LWT-FOOD SCIENCE AND TECHNOLOGY
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2018
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IF 3.129
Lujing Xu,Guobin Xia,Zisheng Luo,Songbai Liu
In this study, an effective ultra-high performance liquid chromatography (UHPLC) method for simultaneous determination of 15 constituents of catechins, caffeine, gallic acid and theaflavins was developed. Employing the developed UHPLC method, the contents of the 15 constituents were analyzed in 245 samples of 6 types of Chinese teas collected from different places. The catechin contents in these samples ranged from 16.50 to 94.35 mg/g. Theaflavins were not detected in green tea and white tea, and caffeine did not strongly relate to germplasm resource or fermentation degree. Principal component analysis (PCA) of UHPLC data revealed that white, oolong and green tea samples could be clustered closely, demonstrating notable difference of functional components between the three types of teas resulting from preparation process and varieties. The constituent profile could be primarily attributed to the structural transformation of catechins and pigments during tea processing. This study would advance our understanding of chemical profile of Chinese teas afforded by different processing technologies.
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JOURNAL OF CHEMICAL THERMODYNAMICS
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2013
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IF 2.297
Jun Jing,Zhiyong Li,Yuanchao Pei,Huiyong Wang,Jianji Wang
In this work, a series of novel room temperature ionic liquids (ILs) have been synthesized with cheap, naturally α-amino acid ester as cations and bis(trifluoromethylsulfonyl)imide as anion. The glass transition temperature and thermal decomposition temperature of these ILs, partition coefficients of some coumarins and purine alkaloids between water and the amino acid ester-based ILs at T = 298.15 K, and Gibbs energy, enthalpy and entropy changes for the transfer of caffeine and 6,7-dihydroxycoumarin from water to [LeuC 2 ][Tf 2 N] have been determined. It is shown that these ILs are highly effective materials for the extraction of drug compounds like coumarin, 4-hydroxycoumarin, 7-hydroxycoumarin, 3-aminocoumarin, coumarin-3-carboxylic acid, 6,7-dihydroxycoumarin, 6,7-dihydroxy-4-methylcoumarin, caffeine, theobromine, theophylline, inosine, and 2,6-diaminopurine. The partition process is driven by enthalpy term, and partition coefficients of the drug molecules increase with the increase of hydrophobicity of both the drug molecules and the ILs. Furthermore, the possible partition mechanism has been investigated from 13 C NMR measurements.
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BIOSENSORS & BIOELECTRONICS
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2014
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IF 6.451
Weiping Wang,Ya-Chun Lu,Hong Huang,Ai-Jun Wang,Jian-Rong Chen,Jiu-Ju Feng
In this report, N, S-codoped fluorescent carbon nanodots (NSCDs) were prepared by a facile, simple, low-cost, and green thermal treatment of ammonium persulfate , glucose, and ethylenediamine . The as-prepared NSCDs displayed bright blue emission with a relatively high fluorescent quantum yield of 21.6%, good water solubility, uniform morphology, and excellent chemical stability, compared to pure CDs. The fluorescence of NSCDs can be significantly quenched by methotrexate (MTX) via fluorescence resonance energy transfer (FRET) between NSCDs and MTX, which was used for highly selective and sensitive detection of MTX with a wide linear range up to 50.0 μM and a low detection limit of 0.33 nM ( S / N =3). Moreover, this method was explored for practical detection of MTX in human serum with satisfied results.
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TALANTA
·
2014
·
IF 3.511
Wei Yin,Huihui Chai,Renhua Liu,Changhu Chu,John A. Palasota,Xiaohui Cai
Iminodiacetic acid (IDA) is dicarboxylic acid amine, which may produce stronger interaction with polar or charged compounds than bidentate α,β-amino acid. In this article, a novel type of tridentate zwitterionic HILIC stationary phase was prepared by covalently bonding N-benzyl IDA on silica gel via copper( I ) catalyzed Huisgen azide-alkyne 1,3-dipolar cycloaddition (CuAAC). The structure of this stationary phase and all related intermediates was confirmed by NMR, FT-IR, MS spectrum and elemental analysis . The new stationary phase showed good HILIC characteristics and high column efficiency (the theoretical plate number is up to 44000 plates m −1 in the case of guanosine) in the application of separation of polar compounds, including organic acids , organic bases, as well as highly polar and hydrophilic compounds, such as cephalosporins and carbapenems . Most of them displayed good peak shape and selectivity.
