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1.
Nature ; 579(7799): 359-363, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32188951

RESUMO

Moiré superlattices can be used to engineer strongly correlated electronic states in two-dimensional van der Waals heterostructures, as recently demonstrated in the correlated insulating and superconducting states observed in magic-angle twisted-bilayer graphene and ABC trilayer graphene/boron nitride moiré superlattices1-4. Transition metal dichalcogenide moiré heterostructures provide another model system for the study of correlated quantum phenomena5 because of their strong light-matter interactions and large spin-orbit coupling. However, experimental observation of correlated insulating states in this system is challenging with traditional transport techniques. Here we report the optical detection of strongly correlated phases in semiconducting WSe2/WS2 moiré superlattices. We use a sensitive optical detection technique and reveal a Mott insulator state at one hole per superlattice site and surprising insulating phases at 1/3 and 2/3 filling of the superlattice, which we assign to generalized Wigner crystallization on the underlying lattice6-11. Furthermore, the spin-valley optical selection rules12-14 of transition metal dichalcogenide heterostructures allow us to optically create and investigate low-energy excited spin states in the Mott insulator. We measure a very long spin relaxation lifetime of many microseconds in the Mott insulating state, orders of magnitude longer than that of charge excitations. Our studies highlight the value of using moiré superlattices beyond graphene to explore correlated physics.

2.
Artigo em Inglês | MEDLINE | ID: mdl-32187577

RESUMO

Negative differential resistance (NDR) effect and magnetoresistance (MR) effect attract a lot of attention since they have been widely applied in fields such as circuit amplifiers and information storage, respectively. In general, the NDR and MR effects derive from different physical mechanisms, which makes it difficult to obtain both NDR effect and large unsaturated MR effect in a device based on the same physical mechanism. In this paper, the NDR and unsaturated MR effect were observed simultaneously in In/SiO2/p-Si/SiO2/In heterojunction devices, and their physical mechanisms were investigated. It is found that under zero magnetic field conditions, the NDR effect can be observed up to 25 K which is much higher than the temperature of NDR obtaining in intrinsic silicon. The NDR effect is significantly enhanced by applying a small magnetic field of 0.1 T. Meanwhile, the unsaturated positive MR effect is obtained when an external magnetic field is applied. Our analysis shows that the NDR effect and the unsaturated MR effect can be explained on the basis of the same physical mechanism of the avalanche breakdown in the In/SiO2/p-Si heterojunction. The NDR effect is mainly resulted from complex effects containing the carrier injection after avalanche breakdown in the heterojunction, the reduction of the Schottky barrier height and the Joule heating effect. The large unsaturated MR effect derives from the suppression of the plasma due to avalanche breakdown by the applied magnetic field. The largest value of MR based on avalanche breakdown can reach about 530%@1 T at 10 K, and MR sensitivity can be as high as about 29.4 T-1 under 0.05 T.

3.
Bioorg Chem ; 97: 103680, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32120078

RESUMO

The phytochemical investigation of Andrographis paniculata resulted in the isolation of a novel 15-spiro diterpenoid dimer bisandrographolide G (1). Its structure was determined by 1D and 2D NMR, HRESIMS, electronic circular dichroism (ECD), and TD DFT calculations of ECD spectra. It showed potent inhibitory activity against human carboxylesterase 2 (CES 2) with an IC50 value of 4.61 ± 0.23 µM, and it was defined as a mixed-competitive type inhibitor with a Ki value of 8.88 µM based on the inhibition kinetics result. This finding gave us a hit to develop new generation of human CES 2 inhibitors.

