Catechin and epicatechin are two isomeric flavonoids. Despite the vital properties highlighted by numerous scientific studies, very little data is available on the intrinsic reactivity of these compounds. To provide m...Catechin and epicatechin are two isomeric flavonoids. Despite the vital properties highlighted by numerous scientific studies, very little data is available on the intrinsic reactivity of these compounds. To provide more details on the stability and reactivity of catechin and epicatechin, this study is performed by means of theoretical calculation methods. For this purpose, geometry optimizations and frequency calculations at the B3LYP/6-31 + G (d, p) level of theory has been carried out and Natural Bond Orbital (NBO) analysis and VEDA (Vibrational Energy Distribution Analysis). The geometric and energy parameters and NBO analysis show that catechin appears more stable than epicatechin. The hydroxyl group position on the ring C of the catechol structure represents a factor that influences this relative stability. The global and local reactivity parameters reveal that epicatechin becomes more reactive than catechin. They indicate that their hydroxyl groups correspond to their most receptive sites. Fukui indices, VEDA and acidity study establish that O28–H29 remains the most reactive.展开更多
Epicatechin(EC)was used in this study to antagonize the cognitive dysfunction caused by lead(Pb)exposure in mice.Eight-week-old male Kunming mice were treated with PbCl_(2)(20 mg/kg)and/or EC(50 mg/kg)by gavage admini...Epicatechin(EC)was used in this study to antagonize the cognitive dysfunction caused by lead(Pb)exposure in mice.Eight-week-old male Kunming mice were treated with PbCl_(2)(20 mg/kg)and/or EC(50 mg/kg)by gavage administration for 4 weeks.Morris water maze test showed that EC could improve memory dysfunction induced by Pb.EC antagonized Ca^(2+)overload,activated Nrf2 signaling pathway and reduced the accumulation of Pb in the brain and serum,which suggested that EC might alter Pb distribution in mice.In vitro,spectroscopic analysis,potentiometric titration and docking studies were applied to inquiry into the interaction between bovine serum albumin(BSA)and Pb^(2+)in presence or absence of EC.EC was proved to chelate Pb^(2+)and reduced the interaction between BSA and Pb^(2+).In summary,EC might protect Pb-induced cognitive impairment by activating Nrf2 signaling pathway,and suppressing Pb accumulation via interference on the binding of Pb to albumin.展开更多
Epicatechin gallate(ECG)is one of the polyphenolic compounds and has attracted much attention due to its various bioactivities.In this study,the neuroprotective eff ect of ECG against H_(2)O_(2)-induced oxidative inju...Epicatechin gallate(ECG)is one of the polyphenolic compounds and has attracted much attention due to its various bioactivities.In this study,the neuroprotective eff ect of ECG against H_(2)O_(2)-induced oxidative injury in PC12 cells as well as the possible mechanisms were investigated.Cell viability was determined by MTT assay.The differentially expressed genes(DEGs),GO enrichment,and KEGG enrichment were analyzed to explore the mechanism of ECG against H_(2)O_(2)-induced oxidative injury by using the RNA-seq method.Finally,the change in the cell cycle was analyzed by fl ow cytometry.H_(2)O_(2)(400-1200μmol/L)inhibited the cell viability in a concentration-dependent manner.ECG(6-150μmol/L)eff ectively attenuated the H_(2)O_(2)-induced decrease in cell viability.RNA-seq analysis showed that ECG regulated 1058 coexpressed DEGs.GO enrichment analysis showed that the cellular component was the dominant group after ECG treatment.KEGG analysis showed that the cell cycle,fanconi anemia pathway,and homologous recombination were the important pathways for ECG in improving H_(2)O_(2)-induced oxidative injury and 28 coexpressed DEGs in the cell cycle pathway were summarized.Finally,cell cycle analysis also proved that ECG improved H_(2)O_(2)-induced cell cycle arrest in the G2/M phase.Our present study demonstrated that ECG attenuated H_(2)O_(2)-induced neurologic oxidative damage by multiple modulatory mechanisms at the molecular transcription level.These fi ndings provide new insights for further study of the molecular mechanism of the neuroprotection of ECG.展开更多
