Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 117
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Dev Growth Differ ; 66(2): 133-144, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38281811

RESUMO

Macrophages play a pivotal role in the response to injury, contributing significantly to the repair and regrowth of damaged tissues. The external lateral line system in aquatic organisms offers a practical model for studying regeneration, featuring interneuromast cells connecting sensory neuromasts. Under normal conditions, these cells remain dormant, but their transformation into neuromasts occurs when overcoming inhibitory signals from Schwann cells and posterior lateral line nerves. The mechanism enabling interneuromast cells to evade inhibition by Schwann cells remains unclear. Previous observations suggest that macrophages physically interact with neuromasts, nerves, and Schwann cells during regeneration. This interaction leads to the regeneration of neuromasts in a subset of zebrafish with ablated neuromasts. To explore whether macrophages achieve this effect through secreted cytokines, we conducted experiments involving tail amputation in zebrafish larvae and tested the impact of cytokine inhibitors on neuromast regeneration. Most injured larvae remarkably regenerated a neuromast within 4 days post-amputation. Intriguingly, removal of macrophages and inhibition of the anti-inflammatory cytokine transforming growth factor-beta (TGF-ß) significantly delayed neuromast regeneration. Conversely, inhibition of the pro-inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) had minor effects on the regeneration process. This study provides insights into how macrophages activate interneuromast cells, elucidating the pathways underlying neuromast regeneration.


Assuntos
Sistema da Linha Lateral , Peixe-Zebra , Animais , Peixe-Zebra/fisiologia , Fator de Crescimento Transformador beta/farmacologia
2.
J Biol Chem ; 298(5): 101904, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35398096

RESUMO

Pancreatic ß-cells express ATP-sensitive potassium (KATP) channels, consisting of octamer complexes containing four sulfonylurea receptor 1 (SUR1) and four Kir6.2 subunits. Loss of KATP channel function causes persistent hyperinsulinemic hypoglycemia of infancy (PHHI), a rare but debilitating condition if not treated. We previously showed that the sodium-channel blocker carbamazepine (Carb) corrects KATP channel surface expression defects induced by PHHI-causing mutations in SUR1. In this study, we show that Carb treatment can also ameliorate the trafficking deficits associated with a recently discovered PHHI-causing mutation in Kir6.2 (Kir6.2-A28V). In human embryonic kidney 293 or INS-1 cells expressing this mutant KATP channel (SUR1 and Kir6.2-A28V), biotinylation and immunostaining assays revealed that Carb can increase surface expression of the mutant KATP channels. We further examined the subcellular distributions of mutant KATP channels before and after Carb treatment; without Carb treatment, we found that mutant KATP channels were aberrantly accumulated in the Golgi apparatus. However, after Carb treatment, coimmunoprecipitation of mutant KATP channels and Golgi marker GM130 was diminished, and KATP staining was also reduced in lysosomes. Intriguingly, Carb treatment also simultaneously increased autophagic flux and p62 accumulation, suggesting that autophagy-dependent degradation of the mutant channel was not only stimulated but also interrupted. In summary, our data suggest that surface expression of Kir6.2-A28V KATP channels is rescued by Carb treatment via promotion of mutant KATP channel exit from the Golgi apparatus and reduction of autophagy-mediated protein degradation.


Assuntos
Carbamazepina/farmacologia , Complexo de Golgi , Canais KATP , Trifosfato de Adenosina/metabolismo , Animais , Autofagia , Linhagem Celular , Complexo de Golgi/genética , Complexo de Golgi/metabolismo , Células HEK293 , Humanos , Canais KATP/genética , Canais KATP/metabolismo , Ratos , Receptores de Sulfonilureias/genética , Receptores de Sulfonilureias/metabolismo
3.
Environ Sci Technol ; 57(46): 18172-18182, 2023 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-37129473

