Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 86
Filtrar
Más filtros

País/Región como asunto
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
Bioorg Chem ; 148: 107428, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38733749

RESUMEN

Five pairs of new merosesquiterpenoid enantiomers, named dauresorcinols A-E (1-5), were isolated from the leaves of Rhododendron dauricum. Their structures were elucidated by comprehensive spectroscopic data analysis, quantum chemical calculations, Rh2(OCOCF3)4-induced ECD, and single-crystal X-ray diffraction analysis. Dauresorcinols A (1) and B (2) possess two new merosesquiterpene skeletons bearing an unprecedented 2,6,7,10,14-pentamethyl-11-oxatetracyclo[8.8.0.02,7.012,17]octadecane and a caged 15-isohexyl-1,5,15-trimethyl-2,10-dioxatetracyclo[7.4.1.111,14.03,8]pentadecane motif, respectively. Plausible biosynthetic pathways of 1-5 are proposed involving key oxa-electrocyclization and Wagner-Meerwein rearrangement reactions. (+)/(-)-1 and 3-5 showed potent α-glucosidase inhibitory activity, 3 to 22 times stronger than acarbose, an antidiabetic drug targeting α-glucosidase. Docking results provide a basis to design and develop merosesquiterpenoids as potent α-glycosidase inhibitors.


Asunto(s)
Inhibidores de Glicósido Hidrolasas , Rhododendron , Rhododendron/química , Estereoisomerismo , Inhibidores de Glicósido Hidrolasas/química , Inhibidores de Glicósido Hidrolasas/farmacología , Inhibidores de Glicósido Hidrolasas/aislamiento & purificación , Estructura Molecular , Relación Estructura-Actividad , Sesquiterpenos/química , Sesquiterpenos/farmacología , Sesquiterpenos/aislamiento & purificación , alfa-Glucosidasas/metabolismo , Simulación del Acoplamiento Molecular , Humanos , Relación Dosis-Respuesta a Droga , Hojas de la Planta/química , Cristalografía por Rayos X , Modelos Moleculares
2.
Bioorg Chem ; 142: 106928, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-37922768

RESUMEN

A systematical investigation on the chemical constituents of the flowers of Rhododendron molle (Ericaceae) led to the isolation and characterization of thirty-eight highly functionalized grayanane diterpenoids (1-38), including twelve novel analogues molleblossomins A-L (1-12). Their structures were elucidated by comprehensive methods, including 1D and 2D NMR analysis, calculated ECD, 13C NMR calculations with DP4+ probability analysis, and single crystal X-ray diffraction. Molleblossomins A (1), B (2), and E (5) are the first representatives of 2ß,3ß:9ß,10ß-diepoxygrayanane, 2,3-epoxygrayan-9(11)-ene, and 5,9-epoxygrayan-1(10),2(3)-diene diterpenoids, respectively. Molleblossomins G (7) and H (8) represent the first examples of 1,3-dioxolane-grayanane conjugates furnished with the acetaldehyde and 4-hydroxylbenzylidene acetal moieties, respectively. All grayanane diterpenoids 1-38 were screened for their analgesic activities in the acetic acid-induced writhing model, and all of them exhibited significant analgesic activities. Diterpenoids 6, 13, 14, 17, 20, and 25 showed more potent analgesic effects than morphine at a lower dose of 0.2 mg/kg, with the inhibition rates of 51.4%, 68.2%, 94.1%, 66.9%, 97.7%, and 60.0%, respectively. More importantly, even at the lowest dose of 0.04 mg/kg, rhodomollein X (14), rhodojaponin VI (20), and rhodojaponin VII (22) still significantly reduced the number of writhes in the acetic acid-induced pain model with the percentages of 61.7%, 85.8%, and 64.6%, respectively. The structure-activity relationship was summarized and might provide some hints to design novel analgesics based on the functionalized grayanane diterpenoids.


