Design, synthesis and biological evaluation of 1-aryldonepezil analogues as anti-Alzheimer's disease agents.

Aim: To design and synthesize a novel series of 1-aryldonepezil analogues. Materials & methods: The 1-aryldonepezil analogues were synthesized through palladium/PCy3-catalyzed Suzuki reaction and were evaluated for cholinesterase inhibitory activities and neuroprotective effects. In silico docking of the most effective compound was conducted. Results: The 4-tert-butylphenyl analogue exhibited good inhibitory potency against acetylcholinesterase and butyrylcholinesterase and had a favorable neuroprotective effect on H2O2-induced SH-SY5Y cell injury. Conclusion: The 4-tert-butylphenyl derivative is a promising lead compound for anti-Alzheimer's disease drug development.

[Box: see text].

Noncanonical autophagy is a new strategy to inhibit HSV-1 through STING1 activation.

STING1 (stimulator of interferon response cGAMP interactor 1) plays an essential role in immune responses for virus inhibition via inducing the production of type I interferon, inflammatory factors and macroautophagy/autophagy. In this study, we found that STING1 activation could induce not only canonical autophagy but also non-canonical autophagy (NCA) which is independent of the ULK1 or BECN1 complexes to form MAP1LC3/LC3-positive structures. Whether STING1-induced NCA has similar characters and physiological functions to canonical autophagy is totally unknown. Different from canonical autophagy, NCA could increase single-membrane structures and failed to degrade long-lived proteins, and could be strongly suppressed by interrupting vacuolar-type H+-translocating ATPase (V-ATPase) activity. Importantly, STING1-induced NCA could effectively inhibit DNA virus HSV-1 in cell model. Moreover, STING1 [1-340], a STING1 mutant lacking immunity and inflammatory response due to deletion of the tail end of STING1, could degrade virus through NCA alone, suggesting that the antiviral effect of activated STING1 could be separately mediated by inherent immunity, canonical autophagy, and NCA. In addition, the translocation and dimerization of STING1 do not rely on its immunity function and autophagy pathway. Similar to canonical autophagy, LC3-positive structures of NCA induced by STING1 could finally fuse with lysosomes, and the degradation of HSV-1 could be reverted by inhibition of lysosome function, suggesting that the elimination of DNA virus via NCA still requires the lysosome pathway. Collectively, we proved that besides its classical immunity function and canonical autophagy pathway, STING1-induced NCA is also an efficient antiviral pathway for the host cell.Abbreviations: ATG: autophagy related; Baf: bafilomycin A1; CASM: conjugation of LC3 to a single membrane; CGAS: cyclic GMP-AMP synthase; cGAMP: cyclic GMP-AMP; CQ: chloroquine; CTD: C-terminal domain; CTT: C-terminal tail; ER: endoplasmic reticulum; ERGIC: ER-Golgi intermediate compartment; HSV-1: herpes simplex virus 1; IRF3: interferon regulatory factor 3; IFNs: interferons; LAMP1: lysosomal associated membrane protein 1; LAP: LC3-associated phagocytosis; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MOI: multiplicity of infection; RB1CC1/FIP200: RB1 inducible coiled-coil 1; STING1: stimulator of interferon response cGAMP interactor 1; TBK1: TANK binding kinase 1; TGOLN2/TGN46: trans-golgi network protein 2; ULK1: unc-51 like autophagy activating kinase 1; V-ATPase: vacuolar-type H+-translocating ATPase; VSV: vesicular stomatitis virus.

Cyclopiazonic Acid and Okaramine Analogues, Including Chlorinated Compounds, from Chrysosporium undulatum YT-1.

Eight new cyclopiazonic acid (1-8) and five new okaramine (9-13) alkaloids together with 13 known compounds were isolated from the fungus Chrysosporium undulatum YT-1. Compounds 2, 4, 5, 7, 10, 11, and 13 were chlorinated indole alkaloids. The structures of compounds 1-13 were elucidated by HRESIMS and NMR spectroscopic data. Their relative and absolute configurations were established by J-based configuration analysis, NOESY, NOEDIFF experiments, ECD spectroscopic data, and biogenetic considerations. Compound 4 inhibited the growth of Bacillus subtilis with an MIC value of 6.3 µg/mL. Compounds 9-11 exhibited strong insecticidal capacity against the third instar larvae of silkworm and cotton bollworm (LD50: ≤7.56 µg/g). At 40 µM, compound 1 showed obvious neuroprotection to the PC12 cells with 6-OHDA treatment.

