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31.
32.
Chang-Shu Cheng Qing-Hui Gu Jin-Ke Zhang Jun-Hong Tao Tian-Rui Zhao Jian-Xin Cao Gui-Guang Cheng Guo-Fang Lai Ya-Ping Liu 《Molecules (Basel, Switzerland)》2022,27(11)
The bud of Vaccinium dunalianum Wight has been traditionally consumed as health herbal tea by “Yi” people in Yunnan Province, China, which was locally named “Que Zui tea”. This paper studied the chemical constituents of five fractions from Vaccinium dunalianum, and their enzyme inhibitory effects of α-glucosidase and pancreatic lipase, antioxidant activity, and cytoprotective effects on H2O2-induced oxidative damage in HepG2 cells. The methanol extract of V. dunalianum was successively partitioned with petroleum ether (PF), chloroform (CF), ethyl acetate (EF), n-butanol (BF), and aqueous (WF) to obtain five fractions. The chemical profiling of the five fractions was analyzed by ultra-high-performance liquid chromatography coupled with a tandem mass spectrometry (UHPLC-MS/MS), and 18 compounds were tentatively identified. Compared to PF, CF, BF and WF, the EF revealed the highest total phenols (TPC) and total flavonoids (TFC), and displayed the strongest enzyme inhibition ability (α-glucosidase and pancreatic lipase) and antioxidant capacity (DPPH, ABTS and FRAP). Furthermore, these five fractions, especially EF, could effectively inhibit reactive oxygen species (ROS) production and cell apoptosis on H2O2-induced oxidative damage protection in HepG2 cells. This inhibitory effect might be caused by the up-regulation of intracellular antioxidant enzyme activity (CAT, SOD, and GSH). The flavonoids and phenolic acids of V. dunalianum might be the bioactive substances responsible for enzyme inhibitory, antioxidant, and cytoprotective activities. 相似文献
33.
Jie Tang Yang Yang Jingjing Qu Wenhuang Ban Hao Song Zhengying Gu Yannan Yang Larry Cai Shevanuja Theivendran Yue Wang Min Zhang Chengzhong Yu 《Chemical science》2022,13(29):8507
Pyroptosis is a programmed cell death widely studied in cancer cells for tumour inhibition, but rarely in dendritic cell (DC) activation for vaccine development. Here, we report the synthesis of sodium stabilized mesoporous aluminosilicate nanoparticles as DC pyroptosis modulators and antigen carriers. By surface modification of sodium-stabilized four-coordinate aluminium species on dendritic mesoporous silica nanoparticles, the resultant Na-IVAl-DMSN significantly activated DC through caspase-1 dependent pyroptosis via pH responsive intracellular ion exchange. The released proinflammatory cellular contents further mediated DC hyperactivation with prolonged cytokine release. In vivo studies showed that Na-IVAl-DMSN induced enhanced cellular immunity mediated by natural killer (NK) cells, cytotoxic T cells, and memory T cells as well as humoral immune response. Our results provide a new principle for the design of next-generation nanoadjuvants for vaccine applications.Na-IVAl-DMSN acts as both antigen carriers and modulators to “hyperactivate” dendritic cells (DCs) via potassium (K+) efflux dependent pyroptosis, eventually leading to enhanced adaptive and innate immunity. 相似文献
34.
Phenothiazine-based covalent organic frameworks with low exciton binding energies for photocatalysis
Weitao Wang Haotian Wang Xiaohui Tang Jinlei Huo Yan Su Chuangye Lu Yujian Zhang Hong Xu Cheng Gu 《Chemical science》2022,13(29):8679
Designing delocalized excitons with low binding energy (Eb) in organic semiconductors is urgently required for efficient photochemistry because the excitons in most organic materials are localized with a high Eb of >300 meV. In this work, we report the achievement of a low Eb of ∼50 meV by constructing phenothiazine-based covalent organic frameworks (COFs) with inherent crystallinity, porosity, chemical robustness, and feasibility of bandgap engineering. The low Eb facilitates effective exciton dissociation and thus promotes photocatalysis by using these COFs. As a demonstration, we subject these COFs to photocatalytic polymerization to synthesize polymers with remarkably high molecular weight without any requirement of the metal catalyst. Our results can facilitate the rational design of porous materials with low Eb for efficient photocatalysis.We report the construction of phenothiazine-based covalent organic frameworks, which exhibited diverse structures, the feasibility of bandgap engineering, and unprecedented ultralow exciton binding energy of ∼50 meV for photocatalytic polymerization. 相似文献
35.
Xiaohui Duan Mina Zhang Huan Du Xiu Gu Caihong Bai Liuqiang Zhang Kaixian Chen Kaifeng Hu Yiming Li 《Molecules (Basel, Switzerland)》2022,27(15)
Scrophulariae Radix (SR) is one of the oldest and most frequently used Chinese herbs for oriental medicine in China. Before clinical use, the SR should be processed using different methods after harvest, such as steaming, “sweating”, and traditional fire-drying. In order to investigate the difference in chemical constituents using different processing methods, the two-dimensional (2D) 1H-13C heteronuclear single quantum correlation (1H-13C HSQC)-based metabolomics approach was applied to extensively characterize the difference in the chemical components in the extracts of SR processed using different processing methods. In total, 20 compounds were identified as potential chemical markers that changed significantly with different steaming durations. Seven compounds can be used as potential chemical markers to differentiate processing by sweating, hot-air drying, and steaming for 4 h. These findings could elucidate the change of chemical constituents of the processed SR and provide a guide for the processing. In addition, our protocol may represent a general approach to characterizing chemical compounds of traditional Chinese medicine (TCM) and therefore might be considered as a promising approach to exploring the scientific basis of traditional processing of TCM. 相似文献
36.
Multiplexed Bioassays: Dual‐Encoded Microbeads through a Host–Guest Structure: Enormous,Flexible, and Accurate Barcodes for Multiplexed Assays (Adv. Funct. Mater. 34/2016) 下载免费PDF全文
37.
This study described palladium-catalyzed chemoselective direct α-arylation of carbonyl compounds with chloroaryl triflates in the Ar–Cl bond. The Pd/SelectPhos system showed excellent chemoselectivity toward the Ar–Cl bond in the presence of the Ar–OTf bond with a broad substrate scope and excellent product yields. The electronic and steric hindrance offered by the –PR2 group of the ligand with the C2-alkyl group was found to be the key factor affecting the reactivity and chemoselectivity of the α-arylation reaction. The chemodivergent approach was also successfully employed in the synthesis of flurbiprofen and its derivatives (e.g., –OMe and –F).Palladium-catalyzed chemoselective direct α-arylation of carbonyl compounds with chloroaryl triflates in the Ar–Cl bond is reported. The effects of –PR2 and C2-alkyl groups of the ligands are investigated using experimental and computational methods. 相似文献
38.
Jian Li Guangrui Chen Zhiyun Meng Zhuona Wu Hui Gan Xiaoxia Zhu Peng Han Taoyun Liu Fanjun Wang Ruolan Gu Guifang Dou 《Molecules (Basel, Switzerland)》2022,27(9)
Cepharanthine (CEP) has excellent anti-SARS-CoV-2 properties, indicating its favorable potential for COVID-19 treatment. However, its application is challenged by its poor dissolubility and oral bioavailability. The present study aimed to improve the bioavailability of CEP by optimizing its solubility and through a pulmonary delivery method, which improved its bioavailability by five times when compared to that through the oral delivery method (68.07% vs. 13.15%). An ultra-performance liquid chromatography tandem-mass spectrometry (UPLC-MS/MS) method for quantification of CEP in rat plasma was developed and validated to support the bioavailability and pharmacokinetic studies. In addition, pulmonary fibrosis was recognized as a sequela of COVID-19 infection, warranting further evaluation of the therapeutic potential of CEP on a rat lung fibrosis model. The antifibrotic effect was assessed by analysis of lung index and histopathological examination, detection of transforming growth factor (TGF)-β1, interleukin-6 (IL-6), α-smooth muscle actin (α-SMA), and hydroxyproline level in serum or lung tissues. Our data demonstrated that CEP could significantly alleviate bleomycin (BLM)-induced collagen accumulation and inflammation, thereby exerting protective effects against pulmonary fibrosis. Our results provide evidence supporting the hypothesis that pulmonary delivery CEP may be a promising therapy for pulmonary fibrosis associated with COVID-19 infection. 相似文献
39.
The impact of cellulose structure on binding interactions with hemicellulose and pectin 总被引:1,自引:0,他引:1
Four cellulose substrates including highly crystalline cellulose nanowhiskers (CNWs) from Gluconacetobacter xylinus (cellulose Iα) or cotton (cellulose Iβ) and amorphous cellulose derived from CNWs (phosphoric acid swollen cellulose nanowhiskers, PASCNWs) were used to explore the interaction between cellulose and well-defined xyloglucan, xylan, arabinogalactan and pectin. The binding behavior was characterized by adsorption isotherm and Langmuir models. The maximum adsorption and the binding constant of xyloglucan, xylan and pectin to any CNWs were always higher than to PASCNWs derived from the same source. The binding affinity of xyloglucan, xylan and pectin to G. xylinus cellulose was generally higher than to cotton cellulose, showing that binding interactions depended on the biological origin of cellulose and associated differences in its structure. The surface area, porosity, crystal plane and degree of order of cellulose substrate may all impact the interactions. 相似文献
40.
Commercial CaO was modified simply with benzyl bromide. The modified CaO had good water resistance, and characterization by FTIR and TG revealed the modifier was chemically bonded to the CaO surface. Commercial CaO and CaO modified with benzyl bromide were investigated as catalysts for the Henry reaction between benzaldehyde and nitromethane. It was found that the catalytic activity of the modified CaO was greatly improved, with high conversion of benzaldehyde to the (E)-phenyl nitroolefin and 1-phenyl-2-nitroethanol, and with different selectivity from commercial CaO. The effect of modification and reaction conditions on yield, selectivity, and mechanism were studied thoroughly. 相似文献