Hypertension is a major problem worldwide. There is much evidence to suggest that reactive oxygen species (ROS) radical may play a role in the development of organ damage associated with cardiovascular disease and hyp...Hypertension is a major problem worldwide. There is much evidence to suggest that reactive oxygen species (ROS) radical may play a role in the development of organ damage associated with cardiovascular disease and hypertension. (-)Epicatechin, a member of tea catechins belonging to flavonoid group, is known to be a potent anti-oxidant. The study has been undertaken to evaluate the effect of (-)epicatechin on markers of oxidative stress: reduced glutathione (GSH) and membrane sulfhydryl (-SH) groups in erythrocytes from hypertensive patients. The effect of (-)epicatechin was also compared with a known anti-oxidant L-ascorbic acid. The erythrocyte intracellular GSH content and membrane -SH group content were significantly (P<0.01) decreased in hypertensive subjects. In vitro incubation with (-)epicatechin caused an increase in GSH and -SH content, the effect was more pronounced in hypertensive erythrocytes. Similar results were obtained with L-ascorbic acid. The observed decrease in the level of GSH and -SH groups in hypertension is an indicator of oxidative stress condition. Observation of an increase in red cell GSH content and the protection of membrane -SH group oxidation by (-)epicatechin in hypertensive subjects is a convincing reason to suggest that high dietary intake of foods rich in catechins may help to reduce oxidative stress and concomitant free radical damage in hypertensive patients.展开更多
基于福建省冬半年沿海和港湾岛屿自动站的逐时极大风观测资料和WRF（Weather Research and Forecast）、EC（European Centre for Medium-Range Weather Forecasts）细网格以及T639（TL639L60）三种模式预报的10 m风场资料，将模式预报...基于福建省冬半年沿海和港湾岛屿自动站的逐时极大风观测资料和WRF（Weather Research and Forecast）、EC（European Centre for Medium-Range Weather Forecasts）细网格以及T639（TL639L60）三种模式预报的10 m风场资料，将模式预报的风向风速与观测资料进行对比检验，结果表明：福建省沿海冬半年大风的盛行风向以东北风为主，大风的时空分布极为不均，沿海风力的脉动性、跳跃性、局地性突出。从三种模式对风速风向的模拟效果来看， WRF和EC细网格的预报效果较好，有可参考性， T639可参考性不高。对于风速，模式预报结果相比实况极大风速偏小，港湾岛屿代表站风速的平均绝对误差均小于沿海代表站，预报平均误差由沿海向内陆逐渐减小，由中部向南北逐渐减小。风向相比风速的预报效果要差， WRF和EC细网格的风向预报误差在45°-50°，有一定的参考意义；港湾岛屿代表站风向的平均绝对误差大于沿海代表站，以浮标站的误差最大。当观测风速出现7级及以上风速时，若对大风进行分级检验，则较低风速的预报平均绝对误差小于较高风速；风向预报的平均绝对误差也大大降低，且误差都在45°以内，具有良好的参考性。展开更多
Long-term regional extreme cold events(ECEs)garner significant attention due to their widespread impact and prolonged duration,posing critical threats to human society and ecosystems.Previous studies have examined ECE...Long-term regional extreme cold events(ECEs)garner significant attention due to their widespread impact and prolonged duration,posing critical threats to human society and ecosystems.Previous studies have examined ECE characteristics at single sites or grid points,however,it is crucial to recognize that such events generally manifest as spatiotemporally continuous regional phenomena.Here,we proposed an objective methodology based on spatiotemporal continuity to identify ECEs in the China-Pakistan Economic Corridor(CPEC)during the winters of 1961-2015.This approach successfully reproduced the dynamic evolution of ECEs,encompassing their initiation,development,and dissipation.We further analyzed the changes of ECE intensity,frequency,and duration,and assessed ECE trends within varying return periods by employing the generalized Pareto distribution(GPD).Our findings reveal a decline in the frequency and duration of ECEs in CPEC over the study period,while their intensity has increased by 50%.ECEs predominantly occur in the northern regions of Azad Kashmir and Balochistan’s Quetta in Pakistan,and Kashgar in China.High recurrence levels are associated with an expansion of ECE-prone areas,particularly in the northern Pamir Plateau,which emerges as a regional hotspot.These results highlight the critical need to remain vigilant to potential future surges in ECEs under global warming,underscoring their implications for regional climate resilience.展开更多
文摘Catechin and epicatechin are two isomeric flavonoids. Despite the vital properties highlighted by numerous scientific studies, very little data is available on the intrinsic reactivity of these compounds. To provide more details on the stability and reactivity of catechin and epicatechin, this study is performed by means of theoretical calculation methods. For this purpose, geometry optimizations and frequency calculations at the B3LYP/6-31 + G (d, p) level of theory has been carried out and Natural Bond Orbital (NBO) analysis and VEDA (Vibrational Energy Distribution Analysis). The geometric and energy parameters and NBO analysis show that catechin appears more stable than epicatechin. The hydroxyl group position on the ring C of the catechol structure represents a factor that influences this relative stability. The global and local reactivity parameters reveal that epicatechin becomes more reactive than catechin. They indicate that their hydroxyl groups correspond to their most receptive sites. Fukui indices, VEDA and acidity study establish that O28–H29 remains the most reactive.