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FOOD CHEMISTRY
·
2024
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IF 8.5
Zhi-Quan Li,Xiao-Li Yin,Hui-Wen Gu,Zhi-Xin Peng,Baomiao Ding,Zhenshun Li,Ying Chen,Wanjun Long,Haiyan Fu,Yuanbin She
The duration of storage significantly influences the quality and market value of Qingzhuan tea (QZT). Herein, a high-resolution multiple reaction monitoring (MRM HR ) quantitative method for markers of QZT storage year was developed. Quantitative data alongside multivariate analysis were employed to discriminate and predict the storage year of QZT. Furthermore, the content of the main biochemical ingredients, catechins and alkaloids, and free amino acids (FAA) were assessed for this purpose. The results show that targeted marker–based models exhibited superior discrimination and prediction performance among four datasets. The R 2 X cum , R 2 Y cum and Q 2 cum of orthogonal projection to latent structure–discriminant analysis discrimination model were close to 1. The correlation coefficient ( R 2 ) and the root mean square error of prediction of the QZT storage year prediction model were 0.9906 and 0.63, respectively. This study provides valuable insights into tea storage quality and highlights the potential application of targeted markers in food quality evaluation.
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PHYTOMEDICINE
·
2024
·
IF 6.7
Yunyi Xu,Qionghua Ding,Yuhuan Xie,Qingqing Zhang,Yangyu Zhou,Hairui Sun,Rui Qian,Liqun Wang,Xuxi Chen,Ying Gao,Yuqin Yao,Yue Xiao
Background Silicosis, an interstitial lung disease caused by inhalation of silica particles, poses a significant health concern globally. Green tea polyphenol (TP) stands out as a promising therapeutic candidate, yet its specific protective effects and in-depth mechanisms against silicosis have not been thoroughly investigated. Purpose This study aimed to systematically assess the protective potential of TP against silicosis and to elucidate the underlying mechanisms of its action. Methods A combination of physiological, transcriptomic, molecular, and computational techniques was employed. HPLC was used to identify the components of TP, and its antioxidant properties were tested with DPPH and ABTS assays. The effects of TP on lung injury were assessed in silicosis mice using histopathology, qRT-PCR, and western blot. Transcriptomic analysis was applied to explore the differentially expressed genes and pathways in response to TP intervention. In vitro studies with mouse alveolar macrophages (MH-S) examined TP's effects on cell viability, proliferation, apoptosis, and inflammation responses. Integrated qRT-PCR, western blot, immunohistochemistry, and molecular docking were performed to confirm the molecular mechanism underlying the protective effects of TP against silicosis. Results TP effectively attenuated pulmonary inflammation and fibrosis in silicosis mice, as evidenced by significant reductions in inflammation and fibrotic markers. Moreover, TP's therapeutic benefits were linked to its cytoprotective effects on alveolar macrophages, notably its ability to protect MH-S cells from silica particle-induced apoptosis, inhibition of proliferation, and inflammatory response, underscoring its targeted protective effects at the cellular level. Mechanistically, TP exerted its anti-silicosis activity by targeting key pathways implicated in inflammatory responses, notably through the inhibition of the IL-17/NF-κB p65 signaling cascade. Molecular docking simulations corroborated these findings, demonstrating favorable binding affinities between TP's bioactive components (EGC, ECG, and EGCG) and crucial proteins (IL-17A, IL-17F, p65, TNF-α, IL-6, and IL-1β) involved in the IL-17/NF-κB p65 signaling pathway. This pathway inhibition led to a significant decrease in the production of pro-inflammatory cytokines, such as TNF-α, IL-6, and IL-1β, thus mitigated silicosis. Conclusion TP demonstrates efficacy in alleviating silica particle-induced lung injury by suppressing inflammation through the IL-17/NF-κB p65 signaling pathway, underscoring its potential as a valuable natural compound for silicosis management.
