The fresh leaves of China green tea, Camellia sinensis, were collected from Fuyang, Zhejiang Province, China, in April. The tea polyphenols was extracted by four different methods (homogenized with distilled water at ...The fresh leaves of China green tea, Camellia sinensis, were collected from Fuyang, Zhejiang Province, China, in April. The tea polyphenols was extracted by four different methods (homogenized with distilled water at room temperature, homogenized with 0.3% citric acid (w/v) at room temperature, 5- min boiling and homogenized with distilled water at room temperature, homogenized with 85°C distilled water), and after preserving at room temperature, the change of the Epigallocatechin gallate (EGCG) contents of the extracts was investigated. Results indicated that the EGCG content of homogenate extracted with 85°C distilled water was the highest before the extract was preserved, followed by that of the extract homogenized with 0.3% citric acid at room temperature. During preservation, EGCG content changed obviously. The EGCG contents of homogenates extracted with distilled water at room temperature and 85°C distilled water declined quickly and separately reduced to 21.52% and 54.6% of their initial contents after preservation for 12 h. The EGCG contents extracted by 0.3% citric acid (w/v) solvent at room temperature and 5- min boiling/homogenized with distilled water at room temperature declined relatively slowly ,and separately reduced to 76.9% and 85.16% of their initial contents after preservation for 12 h. It was also found that the citric acid can prevent the degradation of EGCG and the extract solution color is light展开更多
（-）-Epigallocatechin gallate （EGCG）, a major polyphenolic constituent of green tea, can inhibit activity of specific receptor tyrosine kinases （RTKs） and related downstream signal transduction pathways, resultin...（-）-Epigallocatechin gallate （EGCG）, a major polyphenolic constituent of green tea, can inhibit activity of specific receptor tyrosine kinases （RTKs） and related downstream signal transduction pathways, resulting in the control of unwanted cell proliferation. The epidermal growth factor receptor （EGFR） signaling pathway is one of the most important pathways that regulates growth, survival,proliferation and differentiation in mammalian cells. This review addresses the effects of EGCG on some protein factors involved in the EGFR signaling pathway in a direct or indirect manner. Based on our understanding of the interaction between EGCG and these factors, and based on their structures, EGCG could be used as a lead compound for designing and synthesizing novel drugs with significant biological activity.展开更多
Soluble receptor for advanced glycation end products(sRAGE)acts as a decoy sequestering of RAGE ligands,thus preventing the activation of the ligand-RAGE axis linking human diseases.However,the molecular mechanisms un...Soluble receptor for advanced glycation end products(sRAGE)acts as a decoy sequestering of RAGE ligands,thus preventing the activation of the ligand-RAGE axis linking human diseases.However,the molecular mechanisms underlying sRAGE remain unclear.In this study,THP-1 monocytes were cultured in normal glucose(NG,5.5 mmol/L)and high glucose(HG,15 mmol/L)to investigate the effects of diabetesrelevant glucose concentrations on sRAGE and interleukin-1β(IL-1β)secretion.The modulatory effects of epigallocatechin gallate(EGCG)in response to HG challenge were also evaluated.HG enhanced intracellular reactive oxygen species(ROS)generation and RAGE expression.The secretion of sRAGE,including esRAGE and cRAGE,was reduced under HG conditions,together with the downregulation of a disintegrin and metallopeptidase 10(ADAM10)and nuclear factor erythroid 2-related factor 2(Nrf2)nuclear translocation.Mechanistically,the HG effects were counteracted by siRAGE and exacerbated by siNrf2.Chromatin immunoprecipitation results showed that Nrf2 binding to the ADAM10 promoter and HG interfered with this binding.Our data reinforce the notion that RAGE and Nrf2 might be sRAGE-regulating factors.Under HG conditions,the treatment of EGCG reduced ROS generation and RAGE activation.EGCG-stimulated cRAGE release was likely caused by the upregulation of the Nrf2-ADAM10 pathway.EGCG inhibited HG-mediated NLRP3 inflammasome activation at least partly by stimulating sRAGE,thereby reducing IL-1βrelease.展开更多
Surface properties are considered to be important factors in addressing proper functionalities.In this paper,a multifunctional mussel-inspired coating was prepared via the direct copolymerization of epigallocatechin g...Surface properties are considered to be important factors in addressing proper functionalities.In this paper,a multifunctional mussel-inspired coating was prepared via the direct copolymerization of epigallocatechin gallate(EGCG)and arginine.The coating formation was confirmed by X-ray photoelectron spectroscopy and Fourier transform infrared spectra.The EGCG/arginine coating contained diverse functional groups like amines,phenols and carboxyls,whose densities were also tunable.Such mussel-inspired coating could also be applied as an ad-layer for its secondary reactivity,demonstrated by quartz crystal microbalance technique.Moreover,the tunable surface density of phenols showed potential ability in modulating endothelial cell and smooth muscle cell viability.The coatings rich in phenols presented excellent free radical scavenging property.Current results strongly indicated the potential of EGCG/arginine coatings to be applied as an ad-layer for vascular materials.展开更多
为改善表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)的脂溶性和生物利用度,在乙酸乙酯体系中化学合成乙酰化EGCG。研究酰基供体乙酸酐用量、催化剂吡啶用量、溶剂乙酸乙酯用量、反应温度、反应时间对EGCG乙酰化分子修饰取...为改善表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)的脂溶性和生物利用度,在乙酸乙酯体系中化学合成乙酰化EGCG。研究酰基供体乙酸酐用量、催化剂吡啶用量、溶剂乙酸乙酯用量、反应温度、反应时间对EGCG乙酰化分子修饰取代度的影响。结果表明,以0.19 g的EGCG为原料,乙酸酐用量0.04 m L、吡啶用量0.02 m L、乙酸乙酯用量20~60 m L、反应温度20~25℃、反应时间1~3 h有利于1~3取代度乙酰化EGCG生成;乙酸酐用量0.12~0.20 m L、吡啶用量0.06~0.20 m L、乙酸乙酯用量10~20 m L、反应温度17~25℃、反应时间5~9 h有利于4~6取代度乙酰化EGCG生成;乙酸酐用量0.40~0.80 m L、吡啶用量0.10~0.20 m L、乙酸乙酯用量5~10 m L、反应温度25~40℃、反应时间5~9 h有利于7~8取代度乙酰化EGCG生成。展开更多
文摘The fresh leaves of China green tea, Camellia sinensis, were collected from Fuyang, Zhejiang Province, China, in April. The tea polyphenols was extracted by four different methods (homogenized with distilled water at room temperature, homogenized with 0.3% citric acid (w/v) at room temperature, 5- min boiling and homogenized with distilled water at room temperature, homogenized with 85°C distilled water), and after preserving at room temperature, the change of the Epigallocatechin gallate (EGCG) contents of the extracts was investigated. Results indicated that the EGCG content of homogenate extracted with 85°C distilled water was the highest before the extract was preserved, followed by that of the extract homogenized with 0.3% citric acid at room temperature. During preservation, EGCG content changed obviously. The EGCG contents of homogenates extracted with distilled water at room temperature and 85°C distilled water declined quickly and separately reduced to 21.52% and 54.6% of their initial contents after preservation for 12 h. The EGCG contents extracted by 0.3% citric acid (w/v) solvent at room temperature and 5- min boiling/homogenized with distilled water at room temperature declined relatively slowly ,and separately reduced to 76.9% and 85.16% of their initial contents after preservation for 12 h. It was also found that the citric acid can prevent the degradation of EGCG and the extract solution color is light
文摘（-）-Epigallocatechin gallate （EGCG）, a major polyphenolic constituent of green tea, can inhibit activity of specific receptor tyrosine kinases （RTKs） and related downstream signal transduction pathways, resulting in the control of unwanted cell proliferation. The epidermal growth factor receptor （EGFR） signaling pathway is one of the most important pathways that regulates growth, survival,proliferation and differentiation in mammalian cells. This review addresses the effects of EGCG on some protein factors involved in the EGFR signaling pathway in a direct or indirect manner. Based on our understanding of the interaction between EGCG and these factors, and based on their structures, EGCG could be used as a lead compound for designing and synthesizing novel drugs with significant biological activity.
文摘Soluble receptor for advanced glycation end products(sRAGE)acts as a decoy sequestering of RAGE ligands,thus preventing the activation of the ligand-RAGE axis linking human diseases.However,the molecular mechanisms underlying sRAGE remain unclear.In this study,THP-1 monocytes were cultured in normal glucose(NG,5.5 mmol/L)and high glucose(HG,15 mmol/L)to investigate the effects of diabetesrelevant glucose concentrations on sRAGE and interleukin-1β(IL-1β)secretion.The modulatory effects of epigallocatechin gallate(EGCG)in response to HG challenge were also evaluated.HG enhanced intracellular reactive oxygen species(ROS)generation and RAGE expression.The secretion of sRAGE,including esRAGE and cRAGE,was reduced under HG conditions,together with the downregulation of a disintegrin and metallopeptidase 10(ADAM10)and nuclear factor erythroid 2-related factor 2(Nrf2)nuclear translocation.Mechanistically,the HG effects were counteracted by siRAGE and exacerbated by siNrf2.Chromatin immunoprecipitation results showed that Nrf2 binding to the ADAM10 promoter and HG interfered with this binding.Our data reinforce the notion that RAGE and Nrf2 might be sRAGE-regulating factors.Under HG conditions,the treatment of EGCG reduced ROS generation and RAGE activation.EGCG-stimulated cRAGE release was likely caused by the upregulation of the Nrf2-ADAM10 pathway.EGCG inhibited HG-mediated NLRP3 inflammasome activation at least partly by stimulating sRAGE,thereby reducing IL-1βrelease.
基金The author would like to thank Dr Manfred.F.Maitz for his selfless assistance of this job and appreciate Mr Chongxi Jiang and Mrs Ru Shen for their help and contributions on sample characterization and analysis.Specially thank Miss Si Zhong and Mr Xin Wang for their help of cell compatibility evaluation.This work was supported by Natural Science Foundation of China(Grant 51173149,81330031 and 31270020)Sichuan Province Science and Technology Support Program(No.2014SZ0128)the 111 Project.The Program of Introducing Talents of Discipline to Universities(B16033).
文摘Surface properties are considered to be important factors in addressing proper functionalities.In this paper,a multifunctional mussel-inspired coating was prepared via the direct copolymerization of epigallocatechin gallate(EGCG)and arginine.The coating formation was confirmed by X-ray photoelectron spectroscopy and Fourier transform infrared spectra.The EGCG/arginine coating contained diverse functional groups like amines,phenols and carboxyls,whose densities were also tunable.Such mussel-inspired coating could also be applied as an ad-layer for its secondary reactivity,demonstrated by quartz crystal microbalance technique.Moreover,the tunable surface density of phenols showed potential ability in modulating endothelial cell and smooth muscle cell viability.The coatings rich in phenols presented excellent free radical scavenging property.Current results strongly indicated the potential of EGCG/arginine coatings to be applied as an ad-layer for vascular materials.
文摘为改善表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)的脂溶性和生物利用度,在乙酸乙酯体系中化学合成乙酰化EGCG。研究酰基供体乙酸酐用量、催化剂吡啶用量、溶剂乙酸乙酯用量、反应温度、反应时间对EGCG乙酰化分子修饰取代度的影响。结果表明,以0.19 g的EGCG为原料,乙酸酐用量0.04 m L、吡啶用量0.02 m L、乙酸乙酯用量20~60 m L、反应温度20~25℃、反应时间1~3 h有利于1~3取代度乙酰化EGCG生成;乙酸酐用量0.12~0.20 m L、吡啶用量0.06~0.20 m L、乙酸乙酯用量10~20 m L、反应温度17~25℃、反应时间5~9 h有利于4~6取代度乙酰化EGCG生成;乙酸酐用量0.40~0.80 m L、吡啶用量0.10~0.20 m L、乙酸乙酯用量5~10 m L、反应温度25~40℃、反应时间5~9 h有利于7~8取代度乙酰化EGCG生成。
