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ABSTRACT A highly sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of limonin in beagle dog plasma using nimodipine as internal standard. The analyte and internal standard (IS) were extracted with ether followed by a rapid isocratic elution with 10 m m ammonium acetate buffer-methanol (26:74, v/v) on a C18 column (150 × 2.1 mm i.d.) and subsequent analysis by mass spectrometry in the multiple reaction monitoring mode. The precursor to product ion transitions of m/ z 469.4 → 229.3 and m/ z 417.2 → 122.0 were used to measure the analyte and the IS. The assay was linear over the concentration range of 0.625-100 ng/mL for limonin in dog plasma. The lower limit of quantification was 0.312 ng/mL and the extraction recovery was >90.4% for limonin. The inter- and intra-day precision of the method at three concentrations was less than 9.9%. The method was successfully applied to pharmacokinetic study of limonin in dogs. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A metal−semiconductor transition in the smallest (2,2) single-wall carbon nanotube (SWNT) is predicted theoretically as a function of gate voltage. By hole-doping (or heavy electron-doping), the energy gap of a neutral (2,2) SWNT vanishes with structural change, and the (2,2) SWNT becomes metallic. The (2,2) tube assumes a doubly degenerate ground state around the charge neutral condition with an energy barrier, while this tube has only one nondegenerate metallic ground state over an energy window of −0.12 to .40 eV. Because of a high density of states at the Fermi energy for hole-doped (2,2) SWNTs, a possible superconducting transition is expected. [ABSTRACT FROM AUTHOR]

Metal atomic chain (MAC) is an ultimate one-dimensional structure with unique physical properties, such as quantized conductance, colossal magnetic anisotropy, and quantized magnetoresistance. Therefore, MACs show great potential as possible components of nanoscale electronic and spintronic devices. However, MACs are usually suspended between two macroscale metallic electrodes; hence obvious technical barriers exist in the interconnection and integration of MACs. Here we report a carbon nanotube (CNT)-clamped MAC, where CNTs play the roles of both nanoconnector and electrodes. This nanostructure is prepared by in situ machining a metal-filled CNT, including peeling off carbon shells by spatially and elementally selective electron beam irradiation and further elongating the exposed metal nanorod. The microstructure and formation process of this CNT-clamped MAC are explored by both transmission electron microscopy observations and theoretical simulations. First-principles calculations indicate that strong covalent bonds are formed between the CNT and MAC. The electrical transport property of the CNT-clamped MAC was experimentally measured, and quantized conductance was observed. [ABSTRACT FROM AUTHOR]

Doping NaAlH4 with Ti-catalyst has produced a promising hydrogen storage system that can be reversibly operated at moderate temperature conditions. Of the various dopant precursors, TiCl3 was well recognized due to its pronounced catalytic effect on the reversible dehydrogenation processes of sodium aluminium hydrides. Quite recently we experimentally found that TiF3 was even better than TiCl3 in terms of the critical hydrogen storage properties of the doped hydrides, in particular the dehydriding performance at Na3AlH6/NaH + Al step at moderate temperature. We present here the DFT calculation results of the TiF3 or TiCl3 doped Na3AlH6. Our computational studies have demonstrated that F− and Cl− anions differ substantially from each other with regard to the state and function in the doped sodium aluminium hydride. In great contrast to the case of chloride doping where Cl− anion constitutes the “dead weight” NaCl, the fluoride doping results in a substitution of H− by F− anion in the hydride lattice and accordingly, a favorable thermodynamics adjustment. These results well explain the observed dehydriding performance associated with TiF3/TiCl3-doping. More significantly, the coupled computational and experimental efforts allow us to put forward a “functional anion” concept. This renews the current mechanism understanding in the catalytically enhanced sodium alanate. [ABSTRACT FROM AUTHOR]

The dissociation of SO3 molecules on the walls of armchair (m, m) (m=3, 5) and zigzag (n, 0) (n=5-10) single-wall carbon nanotubes (SWCNTs) was investigated using first-principles calculations. The calculated reaction enthalpies and energy barriers show a nearly linear decrease with decreasing tube diameter. Our results indicate that the dissociation of SO3 on the walls of SWCNTs is strongly dependent on the tube diameter for the selective etching of SWCNTs with small diameters (d<1nm) by gaseous SO3. Our study sheds light on effective separation of SWCNTs for their practical application in many fields. [ABSTRACT FROM AUTHOR]

The chemical constituents of Schizonepetae Spica were qualitatively analyzed by UHPLC-Q-TOF-MS/MS. An Agilent poroshell 120 SB-C&#95;(18) column(3.0 mm×100 mm, 2.7 μm) was used for gradient elution with 0.1% formic acid water(A)-acetonitrile(B) solution as mobile phase at the flow rate of 0.4 mL·min~(-1) and column temperature of 45 ℃. The data were collected by scanning in positive and negative ion modes, and the compounds were identified by comparison of reference materials and PeakView software. Ninety-seven compounds were identified from Schizonepetae Spica, including 28 flavonoids, 23 phenolic acids, 23 fatty acids, 15 terpenoids, and 8 other compounds. The UHPLC-Q-TOF-MS/MS method established in this study can identify the chemical components of Schizonepetae Spica rapidly, accurately, and comprehensively, and provide a basis for the basic study of pharmacodynamic substances of Schizonepetae Spica.

Background: Abelmoschus manihot (L.) Medik ("Huangkui" in Chinese, HK) has been widely used for the treatment of kidney diseases. Nephrotoxicity is the side effect of cisplatin (CDDP), which greatly limits its clinical application. Therefore, CDDP could be used to establish the chronic kidney disease (CKD) model. However, the protective effects of HK on CDDP-induced CKD have not been investigated. Purpose: To explore the protective effect and underlying mechanisms of HK on multiple low-dose CDDP-induced CKD in rats by the integrated analysis of serum, kidney, and urine metabolomics and network pharmacology. Methods: The CKD model was induced by multiple low-dose CDDP. Body weight, organ index, serum biochemical, and kidney histology were examined to evaluate the effect of HK. Serum, kidney, and urine were collected and profiled by HILIC/RPLC-Q-TOF/MS-based metabolomics. Potential biomarkers (PBs) were screened according to the criteria of VIP >1, p < 0.01, and FC > 2, and then identified or assigned. The pathway analysis and PBs enrichment were conducted by MetaboAnalyst and ChemRICH. Furthermore, network pharmacology was adopted to dig out the active components and targets. Finally, the results from metabolomics and network pharmacology were integrated to confirm each other. Results: HK could recover the CDDP-induced abnormal pharmacological and metabolic profile changes. A total of 187 PBs were screened and identified from the serum, kidney, and urine metabolomics. Pathway analysis showed that multiple metabolic pathways, mainly related to amino acid and lipid metabolisms, were involved in the nephroprotective effect of HK, and especially, HK could significantly alleviate the disorder of tryptophan metabolism pathway in serum, kidney, and urine. Meanwhile, network pharmacology analysis revealed that 5 components in HK and 4 key genes could be responsible for the nephroprotection of HK, which also indicated that the metabolism of tryptophan played an important role in HK against CKD. Conclusion: HK has a nephroprotection on CDDP-induced CKD, mainly by restoring the dysregulation of tryptophan metabolism. Integrated analysis of serum, kidney, and urine metabolomics and network pharmacology was a powerful method for exploring pharmacological mechanisms and screening active components and targets of traditional Chinese medicine., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer WY declared a shared parent affiliation with the authors to the handling editor at the time of review., (Copyright © 2022 Liao, Li, Teng, Jian-Chen, Yu, Ju and Zou.)

The samples of Huangqi injection (HI) were analyzed by liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC-TOF-MS), and both positive and negative ion modes were employed to obtain the LC-TOF-MS analysis information of chemical compounds in HI. Then the mass defect filtering (MDF) approach, which was developed based on the previously published articles, was utilized to rapidly screen the astragalosides from the obtained LC-TOF-MS data. Each screened astragaloside was confirmed by the presence of no less than 2 quasi-molecular ions. All the screened astragalosides were then tentatively assigned according to the parent ion and daughter ion information. Finally, a total of 62 astragalosides were screened and characterized from the HI samples, including 15 new detected ones. The identification results indicated that acetylation, hydrogenation, dehydrogenation, methoxylation and hydration might be the major conversion reactions involved in the formation of the astragalosides. The LC-TOF-MS-based MDF approach was proved to be a feasible and efficient tool to screen the chemical constituents in complex matrices such as herbal medicines., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Chinese Pharmaceutical Association.)

Objective: To further explore the anti-cancer effect of Tounong Powder () extracts (TNSEs) on human colon cancer LoVo cells and examine the possible molecular mechanisms., Methods: The contents of TNSEs were determined by liquid chromatograph-mass spectrometer (LC-MS) analysis after extraction with water and methanol. Variations of cell morphological features were observed using fluorescence microscopy. Cytotoxicity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell cycle distribution and apoptosis were analyzed using flow cytometry at different TNSE doses (0, 62.5, 125, or 250 μg/mL). Protein expressions of phosphatidylinositol 3-kinase (PI3K), phosphate protein kinase B (p-AKT), phosphate mammalian target of rapamycin (p-mTOR), p-p70s6k1, cleaved caspase-9 and -3 were detected using Western blot analysis., Results: TNSEs induced cell growth inhibition in a concentration- and time-dependent manner. Flow cytometric analysis showed apoptotic cells and cell cycle arrest at the G phase after TNSEs treatment compared with controls. Furthermore, TNSEs significantly down-regulated the proteins PI3K, p-AKT, p-mTOR, and p-p70s6k1, and up-regulated the proteins cleaved caspase-9 and -3 dosedependently, as determined by Western blot., Conclusions: TNSEs reduced LoVo cell proliferation, and caused apoptosis and cell-cycle arrest in LoVo cells. This effect might be associated with regulation of the PI3K/AKT signaling pathway.

To observe the serum samples and the anti-inflammatory effect of Tripterygium wilfordii in treating RA by using the pharmacokinetic-pharmacodynamic model, make a correlation analysis on concentration-time and effect-time curves, and explore RORγt, IL-17, STAT3, IL-6 mRNA transcriptional levels in rats by PCR. Methotrexate, tripterine and high-dose T. wilfordii could down-regulate RORγt, IL-17, STAT3, IL-6 mRNA transcriptional levels in AA rat lymph nodes. The study on PK-PD model showed correlations between inflammatory factors and blood concentration of T. wilfordii. T. wilfordii and its main active constituent tripterine could show the inflammatory effect and treat RA by inhibiting IL-17 cytokine.

Colorectal cancer is one of the most common malignant tumors, and is associated with significant morbidity and mortality. In this study, recombinant analgesic-antitumor peptide (rAGAP), a protein consisting of small ubiquitin-related modifier (SUMO) linked with a hexa-histidine tag, was used as an antitumor analgesic peptide. The purpose of the present study was to investigate the antitumor activity of rAGAP in human colon adenocarcinoma SW480 cells and its potential molecular mechanisms of action. In this study, cell viability and apoptosis of rAGAP-treated SW480 cells was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry and 4',6-diamidino-2-phenylindole (DAPI) staining. Western blotting was used to investigate the effects of rAGAP on p27, Bcl-2/Bax and PTEN/PI3K/Akt cellular signal transduction. Our results showed that rAGAP not only enhanced apoptosis, but also inhibited the proliferation of SW480 cells. rAGAP upregulates the expression of p27 in SW480 cells and leads to cell cycle arrest in the G1 phase. Furthermore, rAGAP significantly increases the production of Bax and PTEN and suppresses the activation of Bcl-2, phosphatidylinositol 3-kinase (PI3K) and phospho-Akt (p-Akt) in SW480 cells. These results suggest that rAGAP may be a potential new anti-colorectal cancer drug.