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JOURNAL OF MOLECULAR SPECTROSCOPY
·
2024
·
IF 1.4
Ningyi Wang,Xinghao Huang,Jiamin Zhang,Xu Wu,Yan Peng,Yiming Zhu
Caffeine, theophylline and theobromine are representative xanthine alkaloids, commonly used as stimulants due to their effects on the central nervous system. Despite their similar molecular structures, they have different pharmacological effects, necessitating a rapid and accurate identification method. In this study, terahertz time-domain spectroscopy (THz-TDS) was used to measure the absorption spectra of these three xanthine alkaloids within the range of 2.0–17.0 THz. The characteristic absorption peaks were visualized and analyzed basing on the quantum chemical calculations using Hartree-Fock (HF), Møller–Plesset perturbation theory (MP2) and density functional theory (DFT). Caffeine exhibited unique absorption peaks at 4.24, 5.00, and 11.13 THz. Theophylline showed characteristic peaks at 9.25, 12.20, and 15.09 THz. While theobromine exhibited characteristic peaks at 4.45, 7.68, and 11.21 THz. The results demonstrate that combining THz-TDS with DFT calculation can non-destructively, efficiently, and accurately identify these xanthine alkaloids, and providing valuable information for further understanding their pharmacological functions.
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FOOD RESEARCH INTERNATIONAL
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2025
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IF 8
Meng-Lei Xu,Songning Zhao,Wenshuo Ren,Mengmeng Zhang,Xiao Xia Han,Liang Su,Chengcong Chen,Yunfei Xie,Yu Gao
Degradation pathways of the pesticide pyridaben in tea caused by ultraviolet photocatalytic degradation were identified using SERS and GC–MS. Pyridaben in tea decreased from 4.50 mg/kg to 3.46 mg/kg after 2 h and to 0.62 mg/kg after 5 h, with a degradation rate of 86.22 % and a recovery rate of 90.00 %. The pyridaben degradation process involved C–S cleavage, with a SERS band of ν(C–S) at 710 cm −1 disappearing in the first hour. This was followed by cleavage of the N atom and the attached tert butyl group, resulting in the cleavage of the C-N bond in the ring, causing ring opening degradation. The presence of residual pyridaben was not necessarily related to the content of tea polyphenols; however, the UV light significantly reduced the content of theobromine, EGC, EC, and ECG but increased the content of EGCG. Ultraviolet irradiation slightly reduced the moisture content of oolong tea samples and did not significantly affect the total ash content. The content of water extract increaseing irradiation time due to the influence of moisture. UV irradiation time at the range of 60–360 min could degrade pyridaben while reducing its impact on tea quality.
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FOOD CHEMISTRY
·
2024
·
IF 8.5
Lihui Xiang,Chen Zhu,Jiajia Qian,Xiaochen Zhou,Miao Wang,Zhenshuo Song,Changsong Chen,Wenquan Yu,Lin Chen,Lanting Zeng
Most teas, including white tea, are produced from tender shoots containing both leaf and stem. However, the effect of the stem on white tea quality remains unclear, especially during withering, an essential process. Therefore, this study investigated the withering-induced changes in the leaves and stems of Camellia sinensis cv. ‘Fudingdabai’ by multi-group analysis. During withering, the levels of catechin and theobromine (i.e., major flavor-related compounds) decreased slightly, mainly in the leaves. The abundance of some proteinaceous amino acids related to fresh taste increased in stems due to increased protein hydrolysis. In addition, changes in biosynthetic pathways caused a decrease in theanine (a major non-proteinaceous amino acid) and an increase in gamma-aminobutyric acid in stems. Terpenes, mainly in the stems, were partially affected by withering. Phenylacetaldehyde, a major contributor to white tea aroma, increased mainly in the stems. These findings reflect the positive contribution of the stem to white tea quality.
