803 research outputs found

    Bioactivity-guided isolation of trypanocidal coumarins and dihydro-pyranochromones from selected Apiaceae plant species.

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    Bioactivity-guided isolation of natural products from plant matrices is widely used in drug discovery. Here, this strategy was applied to identify trypanocidal coumarins effective against the parasite Trypanosoma cruzi, the etiologic agent of Chagas disease (American trypanosomiasis). Previously, phylogenetic relationships of trypanocidal activity revealed a coumarin-associated antichagasic hotspot in the Apiaceae. In continuation, a total of 35 ethyl acetate extracts of different Apiaceae species were profiled for selective cytotoxicity against T. cruzi epimastigotes over host CHO-K1 and RAW264.7 cells at 10 μg/mL. A flow cytometry-based T. cruzi trypomastigote cellular infection assay was employed to measure toxicity against the intracellular amastigote stage. Among the tested extracts, Seseli andronakii aerial parts, Portenschlagiella ramosissima and Angelica archangelica subsp. litoralis roots exhibited selective trypanocidal activity and were subjected to bioactivity-guided fractionation and isolation by countercurrent chromatography. The khellactone ester isosamidin isolated from the aerial parts of S. andronakii emerged as a selective trypanocidal molecule (selectivity index ∼9) and inhibited amastigote replication in CHO-K1 cells, though it was significantly less potent than benznidazole. The khellactone ester praeruptorin B and the linear dihydropyranochromones 3'-O-acetylhamaudol and ledebouriellol isolated from the roots of P. ramosissima were more potent and efficiently inhibited the intracellular amastigote replication at < 10 μM. The furanocoumarins imperatorin, isoimperatorin and phellopterin from A. archangelica inhibited T. cruzi replication in host cells only in combination, indicative of superadditive effects, while alloimperatorin was more active in fractions. Our study reports preliminary structure-activity relationships of trypanocidal coumarins and shows that pyranocoumarins and dihydropyranochromones are potential chemical scaffolds for antichagasic drug discovery

    Verbascum nigrum : cytotoxicity evaluation in A431 epidermoid carcinoma cells and untargeted LC‐HR‐MS/MS metabolite profiling

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    The crude methanolic extract obtained from Verbascum nigrum aerial parts (VNE) and its six fractions (VNF1-VNF6) were initially screened regarding their effects on the viability of immortalized HaCaT keratinocytes and A431 epidermoid carcinoma cells (MTT assay, 24 h). None of the tested samples affected the viability of HaCaT cells in a concentration range of 25-150 μg/mL. VNE and VNF4 exhibited significant cytotoxic effects in A431 cells, with IC50 values of 81.92 and 12.27 μg/mL, respectively; the selectivity index was higher than 10 for VNF4. The untargeted LC/HR-MS/MS metabolite profiling led to the tentative annotation of a total number of 23 compounds. Of these, VNE comprised mainly iridoid glycosides (harpagoside, laterioside, acylated aucubin derivatives), whereas VNF4 showed a high abundance of triterpene saponin glycosides (ilwensisaponins A and C, songarosaponins A and B), constituents known for their selective cytotoxic potential

    Influence of the post-harvest storage time on the multi-biological potential, phenolic and pyrrolizidine alkaloid content of comfrey (Symphytum officinale L.) roots collected from different European regions

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    Comfrey (Symphytum officinale L.) roots are well-known bioactive ingredients included in various cosmeceutical and pharmaceutical preparations. In this study, the influence of the post-harvest storage on the chemico-biological potential of roots collected from different European regions and stored for up to six months was investigated. Total phenolic content (TPC) and total phenolic acid content (TPAC) were spectrophotometrically estimated, whereas the levels of individual phenolic and pyrrolizidine alkaloidal markers were determined by HPLC-DAD and HPLC-MS/MS, respectively. The changes in the biological potential was tracked via antioxidant (DPPH, ABTS, CUPRAC, and FRAP) and anti-enzymatic (cholinesterase, tyrosinase, glucosidase, and amylase) assays. TPC and TPAC varied from 6.48-16.57 mg GAE/g d.w. root and from 2.67-9.03 mg CAE/g, respectively. The concentration of the four phenolics (rosmarinic acid, globoidnan A, globoidnan B, rabdosiin) and six pyrrolizidine alkaloids generally showed maximum values at 1-3 months, after which their levels significantly decreased. With respect to the bioassays, the samples showed a wide range of antioxidant and anti-enzymatic effects; however, a direct storage time-bioactivity relationship was not observed. Similar conclusions were also revealed by the multivariate and correlation analyses. Our study could improve the current knowledge of the shelf-life properties of comfrey-based products and enhance their industrial exploitation

