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1.
Eur J Med Chem ; 187: 111941, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31821989

RESUMO

Threonyl-tRNA synthetase (ThrRS) is a key member of the aminoacyl-tRNA synthetase (aaRS) family that plays essential roles in protein biosynthesis, and ThrRS inhibitors have potential in the therapy of multiple diseases, such as microbial infections and cancers. Based on a unique tRNA-amino acid dual-site inhibitory mechanism identified recently with the herb-derived prolyl-tRNA synthetase (ProRS) inhibitor halofuginone (HF), a series of compounds have been designed and synthesized by employing a fragment-based target hopping approach to simultaneously target the tRNAThr and l-threonine binding pockets of ThrRS. Among them, compound 30d showed an IC50 value of 1.4 µM against Salmonella enterica ThrRS (SeThrRS) and MIC values of 16-32 µg/mL against the tested bacterial strains. The cocrystal structure of SeThrRS in complex with 30d was determined at high resolution, revealing that 30d simultaneously occupies both binding pockets for the nucleotide A76 of tRNAThr and l-threonine in an ATP-independent manner, a novel mechanism compared to all other reported ThrRS inhibitors. Our study provides a new class of ThrRS inhibitors, and more importantly, it presents the first experimental evidence that the tRNA-amino acid dual-site inhibitory mechanism could apply to other aaRSs beyond ProRS, thus providing great opportunities for designing new mechanistic inhibitors for aaRS-based therapeutics.

2.
Bioorg Chem ; 92: 103292, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31561105

RESUMO

Seven new diterpenoids, euphorantones A-D (1, 3, 6, and 10), 8,12,13-epi-3,7,12-O-triacetyl-8-O-(2-methylbutanoyl)-ingol (9), 8,12,13-epi-3,12-O-diacetyl-7-O-benzoyl-8-methoxyingol (11), 2,3-epi-7,12-diacetate-8-benzoate-ingol (12), together with eighteen known compounds (2, 4-5, 7-8, and 13-25), were isolated from the aerial parts of Euphorbia antiquorum L.. The structures of new compounds 1, 3, 6, and 9-12 were elucidated by extensive spectroscopic analyses. The absolute configurations of new compounds were assigned using X-ray diffraction, Rh2(OCOCF3)4-induced CD spectrum, and confirmed through comparison of the calculated and experimental 13C NMR and electronic circular dichroism (ECD) data. Compounds 1-25 were evaluated for their inhibition of RANKL-induced osteoclastogenesis. Compound 1 showed the most potent inhibition of RANKL-induced osteoclastogenesis with IC50 value of 0.3 µM. It inhibited NFAT transcript activity and osteoclast related genes TRAcP, CTSK, and NFATc1 expression.

3.
Fitoterapia ; 141: 104344, 2019 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-31465814

RESUMO

Two new lignans (1 and 12), together with 15 known compounds (2-11 and 13-17), were isolated from the aerial parts of Saururus chinensis Baill. Their structures were determined through extensive spectroscopic analyses. All the isolates were evaluated for their cytotoxicity against four human nasopharyngeal carcinoma cells (HONE1, CNE1, CNE2, and SUNE1). Compound 13 showed the most potent cytotoxicity toward HONE1, SUNE1, CNE2, and CNE1 cells with IC50 values of 0.76, 5.42, 5.86 and 6.28 µM, respectively. Further studies revealed that compound 13 suppressed cell growth by arresting the cell cycle at the S phase and induced cell apoptosis in the HONE1 cell line.

4.
Artigo em Inglês | MEDLINE | ID: mdl-31010248

RESUMO

Lead exposure is associated with a wide range of adverse effects on human health. The principal exposure route in the general population is through the diet. In this study, we estimate the dietary lead intake and associated health risks among the residents of Guangzhou, China. Data on lead concentrations were derived from the food safety risk monitoring system, which included 6339 samples from 27 food categories collected in 2014-2017. Food consumption data were taken from a 2011 dietary survey of 2960 Guangzhou residents from 998 households. Dietary lead intake was estimated by age group (3-6, 7-17, 18-59, and ≥60 years), and relevant health risks were assessed using the margin of exposure (MOE) method. The mean and 95th percentiles (P95) of dietary lead intake were respectively 0.7466 and 2.4525 µg/kg body weight per day for preschool children aged 3-6 years; 0.4739 and 1.5522 µg/kg bw/day for school children aged 7-17 years; 0.3759 and 1.1832 µg/kg bw/day for adults aged 18-59 years; and 0.4031 and 1.3589 µg/kg bw/day for adults aged ≥60 years. The MOE value was less than 1 for preschool children at the mean exposure level and for all age groups at the P95 exposure level. Rice and its products, leafy vegetables, and wheat flour and its products were found to be the primary food sources of lead exposure. Our findings suggest that the health risk from dietary lead exposure is low for Guangzhou residents overall, but that young children and consumers of certain foods may be at increased risk. Continued efforts are needed to reduce the dietary lead exposure in Guangzhou.