基金supported by the National Key Research and Development Program of China under Grant(2022YFF1102800)the Graduate Scientific Research Innovation Project of Tianji(2022SKY109)+1 种基金the Project of Tianjin Science and Technology Program(22JCYBJC00360)the Project of Tianjin Science and Technology Program(21ZYJDJC00060)。
文摘Epicatechin(EC)was used in this study to antagonize the cognitive dysfunction caused by lead(Pb)exposure in mice.Eight-week-old male Kunming mice were treated with PbCl_(2)(20 mg/kg)and/or EC(50 mg/kg)by gavage administration for 4 weeks.Morris water maze test showed that EC could improve memory dysfunction induced by Pb.EC antagonized Ca^(2+)overload,activated Nrf2 signaling pathway and reduced the accumulation of Pb in the brain and serum,which suggested that EC might alter Pb distribution in mice.In vitro,spectroscopic analysis,potentiometric titration and docking studies were applied to inquiry into the interaction between bovine serum albumin(BSA)and Pb^(2+)in presence or absence of EC.EC was proved to chelate Pb^(2+)and reduced the interaction between BSA and Pb^(2+).In summary,EC might protect Pb-induced cognitive impairment by activating Nrf2 signaling pathway,and suppressing Pb accumulation via interference on the binding of Pb to albumin.
基金This work was supported by College Students Innovation and Entrepreneurship Training Program in 2021(No.202110163003).
文摘Epicatechin gallate(ECG)is one of the polyphenolic compounds and has attracted much attention due to its various bioactivities.In this study,the neuroprotective eff ect of ECG against H_(2)O_(2)-induced oxidative injury in PC12 cells as well as the possible mechanisms were investigated.Cell viability was determined by MTT assay.The differentially expressed genes(DEGs),GO enrichment,and KEGG enrichment were analyzed to explore the mechanism of ECG against H_(2)O_(2)-induced oxidative injury by using the RNA-seq method.Finally,the change in the cell cycle was analyzed by fl ow cytometry.H_(2)O_(2)(400-1200μmol/L)inhibited the cell viability in a concentration-dependent manner.ECG(6-150μmol/L)eff ectively attenuated the H_(2)O_(2)-induced decrease in cell viability.RNA-seq analysis showed that ECG regulated 1058 coexpressed DEGs.GO enrichment analysis showed that the cellular component was the dominant group after ECG treatment.KEGG analysis showed that the cell cycle,fanconi anemia pathway,and homologous recombination were the important pathways for ECG in improving H_(2)O_(2)-induced oxidative injury and 28 coexpressed DEGs in the cell cycle pathway were summarized.Finally,cell cycle analysis also proved that ECG improved H_(2)O_(2)-induced cell cycle arrest in the G2/M phase.Our present study demonstrated that ECG attenuated H_(2)O_(2)-induced neurologic oxidative damage by multiple modulatory mechanisms at the molecular transcription level.These fi ndings provide new insights for further study of the molecular mechanism of the neuroprotection of ECG.