Asunto(s)
Diterpenos , Rhododendron , Rhododendron/química , Estructura Molecular , Flores/química , Analgésicos/farmacología , Analgésicos/uso terapéutico , Analgésicos/química , Diterpenos/farmacología , Diterpenos/uso terapéutico , Diterpenos/química , Ácido Acético/análisis
3.
J Am Chem Soc ; 145(5): 3196-3203, 2023 02 08.
Artículo en Inglés | MEDLINE | ID: mdl-36696679

RESUMEN

Extracellular protein disulfide isomerase (PDI) is a promising target for thrombotic-related diseases. Four potent PDI inhibitors with unprecedented chemical architectures, piericones A-D (1-4), were isolated from Pieris japonica. Their structures were elucidated by spectroscopic data analysis, chemical methods, quantum 13C nuclear magnetic resonance DP4+ and electronic circular dichroism calculations, and single-crystal X-ray diffraction analysis. Piericones A (1) and B (2) were nanomolar noncompetitive PDI inhibitors possessing an unprecedented 3,6,10,15-tetraoxatetracyclo[7.6.0.04,9.01,12]pentadecane motif with nine contiguous stereogenic centers. Their biosynthetic pathways were proposed to include a key intermolecular aldol reaction and an intramolecular 1,2-migration reaction. Piericone A (1) significantly inhibited in vitro platelet aggregation and fibrin formation and in vivo thrombus formation via the inhibition of extracellular PDI without increasing the bleeding risk. The molecular docking and dynamics simulation of 1 and 2 provided a novel structure basis to develop PDI inhibitors as potent antithrombotics.


Asunto(s)
Proteína Disulfuro Isomerasas , Trombosis , Humanos , Proteína Disulfuro Isomerasas/química , Plaquetas/metabolismo , Fibrinolíticos/metabolismo , Simulación del Acoplamiento Molecular , Trombosis/metabolismo
4.
Small ; 19(49): e2303784, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37612805

RESUMEN

Li-S batteries are regarded as promising devices for energy storage systems owing to high energy density, low cost, and environmental friendliness. However, challenges of polysulfides shuttling in sulfur cathode and dendrite growth of lithium anode severely hinder the practical application. Developing advanced skeletons simultaneously regulating the cathode and anode is significant and challenging. Hence, a novel and scalable strategy combining spray drying and topological nitriding is proposed, and hierarchically assembled rGO hollow microspheres encapsulated highly porous nanospheres consisted of ultrafine Nb4 N5 -Nb2 O5 or Nb4 N5 nanoparticles as multifunctional skeletons for S and Li are designed. In such unique architecture, a 3D highly porous structure provides abundant void space for loading of S and Li, and accommodates volume change during cycling. Moreover, Nb4 N5 -Nb2 O5 heterostructured interface promotes adsorption-conversion process of polysulfides, while strong lithophilic Nb4 N5 induces the selective infiltration of Li into the void of the skeleton and regulates the uniform deposition and growth. More interestingly, in situ generated Li3 N@Nb ion/electron conducting interfaces induced by the reaction of Nb4 N5 and Li reduce the nucleation overpotential and induce selective deposition of Li into the cavity. Consequently, the Li-S full cell exhibits superior cycling stability and impressive rate performance with a low capacity ratio of negative/positive.

5.
Chemistry ; 29(70): e202302773, 2023 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-37750566

RESUMEN

Lithium (Li) metal is a promising anode candidate for high-energy-density batteries owing to its high theoretical capacity and low electrochemical potential. However, uneven Li nucleation, uncontrollable dendritic growth, infinite voltage change and even safety issues hinder its commercial application. Herein, a three-dimensional (3D) framework of freestanding vanadium nitride nanowires (VN NWs) is established as Li host for dendrite-free Li metal anode. A lithiophilic Li3 N interlayer which in situ formed by the surface reaction between molten Li and VN NWs is utilized to guide a uniform Li nucleation and deposition within the skeleton, as well as avoid the dendrite formation. Meanwhile, VN NWs can decrease local current density, homogenize Li-ion flux and accommodate volume fluctuations of the anode due to its 3D structure with high electron conductivity. Thus, the corresponding composite Li metal anode delivers a long-life span of 500 cycles (1000 h) at a current density of 0.5 mA cm-2 , and exhibits lower nucleation over-potential and voltage hysteresis at different current densities from 0.5~5 mA cm-2 in carbonate electrolyte. In conclusion, this work provides a new type of scaffold with both high electronic conductivity and excellent lithiophilicity for stable Li anodes.