Assuntos
Exposição Dietética/estatística & dados numéricos , Contaminação de Alimentos , Chumbo , Adolescente , Adulto , Criança , Pré-Escolar , China , Dieta/estatística & dados numéricos , Exposição Ambiental , Feminino , Farinha , Humanos , Masculino , Pessoa de Meia-Idade , Oryza , Inquéritos e Questionários , Triticum , Verduras , Adulto Jovem
5.
J Nat Prod ; 82(2): 349-357, 2019 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-30726671

RESUMO

Twelve new guaianolide-type sesquiterpenoids (1-12) and five known guaianolide derivatives (13-17) were isolated from an aqueous ethanol extract of the aerial parts of Chrysanthemum indicum. Their structures were determined through spectroscopic data analysis. The absolute configurations of the new compounds were assigned by X-ray crystallography and electronic circular dichroism. Compound 5 shows multiple cytotoxic activities against four human naso-pharyngeal carcinoma (NPC) cell lines (CNE1, CNE2, SUNE-1, and HONE-1) and one human intestinal epithelial cell line (HT-29) with IC50 values of 4.6, 6.0, 3.5, 4.3, and 9.6 µM, respectively. Compound 16 exhibits weak cytotoxicity against four NPC cell lines, CNE1 (IC50 = 7.3 µM), CNE2 (IC50 = 7.4 µM), HONE-1 (IC50 = 7.6 µM), and SUNE-1 (IC50 = 5.6 µM), but no cytotoxicity against HT-29 (IC50 > 10 µM).

6.
Fitoterapia ; 130: 105-111, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30145333

RESUMO

Two new sesquiterpenoids (1-2), together with 30 known compounds including one sesquiterpenoid (3), six diterpenoids (4-9), fourteen lignans (10-23), and nine other kinds of compounds (24-32), were isolated from the stems of Daphne tangutica Maxim. Their structures were determined through extensive spectroscopic analyses, and the absolute configuration of daphnoid A (1) and B (2) were determined by the experimental and calculated electron circular dichroism (ECD) spectra. All the isolates were evaluated against two human nasopharyngeal carcinoma cells (HONE-1 and SUNE-1). Compound 25 (daphnenone) showed potent cytotoxicity toward HONE-1 and SUNE-1with IC50 values of 2.23 and 1.43 µM, respectively. Further studies indicated that compound 25 exhibited cytotoxic effects by inducing tumor cell apoptosis and arresting the cell cycle at G2/M phases in HONE-1 cells.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Daphne/química , Sesquiterpenos/farmacologia , Antineoplásicos Fitogênicos/isolamento & purificação , Apoptose , Carcinoma/patologia , Pontos de Checagem do Ciclo Celular , Linhagem Celular Tumoral , China , Humanos , Estrutura Molecular , Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas/patologia , Compostos Fitoquímicos/isolamento & purificação , Compostos Fitoquímicos/farmacologia , Caules de Planta/química , Sesquiterpenos/isolamento & purificação
7.
Sci Rep ; 5: 16715, 2015 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-26581251

RESUMO

In this work, a hierarchical DNA-directed self-assembly strategy to construct structure-controlled Au nanoassemblies (NAs) has been demonstrated by conjugating Au nanoparticles (NPs) with internal-modified dithiol single-strand DNA (ssDNA) (Au-B-A or A-B-Au-B-A). It is found that the dithiol-ssDNA-modified Au NPs and molecule quantity of thiol-modified ssDNA grafted to Au NPs play critical roles in the assembly of geometrically controlled Au NAs. Through matching Au-DNA self-assembly units, geometrical structures of the Au NAs can be tailored from one-dimensional (1D) to quasi-2D and 2D. Au-B-A conjugates readily give 1D and quasi-2D Au NAs while 2D Au NAs can be formed by A-B-Au-B-A building blocks. Surface-enhanced Raman scattering (SERS) measurements and 3D finite-difference time domain (3D-FDTD) calculation results indicate that the geometrically controllable Au NAs have regular and linearly "hot spots"-number-depended SERS properties. For a certain number of NPs, the number of "hot spots" and accordingly enhancement factor of Au NAs can be quantitatively evaluated, which open a new avenue for quantitative analysis based on SERS technique.


Assuntos
DNA/química , Ouro/química , Nanopartículas Metálicas/química , Conformação Molecular , Análise Espectral Raman , Tolueno/análogos & derivados , Simulação por Computador , Eletroforese em Gel de Ágar , Nanopartículas Metálicas/ultraestrutura , Espectrofotometria Ultravioleta , Tolueno/química
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