RESUMO

China's nitrogen oxide (NOx) emissions have undergone significant changes over the past few decades. However, nonfossil fuel NOx emissions are not yet well constrained in urban environments, resulting in a substantial underestimation of their importance relative to the known fossil fuel NOx emissions. We developed an approach using machine learning that is accurate enough to generate a long time series of the nitrogen isotopic composition (δ15N) of atmospheric nitrate using high-level accuracies of air pollutants and meteorology data. Air temperature was found to be the critical driver of the variation of nitrate δ15N at daily resolution based on this approach, while significant reductions of aerosol and its precursor emissions played a key role in the change of nitrate δ15N on the yearly scale. Predictions from this model found a significant decrease in nitrate δ15N in Chinese megacities (Beijing and Guangzhou as representative cities in the north and south, respectively) since 2013, implying an enhanced contribution of nonfossil fuel NOx emissions to nitrate aerosols (up to 22%-26% in 2021 from 18%-22% in 2013 quantified by an isotope mixing model), as confirmed by the Weather Research and Forecasting model coupled with online chemistry (WRF-Chem) simulation. Meanwhile, the declining contribution in coal combustion (34%-39% in 2013 to 31%-34% in 2021) and increasing contribution of natural gas combustion (11%-14% in 2013 to 14%-17% in 2021) demonstrated the transformation of China's energy structure from coal to natural gas. This approach provides missing records for exploring long-term variability in the nitrogen isotope system and may contribute to the study of the global reactive nitrogen biogeochemical cycle.


Assuntos
Poluentes Atmosféricos , Nitratos , Nitratos/análise , Gás Natural , Estações do Ano , Monitoramento Ambiental/métodos , China , Poluentes Atmosféricos/análise , Carvão Mineral/análise , Óxido Nítrico , Isótopos de Nitrogênio/análise , Aerossóis/análise , Material Particulado/análise
4.
Bioorg Chem ; 141: 106843, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37696148

RESUMO

In the present study, the undescribed schitriterpenoids, kadsujanonols A-I (1-9), and eleven reported compounds (10-20) were isolated from K. japonica L. vines. Their structures of 3,4-seco-schitriterpenoids were elucidated mainly by spectroscopic analyses including 1H-, 13C-, and 2D-NMR, IR, HRESIMS spectra. The spatial configurations were determined by the single-crystal X-ray diffraction analysis of kadsujapnonol A (1), 15, 17, and 18, CD data and computational analysis. Furthermore, all isolates were evaluated for the anti-neuroinflammatory activity on LPS-stimulated NO production in BV2 microglial cells and compounds 2, 4, 5, 7, 9, 11, 13-16, and 18 exposed better or comparable suppression abilities than PDTC. Among them, kadlongilactone B (14) showed the best significant inhibiting ability (IC50 = 0.87 µg/mL) and the effect is through the attenuation of the inflammatory transcription factor p65NF-κB. Preliminary structure-activity relationship revealed that δ-lactone at the side chain and 7-member lactone at C-3/C-4, and 3,4:9,10 ring opening are important.


Assuntos
Kadsura , Kadsura/química , Relação Estrutura-Atividade , Microglia , Lactonas , Lipopolissacarídeos/farmacologia , Estrutura Molecular
5.
Pharmacol Res ; 184: 106424, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36064077

RESUMO

The global COVID-19 pandemic remains a critical public health threat, as existing vaccines and drugs appear insufficient to halt the rapid transmission. During an outbreak from May to August 2021 in Taiwan, patients with severe COVID-19 were administered NRICM102, which was a traditional Chinese medicine (TCM) formula developed based on its predecessor NRICM101 approved for treating mild cases. This study aimed to explore the mechanism of NRICM102 in ameliorating severe COVID-19-related embolic and fibrotic pulmonary injury. NRICM102 was found to disrupt spike protein/ACE2 interaction, 3CL protease activity, reduce activation of neutrophils, monocytes and expression of cytokines (TNF-α, IL-1ß, IL-6, IL-8), chemokines (MCP-1, MIP-1, RANTES) and proinflammatory receptor (TLR4). NRICM102 also inhibited the spread of virus and progression to embolic and fibrotic pulmonary injury through reducing prothrombotic (vWF, PAI-1, NET) and fibrotic (c-Kit, SCF) factors, and reducing alveolar type I (AT1) and type II (AT2) cell apoptosis. NRICM102 may exhibit its protective capability via regulation of TLRs, JAK/STAT, PI3K/AKT, and NET signaling pathways. The study demonstrates the ability of NRICM102 to ameliorate severe COVID-19-related embolic and fibrotic pulmonary injury in vitro and in vivo and elucidates the underlying mechanisms.