4.
Artigo em Inglês | MEDLINE | ID: mdl-32009375

RESUMO

Due to the limited thermoelectric (TE) performance of conducting polymers and rigidity of inorganic materials, it is still a huge challenge to prepare low-cost, highly flexible, and high-performance TE materials. Herein, we fabricated n-type Ag2Se films using a porous nylon membrane as a flexible substrate by vacuum-assisted filtration, followed by hot pressing. A very high power factor of ∼1882 µW m-1 K-2 at room temperature is obtained. The high power factor is mainly the result of the high density of the Ag2Se film and the tuned grain orientation, which is realized by the synthesis of multisized Ag2Se nanostructures. The film also exhibits excellent flexibility with 90.7% retention of the power factor after bending around a rod of 4 mm radius for 1000 times. A four-leg TE generator is assembled with the Ag2Se film, and its maximum output power is up to 3.2 µW at a temperature difference of 30 K, corresponding to the maximum power density of 22.0 W m-2 and a normalized maximum power density of 408 µW m-1 K-2. This work provides an effective route to achieve high-power-factor, high-flexibility, and low-cost TE films.

5.
J Asian Nat Prod Res ; : 1-11, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32102545

RESUMO

Four new alkaloids (1-4) and one known alkaloid were isolated from the stems of Picrasma quassioides. The structures of these isolated compounds were elucidated by spectroscopic analyses, a combination of computer-assisted structure elucidation software (ACD/Structure Elucidator) and gauge-including atomic orbital (GIAO) calculation of 1 D NMR data. All compounds were evaluated for their cytotoxic activities against hepatocellular carcinoma HepG2 and Hep3B cells. However, they did not show obvious inhibitory activities.[Figure: see text].

6.
Bioorg Chem ; 96: 103637, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32032849

RESUMO

The inhibition of soluble epoxide hydrolase (sEH) is a promising therapeutic approach to treat inflammation and other disorders. In our present investigation on searching for sEH inhibitors from traditional Chinese medicines, we found that Alisma orientale displayed inhibition of sEH. We constructed a small library of protostane-type triterpenoids (1-25) isolated from A. orientale, and screened their inhibitory activities. Alismanin B (1), 11-deoxy-25-anhydro alisol E (4), 11-deoxy alisol B (5), and 25-O-ethyl alisol A (15) displayed concentration-dependently inhibitory activities against sEH with IC50 values from 3.40 ± 0.57 µM to 9.57 ± 0.88 µM. 11-Deoxy-25-anhydro alisol E (4) and 11-deoxy alisol B (5) were defined as mixed-type competitive inhibitors with Ki values of 12.6 and 3.48 µM, respectively, based on the result of inhibition kinetics. The potential interaction mechanism of 11-deoxy alisol B (5) with sEH was analyzed by molecular docking and molecular dynamics, revealing that amino acid residues Trp336 and Tyr466 were vital for its inhibitory activity.

7.
J Nat Prod ; 82(12): 3302-3310, 2019 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-31789520

RESUMO

Nine new monoterpenoid indole alkaloids, uncarialins A-I (1-9), were isolated from Uncaria rhynchophylla as well as 14 known analogues (10-23). Their structures were determined by HRESIMS, 1D and 2D NMR, and experimental and calculated electronic circular dichroism data. Compounds 5, 7, 15, and 22 displayed significant agonistic effects against the 5-HT1A receptor with EC50 values of 2.2 ± 0.1, 0.1 ± 0.1, 1.6 ± 0.3, and 2.0 ± 0.5 µM, respectively. The mechanisms of action of these four compounds with the 5-HT1A receptor were investigated by molecular docking, and the results suggested that amino acid residues Asp116, Thr196, Asn386, and Tyr390 played critical roles in the observed activity of the above-mentioned compounds.

8.
ACS Appl Mater Interfaces ; 11(49): 45875-45884, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31738501

RESUMO

How to prevent the agglomeration of nanoparticles in nanocomposites remains a key challenge. Using nanometer suspension as a doping agent provides an effective approach to solve this challenge. A new technique that consists of chemical coprecipitation, ball milling and sedimentation separation metheds was developed for preparing hard magnetic M-type BaFe12O19 nanometer suspension. The single-phase BaFe12O19 nanoparticles dispersed uniformly in alcohol have been prepared by this new technique. Magnetic nanocomposite thermoelectric materials with a homogeneous dispersion of BaFe12O19 nanoparticles were prepared through a combination process of an ultrasonic mixing of BaFe12O19 nanometer suspension and In-filled CoSb3 thermoelectric matrix material and spark plasma sintering. The microstructure analysis of magnetic nanocomposite thermoelectric materials confirmed that using the nanometer suspension as a doping agent is an effective way to solve the agglomeration phenomenon of nanoparticles in nanocomposites. In addition, the decline of thermoelectric performance in the high-temperature intrinsic excitation region of In-filled CoSb3 can be effectively suppressed by the magnetic phase transition of BaFe12O19 nanoparticles dried by nanometer suspension from ferromagnetism to paramagnetism. It is also confirmed that using the BaFe12O19 nanometer suspension as a thermoelectric performance enhancer is an effective way to solve the challenging problem of performance deterioration of thermoelectric materials at high temperature.

9.
Sci Rep ; 9(1): 17162, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31748581

RESUMO

Ultra-low-loss and large-effective-area fiber has been successfully applied in transoceanic transmission, which is considered as a promising candidate for 100 Gbit/s and beyond 100 Gbit/s coherent long-haul terrestrial optical networks. Several theoretical and experimental investigations have been reported, including provincial terrestrial field trial. To support long-haul terrestrial application, it is urgent to prove that the ultra-low-loss and large-effective-area fiber after terrestrial deployment can significantly enhance the performance of long-haul transmission over 1000 km compared with the conventional single mode fiber. In this paper, we extended our previous work and summarized design methods for complex terrestrial environment. To verify the fiber characteristics in long-haul terrestrial transmission, we installed the longest terrestrial ultra-low-loss and large-effective-area fiber link in the world with a total length of 1539.6 km. The results show that the transmission performances of wavelength-division-multiplexed signals with per-channel data rates of 100 Gbit/s, 200 Gbit/s, and 400 Gbit/s over the ultra-low-loss and large-effective-area fiber are all obviously improved, demonstrating that this fiber is more suitable for ultrahigh-speed long-haul terrestrial transmission.

10.
Water Res ; 164: 114896, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31377526

RESUMO

N-nitrosamines in water have drawn significant concerns for the health of water consumers due to their carcinogenic properties. N-nitrosamines are formed during disinfection of wastewater as well as different industrial and agricultural processes. This study characterized the N-nitrosamines compositions in eleven different wastewaters in the Pearl River Delta (PRD) in Southeast China, and the spatial distributions and the abundances of N-nitrosamines in the Pearl River water were detected. The results indicated that five N-nitrosamines species, including N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosopyrrolidine (NPYR), N-nitrosomorpholine (NMOR) and N-nitrosodibutylamine (NDBA) were found in the industrial wastewater samples in the PRD. Remarkably high concentrations of NDMA (up to 4000 ng/L) were found in the wastewaters from the textile printing and dyeing as well as the electroplating, whereas NDMA, NDEA and NMOR were detected in the domestic wastewaters at concentrations lower than 15 ng/L. Moreover, we found that certain treatment processes for the electroplating wastewater could form a significant amount of NDMA, NPYR and NMOR. Analyses of the Pearl River water samples showed occurrences of different N-nitrosamines species, including NDMA (5.7 ng/L), NDEA (1.7 ng/L), NPYR (2.2 ng/L), NMOR (2.2 ng/L) and NDBA (4.9 ng/L). The abundances of N-nitrosamines species varied spatially due to the inputs from the different sources. Thus, our study provides unique and valuable information for occurrences, abundances and source characteristics of N-nitrosamines in the PRD.


Assuntos
Nitrosaminas , Rios , China , Dimetilnitrosamina , Águas Residuárias
11.
J Nat Prod ; 82(6): 1510-1517, 2019 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-31150241

RESUMO

Chromatographic purification of the roots of Daphne genkwa led to 11 new guaiane-type sesquiterpenoids (1-11), named genkwanoids A-K, and six known analogues (12-17). A comprehensive set of spectroscopic methods including IR, UV, HRESIMS, and 1D/2D NMR were used to elucidate the structures and relative configurations of 1-11. The absolute configurations were determined by the optical rotation calculations and the modified Mosher's method. The possible biosynthetic pathways for 1-11 are proposed. Furthermore, the neuroprotective effects of 1-17 on H2O2-induced damage in human neuroblastoma SH-SY5Y cells were screened using an MTT assay. Compounds 9, 10, and 16 exhibited moderate neuroprotective effects, with survival rates of 79.34%, 79.94%, and 75.64% after treatment with 12.5 µM, values that were comparable to the positive control, Trolox (78.65%). Furthermore, annexin V-FITC/PI staining of cells treated with 9, 10, and 16 showed that the neuroprotective effects of these compounds may arise from inhibiting cell apoptosis.

12.
Pol J Microbiol ; 68(1): 83-92, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31050256

RESUMO

This study focused on the microbiota and chemical compounds of the fermented Pinelliae Rhizoma produced in Longchang (LC), Zizhong (ZZ) and Xindu (XD), in Sichuan Province (China). High-throughput sequencing was used to analyze the microbiota. GC-MS and LC-MS were used to detect the compounds produced during the three different Pinelliae Rhizoma fermentation processes. The bacteria and fungi of the three fermented Pinelliae Rhizoma differed substantially, with the bacterial content mainly composed of the Bacillus genus, while the common fungi were only included in four OTUs, which belong to three species of Eurotiomycetes and Aspergillus cibarius. 51 volatile compounds were detected; they varied between LC, XD, and ZZ fermented Pinelliae Rhizoma. C10 and C15 terpenes were most frequently detected, and only curcumene and ß-bisabolene were detected in the three fermented Pinelliae Rhizoma. 65 non-volatile compounds were detected by LC-MS, most were of C16, C18, C20, C21 and C22 structures. Cluster analysis showed more similarity between LC and XD fermented Pinelliae Rhizoma with regards to volatile compound content, but more similarity between the XD and ZZ fermented Pinelliae Rhizoma for non-volatiles. Moreover, no correlation between geographical distance and microflora or compounds of fermented Pinelliae Rhizoma was observed. These results showed that hundreds of compounds are produced by the natural mixed fermentation of Pinelliae Rhizoma, and may mostly relate to the microorganisms of five species.This study focused on the microbiota and chemical compounds of the fermented Pinelliae Rhizoma produced in Longchang (LC), Zizhong (ZZ) and Xindu (XD), in Sichuan Province (China). High-throughput sequencing was used to analyze the microbiota. GC-MS and LC-MS were used to detect the compounds produced during the three different Pinelliae Rhizoma fermentation processes. The bacteria and fungi of the three fermented Pinelliae Rhizoma differed substantially, with the bacterial content mainly composed of the Bacillus genus, while the common fungi were only included in four OTUs, which belong to three species of Eurotiomycetes and Aspergillus cibarius. 51 volatile compounds were detected; they varied between LC, XD, and ZZ fermented Pinelliae Rhizoma. C10 and C15 terpenes were most frequently detected, and only curcumene and ß-bisabolene were detected in the three fermented Pinelliae Rhizoma. 65 non-volatile compounds were detected by LC-MS, most were of C16, C18, C20, C21 and C22 structures. Cluster analysis showed more similarity between LC and XD fermented Pinelliae Rhizoma with regards to volatile compound content, but more similarity between the XD and ZZ fermented Pinelliae Rhizoma for non-volatiles. Moreover, no correlation between geographical distance and microflora or compounds of fermented Pinelliae Rhizoma was observed. These results showed that hundreds of compounds are produced by the natural mixed fermentation of Pinelliae Rhizoma, and may mostly relate to the microorganisms of five species.


Assuntos
Bactérias/classificação , Bactérias/isolamento & purificação , Fungos/classificação , Fungos/isolamento & purificação , Pinellia/química , Pinellia/microbiologia , Compostos Orgânicos Voláteis/química , Bactérias/genética , China , Fermentação , Fungos/genética , Cromatografia Gasosa-Espectrometria de Massas , Sequenciamento de Nucleotídeos em Larga Escala , Microbiota/genética , Sesquiterpenos/química , Terpenos/química
13.
Biochem Biophys Res Commun ; 513(2): 360-367, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-30961932

RESUMO

Apoptosis of tubular epithelium cells (TECs) plays critical roles in renal ischemia reperfusion (I/R) injury, but the molecular regulatory mechanisms of apoptosis still require further investigation. Recently, phosphatase family members have been suggested to regulate multiple aspects of the injury and regeneration response. However, the roles of SHP-1, an important protein-tyrosine phosphatase, in the regulation of renal I/R injury remain unknown. Here, we found that SHP-1 knockdown in vivo significantly increased renal I/R injury and aggravated the apoptosis of TECs. Consistently, after SHP-1 knockdown in TECs in vitro, a sharp increase of apoptosis induced by cobalt dichloride was found. The protective role of SHP-1 was also validated in a TEC cell line stably overexpressing SHP-1. Mechanistically, the ASK1/MKK4/JNK pro-apoptosis signal was over activated after SHP-1 knockdown, and SHP-1 could bind to and dephosphorylate ASK1 to inhibit its activation, thus repressing apoptosis.

14.
Planta Med ; 85(8): 648-656, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30974464

RESUMO

Four pairs of ß-carboline enantiomers (1A: /1B: -4A: /4B: ), 2 ß-carboline derivatives (5:  - 6: ) with a single enantiomeric configuration, together with 2 known achiral congeners (7:  - 8: ) were isolated from the stems of Picrasma quassioides. Their structures were elucidated on the basis of extensive spectroscopic analyses and quantum mechanical calculations. Compound 5: possesses a 4,5-seco ß-carboline framework and represents the first example of this type of ß-carboline alkaloids from nature. A possible biosynthetic pathway is proposed to generate the racemate 4: and the enantiomerically pure compounds 5: and 6: . All isolates were screened for their cytotoxicity against hepatocellular carcinoma Hep3B and HepG2 cells, which revealed that enantiomeric compounds 4A: and 4B: had distinctive effects in HepG2 cells. Further investigation showed that 4B: could induce apoptosis in HepG2 cells.


Assuntos
Alcaloides/isolamento & purificação , Antineoplásicos Fitogênicos/isolamento & purificação , Carbolinas/isolamento & purificação , Medicamentos de Ervas Chinesas/farmacologia , Picrasma/química , Alcaloides/química , Alcaloides/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Carbolinas/química , Carbolinas/farmacologia , Cromatografia , Ensaios de Seleção de Medicamentos Antitumorais , Células Hep G2 , Humanos , Estrutura Molecular , Estereoisomerismo
15.
J Nat Prod ; 82(4): 714-723, 2019 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-30917277

RESUMO

Quassinoids are a class of highly oxygenated degraded triterpenoids exclusively discovered from plants of the Simaroubaceae family. In this study, eight new (1-8) and 15 known quassinoids (9-23) were isolated from an extract of the stems of Picrasma quassioides. The structures were elucidated by spectroscopic analysis and electronic circular dichroism spectra combined with quantum chemical calculations. Compounds 4 and 5 represent the first examples of 18-nor-quassinoids from P. quassioides. All isolates were screened for their neuroprotective activities toward H2O2-induced cell damage in SH-SY5Y cells. Further study revealed that the potential protective activities of these compounds appeared to occur via the suppression of cell apoptosis and downregulation of caspase-3 activation.

16.
Phytochemistry ; 161: 163-171, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30661806

RESUMO

Five pairs of enantiomeric lignanamides including nine undescribed compounds along with a known one were obtained from Solanum nigrum L. (Solanaceae). Their structures with absolute configurations were elucidated based on comprehensive spectroscopic analyses and quantum chemical calculations of electronic circular dichroism (ECD) curves. Additionally, all isolates were evaluated for their neuroprotective activity against MPP+ (1-methyl-4-phenylpyridinium)-induced SH-SY5Y cells injury. Among them, cannabisin F showed the most significant neuroprotective effects at different concentrations (12.5, 25, 50 µM). Further studies by Hoechst 33258 staining, monodansylcadaverine (MDC) staining and Annexin V/PI analysis demonstrated that cannabisin F could induce protective autophagy to protect SH-SY5Y cells from MPP+-induced apoptosis.


Assuntos
Amidas/farmacologia , Lignanas/farmacologia , Fármacos Neuroprotetores/farmacologia , Solanum nigrum/química , 1-Metil-4-fenilpiridínio/farmacologia , Amidas/química , Apoptose/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Lignanas/química , Estrutura Molecular , Fármacos Neuroprotetores/química , Estereoisomerismo , Relação Estrutura-Atividade
17.
Bioorg Chem ; 84: 309-318, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30530072

RESUMO

Seven new tirucallane-type triterpenoids (1-7), kumuquassin A-G, along with 20 known analogues (8-27) were isolated from the stems of Picrasma quassioides. The structures and the absolute configurations of new compounds were elucidated by spectroscopic data, electronic circular dichroism (ECD) spectroscopic analyses and quantum ECD calculations. Notably, kumuquassin A (1) contains a rare Δ17, 20 double bond, kumuquassin B (2) is the first example of tirucallane triterpenoid possessing a 5/3 biheterocyclic ring system at the side chain. All the compounds were screened for the cytotoxicity against two human hepatoma cell lines, HepG2 and Hep3B, and several compounds exhibited promising activity. The most potential compound 3 was selected for cell cycle analysis, which showed that 3 could cause an accumulation of HepG2 cells at subG1 peak. Annexin V-FITC/PI staining further confirmed that compound 3 caused death of hepatoma cells through apoptosis induction.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Picrasma/química , Triterpenos/química , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Conformação Molecular , Picrasma/metabolismo , Caules de Planta/química , Caules de Planta/metabolismo , Triterpenos/isolamento & purificação , Triterpenos/farmacologia
18.
Pediatr Transplant ; 23(1): e13306, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30593730

RESUMO

RTx is currently the best treatment for children with ESRD. This study retrospectively analyzed the outcomes of growth after RTx using the pediatric-to-pediatric allocation strategy and some factors that may affect it. From March 2012 to August 2016, 8 en bloc and 38 single pediatric RTxs were performed at our center using organs from small pediatric deceased donors (weight < 15 kg). Growth before and after RTx was analyzed according to the height-for-age z-score at RTx, the 3-year follow-up, and adulthood and compared between the procedures. The chi-square test and multiple linear regression analysis were used for statistical analyses. Overall, 79.2% of children were diagnosed with chronic nephritis before RTx; 14.6% of cases were due to congenital urinary tract malformation, and 6.3% of cases were due to unknown causes. All grafts and patients survived postoperatively. The mean estimated GFRs were 92.7 ± 28.6 mL/min/1.73 m2 , 100.9 ± 32.3 mL/min/1.73 m2 , and 110.1 ± 34.8 mL/min/1.73 m2 at 1, 2, and 3 years' postoperatively, respectively. The children's postoperative growth and development, particularly during the first year postoperatively, improved but were negatively correlated with age and the height-for-age z-score before RTx. The growth of children after RTx was moderate and accelerated during prepubescence. The rate of post-RTx growth during the first year postoperatively was unrelated to the recipient's sex or duration of dialysis (P > 0.05) but was negatively correlated with age at RTx (r = -0.349, P = 0.043). Future studies on the long-term outcomes are still needed.


Assuntos
Estatura , Peso Corporal , Seleção do Doador/métodos , Transtornos do Crescimento/etiologia , Falência Renal Crônica/cirurgia , Transplante de Rim , Complicações Pós-Operatórias/etiologia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Seguimentos , Transtornos do Crescimento/diagnóstico , Transtornos do Crescimento/epidemiologia , Humanos , Modelos Lineares , Masculino , Complicações Pós-Operatórias/diagnóstico , Complicações Pós-Operatórias/epidemiologia , Estudos Retrospectivos , Fatores de Risco , Doadores de Tecidos , Resultado do Tratamento , Adulto Jovem
19.
Phytochemistry ; 159: 39-45, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30577000

RESUMO

Four pairs of enantiomeric ß-carboline alkaloids, (+/-)-kumudine A-D, along with their biosynthesis-related compound kumudine E, were obtained from the stems of Picrasma quassioides. Their structures, including the absolute configurations, were determined via extensive spectroscopic data combined with electronic circular dichroism (ECD) spectroscopic analyses and quantum mechanical ECD calculations. (+/-)-Kumudine A possessed a scaffold of ß-carboline-phenylpropanoid adduct, which were the first examples of this type of ß-carboline alkaloid from nature. The cytotoxicity assay against hepatocellular carcinoma Hep3B and HepG2 cells was evaluated by SRB assay, which showed that (-)-Kumudine B had stronger effect than its enantiomer (+)-Kumudine B in Hep3B cells. Moreover, further flow cytometry analysis also supported the enantioselectivity between (+)-Kumudine B and (-)-Kumudine B, suggesting that the compounds caused death of hepatoma cells through apoptosis induction.


Assuntos
Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/uso terapêutico , Carbolinas/isolamento & purificação , Carbolinas/uso terapêutico , Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológico , Picrasma/química , Caules de Planta/química , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Carbolinas/química , Carbolinas/farmacologia , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Cromatografia Líquida de Alta Pressão , Dicroísmo Circular , Dimerização , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Neoplasias Hepáticas/patologia , Estrutura Molecular , Análise Espectral/métodos , Estereoisomerismo
20.
Front Physiol ; 9: 1526, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30487750

RESUMO

Acute kidney injury (AKI), which involves the loss of kidney function caused by damage to renal tubular cells, is an important public health concern. We previously showed that sirtuin (SIRT)3 protects the kidneys against mitochondrial damage by inhibiting the nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasome, attenuating oxidative stress, and downregulating proinflammatory cytokines. In this article, we investigated the role of autophagy, mediated by a mammalian target of rapamycin (mTOR) and AMP-activated protein kinase (AMPK), in the protective effect of SIRT3, against sepsis-induced AKI, in a mouse model of cecal ligation and puncture (CLP). The AKI in CLP mice was associated with the upregulation of autophagy markers; this effect was abolished in SIRT3- mice in parallel with the downregulation of phospho (p)-AMPK and the upregulation of p-mTOR. Pretreatment with the autophagy inhibitor 3-methyladenine (3-MA) or AMPK inhibitor compound isotonic saline (C), exacerbated AKI. SIRT3 overexpression promoted autophagy, upregulated p-AMPK and downregulated p-mTOR in CLP mice, attenuating sepsis-induced AKI, tubular cell apoptosis, and inflammatory cytokine accumulation in the kidneys. The blockage of autophagy induction largely abolished the protective effect of SIRT3 in sepsis-induced AKI. These findings indicate that SIRT3 protects against CLP-induced AKI by inducing autophagy through regulation of the AMPK/mTOR pathway.

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