文摘Hypertension is a major problem worldwide. There is much evidence to suggest that reactive oxygen species (ROS) radical may play a role in the development of organ damage associated with cardiovascular disease and hypertension. (-)Epicatechin, a member of tea catechins belonging to flavonoid group, is known to be a potent anti-oxidant. The study has been undertaken to evaluate the effect of (-)epicatechin on markers of oxidative stress: reduced glutathione (GSH) and membrane sulfhydryl (-SH) groups in erythrocytes from hypertensive patients. The effect of (-)epicatechin was also compared with a known anti-oxidant L-ascorbic acid. The erythrocyte intracellular GSH content and membrane -SH group content were significantly (P<0.01) decreased in hypertensive subjects. In vitro incubation with (-)epicatechin caused an increase in GSH and -SH content, the effect was more pronounced in hypertensive erythrocytes. Similar results were obtained with L-ascorbic acid. The observed decrease in the level of GSH and -SH groups in hypertension is an indicator of oxidative stress condition. Observation of an increase in red cell GSH content and the protection of membrane -SH group oxidation by (-)epicatechin in hypertensive subjects is a convincing reason to suggest that high dietary intake of foods rich in catechins may help to reduce oxidative stress and concomitant free radical damage in hypertensive patients.
文摘基于福建省冬半年沿海和港湾岛屿自动站的逐时极大风观测资料和WRF（Weather Research and Forecast）、EC（European Centre for Medium-Range Weather Forecasts）细网格以及T639（TL639L60）三种模式预报的10 m风场资料，将模式预报的风向风速与观测资料进行对比检验，结果表明：福建省沿海冬半年大风的盛行风向以东北风为主，大风的时空分布极为不均，沿海风力的脉动性、跳跃性、局地性突出。从三种模式对风速风向的模拟效果来看， WRF和EC细网格的预报效果较好，有可参考性， T639可参考性不高。对于风速，模式预报结果相比实况极大风速偏小，港湾岛屿代表站风速的平均绝对误差均小于沿海代表站，预报平均误差由沿海向内陆逐渐减小，由中部向南北逐渐减小。风向相比风速的预报效果要差， WRF和EC细网格的风向预报误差在45°-50°，有一定的参考意义；港湾岛屿代表站风向的平均绝对误差大于沿海代表站，以浮标站的误差最大。当观测风速出现7级及以上风速时，若对大风进行分级检验，则较低风速的预报平均绝对误差小于较高风速；风向预报的平均绝对误差也大大降低，且误差都在45°以内，具有良好的参考性。
基金Under the auspices of the Key R&D Program of Xinjiang Uygur Autonomous Region(No.2022B03021)Tianshan Talent Training Program of Xinjiang Uygur Autonomous Region(No.2022TSYCLJ0011)+2 种基金Transformation of Scientific and Technological Achievements from the Qinghai Province(No.2020-SF-145)the 2020 Qinghai Kunlun Talents-leading Scientists Project(No.2020-LCJ-02)Key Program of International Cooperation,Bureau of International Cooperation,Chinese Academy of Sciences(No.131551KYSB20210030)。
文摘Long-term regional extreme cold events(ECEs)garner significant attention due to their widespread impact and prolonged duration,posing critical threats to human society and ecosystems.Previous studies have examined ECE characteristics at single sites or grid points,however,it is crucial to recognize that such events generally manifest as spatiotemporally continuous regional phenomena.Here,we proposed an objective methodology based on spatiotemporal continuity to identify ECEs in the China-Pakistan Economic Corridor(CPEC)during the winters of 1961-2015.This approach successfully reproduced the dynamic evolution of ECEs,encompassing their initiation,development,and dissipation.We further analyzed the changes of ECE intensity,frequency,and duration,and assessed ECE trends within varying return periods by employing the generalized Pareto distribution(GPD).Our findings reveal a decline in the frequency and duration of ECEs in CPEC over the study period,while their intensity has increased by 50%.ECEs predominantly occur in the northern regions of Azad Kashmir and Balochistan’s Quetta in Pakistan,and Kashgar in China.High recurrence levels are associated with an expansion of ECE-prone areas,particularly in the northern Pamir Plateau,which emerges as a regional hotspot.These results highlight the critical need to remain vigilant to potential future surges in ECEs under global warming,underscoring their implications for regional climate resilience.