6.
Bioorg Med Chem ; 90: 117338, 2023 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-37269687

RESUMEN

Owing to the urgency and importance of developing fourth-generation EGFR inhibitors that can effectively overcome C797S site mutation in NSCLC, Brigatinib was used in this work as a lead compound to modify its structure to obtain a series of phosphoroxy quinazoline derivatives. Biological study indicated that the inhibitory activity and selectivity of the target compounds on EGFRL858R/T790M/C797S/EGFRDel19/T790M/C797S enzymes and EGFRDel19/T790M/C797S overexpressed Ba/F3 cells were significantly better than those of Brigatinib. Among the target compounds, 8a exhibited the best biological activity in vitro. More importantly, 8a presented acceptable pharmacokinetic behaviors and showed potent anti-tumor efficacy in the Ba/F3-EGFRDel19/T790M/C797S subcutaneous xenograft mice model with the tumor growth inhibition value of 82.60% at a dose of 30 mg/kg. These results indicated that 8a, as a drug candidate of the novel fourth-generation EGFR small-molecule inhibitor, has high potentials to treat with NSCLC on EGFR with C797S mutation.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Humanos , Animales , Ratones , Quinazolinas/farmacología , Receptores ErbB/genética , Mutación , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/patología , Inhibidores de Proteínas Quinasas/química , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/patología , Resistencia a Antineoplásicos , Línea Celular Tumoral
7.
Bioorg Chem ; 132: 106374, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36682149

RESUMEN

Twenty-eight grayanane diterpenoids (1-28) including 13 new ones, named daublossomins A-M (1-13), and two new natural products, 3-O-acetylgrayanotoxin II (14) and 10-epi-grayanotoxin III (15), were isolated from the flowers of Rhododendron dauricum L. (Ericaceae). Their structures were elucidated by means of comprehensive spectroscopic methods and quantum chemical calculations (13C NMR-DP4+ analysis and calculated ECD), and the absolute configurations of ten grayanane diterpenoids 1, 4, 5, 7, 8, 22, 23, 25, 27, and 28 were determined by X-ray crystallographic analysis. Daublossomin A (1) represents the first example of an 11,16-epoxygrayan-6-one diterpenoid. Daublossomins B (2) and C (3) are the first examples of 9ß,10ß-epoxygrayanane diterpenoids, and daublossomin I (9) is the second conjugated grayan-1(5),6(7),9(10)-triene diterpenoid. Compounds 1-11 and 13-27 were evaluated for their analgesic activities in the HOAc-induced writhing test in mice, and 1-8, 10, 11, 13, 15, 17, 18, 22-24, and 26 exhibited significant analgesic effects at a dose of 5.0 mg/kg (inhibition rates > 50%). Among them, daublossomins A (1) and F (6) still showed potent analgesic activity even at a lower dose of 0.2 mg/kg with the inhibition rates of 54.4% and 55.2%, respectively. Grayanotoxin III (20) showed more potent analgesic activities than the positive control, morphine, at a dose of 0.04 mg/kg. A preliminary structure-activity relationship for the analgesic grayanane diterpenoids was discussed, providing some useful clues to design and develop structurally novel potent analgesics.


Asunto(s)
Diterpenos , Rhododendron , Ratones , Animales , Rhododendron/química , Estructura Molecular , Hojas de la Planta/química , Analgésicos/farmacología , Analgésicos/química , Flores/química , Diterpenos/farmacología , Diterpenos/química
8.
Funct Integr Genomics ; 23(1): 6, 2022 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-36536232

RESUMEN

Immunotherapy has yielded encouraging results in the treatment of advanced hepatocellular carcinoma (HCC). However, the relationship between epithelial-mesenchymal transition (EMT) and immunotherapy for HCC has not been adequately explained. In this study, we comprehensively analyzed a bulk RNA sequence dataset of 365 HCC patients in The Cancer Genome Atlas (TCGA) dataset. Subsequently, we constructed a prognostic signature based on 6 EMT-related genes and divided 365 HCC patients into high- and low-risk groups. The predictive efficacy of the signature was well validated in different clinical subgroups and in two independent external datasets. We further explored the relationship between prognostic signature and immunotherapy response in terms of immune cell infiltration, somatic mutations, tumor mutation burden (TMB), microsatellite instability (MSI), immune checkpoint-associated gene expression, single-nucleotide variants (SNV) neoantigens, cancer testicular antigens (CTA) scores, and tumor immune dysfunction and exclusion (TIDE) scores. We validated the predictive efficacy of prognostic signature for immunotherapy response using external independent immunotherapy data. Real-time quantitative polymerase chain reaction (qRT-PCR) was used to validate EMT-related gene overexpression in HCC tissue samples. Prognostic signature was an independent risk factor affecting the prognosis of HCC patients and has shown superiority in predicting patient survival compared to other clinical factors. Compared with the low-risk group, the proportion of Activated_CD4_T_cell, Type_2_T_helper_cel, and macrophages were higher in the tumor microenvironment of HCC patients in the high-risk group, while the Activated_CD8_T_cell and CD56bright_natural_killer_cell proportions were lower. The prognostic signature was positively correlated with TMB scores, MSI scores, SNV neoantigens scores, expression levels of immune checkpoint-related genes, and TIDE scores, and patients in the high-risk group were more suitable for immunotherapy. qRT-PCR confirms overexpression of 6 EMT-related genes in HCC tissues for the construction of prognostic signature. Our novel prognostic signature can effectively predict the prognosis and immunotherapy response of HCC patients. In the future, it will be an effective tool for physicians to screen suitable immunotherapy populations and improve response rates and overall survival (OS).