    Genome-wide association study of non-alcoholic fatty liver and steatohepatitis in a histologically-characterised cohort

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    Correction: Volume: 74 Issue: 5 Pages: 1274-1275 DOI: 10.1016/j.jhep.2021.02.003 Correction: Volume78, Issue5 Page: 1085-1086 DOI: 10.1016/j.jhep.2023.02.028 Published MAY 2023Background and Aims Genetic factors associated with non-alcoholic fatty liver disease (NAFLD) remain incompletely understood. To date, most GWAS studies have adopted radiologically assessed hepatic triglyceride content as reference phenotype and so cannot address steatohepatitis or fibrosis. We describe a genome-wide association study (GWAS) encompassing the full spectrum of histologically characterized NAFLD. Methods The GWAS involved 1483 European NAFLD cases and 17781 genetically-matched population controls. A replication cohort of 559 NAFLD cases and 945 controls was genotyped to confirm signals showing genome-wide or close to genome-wide significance. Results Case-control analysis identified signals showing p-values ≤ 5 x 10-8 at four locations (chromosome (chr) 2 GCKR/C2ORF16; chr4 HSD17B13; chr19 TM6SF2; chr22 PNPLA3) together with two other signals with pPeer reviewe

    Phyto-Functionalized Silver Nanoparticles Derived from Conifer Bark Extracts and Evaluation of Their Antimicrobial and Cytogenotoxic Effects

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    Silver nanoparticles synthesized using plant extracts as reducing and capping agents showed various biological activities. In the present study, colloidal silver nanoparticle solutions were produced from the aqueous extracts of Picea abies and Pinus nigra bark. The phenolic profile of bark extracts was analyzed by liquid chromatography coupled to mass spectrometry. The synthesis of silver nanoparticles was monitored using UV-Vis spectroscopy by measuring the Surface Plasmon Resonance band. Silver nanoparticles were characterized by attenuated total reflection Fourier transform infrared spectroscopy, Raman spectroscopy, dynamic light scattering, scanning electron microscopy, energy dispersive X-ray and transmission electron microscopy analyses. The antimicrobial and cytogenotoxic effects of silver nanoparticles were evaluated by disk diffusion and Allium cepa assays, respectively. Picea abies and Pinus nigra bark extract derived silver nanoparticles were spherical (mean hydrodynamic diameters of 78.48 and 77.66 nm, respectively) and well dispersed, having a narrow particle size distribution (polydispersity index values of 0.334 and 0.224, respectively) and good stability (zeta potential values of −10.8 and −14.6 mV, respectively). Silver nanoparticles showed stronger antibacterial, antifungal, and antimitotic effects than the bark extracts used for their synthesis. Silver nanoparticles obtained in the present study are promising candidates for the development of novel formulations with various therapeutic applications

    Physics case for an LHCb Upgrade II - Opportunities in flavour physics, and beyond, in the HL-LHC era

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    The LHCb Upgrade II will fully exploit the flavour-physics opportunities of the HL-LHC, and study additional physics topics that take advantage of the forward acceptance of the LHCb spectrometer. The LHCb Upgrade I will begin operation in 2020. Consolidation will occur, and modest enhancements of the Upgrade I detector will be installed, in Long Shutdown 3 of the LHC (2025) and these are discussed here. The main Upgrade II detector will be installed in long shutdown 4 of the LHC (2030) and will build on the strengths of the current LHCb experiment and the Upgrade I. It will operate at a luminosity up to 2×1034 cm−2s−1, ten times that of the Upgrade I detector. New detector components will improve the intrinsic performance of the experiment in certain key areas. An Expression Of Interest proposing Upgrade II was submitted in February 2017. The physics case for the Upgrade II is presented here in more depth. CP-violating phases will be measured with precisions unattainable at any other envisaged facility. The experiment will probe b → sl+l−and b → dl+l− transitions in both muon and electron decays in modes not accessible at Upgrade I. Minimal flavour violation will be tested with a precision measurement of the ratio of B(B0 → μ+μ−)/B(Bs → μ+μ−). Probing charm CP violation at the 10−5 level may result in its long sought discovery. Major advances in hadron spectroscopy will be possible, which will be powerful probes of low energy QCD. Upgrade II potentially will have the highest sensitivity of all the LHC experiments on the Higgs to charm-quark couplings. Generically, the new physics mass scale probed, for fixed couplings, will almost double compared with the pre-HL-LHC era; this extended reach for flavour physics is similar to that which would be achieved by the HE-LHC proposal for the energy frontier
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