Sesquiterpene lactones with anti-inflammatory and cytotoxic activities from the roots of Cichorium intybus.

Cichorium intybus L. (Asteraceae), belonging to the tribe Cichorieae of the family Asteraceae, has a long history as an edible and medicinal food. Sesquiterpene lactones are commonly considered as its major active constituents. In the current study, five unreported sesquiterpene lactones, including one 12,8-guaianolide and four 12,6-guaianolides were isolated from C. intybus roots, as well as 16 known analogues. The planar structures and relative configurations of these compounds were elucidated by extensive spectroscopic analysis. The absolute configurations were determined by the time-dependent density functional theory (TDDFT)-based electronic circular dichroism (ECD) calculation method. Bioassay results showed that seven of the isolates exhibited remarkable NO production inhibitory activity in LPS-stimulated RAW264.7 macrophages, with IC50 values ranging from 1.83 to 38.81 µM. Some of them can significantly decrease the secretion of inflammatory cytokines (TNF-α and IL-6). Cytotoxicity assays demonstrated that intybusins B, as well as four known compounds, displayed obvious inhibitory activities against four human tumor cells, with IC50 values ranging from 9.01 to 27.07 µM.

Can cervical vascular ultrasound combined with transcranial Doppler ultrasound accurately diagnose cerebral infarction?: A protocol for a systematic review and meta-analysis.

BACKGROUND: The purpose of this study is to investigate the impact of cervical vascular ultrasound (CVU) combined transcranial Doppler ultrasound (TDU) in the diagnosis of cerebral infarction (CI). METHODS: The following electronic databases will be sought from PUBMED, EMBASE, Cochrane Library, PSYCINFO, Web of Science, Allied and Complementary Medicine Database, WANGFANG, VIP database, and China National Knowledge Infrastructure. The search period will cover from the initial indexing to March 1, 2020 without restrictions of language and publication status. All case-controlled studies which identifying the impact of CVU combined TDU in the diagnosis of CI will be considered. Two authors will independently perform the whole process of study selection, data extraction, and quality assessment, respectively. If any disagreements occur between two authors, we will invite a third experienced author to help solve them through discussion. Quality Assessment of Diagnostic Accuracy Studies tool will be used to check study quality, and RevMan V.5.3 software and Stata V.12.0 software will be utilized to carry out statistical analysis. RESULTS: This study will summarize the most recent evidence that focusing on the impact of CVU combined TDU in the diagnosis of CI. CONCLUSION: This study will provide helpful evidence to determine whether CVU combined TDU is an accurate diagnosis tool for CI or not. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42020171367.

The Native Plasmid pML21 Plays a Role in Stress Tolerance in Enterococcus faecalis ML21, as Analyzed by Plasmid Curing Using Plasmid Incompatibility.

To investigate the role of the native plasmid pML21 in Enterococcus faecalis ML21's response to abiotic stresses, the plasmid pML21 was cured based on the principle of plasmid incompatibility and segregational instability, generating E. faecalis mutant strain ML0. The mutant and the wild strains were exposed to abiotic stresses: bile salts, low pH, H2O2, ethanol, heat, and NaCl, and their survival rate was measured. We found that curing of pML21 lead to reduced tolerance to stress in E. faecalis ML0, especially oxidative and osmotic stress. Complementation analysis suggested that the genes from pML21 played different role in stress tolerance. The result indicated that pML21 plays a role in E. faecalis ML21's response to abiotic stresses.

Exclusive chemoselective reduction of imines in the coexistence of aldehydes using AuNPore catalyst.

Aldimines (R(1)HC═NR(2)) were reduced in the coexistence of aldehydes (R(1)CHO) with 100% chemoselectivity by the use of AuNPore giving corresponding amines (R(1)H2C-NHR(2)) in high chemical yields.

[Spectra and influences of Rayleigh and stimulated Brillouin scattering in fiber-optic distributed disturbance sensor].

Spectra and influences of Rayleigh backscattering (RB) and stimulated Brillouin scattering (SBS) in the fiber-optic distributed disturbance sensor (FDDS) were investigated. Models of RB, double RB (DRB) and SBS in long fibers were established. By numerical simulation, it was found that optical signal-to-noise ratio is extraordinarily reduced due to SBS and RB, which results in location errors. Numerical results were confirmed by experiments and helpful to improving the location precision for applications with long monitored length.

Lewis-acid assisted cross metathesis of acrylonitrile with functionalized olefins catalyzed by phosphine-free ruthenium carbene complex.

The exchange of the PPh3 ligand in the complex [1,3-bis(2,6-dimethylphenyl)4,5-dihydroimidazol-2-ylidene](PPh3)(Cl)2Ru=CHPh (7) for a pyridine ligand at ambient temperature leads to the formation of the stable phosphine-free carbene ruthenium complex [1,3-bis(2,6-dimethylphenyl)4,5-dihydroimidazol-2-ylidene](C5H5N)2(Cl)2 Ru=CHPh (8). The resulted ruthenium complex exhibits highly catalytic activity for the cross metathesis of acrylonitrile with various functionalized olefins under mild conditions, and its activity can be further improved by the addition of a Lewis acid such as Ti(OiPr)4. In the mixture products, the Z-isomer predominates.