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Journal of Advanced Research
·
2025
·
IF 13
Yating Guo,Yani Pan,Xinyu Feng,Haowei Guo,Liping Liu,Kexin Zhang,Haojun Xie,Binkai Zhu,Shuying Gong,Qiang Chu,Hua Fang,Ping Chen
Introduction Traditionally, the mechanism of dark tea quality formation has centered on microorganisms, with quality regulated by manipulating microorganisms and their fermentation environment. Nevertheless, raw teas, the natural selective medium of microbial community, was completely ignored in the formation of dark tea unique flavors. Objectives This study aims to uncover the previously unappreciated interactions between raw tea and microorganisms, demonstrating the significant role of raw tea in the formation of dark tea quality. Methods Sun-dried raw tea (SDT), baked raw tea (BT), and pan-fried raw tea (PFT) were pile fermented. Chemical profiles, microbial communities, and sensory qualities were assessed by metabolomics, high-throughput sequencing, and sensory evaluation, with correlation and multiple factor analyses used to explore their relationships. Results Compared to PFT and BT, SDT had 18 % lower flavonoid content and 26 % lower catechin content, which favored dominant Agathobacter and Wickerhamomyces . Wickerhamomyces contributed to flower aroma by producing alcohols, esters and terpenes, while Agathobacter amplified acid production. The distinctive dominant bacterium Acidovorax in BT was positively correlated with alcohols and hydrocarbons, with Pearson’s r > 0.6, resulting in a 47 % increase in volatile alcohol level, enhancing the fresh and refreshing attributes. A 70–80 % increase in iron concentration in PFT compared to SDT and BT resulted in the predominance of Geobacter , which exhibited a negative correlation with aldehydes. The presence of distinctive bacteria, Streptococcus and Ligilactobacillus , in PFT led to a significant rise in volatile acid content, increasing from 5 % to 25 %. Conclusion The chemical profiles of raw tea could reshape local microbiota, which then drives unique qualities of dark tea. This indicates dark tea quality is not passively shaped by the environmental microorganisms, but actively screened by raw tea chemistry. This study paves the way for targeted manipulation of raw tea chemical profiles to achieve desired dark tea flavor characteristics.
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TALANTA
·
2025
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IF 6.1
Tong Mu,Yudie Hu,Li Wen,Li Ding,Maolong Chen,Yunhui Cheng,Li Yao,Zhou Xu
Magnetic relaxation switch (MRS) sensors based on magnetic nanoparticles have received much attention in the field of environmental monitoring due to their rapid response and resistance to complex matrix interference. However, conventional MRS (cMRS) sensors constructed using magnetic nanoparticles have low sensitivity due to the lower relaxation rate of the magnetic probe. In this study, self-generated porous Fe 3 O 4 were employed in the MRS sensors for detection of caffeine, and the regulation of transverse relaxation performance by porous structure has been explored. The abundant porous structure of self-generated porous Fe 3 O 4 restricted the diffusion of the surrounding water molecules, and the controllable pore size can effectively adjust the apparent diffusion coefficient (ADC), as a result, improving the transverse relaxation properties. The developed MRS sensor exhibits a wide linear detection range from 0.5 to 100 ng/mL and a low limit of detection (LOD) of 0.047 ng/mL for caffeine. The LOD is 12 times lower than that of cMRS sensors. Consequently, the MRS sensor was further applied to the detection of caffeine in surface water samples. The results were consistent with those detected using high-performance liquid chromatography, demonstrating its superior anti-interference ability and the significant potential in environmental monitoring and food safety domains.
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ANALYST
·
2019
·Vol. 144
·期 14
·4386-4394
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IF 4.019
Zhenkun Mao,Changjun Hu,Zhentao Li,Zilin Chen
A novel organic polymer monolithic column with reversed-phase/hydrophilic (RPLC/HILIC) bifunctional interaction mixed-mode was successfully synthesized with the monomers 4-vinylbiphenyl and vinylbenzyl trimethylammonium chloride and the cross-linker ethylene dimethacrylate by in situ copolymerization in a binary porogenic solvent consisting of cyclohexanol and dodecanol for capillary electrochromatography. The stationary phases formed by styrene-based monomers can allow powerful π–π, hydrophobic and hydrophilic interactions, which is beneficial for the chromatographic separation with high resolution and high column efficiency. One mixed-mode monolithic column can work as two individual mode columns based on the combination of binary RPLC and HILIC separation mechanisms. Vanillin substances and neutral and alkaline compounds can be separated perfectly on the monolithic column in different chromatographic modes which can be switched by changing the content of the organic modifier in the running phase. For benzene, the highest column efficiency was 3.49 × 105 plates per m (theoretical plates, N). The relative standard deviations of retention time of different test analytes for intra-day (n = 5), inter-day (n = 5), column-to-column (n = 3) and batch-to-batch (n = 3) reproducibility were all less than 5.0%. All these results demonstrate that the monolithic column with RPLC/HILIC mixed-mode has great application potential.
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危险品化学品经营许可证（带存储）