Suppression of ATG4B by copper inhibits autophagy and involves in Mallory body formation.

Autophagy is an evolutionarily conserved self-protecting mechanism implicated in cellular homeostasis. ATG4B plays a vital role in autophagy process via undertaking priming and delipidation of LC3. Chemical inhibitors and regulative modifications such as oxidation of ATG4B have been demonstrated to modulate autophagy function. Whether and how ATG4B could be regulated by metal ions is largely unknown. Copper is an essential trace metal served as static co-factors in redox reactions in physiology process. Excessive accumulation of copper in ATP7B mutant cells leads to pathology progression such as insoluble Mallory body (MB) in Wilson disease (WD). The clearance of MB via autophagy pathway was thought as a promising strategy for WD. Here, we discovered that copper ion instead of other ions could inhibit the activity of ATG4B followed by autophagy suppression. In addition, copper could induce ATG4B oligomers depending on cysteine oxidation which could be abolished in reduced condition. Copper also promotes the formation of insoluble ATG4B aggregates, as well as p62-and ubiquitin-positive aggregates, which is consistent with the components of MB caused by copper overload in WD cell model. Importantly, overexpression of ATG4B could partially reduce the formation of MB and rescue impaired autophagy. Taken together, our results uncovered for the first time a new damage mechanism mediated by copper and implied new insights of the crosstalk between the toxicity of copper and autophagy in the pathogenesis of WD.

An Insight on the Pathways Involved in Crizotinib and Sunitinib Induced Hepatotoxicity in HepG2 Cells and Animal Model.

Both crizotinib and sunitinib, novel orally-active multikinase inhibitors, exhibit antitumor activity and extend the survival of patients with a malignant tumor. However, some patients may suffer liver injury that can further limit the clinical use of these drugs, however the mechanisms underlying hepatotoxicity are still to be elucidated. Thus, our study was designed to use HepG2 cells in vitro and the ICR mice model in vivo to investigate the mechanisms of hepatotoxicity induced by crizotinib and sunitinib. Male ICR mice were treated orally with crizotinib (70 mg/kg/day) or sunitinib (7.5 mg/kg/day) for four weeks. The results demonstrated that crizotinib and sunitinib caused cytotoxicity in HepG2 cells and chronic liver injury in mice, which were associated with oxidative stress, apoptosis and/or necrosis. Crizotinib- and sunitinib-induced oxidative stress was accompanied by increasing reactive oxygen species and malondialdehyde levels and decreasing the activity of superoxide dismutase and glutathione peroxidase. Notably, the activation of the Kelch-like ECH-associated protein-1/Nuclear factor erythroid-2 related factor 2 signaling pathway was involved in the process of oxidative stress, and partially protected against oxidative stress. Crizotinib and sunitinib induced apoptosis via the mitochondrial pathway, which was characterized by decreasing Bcl2/Bax ratio to dissipate the mitochondrial membrane potential, and increasing apoptotic markers levels. Moreover, the pan-caspase inhibitor Z-VAD-FMK improved the cell viability and alleviated liver damage, which further indicated the presence of apoptosis. Taken together, this study demonstrated that crizotinib- and sunitinib-caused oxidative stress and apoptosis finally impaired hepatic function, which was strongly supported by the histopathological lesions and markedly increased levels of serum alanine aminotransferase, alkaline phosphatase and lactate dehydrogenase.

Binding Features and Functions of ATG3.

Autophagy is an evolutionarily conserved catabolic process that is essential for maintaining cellular, tissue, and organismal homeostasis. Autophagy-related (ATG) genes are indispensable for autophagosome formation. ATG3 is one of the key genes involved in autophagy, and its homologs are common in eukaryotes. During autophagy, ATG3 acts as an E2 ubiquitin-like conjugating enzyme in the ATG8 conjugation system, contributing to phagophore elongation. ATG3 has also been found to participate in many physiological and pathological processes in an autophagy-dependent manner, such as tumor occurrence and progression, ischemia-reperfusion injury, clearance of pathogens, and maintenance of organelle homeostasis. Intriguingly, a few studies have recently discovered the autophagy-independent functions of ATG3, including cell differentiation and mitosis. Here, we summarize the current knowledge of ATG3 in autophagosome formation, highlight its binding partners and binding sites, review its autophagy-dependent functions, and provide a brief introduction into its autophagy-independent functions.

Palladium-Catalyzed Synthesis and Anticancer Activity of Paclitaxel-Dehydroepiandrosterone Hybrids.

According to the activity-structure relationship of the C-13 side chain in paclitaxel or docetaxel, eighteen novel paclitaxel-dehydroepiandrosterone (DHEA) hybrids were designed and synthesized by Pd(II)-catalyzed Suzuki-Miyaura cross-coupling of 17-trifluoromethanesulfonic enolate-DHEA with different aryl boronic acids. The in vitro anticancer activity of the hybrids against a human liver cancer cell line (HepG-2) was evaluated by MTT assay, showing that most of these hybrids possessed moderate antiproliferative activity against the HepG-2 cancer cell line. Among these hybrids, three ones (7b, 7g, and 7i) with ortho-substituents in the phenyl group of the D-ring of DHEA analogues exhibited moderate anticancer activity. The optimal compound 7i showed superior anticancer activity against the HepG-2 cell line with an IC50 value of 26.39 µM.

Natural products as important tyrosine kinase inhibitors.

As an important source of drugs, natural products play an important role in the discovery and development of new drugs. More than 60% of anti-tumor drugs are closely related to natural products. At the same time, as the main cause of tumors, the abnormal activity of tyrosine kinase has become an important target for clinical treatment. Although, small molecule targeted drugs dominate the cancer treatment. Natural active products are driving the development of new tyrosine kinase inhibitors with their unique mode of action and molecular structure diversity. Obtaining new chemical entities with tyrosine kinase inhibitory activity from natural active products will bring new breakthroughs in the research of anticancer drugs. In this paper, different tyrosine kinases are mainly classified as targets, and natural products and derivatives which have been found to inhibit tyrosine kinase activity have been described. It is hoped that by analyzing the different aspects of the source, structural characteristics, mechanism of action and biological activity of these natural products, we will find new members that can be developed into drugs and promote the development of anti-tumor drugs.

α-bisabolol enhances radiotherapy-induced apoptosis in endometrial cancer cells by reducing the effect of XIAP on inhibiting caspase-3.

Endometrial cancer (EC) is one of the most common cancers in females. Although the diagnosis and treatment in early stages can greatly improve the survival rate of patients, the advanced EC still is lethal. Radiotherapy is widely used against EC, and it is a great challenge to find an effective way to overcome the resistance of EC during radiotherapy. α-bisabolol is a promising drug, which has already exhibited its anti-tumor effect in some malignancies. Here we reported that α-bisabolol could inhibit the proliferation of EC cells. It is also shown that their abilities of migration and invasion were effectively reduced by α-bisabolol. Furthermore, our results also demonstrated that α-bisabolol could improve sensitivity of EC cells in radiotherapy and further inhibited the growth of EC cells. By Western blot, we found the expression of matrix metalloproteinases-9 (MMP-9) and cyclin E were significantly decreased, which indicated that EC cells can be further suppressed by using α-bisabolol and radiotherapy. It is also demonstrated in our study that the rate of apoptotic cells is markedly increased in EC by using these two treatments. The significant decrease in X-linked inhibitor of apoptosis protein (XIAP) and increase in caspase-3 detected in our study suggested that the enhancement of apoptosis is mediated by XIAP/caspase-3 pathway, which was further confirmed by examining the downstream effectors of caspase-3, COX-2, PARP and cleaved PARP. In the present study, we demonstrated that α-bisabolol could enhance the sensitivity of EC cells to radiotherapy, which provide a novel alternative for overcoming radioresistance of EC cells and achieving a better outcome in radiotherapy.

Gas-phase intramolecular hydroxyl-amino exchange of protonated arginine and verified by the synthetic intermediate compound.

A new fragmentation process was proposed to interpret the characteristic product ion at m/z 130 of protonated arginine. The α-amino group was dissociated from protonated arginine and then combined with the (M + H-NH3 ) fragment to form an ion-neutral complex which further generated a hydroxyl-amino exchange intermediate compound through an ion-molecule reaction. This intermediate compound was synthesized from argininamide through a diazo reaction, and then the reaction mixture was analyzed using liquid chromatography combined with mass spectrometry (LC-MS). The collision-induced dissociation experiments under the same conditions revealed that this intermediate compound produced the characteristic product ion at m/z 130 as well as protonated arginine, and in addition, density functional theory calculations were performed to confirm simultaneous loss of NH3 and CO from this intermediate to give the m/z 130 ion.

Hydroxycinnamoylmalated flavone C-glycosides from Lemna japonica.

Three previously undescribed flavone C-glycosides (1-3), along with seven known ones (4-10), were isolated and characterized from the smallest flowering aquatic plant, Lemna japonica. On the basis of spectroscopic analysis and alkaline hydrolysis, compounds 1-3 were identified to be luteolin 6-C-(2″-O-trans-caffeoyl-d-malate)-ß-glucoside (1), apigenin 6-C-(2″-O-trans-caffeoyl-d-malate)-ß-glucoside (2), and luteolin 6-C-(2″-O-trans-coumaroyl-d-malate)-ß-glucoside (3). Compounds 1-3 are characteristic of a trans-coumaroyl-d-malate or trans-caffeoyl-d-malate linked to C-2″ of the glucose, which was reported for the first time. Compounds 1-3 exhibited weak cytotoxicity against HepG-2, SW-620, and A-549 cell lines, with IC50 values between 42.5 and 19.2µg/ml, and moderate antioxidant activity. Meanwhile compound 3 displayed moderate nematocidal activity with an EC50 value of 1.56mg/ml.

Cytotoxic triterpenoid saponins from Clematis tangutica.

Eight previously undescribed oleanane-type triterpenoid saponins, clematangoticosides A-H, together with eight known saponins, were isolated from the whole plants of Clematis tangutica (Maxim.) Korsh. Their structures were elucidated by extensive spectroscopic analysis, in combination with chemical methods (acid hydrolysis and mild alkaline hydrolysis). Clematangoticosides D-G were found to be unusual 23, 28-bidesmosidic glycosides. The cytotoxic activities of all of the isolated saponins were evaluated against the four human cancer cell lines SGC-7901, HepG2, HL-60 and U251MG. Clematoside S, sapindoside B, kalopanax saponin A, and koelreuteria saponin A exhibited cytotoxicity against all of the test cancer cell lines with IC50 values in the range of 1.88-27.20 µM, while clematangoticoside D and F showed selective cytotoxicity against SGC-7901 with IC50 values of 24.22 and 21.35 µM, respectively.

[Chemical Constituents from Przewalskia tangutica].

Objective: To study the Chemical constituents from Przewalskia tangutica. Methods: The compounds were isolated and identified from n-butanol extract of Przewalskia tangutica by various chromatographic and spectral techniques. Results: Twelve polar compounds were isolated and identified as scopolin( 1),fabiatrin( 2),rutin( 3),queroetin-3-O-rutinoside-7-O-ß-D-glucopyranoside( 4),protocatechuate( 5),vanillic acid( 6),thymine( 7),uracil( 8),cytosine( 9),adenine( 10),uridine( 11) and adenosine( 12). Conclusion: Compounds 3 ~ 5,8 ~ 12 are obtained from Przewalskia tangutica for the first time.

Lathyrol diterpenes as modulators of P-glycoprotein dependent multidrug resistance: structure-activity relationship studies on Euphorbia factor L3 derivatives.

Five series of 37 new acylate and epoxide derivatives (3-39) of Euphorbia factor L3, a lathyrol diterpene isolated from Euphorbia lathyris, were designed by modifying the hydroxyl moiety of C-3, C-5, or C-15. Chemoreversal effects of the acylates on multidrug resistance (MDR) were evaluated in breast cancer multidrug-resistant MCF-7/ADR cells that overexpress P-glycoprotein (P-gp). Eight derivatives exhibited greater chemoreversal ability than verapamil (VRP) against adriamycin (ADR) resistance. Compounds 19 and 25 exhibited 4.8 and 4.0 times, respectively, more effective reversal ability than VRP against ADR resistance. To determine the key characteristics of Euphorbia factor L3 derivatives that contribute to MDR reversal, we conducted a structure-activity relationship study of these compounds. The simulation studies indicated different possible mechanisms and revealed the important influence of hydrophobic interactions and hydrogen bonds in the flexible cavity of P-gp.

Analysis of cipadesin limonoids from Cipadessa cinerascens using electrospray ionization quadrupole time-of-flight tandem mass spectrometry and quantum chemical calculations.

RATIONALE: Limonoids, a class of tetranortriterpenoids, exhibit various biological effects, such as insect antifeedant and growth regulating activities, antimicrobial activity, potent cell adhesion inhibitory effects, antimalarial activity, anticancer activities, and antioxidant activity. The potential application brings the need for reliable, fast and low-cost analysis of this class of compounds. METHODS: Six cipadesin limonoids (1-6), including a pairs of isomers, from leaves and barks of Cipadessa cinerascens were investigated by electrospray ionization quadrupole time-of-flight tandem mass spectrometry (ESI-QTOF-MS/MS) in positive-ion mode. Characteristic processes were further studied by theoretical calculations. RESULTS: 1,3-Hydrogen rearrangement might play a significant role in the cleavage of -O- bridge bond in ring B and further produces some characteristic ions. For [M + Na](+) precursor ions, the product ion at m/z 133 might indicate the structure of ring A and the losses of CO(2) and AcOH occur readily. Interestingly, the radical product ion at m/z 460 from [M + Na](+) ions seems to be the characteristic ion for compound 1. A deuterium-labeling experiment supported the processes forming the radical ion. For [M + NH(4)](+) ions, high-abundance product ions resulting from sequential loss of AcOH can be observed. In addition, a pairs of isomers was unambiguously differentiated based on MS or MS/MS spectra. CONCLUSIONS: In summary, sufficient information obtained from fragmentation experiments of [M + Na](+), [M + NH(4)](+) or [M + H](+) precursor ions is especially valuable for rapid identification of these limonoids or their metabolites in complex mixtures. The high-abundance radical product ion is of scientific interest.

Brevianamide J, a new indole alkaloid dimer from fungus Aspergillus versicolor.

Brevianamide J (1), a new indole alkaloid dimer, was isolated together with four new diketopiperazine alkaloids (brevianamide K-N, 2-5) from the solid-state fermented culture of Aspergillus versicolor. Their structures were elucidated on the basis of spectral data. X-ray crystallographic analysis confirmed the structures of 1 and 4.

Determination of daunomycin in human plasma and urine by using an interference-free analysis of excitation-emission matrix fluorescence data with second-order calibration.

Daunorubicin (DNR) is a significant antineoplastic antibiotic, which is usually applied to a chemotherapy of acute lymphatic and myelogenous leukaemia. Unfortunately, cardiotoxicity research in animals has indicated that DNR is cardiotoxic. Therefore, it is important to quantify DNR in biological fluids. A new algorithm, the alternating fitting residue (AFR) method, and the traditional parallel factor analysis (PARAFAC) have been utilized to directly determine DNR in human plasma and urine. These methodologies fully exploit the second-order advantage of the employed three-way fluorescence data, allowing the analyte concentrations to be quantified even in the presence of unknown fluorescent interferents. Furthermore, in contrast to PARAFAC, more satisfactory results were gained with AFR.