcomes].

BACKGROUND: Most pregnant women tend to reduce physical activities during pregnancy because they are uncertain of the amount of moderate-level physical activity they should do. As the influence of physical activity during the third trimester remains unclear, it is important to clarify the pregnancy outcomes of physical activity during pregnancy and weight management among Taiwanese women. PURPOSE: To examine the potential association between physical activity during the third trimester of pregnancy and the birth weight or delivery mode of the baby in order to see whether weight gain during pregnancy affects birth weight and delivery mode and to estimate the associations between pre-pregnancy body mass index and birth weight. METHODS: A prospective study was performed. Data were collected from 123 pregnant women, all between 28 and 40-weeks gestation, at a medical center in central Taiwan. The Chinese version of the 'pregnancy physical activity questionnaire' was used to collect data. Birth weight, delivery data, and the last weight measurement before delivery were retrieved from the medical records or via a postpartum telephone interview. RESULTS: The results revealed that the amount of weight gained during pregnancy was a significant predictor of birth weight. Birth weight was not associated with pre-pregnancy body mass index or with physical activity and intensity of activity during the third trimester. Results provide no consistent evidence for an association between weight gain during pregnancy and the mode of delivery. Although no association was identified between total physical activity and delivery mode, the intensity of activity made a difference, with moderate-intensity activity of pregnant women increased 1 MET-hour/week. Thus, the odds of vaginal delivery over caesarean section increased by 1.017 times (COR = 1.014; p < .05; AOR = 1.017; p < .05). CONCLUSIONS / IMPLICATIONS FOR PRACTICE: The findings of the present study indicate that weight gain during pregnancy and moderate-intensity activity are both associated with birth weight and delivery mode. These findings provide evidence that health counseling during pregnancy as well as offering physical activity guidance may be done using a more empirical research base.

Biological Evaluation of Ferrocenyl Olefins: Cancer Cell Growth Inhibition, ROS Production, and Apoptosis Activity.

The antiproliferative effects of various ferrocenyl olefins were evaluated against the cell lines MCF-7 (human breast cancer cells), DLD-1 (human colon adenocarcinoma cells), HUVEC (human umbilical vein endothelial cells), and A549 (human lung carcinoma cells), using the MTT test. IC50 values were determined. Compounds 8, 9, 11, and 12 with high antiproliferative activity were tested for their reactive oxygen species (ROS) production, and cell cycle analysis was performed on A549 cells. The results show that these compounds might perform their antiproliferative activity through inducing ROS generation, apoptosis induction, and cell cycle arrest.

LC-UV Determination of Baicalin in Rabbit Plasma and Tissues for Application in Pharmacokinetics and Tissue Distribution Studies of Baicalin after Intravenous Administration of Liposomal and Injectable Formulations.

A simple and sensitive LC-UV method to investigate the pharmacokinetics and biodistribution pattern of baicalin in rabbits was established and validated. Baicalin and the internal standard, rutin, were extracted from biosamples using acetonitrile as protein precipitation after pretreated with ammonium acetate buffer (pH 3.5; 1 M) to obtain a pure chromatographic peak and high extraction recovery. Chromatographic separation was achieved on a reverse-phase C18 column with a gradient elution at flow rate of 1.0 mL/min. UV absorption was set at 278 nm. Chromatographic response was linear over the ranges of 0.05-10.00 µg/mL in plasma and 0.05-300.00 µg/g in tissues with the limits of quantification of 50.0 ng/mL in plasma and tissues, and the limit of detection of baicalin in bio-samples of 15 ng/mL. The RSD of intra-and inter-day for the biosamples were from 4.19% to 10.84% and from 4.37% to 10.93%, respectively. The accuracy of plasma and tissue samples ranged from 81.6% to 95.2% and 80.8% to 98.4%, respectively. The extraction recoveries ranged from 81.5% to 88.3% for plasma, from 73.1% to 93.2% for tissues, respectively. Baicalin was stable in rabbit biosamples. The validated method was successfully applied to the study of the pharmacokinetics and tissue distribution of baicalin after intravenous administration of liposomal and injectable formulations to rabbits. Compared to baicalin injection, the pharmacokinetics and biodistribution behavior of baicalin was altered significantly in rabbits treated with its liposomes and drug concentration in the lungs was greatly increased.

Iridium-Catalyzed Direct C-H Sulfamidation of Aryl Nitrones with Sulfonyl Azides at Room Temperature.

Ir(III)-catalyzed direct C-H sulfamidation of aryl nitrones has been developed to synthesize various sulfamidated nitrones in moderate to excellent yields with excellent regioselectivity and broad functional group tolerance. This transformation could proceed smoothly at room temperature with low catalyst loading in the absence of external oxidants, acids, or bases. Molecular nitrogen was released as the sole byproduct, thus providing an environmentally benign sulfamidation process. And this protocol could efficiently apply to synthesize the substituted benzisoxazoline via one-step transformation from the product.