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Transición Epitelial-Mesenquimal , Microambiente Tumoral , Inmunoterapia , Biomarcadores de Tumor , Regulación Neoplásica de la Expresión Génica
9.
Small ; 18(22): e2201137, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35527344

RESUMEN

Cost-effective electrocatalysts for the hydrogen evolution reaction (HER) spanning a wide pH range are highly desirable but still challenging for hydrogen production via electrochemical water splitting. Herein, Mo5 N6 -MoS2 heterojunction nanosheets prepared on hollow carbon nanoribbons (Mo5 N6 -MoS2 /HCNRs) are designed as Mott-Schottky electrocatalysts for efficient pH-universal HER. The in-plane Mo5 N6 -MoS2 Mott-Schottky heterointerface induces electron redistribution and a built-in electric field, which effectively activates the inert MoS2 basal planes to intrinsically increase the electrocatalytic activity, improve electronic conductivity, and boost water dissociation activity. Moreover, the vertical Mo5 N6 -MoS2 nanosheets provide more activated sites for the electrochemical reaction and facilitate mass/electrolyte transport, while the tightly coupled HCNRs substrate and metallic Mo5 N6 provide fast electron transfer paths. Consequently, the Mo5 N6 -MoS2 /HCNRs electrocatalyst delivers excellent pH-universal HER performances exemplified by ultralow overpotentials of 57, 59, and 53 mV at a current density of 10 mA cm-2 in acidic, neutral, and alkaline electrolytes with Tafel slopes of 38.4, 43.5, and 37.9 mV dec-1 , respectively, which are superior to those of the reported MoS2 -based catalysts and outperform Pt in overall water splitting. This work proposes a new strategy to construct an in-plane heterointerface on the nanoscale and provides fresh insights into the HER electrocatalytic mechanism of MoS2 -based heterostructures.

10.
Small ; 18(39): e2203173, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-36026534

RESUMEN

2D transition metal disulfides (TMDs) are promising and cost-effective alternatives to noble-metal-based catalysts for hydrogen production. Activation of the inert basal plane of TMDs is crucial to improving the catalytic efficiency. Herein, introduction of in-plane sulfur vacancies (Sv ) and 3d transition metal dopants in concert activates the basal planes of MoS2 (M-Sv -MoS2 ) to achieve high activities in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Acetate introducing mild wet chemical etching removes surface S atoms facilitating subsequent cation exchange between the exposed Mo atoms and targeted metal ions in solution. Density-functional theory calculation demonstrates that the exposed 3d transition metal dopants in MoS2 basal planes serve as multifunctional active centers, which not only reduce ΔGH* but also accelerate water oxidation. As a result, the optimal Ni-Sv -MoS2 and Co-Sv -MoS2 electrocatalysts show excellent stability and alkaline HER and OER characteristics such as low overpotentials of 101 and 190 mV at 10 mA cm-2 , respectively. The results reveal a strategy to activate the inert MoS2 basal planes by defect and doping co-engineering and the technique can be extended to other types of TMDs for high-efficiency electrocatalysis beyond water splitting.

11.
Environ Sci Technol ; 56(12): 8854-8863, 2022 06 21.
Artículo en Inglés | MEDLINE | ID: mdl-35536552

RESUMEN

Understanding the formation and inhibition of more toxic polychlorinated byproducts from the catalytic oxidation elimination of chlorinated volatile organic compounds (Cl-VOCs) and unveiling efficient strategies have been essential and challenging. Here, RuOx supported on CePO4-doped CeO2 nanosheets (Ru/Pi-CeO2) is designed for boosting catalytic oxidation for the removal of dichloromethane (DCM) as a representative Cl-VOC. The promoted acid strength/number and sintering resistance due to the doping of electron-rich and thermally stable CePO4 are observed along with the undescended redox ability and the exposed multi-active sites, which demonstrates a high activity and durability of DCM oxidation (4000 mg/m3 and 15,000 mL/g·h, stable complete-oxidation at 300 °C), exceptional versatility for different Cl-VOCs, alkanes, aromatics, N-containing VOCs, CO and their multicomponent VOCs, and enhanced thermal stability. The suppression of polychlorinated byproducts is determined over Ru/Pi-CeO2 and oxy-anionic S, V, Mo, Nb, or W doping CeO2, thus the oxy-anionic doping strategy is proposed based on the quenching of the electron-rich oxy-anions on chlorine radicals. Moreover, the simple mechanical mixing with these oxy-anionic salts is also workable even for other catalysts such as Co, Sn, Mn, and noble metal-based catalysts. This work offers further insights into the inhibition of polychlorinated byproducts and contributes to the convenient manufacture of monolithic catalysts with superior chlorine-poisoning resistance for the catalytic oxidation of Cl-VOCs.


Asunto(s)
Compuestos Orgánicos Volátiles , Aniones , Catálisis , Cloro , Oxidación-Reducción
12.
Bioorg Med Chem ; 70: 116907, 2022 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-35810715

RESUMEN

EGFRT790M/C797S is an important target for the development of new generation of EGFR kinase inhibitors without drug resistance. In this work, a series of anilinopyrimidine derivatives that targeting EGFRT790M/C797S were designed, synthesized, and evaluated in vitro for the inhibitory effect on triple mutations kinases and cell lines. Based on the pharmacology data, the anilinopyrimidine derivatives showed high inhibitory activity on triple mutations kinases (EGFRdel 18/T790M/C797S and EGFRL858R/T790M/C797S) as well as the cell line Ba/F3 with highly expression of EGFRdel 18/T790M/C797S. In addition, the anilinopyrimidine derivatives had a more than 50-fold selectivity towards EGFRdel 18/T790M/C797S as compared with EGFRWT. In vivo antitumor activity test also indicated that 8j had good pharmacokinetic parameters, low toxicity and better inhibitory activity. Overall, the anilinopyrimidine derivatives could be regarded as promising candidates for the further development of novel EGFRT790M/C797S inhibitors for clinical application.


Asunto(s)
Receptores ErbB , Neoplasias Pulmonares , Línea Celular Tumoral , Resistencia a Antineoplásicos , Humanos , Neoplasias Pulmonares/genética , Mutación , Inhibidores de Proteínas Quinasas/farmacología
13.
Plant Physiol ; 184(1): 176-193, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32636342

RESUMEN

Actin binding proteins and transcription factors are essential in regulating plant root hair growth in response to various environmental stresses; however, the interaction between these two factors in regulating root hair growth remains poorly understood. Apical and subapical thick actin bundles are necessary for terminating rapid elongation of root hair cells. Here, we show that Arabidopsis (Arabidopsis thaliana) actin-bundling protein Villin1 (VLN1) decorates filaments in shank, subapical, and apical hairs. vln1 mutants displayed significantly longer hairs with longer hair growing time and defects in the thick actin bundles and bundling activities in the subapical and apical regions, whereas seedlings overexpressing VLN1 showed different results. Genetic analysis showed that the transcription factor GLABRA2 (Gl2) played a regulatory role similar to that of VLN1 in hair growth and actin dynamics. Moreover, further analyses demonstrated that VLN1 overexpression suppresses the gl2 mutant phenotypes regarding hair growth and actin dynamics; GL2 directly recognizes the promoter of VLN1 and positively regulates VLN1 expression in root hairs; and the GL2-mediated VLN1 pathway is involved in the root hair growth response to osmotic stress. Our results demonstrate that the GL2-mediated VLN1 pathway plays an important role in the root hair growth response to osmotic stress, and they describe a transcriptional mechanism that regulates actin dynamics and thereby modulates cell tip growth in response to environmental signals.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas de Homeodominio/metabolismo , Raíces de Plantas/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Regulación de la Expresión Génica de las Plantas , Proteínas de Homeodominio/genética , Presión Osmótica , Raíces de Plantas/genética
14.
Bioorg Med Chem Lett ; 36: 127820, 2021 03 15.
Artículo en Inglés | MEDLINE | ID: mdl-33513389

RESUMEN

Phosphoglycerate mutase 1 (PGAM1) is a promising target for cancer treatment. Herein, we found that α-mangostin and γ-mangostin exhibited moderate PGAM1 inhibitory activities, with IC50 of 7.2 µM and 1.2 µM, respectively. Based on α-mangostin, a series of 1,3,6,7-tetrahydroxyxanthone derivatives were designed, synthesized and evaluated in vitro for PGAM1 inhibition. The significant structure-activity relationships (SAR) and a fresh binding mode of this kind of new compounds were also clearly described. This study provides valuable information for further optimization of PGAM1 inhibitors with 1,3,6,7-tetrahydroxyxanthone backbone or de novo design of novel inhibitor.


Asunto(s)
Antineoplásicos/farmacología , Diseño de Fármacos , Inhibidores Enzimáticos/farmacología , Fosfoglicerato Mutasa/antagonistas & inhibidores , Xantonas/farmacología , Antineoplásicos/síntesis química , Antineoplásicos/química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Humanos , Estructura Molecular , Fosfoglicerato Mutasa/metabolismo , Relación Estructura-Actividad , Xantonas/síntesis química , Xantonas/química
15.
J Nat Prod ; 84(5): 1442-1452, 2021 05 28.
Artículo en Inglés | MEDLINE | ID: mdl-33978415

RESUMEN

Twenty-four diterpenoids (1-24), classified into nine diverse carbon skeletal types, 8-nor-7(8→14),9(8→7)-di-abeo-abietane (1, 2, and 13), 7(8→14),9(8→7)-di-abeo-abietane (3 and 4), 6-nor-6,7-seco-abietane (5 and 6), 6,7-seco-abietane (7 and 11), 9,10-seco-abietane (8), abietane (9, 10, and 14-21), 11(9→8),20(10→11)-di-abeo-abietane (12), 15(13→12)-abeo-abietane (22 and 23), and 4,5-seco-20(10→5)-abeo-abietane (24), respectively, were isolated from the roots of Salvia deserta. The structures of 10 new diterpenoids, named salviadesertins A-J (1-10), were elucidated by spectroscopic data interpretation, quantum-chemical calculations including calculated 13C NMR-DP4+ analysis and electronic circular dichroism as well as X-ray crystallography analysis. The absolute configurations of compounds 1-3, 7, 14, and 22 were defined by single-crystal X-ray diffraction analysis. All the isolated diterpenoids 1-24 were evaluated for their cytotoxicity against five cancer cell lines, and 6-hydroxysalvinolone (14) showed micromolar potencies against MCF-7, A-549, SMMC-7721, and HL-60 cells, whereas the other diterpenoids were inactive (half-maximal inhibitory concentration greater than 10.0 µM).


Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Diterpenos/farmacología , Salvia/química , Abietanos , Antineoplásicos Fitogénicos/química , Línea Celular Tumoral , China , Diterpenos/química , Humanos , Estructura Molecular , Fitoquímicos/química , Fitoquímicos/farmacología , Raíces de Plantas/química
16.
J Nat Prod ; 84(4): 1326-1334, 2021 04 23.
Artículo en Inglés | MEDLINE | ID: mdl-33826318

RESUMEN

A novel triamino monoterpene indole alkaloid with an unprecedented skeleton, gelstriamine A (1), four new monoterpene indole alkaloids (2-5), and 12 known analogues (6-17) were isolated from Gelsemium elegans. The structures of 1-5 were established using extensive spectroscopic techniques, NMR calculations with iJ/dJ-DP4 and 2D C-H COSY ANNs analysis, ECD calculations, chemical methods, and single crystal X-ray diffraction analysis. Gelstriamine A (1) possesses an unprecedented 6/5/7/6/6/5 heterohexacyclic scaffold bearing a unique hexahydrooxazolo[4,5-b]pyridin-2(3H)-one motif, and a plausible biosynthetic pathway was proposed. All the isolated alkaloids 1-17 showed discernible analgesic activities in an acetic acid-induced writhing test in mice, and N-desmethoxyhumantenine N4-oxide (3) exhibited more potent analgesic activities than those of morphine at doses of 0.04 and 0.2 mg/kg.


Asunto(s)
Analgésicos/farmacología , Gelsemium/química , Alcaloides Indólicos/farmacología , Monoterpenos/farmacología , Analgésicos/aislamiento & purificación , Animales , China , Femenino , Alcaloides Indólicos/aislamiento & purificación , Masculino , Ratones , Estructura Molecular , Monoterpenos/aislamiento & purificación , Fitoquímicos/aislamiento & purificación , Fitoquímicos/farmacología , Tallos de la Planta/química
17.
Appl Opt ; 60(14): 4064-4067, 2021 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-33983157

RESUMEN

An all-fiber rotation speed measurement structure based on dual-beam speckle interference is proposed. A distributed feedback laser as the light source generates two independent laser beams through a coupler and two circulators. Scattered by the object, the two laser beams interfere separately with the light reflected from the ends of the two fibers, which can be used to measure the rotation speed. The experiment results show that the structure can accurately measure the rotation speed of the object, with relative errors less than 0.5%.

18.
Appl Opt ; 60(5): 1267-1272, 2021 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-33690569

RESUMEN

A laser Doppler rotary velocity measurement method based on an all-fiber homodyne interferometer is proposed in this paper. In this method, the target rotary velocity is measured by the difference of two Doppler frequencies, detected by two homodyne interferometers with a single photodetector (PD), which can be located anywhere on the side of the turntable, and then the rotary velocity can be measured very flexibly without measuring the incident angle. This method can miniaturize the dual-beam rotary speed measurement device. The experimental results show that the relative errors are below 0.5%.

19.
Angew Chem Int Ed Engl ; 60(2): 1011-1021, 2021 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-32965789

RESUMEN

Pseudocapacitive behavior and ion hybrid capacitors can improve the energy density of supercapacitors, but research has only considered the reaction of cations during the electrochemical process, leading to a flawed mechanistic understanding. Here, the effects of various anions carriers on the electrochemical behaviors of titanium nitride-based zinc ion capacitor (Zn-TiN capacitor) were explored. DFT calculations revealed the stable structure of TiN-SO4 after adsorbed process, enabling SO4 2- participate in the electrochemical process and construct a two-step adsorption and intercalation energy storage mechanism, improving the capacitance and anti-self-discharge ability of the Zn-TiN capacitor, which delivered an ultrahigh capacitance of 489.8 F g-1 and retained 83.92 % of capacitance even after 500 h resting time. An energy storage system involving anions in the electrochemical process can improve capacitance and anti-self-discharge ability of ion hybrid capacitors.

20.
Molecules ; 25(14)2020 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-32679654

RESUMEN

Structural design is often investigated to decrease the electron transfer depletion in/on the pseudocapacitive electrode for excellent capacitance performance. However, a simple way to improve the internal and external electron transfer efficiency is still challenging. In this work, we prepared a novel structure composed of cobalt (Co) nanoparticles (NPs) embedded MnO nanowires (NWs) with an N-doped carbon (NC) coating on carbon cloth (CC) by in situ thermal treatment of polydopamine (PDA) coated MnCo2O4.5 NWs in an inert atmosphere. The PDA coating was carbonized into the NC shell and simultaneously reduced the MnCo2O4.5 to Co NPs and MnO NWs, which greatly improve the surface and internal electron transfer ability on/in MnO boding well supercapacitive properties. The hybrid electrode shows a high specific capacitance of 747 F g-1 at 1 A g-1 and good cycling stability with 93% capacitance retention after 5,000 cycles at 10 A g-1. By coupling with vanadium nitride with an N-doped carbon coating (VN@NC) negative electrode, the asymmetric supercapacitor delivers a high energy density of 48.15 Wh kg-1 for a power density of 0.96 kW kg-1 as well as outstanding cycling performance with 82% retention after 2000 cycles at 10 A g-1. The electrode design and synthesis suggests large potential in the production of high-performance energy storage devices.


Asunto(s)
Carbono/química , Cobalto/química , Capacidad Eléctrica , Nanocables/química , Algoritmos , Técnicas de Química Sintética , Conductividad Eléctrica , Compuestos de Manganeso/química , Modelos Teóricos , Nanocables/ultraestructura , Óxidos/química , Análisis Espectral
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA