Mesoporous Vinylene-Linked Covalent Organic Frameworks with Heteroatom-Tuned Crystallinity and Photocatalytic Behaviors.

Owing to its prominent π-delocalization and stability, vinylene linkage holds great merits in the construction of covalent organic frameworks (COFs) with promising semiconducting properties. However, carbon-carbon double bond formation reaction always exhibits relatively low reversibility, unfavorable for the formation of high crystalline frameworks through self-error correction and assembling processes. In this work, we report a heteroatom-tuned strategy to build up a series of two-dimensional (2D) vinylene-linked COFs by Knoevenagel condensation of an electron-deficient methylthiazolyl-based monomer with different triformyl substituted (hetero-)aromatic derivatives. The resulting COFs show high-quality periodic mesoporous structures with high surface areas. Embedding heteroatoms into the backbones enables significantly improving their crystallinity, and finely tailoring their semiconducting structures. Upon visible light stimulation, one of the as-prepared COFs with donor-π-acceptor structure could deliver a nearly seven-fold increase in the catalytic activity of hydrogen generation as compared with the other two. Meanwhile, in combination with high crystallinity and the matched conduction band energy level, such kind of COFs can be able to selectively generate singlet oxygen and superoxide radicals in a high ratio of up to 30:1, allowing for catalyzing aerobic thioanisole oxidation in distinctly tunable activities through the substituent electronic effect of the substrates.

Pyridazine-Promoted Construction of Vinylene-Linked Covalent Organic Frameworks with Exceptional Capability of Stepwise Water Harvesting.

In this study, we successfully developed two novel vinylene-linked covalent organic frameworks (COFs) using 2-connected 3,6-dimethylpyridazine through Knoevenagel condensation. These COFs featured finely tailored micro-/nano-scale pore sizes, high surface areas and stable non-polar vinylene linkages. Finely resolved powder X-ray diffraction patterns demonstrated highly crystalline structures with a hexagonal lattice in the AA layer stacking. The resulting one-dimensional channels possess strong hydrogen-bond accepting sites arising from the decorated cis-azo/azine units with two pairs of fully exposed lone pair electrons, endowing the as-prepared COFs with exceptional water absorption properties. The g-DZPH-COF exhibited successive steep water uptake steps starting from low relative pressures (P/PSTA=0.1), with the remarkable water uptake capacity of 0.26 g/g at P/PSTA=0.2 (25 °C), which is the optimal value recorded among the reported COFs. Dynamic vapour sorption measurements revealed the fast kinetics of these COFs, even in the cluster formation process. Water uptake and release cycling tests demonstrated their outstanding hydrolytic stability, durability, and adsorption-desorption retention ability.

(±)-Hypernumqulins A-H: Eight pairs of unexpected [2+2] cycloaddition sesquiterpenoid alkaloid with 6/6/6/4/10 ring system from Hypericum monogynum L.

(±)-Hypernumqulins A-H (1-8), eight pairs of enantiomeric quinoline alkaloids fused with an isopentenyl and a germacrane-type sesquiterpenoid, featuring an unprecedented skeleton with 6/6/6/4/10 ring system, were isolated from Hypericum monogynum L. under the guidance of molecular networking strategy. Their structures including absolute configuration were elucidated by NMR spectroscopy analysis, X-ray crystallography and quantum chemical calculation. The proposed [2+2] cycloaddition may play a key biogenic step in building the unexpected skeleton. Most of the isolates exhibited cytotoxicity with IC50 values ranging from 2.82 ± 0.03 to 45.25 ± 1.26 µM against MCF-7, A549 or SGC7901 cells. Furthermore, compounds (±)-1 and (-)-1 could induce apoptosis by upregulating the protein expression level of Bax and downregulating of Bcl-2 in MCF-7 cells. These findings provided the first example of germacrane sesquiterpene quinoline alkaloids, and supported the possibilities for the development of new anti-tumor agents.

Ptehosides A-I: Nine undescribed iridoids with in vitro cytotoxicity from the whole plant of Pterocephalus hookeri (C.B. Clarke) Höeck.

Nine previously undescribed iridoids, ptehosides A-I (1-9), together with 12 known ones (10-21), were isolated from Pterocephalus hookeri (C.B. Clarke) Höeck. Their structures were elucidated using various spectroscopic methods including HR-ESI-MS, NMR, UV, IR and CD, etc. The cytotoxic activities of all isolates were evaluated using MTT method in three human cancer cell lines (Caco2, Huh-7, and SW982). As result, compound 9 exhibited substantial inhibitory activity on Caco2, Huh-7, and SW982 cells with IC50 values of 1.17 ± 0.05, 1.15 ± 0.05 and 1.14 ± 0.04 µM, respectively. A preliminary mechanism study showed that 9 arrested the cell cycle of SW982 cells in the G0/G1 phase and induced apoptosis by upregulating Bax expression and downregulating Bcl-2 expression.

Dehydrocostus lactone alleviates irinotecan-induced intestinal mucositis by blocking TLR4/MD2 complex formation.

BACKGROUND: Irinotecan (CPT-11) is used as chemotherapeutic drug for treatment of colorectal cancer. However, without satisfactory treatments, its gastrointestinal toxicities such as diarrhea and intestinal inflammation severely restrained its clinical application. Roots of Aucklandia lappa Decne. are used as traditional Chinese medicine to relieve gastrointestinal dysfunction and dehydrocostus lactone (DHL) is one of its main active components. Nevertheless, the efficacy and mechanism of DHL against intestinal mucositis remains unclear. PURPOSE: The present study aimed to investigate the protective effects of DHL on CPT-11-induced intestinal mucositis and its underlying mechanisms. METHODS: The protective effect of DHL was investigated in CPT-11-induced mice and lipopolysaccharide (LPS)+CPT-11 induced THP-1 macrophages. Body weight, diarrhea score, survival rate, colon length, and histopathological changes in mice colon and jejunum were analyzed to evaluate the protective effect of DHL in vivo. And DHL on reducing inflammatory response and regulating TLR4/NF-κB/NLRP3 pathway in vivo and in vitro were explored. Moreover, DHL on the interaction between TLR4 and MD2 was investigated. And silencing TLR4 targeted by siRNA was performed to validate the mechanisms of DHL on regulating the inflammation. RESULTS: DHL prevented CPT-11-induced intestinal damage, represented by reducing weight loss, diarrhea score, mortality rate and the shortening of the colon. Histological analysis confirmed that DHL prevented intestinal epithelial injury and improved the intestinal barrier function in CPT-11 induced mice. Besides, DHL significantly downregulated the level of inflammatory cytokines by inhibiting TLR4/NF-κB/NLRP3 signaling pathway in CPT-11-induced mice and LPS+CPT-11-induced THP-1 macrophages. In addition, DHL blocked TLR4/MD2 complex formation. Molecular docking combined with SIP and DARTS assay showed that DHL could bind to TLR4/MD2 and occludes the hydrophobic pocket of MD2. Furthermore, Silencing TLR4 abrogated the effect of DHL on LPS+CPT-11 induced inflammatory response in THP-1 macrophages. Additionally, DHL ameliorate the CPT-11-induced intestinal mucositis without affecting the anti-tumor efficacy of CPT-11 in the tumor xenograft mice. CONCLUSION: This study found that DHL exhibited the anti-inflammatory effects in CPT-11-induced intestinal mucositis by inhibiting the formation of TLR4/MD2 complex and then regulation of NF-κB/NLRP3 signaling pathway. DHL is potentially served as a novel strategy of combined medication with CPT-11.

The Alterations in the Brain Corresponding to Low Back Pain: Recent Insights and Advances.

Low back pain (LBP) is a leading cause of global disabilities. Numerous molecular, cellular, and anatomical factors are implicated in LBP. Current issues regarding neurologic alterations in LBP have focused on the reorganization of peripheral nerve and spinal cord, but neural mechanisms of exactly what LBP impacts on the brain required further researches. Based on existing clinical studies that chronic pain problems were accompanying alterations in brain structures and functions, researchers proposed logical conjectures that similar alterations occur in LBP patients as well. With recent extensive studies carried out using noninvasive neuroimaging technique, increasing number of abnormalities and alterations has been identified. Here, we reviewed brain alterations including white matters, grey matters, and neural circuits between brain areas, which are involved in chronic LBP. Moreover, brain structural and functional connectivity abnormalities are correlated to the happening and transition of LBP. The negative emotions related to back pain indicate possible alterations in emotional brain regions. Thus, the aim of this review is to summarize current findings on the alterations corresponding to LBP in the brain. It will not only further our understanding of etiology of LBP and understanding of negative emotions accompanying with back pain but also provide ideas and basis for new accesses to the diagnosis, treatment, and rehabilitation afterward based on integral medicine.

Optical Information Transmission and Multimode Fluorescence Anticounterfeiting of Ca2-xMgxGe7O16:Mn2.

Multimode emission of Mn2+ for multimode fluorescence anticounterfeiting is achieved by cation site and interstitial occupancy in Ca2-xMgxGe7O16. The rings in Ca2-xMgxGe7O16 have a significant distortion for Mn2+ ions to enter the ring interstitials with a luminescence center at 665 nm, which is supported by XRD refinement results and first-principles calculations. The interstitial Mn2+ ion has good thermal stability with an activation energy of 0.36 eV. Surprisingly, these two luminescence centers, the cation site Mn and the interstitial Mn, have an obvious afterglow, and the disappearing afterglow will reappear by heating or irradiating with the 980 nm laser. The afterglow is significantly enhanced, as MnO2 is used as the manganese source, which is explained in detail by the thermal luminescence spectrum. Finally, Ca2-xMgxGe7O16:Mn2+ fully demonstrates its excellent prospects in fluorescent anticounterfeiting, information encryption, and optical information storage.

Dracotangusions A and B, two new sesquiterpenes from Dracocephalum tanguticum Maxim. with anti-inflammatory activity.

Two new guaiane sesquiterpenoids were isolated from the dried aerial parts of Dracocephalum tanguticum Maxim., named as dracotangusions A (1) and B (2), together with four known sesquiterpenoids, which were identified as Curcumenone (3), (4Z,7Z,9Z)-11-Hydroxy-4,7,9-germacratriene-1,6-dione (4), Kobusone (5), and (1S,10S), (4S, 5S)-(+)-germacrone-1(10)-4-diepoxide (6). The structures of isolates were determined by UV, IR, HR-ESI-MS, and NMR analysis. What is noteworthy is that four known sesquiterpenoids were isolated for the first time from the genus of Dracocephalum L. All compounds inhibited the extremely significant difference (p < 0.01) in anti-inflammatory activity, suggesting that these compounds may be promising candidates as an anti-inflammatory agent.

Tuning the Pyridine Units in Vinylene-Linked Covalent Organic Frameworks Boosting 2e- Oxygen Reduction Reaction.

The N-doped carbon materials are supposed to be the efficient oxygen reduction reaction (ORR) catalysts with the undefined N-doped carbon ring groups. It is essential to well define the role of the nitrogen atoms of these carbon structures in active behavior. Even though, the covalent organic frameworks (COFs) with precise structures are well developed, but unable to exclude the polar linkages influence. This study presents a series of pyridine-containing COFs linked via nonpolar carbon-carbon double bonds (C = C). Their catalytic activity and selectivity for 2e- ORR are successfully modulated by locating the embedded pyridine nitrogen in the backbones through the linking modes of pyridine moieties within the frameworks. Such phenomena can be attributed to their different binding abilities toward O2, leading to the different binding strength of the intermediate OH* to the catalytic sites, also verified by the theoretical calculation. This work provides us a new insight to design high-efficiency ORR catalysts through the exact location of pyridine nitrogen.

The discovery of a new potent FXR agonist based on natural product screening.

FXR agonistic activity screening was conducted based on natural product resources containing 38 structurally diverse sesquiterpenoids isolated from Xylopia vielana. Among them, 34 undescribed sesquiterpenoids with 5 different skeleton types were first characterized by HRESIMS, NMR data, ECD calculations and X-ray crystallographic analysis. High-content screening for FXR agonistic activity of these compounds demonstrated that 13 compounds could activate FXR. Then molecular docking results suggested that hydrogen bonding and hydrophobic interactions might contribute to the main interaction of active compounds with FXR. The preliminary structure-activity relationships (SARs) of those isolates were also discussed. The most potent compound 27 significantly elevated the transcriptional activity of the FXR target gene BSEP promoter (EC50 = 14.26 µM) by a dual-luciferase reporter assay. Western blotting indicated that compound 27 activated the FXR-associated pathway, thereby upregulating SHP and BSEP expression, and downregulating CYP7A1 and NTCP expression. We further revealed that FXR was the target protein of compound 27 through diverse target validation methods, including CETSA, SIP, and DARTS under the intervention of temperature, organic reagents and protease. Pharmacological in vivo experiments showed that compound 27 effectively ameliorated α-naphthyl isothiocyanate (ANIT)-induced cholestasis in mice, as evidenced by the ameliorative histopathology of the liver and the decrease in biochemical markers: alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total bilirubin (TBIL), direct bilirubin (DBIL), and total bile acid (TBA). This work showed a practical strategy for the discovery of new FXR agonists from natural products and provided potential insights for sesquiterpenoids as FXR agonist lead compounds.

Herpetrione, a New Type of PPARα Ligand as a Therapeutic Strategy Against Nonalcoholic Steatohepatitis.

Non-alcoholic fatty liver disease, especially nonalcoholic steatohepatitis (NASH), is a leading cause of cirrhosis and liver cancer worldwide; nevertheless, there are no Food and Drug Administration-approved drugs for treating NASH until now. Peroxisome proliferator-activated receptor alpha (PPARα) is an interesting therapeutic target for treating metabolic disorders in the clinic, including NASH. Herpetrione, a natural lignan compound isolated from Tibetan medicine Herpetospermum caudigerum, exerts various hepatoprotective effects, but its efficacy and molecular mechanism in treating NASH have not yet been elucidated. Here, we discovered that herpetrione lessened lipid accumulation and inflammation in hepatocytes stimulated with oleic acid and lipopolysaccharide, and effectively alleviated NASH caused by a high-fat diet or methionine-choline-deficient diet by regulating glucolipid metabolism, insulin resistance, and inflammation. Mechanistically, RNA-sequencing analyses further showed that herpetrione activated PPAR signaling, which was validated by protein expression. Furthermore, the analysis of molecular interactions illustrated that herpetrione bound directly to the PPARα protein, with binding sites extending to the Arm III domain. PPARα deficiency also abrogated the protective effects of herpetrione against NASH, suggesting that herpetrione protects against hepatic steatosis and inflammation by activation of PPARα signaling, thereby alleviating NASH. Our findings shed light on the efficacy of a natural product for treating NASH, as well as the broader prospects for NASH treatment by targeting PPARα.

Mitochondrial complex I inhibition by homoharringtonine: A novel strategy for suppression of chronic myeloid leukemia.

Chronic myeloid leukemia (CML) is a hematologic malignancy predominantly driven by the BCR-ABL fusion gene. One of the significant challenges in treating CML lies in the emergence of resistance to tyrosine kinase inhibitors (TKIs), especially those associated with the T315I mutation. Homoharringtonine (HHT) is an FDA-approved, naturally-derived drug with known anti-leukemic properties, but its precise mechanisms of action remain incompletely understood. In this study, we rigorously evaluated the anti-CML activity of HHT through both in vitro and in vivo assays, observing substantial anti-CML effects. To elucidate the molecular mechanisms underpinning these effects, we performed proteomic analysis on BCR-ABL T315I mutation-bearing cells treated with HHT. Comprehensive pathway enrichment analysis identified oxidative phosphorylation (OXPHOS) as the most significantly disrupted, suggesting a key role in the mechanism of action of HHT. Further bioinformatics exploration revealed a substantial downregulation of proteins localized within mitochondrial complex I (MCI), a critical OXPHOS component. These results were validated through Western blot analysis and were supplemented by marked reductions in MCI activity, ATP level, and oxygen consumption rate (OCR) upon HHT exposure. Collectively, our results shed light on the potent anti-CML properties of HHT, particularly its effectiveness against T315I mutant cells through MCI inhibition. Our study underscores a novel therapeutic strategy to overcome BCR-ABL T315I mutation resistance, illuminating a previously uncharted mechanism of action for HHT.

Narrow-Pore Engineering of Vinylene-Linked Covalent Organic Frameworks with Weak Interaction-Triggered Multiple Responses.

Vinylene-linked covalent organic frameworks (COFs) are emerging as promising crystalline materials, but their narrow pore engineering is severely impeded by the weak reversibility of the carbon-carbon double bond formation reaction, which has led to less exploration of their ultramicroporous structures and properties. Herein, we developed a single aromatic ring-based tetratopic monomer, tetramethylpyrazine, which undergoes a smooth Knoevenegal condensation at its four arylmethly carbon atoms with linear aromatic dialdehyde monomers upon the self-catalyzed activation of pyridine nitrogen-containing monomers in the presence of an organic anhydride. This has resulted in the formation of two vinylene-linked COFs, which both crystallized in orthorhombic lattices, and layered in AA stacking fashions along the vertical directions. They exhibit high surface areas and well-tailored ultramicropore sizes up to 0.5 nm. The unique cross-linking mode at two pairs of para-positions of each pyrazine unit through carbon-carbon double bonds afford them with π-extended conjugation over the in-plane backbones and substantial semiconducting characters. The resultant COFs can be well-dispersed in water to form stable sub-microparticles with negative charges (zeta potentials: ca. -30 mV), and exhibiting tunable aggregation behaviors through protonation/deprotonation. As a consequence, they exhibit pore-size-dependent colorimetric responses to various anions with different pKa values in high selectivity.

Hexatopic Vertex-Directed Approach to Vinylene-Linked Covalent Organic Frameworks with Heteroporous Topologies.

A D3h-symmetric hexatopic monomer was first prepared by attaching the three-fold ditopic moiety 2,6-dimethylpyridine to the meta-positions of a phenyl ring. It was further condensed at its six pyridylmethyl carbons with linear ditopic aromatic dialdehydes, resulting in two vinylene-linked COFs with heteroporous topologies, as revealed by powder X-ray diffraction (PXRD), nitrogen sorption, and pore-size distribution analyses, as well as transmission electron microscopy (TEM) image. The linear- and cross-conjugations, respectively, arising from the 2,6-linked pyridines and meta-linked phenylenes in the hexatopic nodes rendered the resultant COFs with well-patterned π-delocalization, allowing for efficiently catalyzing the bromination of aromatic derivatives with the pore-size-dependent conversion yields and regioselectivity under the irradiation of green light.

Chemical constituents from the roots of Dolomiaea souliei.

A new benzofuran-type neolignan (1), two new phenylpropanoids (2 - 3), and one new C21 steroid (4) were isolated from the ethyl acetate extract of the roots of Dolomiaea souliei by chromatographic methods, including silica gel, ODS column chromatography, MPLC, and semi-preparative HPLC. Their structures were identified as dolosougenin A (1), (S)-3-isopropylpentyl (E)-3-(4-hydroxy-3-methoxyphenyl) acrylate (2), (S)-3-isopropylpentyl (Z)-3-(4-hydroxy-3-methoxyphenyl) acrylate (3) and dolosoucin A (4) through various spectroscopic techniques including 1D NMR, 2D NMR, IR, UV, HR ESI MS, ORD, and computational ORD methods.

Salidroside alleviates acetaminophen-induced hepatotoxicity via Sirt1-mediated activation of Akt/Nrf2 pathway and suppression of NF-κB/NLRP3 inflammasome axis.

Acetaminophen (APAP) overdose-induced hepatotoxicity is the most common cause of drug-induced liver injury worldwide, which is significantly linked to oxidative stress and sterile inflammation. Salidroside is the main active component extracted from Rhodiola rosea L., with anti-oxidative and anti-inflammatory activities. Herein, we investigated the protective effects of salidroside on APAP-induced liver injury and its underlying mechanisms. Pretreatment with salidroside reversed the impacts of APAP on cell viability, LDH release, and cell apoptosis in L02 cells. Moreover, the phenomena of ROS accumulation and MMP collapse caused by APAP were reverted by salidroside. Salidroside elevated the levels of nuclear Nrf2, HO-1, and NQO1. Using PI3k/Akt inhibitor LY294002 further confirmed that salidroside mediated the Nrf2 nuclear translocation through the Akt pathway. Pretreatment with Nrf2 siRNA or LY294002 markedly prevented the anti-apoptotic effect of salidroside. Additionally, salidroside reduced the levels of nuclear NF-κB, NLRP3, ASC, cleaved caspase-1, and mature IL-1ß elevated by APAP. Moreover, salidroside pretreatment increased Sirt1 expression, whereas Sirt1 knock-down diminished the protective activities of salidroside, simultaneously reversing the up-regulation of the Akt/Nrf2 pathway and the down-regulation of NF-κB/NLRP3 inflammasome axis mediated by salidroside. We then used C57BL/6 mice to establish APAP-induced liver injury models and found that salidroside significantly alleviated liver injury. Furthermore, western blot analyses showed that salidroside promoted the Sirt1 expression, activated the Akt/Nrf2 pathway, and inhibited the NF-κB/NLRP3 inflammasome axis in APAP-treated mice. The findings of this study support a possible application of salidroside in the amelioration of APAP-induced hepatotoxicity.

In situ potential-regulated architecture of an ultrafine Ru-based electrocatalyst for ultralow overpotential lithium-oxygen batteries.

An in situ electrochemical reduction strategy is proposed to avoid the aggregation of nano-Ru in lithium batteries for the first time. The high-dispersion face-centered cubic (fcc) nano-Ru is successfully synthesized with an average diameter of 2.0 nm, and the as-assembled lithium-oxygen batteries deliver an excellent cycling performance of 185 cycles and an ultralow overpotential of only 0.20 V at 100 mA g-1.

Single-cell-array biomass-templated architecture of hierarchical porous electrocatalysts for Zn-air and Zn-H2O2 batteries.

Hierarchically macro-meso-microporous ZIF-67/nori-derived electrocatalysts were synthesized by using single-cell-array nori and ZIF-67 as macroporous and microporous templates, and KOH as a meso/micropore-forming reagent. The ZIF-67/nori-800-based Zn-H2O2 battery achieved a high maximum power density, of 476 mW cm-2, and a specific energy density of 964 W h kg-1 at 50 mA cm-2.

Comprehensive monitoring of mitochondrial viscosity variation during different cell death processes by a NIR mitochondria-targeting fluorescence probe.

Cell death is a fundamental feature of multicellular organisms, in which mitochondria play crucial roles. Therefore, revealing and monitoring the microenvironment of mitochondria are significant to investigate cell death process. Herein, the mitochondrial viscosity variation behaviors of a series of different cell death processes were monitored with a NIR mitochondria-targeting fluorescence probe FLV. FLV was designed based on a rotatable flavylocyanine fluorophore that presented selective and sensitive NIR fluorescence enhancement response with the increase of environmental viscosity. Fluorescence imaging experiments of living cells incubated with nystatin or under different temperature indicated that FLV was capable of imaging the change of mitochondrial viscosity. Finally, FLV was applied for monitoring the mitochondrial viscosity variation during different cell death processes. It was found that there were obvious mitochondrial viscosity increases during apoptosis, necrosis and autophagy; however, no detectable mitochondrial viscosity variation was observed in ferroptosis process incubated with ferroptosis inducer erastin or RSL3 for 6 h. These results demonstrated that FLV is a viable tool for monitoring the mitochondrial viscosity variation and is likely to be used in the diagnosis of the mitochondrial viscosity-associated cell processes and diseases.