Assuntos
Tratamento Farmacológico da COVID-19 , Lesão Pulmonar , Embolia Pulmonar , Enzima de Conversão de Angiotensina 2 , Quimiocina CCL5 , Citocinas , Fibrose , Humanos , Interleucina-6/metabolismo , Interleucina-8 , Lesão Pulmonar/tratamento farmacológico , Pandemias , Fosfatidilinositol 3-Quinases , Inibidor 1 de Ativador de Plasminogênio , Proteínas Proto-Oncogênicas c-akt , Embolia Pulmonar/tratamento farmacológico , Glicoproteína da Espícula de Coronavírus , Receptor 4 Toll-Like/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Fator de von Willebrand
6.
Environ Sci Technol ; 56(7): 3905-3914, 2022 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-35294169

RESUMO

Sulfate (SO42-) is a major species in atmospheric fine particles (PM2.5), inducing haze formation and influencing Earth's climate. In this study, the δ34S values in PM2.5 sulfate (δ34S-SO42-) were measured in Hangzhou, east China, from 2015 September to 2016 October. The result showed that the δ34S-SO42- values varied from 1.6 to 6.4‰ with the higher values in the winter. The estimated fractionation factor (α34Sg→p) from SO2 to SO42- averaged at 3.9 ± 1.6‰. The higher α34Sg→p values in the winter were mainly attributed to the decrease of ambient temperature. We further compared the quantified source apportionments of sulfate by isotope techniques with and without the consideration of fractionation factors. The result revealed that the partitioned emission sources to sulfate with the consideration of the fractionation effects were more logical, highlighting that fractionation effects should be considered in partitioning emission sources to sulfate using sulfur isotope techniques. With considering the fractionation effects, coal burning was the dominant source to sulfate (85.5%), followed by traffic emissions (12.8%) and oil combustion (1.7%). However, the coal combustion for residential heating contributed only 0.9% to sulfate on an annual basis in this megacity.


Assuntos
Poluentes Atmosféricos , Aerossóis/análise , Poluentes Atmosféricos/análise , China , Monitoramento Ambiental/métodos , Material Particulado/análise , Estações do Ano , Sulfatos , Isótopos de Enxofre
7.
Environ Sci Technol ; 56(11): 6870-6879, 2022 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-34428888

RESUMO

Until now, there has been a lack of knowledge regarding the vertical profiles of nitrate formation in the urban boundary layer (BL) based on triple oxygen isotopes. Here, we conducted vertical measurements of the oxygen anomaly of nitrate (Δ17O-NO3-) on a 325 m meteorological tower in urban Beijing during the winter and summer. The simultaneous vertical measurements suggested different formation mechanisms of nitrate aerosols at ground level and 120 and 260 m in the winter due to the less efficient vertical mixing under stable atmospheric conditions. Particularly, different chemical processes of nitrate aerosols at the three heights were found between clean days and polluted days in the winter. On clean days, nocturnal chemistry (NO3 + HC and N2O5 uptake) contributed to nitrate production equally with OH/H2O + NO2 at ground level, while it dominated aloft (contributing 80% of nitrate production at 260 m), due to the higher aerosol liquid water content and O3 concentration there. On polluted days, nocturnal reactions dominated the formation of nitrate at the three heights. Particularly, the contribution of the OH/H2O + NO2 pathway to nitrate production increased from the ground level to 120 m might be attributed to the hydrolysis of NO2 to HONO and then further photolysis to OH radicals in the day. In contrast, the proportion of N2O5 + H2O decreased at 260 m, likely due to the low relative humidity aloft that inhibited the N2O5 hydrolysis reactions in the residual layer. Our results highlighted that the differences between meteorology and gaseous precursors could largely affect particulate nitrate formation at different heights within the polluted urban BL.


Assuntos
Poluentes Atmosféricos , Nitratos , Aerossóis , Poluentes Atmosféricos/análise , Pequim , China , Monitoramento Ambiental , Nitratos/análise , Dióxido de Nitrogênio , Óxidos de Nitrogênio/análise , Compostos Orgânicos , Isótopos de Oxigênio/análise , Estações do Ano
8.
Environ Res ; 206: 112554, 2022 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-34951988

RESUMO

Humic-like substances (HULIS), as important components of brown carbon (BrC), play an important role in climate change. In this study, one-year PM2.5 samples from 2017 to 2018 were collected at Nanjing, China and the water soluble HULIS and other chemical species were analyzed to investigate the seasonal variations, optical properties and possible sources. The HULIS concentrations exhibited highest in winter and lowest in summer. The annual averaged HULIS concentration was 2.61 ± 1.79 µg m-3, accounting for 45 ± 13% of water-soluble organic carbon (WSOC). The HULIS light absorption coefficient at 365 nm (Abs365, HULIS) averagely accounted for 71 ± 19% of that of WSOC, suggesting that HULIS are the main light-absorbing components in WSOC. The annual averaged Ångström absorption exponent and mass absorption efficiency of HULIS at 365 nm were 5.22 ± 0.77 and 1.71 ± 0.70 m2 g-1. Good correlations between HULIS with levoglucosan and K+ suggested biomass burning (BB) influence on HULIS. High concentrations of HULIS and secondary species (e.g., NO3-, SO42-, NH4+, C2O42-) were found in present of high relative humidity, indicating strong aqueous phase secondary HULIS formation. Secondary HULIS produced from anthropogenic and biogenic precursors were quantified based on the positive matrix factorization (PMF) model and the results showed that both fossil (55%) and biogenic (45%) emission sources made great contributions to HULIS. Fossil fuel combustion significantly contributed to HULIS formation throughout the whole year, which were enriched with more secondary HULIS (30%) than primary HULIS (25%). Strongest BB contribution (39%) was found in winter and biogenic SOA contribution (32%) was found in summer. A multiple linear regression (MLR) method was further applied to obtain specific source contributions to Abs365, HULIS and the results showed that strong light-absorbing chromophores were produced from anthropogenic precursors. Our results highlight the anthropogenic SOA and fossil fuels combustion contributions to HULIS in addition to the biggest contributor, BB, in urban area in China.


Assuntos
Poluentes Atmosféricos , Material Particulado , Aerossóis/análise , Poluentes Atmosféricos/análise , Carbono/análise , China , Monitoramento Ambiental/métodos , Substâncias Húmicas/análise , Material Particulado/análise , Água/química
9.
Environ Res ; 211: 112984, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35245534

RESUMO

The Coronavirus Disease 2019 (COVID-19) lockdown policy reduced anthropogenic emissions and impacted the atmospheric chemical characteristics in Chinese urban cities. However, rare studies were conducted at the high mountain site. In this work, in-situ measurements of light absorption by carbonaceous aerosols and carbon dioxide (CO2) concentrations were conducted at Waliguan (WLG) over the northeastern Tibetan Plateau of China from January 3 to March 30, 2020. The data was employed to explore the influence of the COVID-19 lockdown on atmospheric chemistry in the background-free troposphere. During the sampling period, the light absorption near-infrared (>470 nm) was mainly contributed by BC (>72%), however, BC and brown carbon (BrC) contributed equally to light absorption in the short wavelength (∼350 nm). The average BC concentrations in the pre-, during and post-lockdown were 0.28 ±â€¯0.25, 0.18 ±â€¯0.16, and 0.28 ±â€¯0.20 µg m-3, respectively, which decreased by approximately 35% during the lockdown period. Meanwhile, CO2 also showed slight decreases during the lockdown period. The declined BC was profoundly attributed to the reduced emissions (∼86%), especially for the combustion of fossil fuels. Moreover, the declined light absorption of BC, primary and secondary BrC decreased the solar energy absorbance by 35, 15, and 14%, respectively. The concentration weighted trajectories (CWT) analysis suggested that the decreased BC and CO2 at WLG were exclusively associated with the emission reduction in the eastern region of WLG. Our results highlighted that the reduced anthropogenic emissions attributed to the lockdown in the urban cities did impact the atmospheric chemistry in the free troposphere of the Tibetan Plateau.


Assuntos
Poluentes Atmosféricos , COVID-19 , Aerossóis/análise , Poluentes Atmosféricos/análise , COVID-19/epidemiologia , COVID-19/prevenção & controle , Dióxido de Carbono/análise , China/epidemiologia , Controle de Doenças Transmissíveis , Monitoramento Ambiental , Humanos , Material Particulado/análise , Fuligem/análise
10.
Environ Sci Technol ; 55(18): 12261-12271, 2021 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-34469681

RESUMO

Formation pathways and sources of atmosphere nitrate (NO3-) have attracted much attention as NO3- had detrimental effects on Earth's ecosystem and climate change. Here, we measured nitrogen (δ15N-NO3-) and oxygen (δ18O-NO3- and Δ17O-NO3-) isotope compositions in nitrate aerosols at the Qomolangma station (QOMS) over the Himalayan-Tibetan Plateau (HTP) to quantify the formation mechanisms and emission sources of nitrate at the background site. At QOMS, the enhanced NO3- concentrations were observed in the springtime. The average δ15N-NO3-, δ18O-NO3-, and Δ17O-NO3- values were 0.4 ± 4.9, 64.7 ± 11.5 and 27.6 ± 6.9‰, respectively. Seasonal variations of isotope ratios at QOMS can be explained by the different emissions and formation pathways to nitrate. The average fractions of NO2 + OH and N2O5 + H2O to nitrate production were estimated to be 43 and 52%, respectively, when the NO3 + hydrocarbon (HC)/dimethyl sulfide (DMS) (NO3 + HC/DMS) pathway was assumed to be 5%. Using stable isotope analysis in the R (SIAR) model, the relative contributions of biomass burning (BB), biogenic soil emission, traffic, and coal combustion to nitrate were estimated to be 28, 25, 24, and 23%, respectively, on yearly basis. By FLEXible PARTicle (FLEXPART) dispersion model, we highlighted that NOx from BB emission over South Asia that had undergone N2O5 + H2O processes enhanced the nitrate concentrations in the springtime over the HTP region.


Assuntos
Nitratos , Nitrogênio , Aerossóis , China , Ecossistema , Monitoramento Ambiental , Nitratos/análise , Nitrogênio/análise , Isótopos de Nitrogênio/análise , Isótopos de Oxigênio/análise , Tibet
11.
J Nat Prod ; 84(2): 259-267, 2021 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-33459007

RESUMO

Seven new polyhydroxylated oleanane-type triterpene saponins, arenarosides A-G (1-7), together with four known compounds, were isolated from an ethanol extract of the aerial parts of the Vietnamese plant Polycarpaea arenaria. The chemical structures of the newly isolated oleanane saponins were elucidated on the basis of spectroscopic and spectrometric analysis, especially 2D NMR and HRMS. Biological evaluation revealed that 3, 4, 6, and 7 showed moderate activities against four human cancer cell lines (A549, HTC116, PC3, and RT112) with IC50 values of 6.0-9.9 µM, and 3, 4, 5, and 7 also displayed promising antiangiogenesis effects with IC50 values <5 µM in the test system used. Among the isolates, arenaroside D (4) exhibited the most potent inhibitory effects, not only in cancer cell proliferation but also in angiogenic activities. Preliminary SAR studies revealed that the presence of an acetyl group at C-22 in oleanane-type triterpene saponins increases these bioactivities.


Assuntos
Inibidores da Angiogênese/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Caryophyllaceae/química , Ácido Oleanólico/análogos & derivados , Saponinas/farmacologia , Inibidores da Angiogênese/isolamento & purificação , Antineoplásicos Fitogênicos/isolamento & purificação , Linhagem Celular Tumoral , Humanos , Ácido Oleanólico/isolamento & purificação , Ácido Oleanólico/farmacologia , Compostos Fitoquímicos/isolamento & purificação , Compostos Fitoquímicos/farmacologia , Componentes Aéreos da Planta/química , Saponinas/isolamento & purificação , Vietnã
12.
Bioorg Chem ; 109: 104700, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33607361

RESUMO

A chemical investigation of the zoantharian Zoanthus vietnamensis, collected off Taiwan, yielded eleven new alkaloids, 7α-hydroxykuroshine J (1), 18ß-hydroxykuroshine J (2), 5α-hydroxyzoanthenamine (3), 5ß-hydroxyzoanthenamine (4), 14α-hydroxyzoanthenamine (5), 30-hydroxyzoanthenamine (6), 11-dehydroxy-18-epi-kuroshine A (7), 5α-hydroxykuroshine A (8), 7ß-hydroxykuroshine A (9), 11-keto-oxyzoanthamine (10), and 30-hydroxyzoanthamine (11), along with eight known compounds (12-19). The structures of these compounds were identified by detailed spectroscopic data, including HRESIMS, IR, NMR, and UV spectra. All secondary metabolites isolated from Z. vietnamensis were investigated for the anti-angiogenic effect in human endothelial progenitor cells (EPCs). Compounds 6, 7, 11, and 13 exhibited mild anti-angiogenic effect by blocking cell growth and tube formation of EPCs. The neuroprotective potential of four major compounds 12, 14, 15, and 19 against paclitaxel-induced neurotoxicity was evaluated. Pretreatment of 14 and 15 protected paclitaxel-damaged neurite outgrowth of dorsal root ganglion (DRG) neurons, without interfering the cytotoxic activity of paclitaxel on cervical cancer SiHa cells.


Assuntos
Alcaloides/farmacologia , Antozoários/química , Antineoplásicos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Neovascularização Patológica/tratamento farmacológico , Neurônios/efeitos dos fármacos , Alcaloides/química , Animais , Antineoplásicos/química , Linhagem Celular Tumoral , Descoberta de Drogas , Gânglios Espinais/citologia , Humanos , Camundongos , Estrutura Molecular , Paclitaxel/toxicidade , Células-Tronco/efeitos dos fármacos
13.
Mar Drugs ; 19(3)2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33669051

RESUMO

Application of LC-MS/MS-based molecular networking indicated the ethanol extract of octocoral Asterospicularia laurae is a potential source for the discovery of new xenicane derivatives. A natural product investigation of this soft coral resulted in the isolation of four new xenicane diterpenoids, asterolaurins O‒R (1‒4), together with six known compounds, xeniolide-A (5), isoxeniolide-A (6), xeniolide-B (7), 7,8-epoxyxeniolide-B (8), 7,8-oxido-isoxeniolide-A (9), and 9-hydroxyxeniolide-F (10). The structures of isolated compounds were characterized by employing spectroscopic analyses, including 2D-NMR (COSY, HMQC, HMBC, and NOESY) and high-resolution electrospray ionization mass spectrometry (HRESIMS). Asterolaurin O is the first case of brominated tricarbocyclic type floridicin in the family Xeniidae. Concerning bioactivity, the cytotoxic activity of those isolates was evaluated. As a result, compounds 1 and 2 demonstrated a selective cytotoxic effect against the MCF-7 cell line at IC50 of 14.7 and 25.1 µM, respectively.


Assuntos
Antozoários/química , Antineoplásicos/isolamento & purificação , Diterpenos/isolamento & purificação , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Cromatografia Líquida , Diterpenos/química , Diterpenos/farmacologia , Humanos , Concentração Inibidora 50 , Células MCF-7 , Taiwan , Espectrometria de Massas em Tandem
14.
Molecules ; 26(12)2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34203624

RESUMO

Millettia pulchra is traditionally used for treating diseases, including joint pain, fever, anemia, and allergies. It is also a potential resource of natural flavonoid derivatives, which represents major constituents of this plant. This study aimed to isolate the major compounds from M. pulchra radix, develop and validate the HPLC-PDA method to determine their contents, and optimize its extraction. Four major flavonoid derivatives (karanjin, lanceolatin B, 2",2"-dimethylpyrano-[5″,6″:7,8]-flavone, and pongamol) were isolated using silica gel column chromatography, crystallization techniques in large amounts with high purities (>95%). A simple, accurate high-performance liquid chromatography-photodiode array (HPLC-PDA) detection method has been developed and validated with significantly statistical impacts according to International Conference on Harmonization (ICH) guidelines. The Response Surface Methodology (RSM), Artificial Neural Network (ANN) models were employed to predictive performance and optimization of the extraction process. The optimized conditions for the extraction of major flavonoids were: extraction time (twice), solvent/material ratio (9.5), and ethanol concentration (72.5%). Our research suggests an effective method, which will be helpful for quality control in the pharmaceutical development of this species.


Assuntos
Flavonoides/química , Flavonoides/isolamento & purificação , Millettia/química , Antioxidantes/química , China , Cromatografia Líquida de Alta Pressão/métodos , Etanol/química , Millettia/metabolismo , Extratos Vegetais/química , Raízes de Plantas/química , Solventes/química
15.
Anal Chem ; 92(21): 14373-14382, 2020 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-33047954

RESUMO

Carbon content constitutes a major fraction of atmospheric particulate matter (PM) and directly influences the earth's climate and human health. The stable carbon isotope ratios (δ13C) can be used to track potential sources and atmospheric processes of carbonaceous aerosols. Previously, determination of δ13C was always conducted in offline carbonaceous aerosol samples. The poor time-resolution results cannot provide information regarding the temporal evolution of δ13C at a short-time scale. In this study, we developed a new system for online measurements of δ13C in atmospheric carbonaceous aerosols by combining a semicontinuous organic carbon/elemental carbon (OC/EC) analyzer and online cavity ring-down spectroscopy (CRDS) (OC/EC analyzer-CRDS). To provide better stability in the determination of δ13C, a carrier gas with CO2 (∼200 ppm) in "balance gas" was used, and Keeling analysis was employed to separate the δ13C signal of the sample from background CO2 gas. Our results showed that the accuracy and absolute precision of the δ13C measurements by the OC/EC analyzer-CRDS system were better than 0.1‰ and 0.5‰, respectively, for the samples containing carbon content more than 5 µg. Furthermore, we employed this system to monitor δ13C (δ13C-TC) in particulate total carbon (TC) with a time resolution of 2-4 h over Beijing in late summer and early autumn, 2019. During the sampling period, the TC concentrations varied from 0.1 to 12.0 µg m-3 with a mean value of 6.0 ± 2.4 µg m-3. The δ13C-TC ranged from -28.2 to -24.2‰ (mean value was -25.9 ± 0.9‰) without significant diurnal variations, suggesting similar contributing sources to TC. Comparing the δ13C signatures of different emissions, we found that liquid fuels and primary and secondary C3 plants were likely the dominant sources of particulate TC. Finally, we found that atmospheric heavy precipitation washed out the aged aerosols from the polluted air, resulting in significant depletion (∼2.4‰) of δ13C-TC in the atmosphere. This paper described a novel system for conducting online measurements of δ13C in atmospheric carbonaceous aerosols and provided us information to better understand the temporal evolution of emission sources and atmospheric processes of carbonaceous aerosols.


Assuntos
Atmosfera/química , Isótopos de Carbono/análise , Isótopos de Carbono/química , Análise Espectral/métodos , Aerossóis
16.
J Nat Prod ; 83(5): 1400-1408, 2020 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-32357011

RESUMO

Seven new cucurbitane-type triterpenoids, kuguaovins A-G (1-7), and five known ones were isolated from the rattans of wild Momordica charantia. Their structures were established by spectroscopic data analyses, including 1D and 2D NMR, IR, and MS techniques. The absolute configurations of the cucurbitanes were determined from NOESY data and partially by X-ray crystallographic analysis. In pharmacological studies, compounds 1-7 and 9-12 exhibited weak anti-inflammatory effects (IC50 = 15-35 µM), based on an anti-NO production assay.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Glicosídeos/farmacologia , Momordica charantia/química , Extratos Vegetais/farmacologia , Triterpenos/farmacologia , Animais , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Camundongos , Estrutura Molecular , Óxido Nítrico/antagonistas & inibidores , Óxido Nítrico/biossíntese , Extratos Vegetais/química , Células RAW 264.7 , Espectrofotometria Infravermelho , Difração de Raios X
17.
Molecules ; 25(3)2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-32012805

RESUMO

In folk medicine, Stahlianthus thorelii Gagnep. has been used to treat diseases related to inflammation, ulcers, and cancer. There are no reports concerning the chemical components and bioactivities of S. thorelii; thus, this study aims to explore the phytochemicals, quantify the main compounds, and test the anticancer activity of isolates from S. thorelii. Dried rhizomes were extracted with 95% ethanol and, then, partitioned, fractionated, and isolated. On the basis of the result of the antiproliferative activity of the fractions, seven isolates were yielded and were identified by spectroscopic analyses. The inhibition of cancer proliferation was determined by an MTT assay and the deployed IC50 to value their efficacy. Seven compounds containing one new C-benzylated dihydrochalcone derivative, thorechalcone A (1) and 2-7 were isolated from S. thorelii. In terms of the bioactivity, compounds 1 and 3 displayed promising antiproliferative activity (WiDr, A549, and HepG2), with IC50 values <40 µM. The HPLC-UV method of quantification of two major compounds (3 and 4) was also validated. This study presented the isolations of antiproliferative potentials of new chalcone and known flavonoid derivatives from S. thorelii. The validated simple, accurate, and rapid HPLC method could be deployed for the quality control of herbal drugs.


Assuntos
Antineoplásicos Fitogênicos/isolamento & purificação , Chalconas/isolamento & purificação , Flavonoides/isolamento & purificação , Zingiberaceae/química , Células A549 , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Chalconas/química , Chalconas/farmacologia , Cromatografia Líquida de Alta Pressão , Flavonoides/química , Flavonoides/farmacologia , Células Hep G2 , Humanos , Concentração Inibidora 50 , Células MCF-7 , Estrutura Molecular , Compostos Fitoquímicos/isolamento & purificação , Compostos Fitoquímicos/farmacologia
18.
Molecules ; 25(10)2020 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-32414033

RESUMO

Plants of the genus Callicarpa are known to possess several medicinal effects. The constituents of the Taiwan endemic plant Callicarpa hypoleucophylla have never been studied. Therefore, C. hypoleucophylla was selected for our phytochemical investigation. Two new clerodane-type diterpenoids, named callihypolins A (1) and B (2), along with seven known compounds were isolated from the leaves and twigs of the Lamiaceae plant C. hypoleucophylla and then characterized. The structures of compounds 1 and 2 were elucidated by spectroscopic data analysis, specifically, two-dimension nuclear magnetic resonance (NMR). The anti-inflammatory activity of compounds 1-9 based on the suppression of superoxide anion generation and elastase release was evaluated. Among the isolates, compounds 2-4 showed anti-inflammatory activity (9.52-32.48% inhibition at the concentration 10 µm) by suppressing superoxide anion generation and elastase release. Our findings not only expand the description of the structural diversity of the compounds present in plants of the genus Callicarpa but also highlight the possibility of developing anti-inflammatory agents from Callicarpa endemic species.


Assuntos
Anti-Inflamatórios , Callicarpa/química , Diterpenos Clerodânicos , Neutrófilos/metabolismo , Adulto , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Diterpenos Clerodânicos/química , Diterpenos Clerodânicos/farmacologia , Feminino , Humanos , Masculino , Neutrófilos/patologia , Superóxidos/metabolismo
19.
Molecules ; 24(7)2019 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-30965662

RESUMO

Six new dammarane-type saponins, gypenosides CP1-6 (16), along with 19 known compounds 7⁻25, were isolated and characterized from the aerial parts of Gynostemma pentaphyllum. Among these compounds, eight dammarane-type saponins, 2, 5, 6, 7, 11, 12, 13, and 15, exhibited the greatest antiproliferative effects against two human tumor cell lines (A549 and HepG2).


Assuntos
Antineoplásicos Fitogênicos/isolamento & purificação , Gynostemma/química , Saponinas/isolamento & purificação , Células A549 , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Células Hep G2 , Humanos , Estrutura Molecular , Componentes Aéreos da Planta/química , Extratos Vegetais/química , Saponinas/química , Saponinas/farmacologia , Triterpenos , Damaranos
20.
Planta Med ; 84(18): 1348-1354, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29986352

RESUMO

Phytochemical investigation of ethanol extracts from two Taiwanese collections of Vernonia cinerea resulted in the isolation of eighteen hirsutinolide-type sesquiterpenoids, including seven new ones designated as vernolides E - K (1: -7: ). All structures were determined by a combination of detailed spectroscopic analyses (NMR and MS) and comparison with reported data. In an in vitro anti-inflammatory assay, compounds 3, 7, 9, 11: , and 14: exhibited strong inhibitory activities toward NO production by LPS-induced RAW264.7 macrophages, with IC50 values of 1.18, 0.85, 0.66, 0.71 and 0.45 µM, respectively, without affecting cellular viability at 40 µM. Preliminary structure-activity relationships indicate that the ester groups at C-8 and C-13 may enhance inhibition of NO production.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Óxido Nítrico/biossíntese , Sesquiterpenos/química , Sesquiterpenos/farmacologia , Vernonia/química , Animais , Anti-Inflamatórios não Esteroides/química , Avaliação Pré-Clínica de Medicamentos/métodos , Concentração Inibidora 50 , Lipopolissacarídeos/farmacologia , Espectroscopia de Ressonância Magnética , Camundongos , Estrutura Molecular , Células RAW 264.7 , Espectrometria de Massas por Ionização por Electrospray , Relação Estrutura-Atividade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA