通过Curtius重排反应,将高荧光量子产率的蒽基团通过脲基连接在N,N-二甲基苯胺单元上,合成了二元给受电子体系9-(4-N,N-二甲胺基苯基)脲基蒽(DMA-An)。选择性激发蒽单元,该二元体系发生从N,N-二甲基苯胺到蒽的光诱导电子转移反应(photoi...通过Curtius重排反应,将高荧光量子产率的蒽基团通过脲基连接在N,N-二甲基苯胺单元上,合成了二元给受电子体系9-(4-N,N-二甲胺基苯基)脲基蒽(DMA-An)。选择性激发蒽单元,该二元体系发生从N,N-二甲基苯胺到蒽的光诱导电子转移反应(photoinduced electron transfer PET),导致蒽荧光猝灭。酸化使N,N-二甲基苯胺基质子化,PET过程受阻,DMA-An的荧光恢复。此时,向该体系中加入三乙胺可使DMA-An的荧光恢复至初始的猝灭状态。多次实验证明此荧光猝灭-增大过程是可逆的,即DMA-An的荧光随酸碱变化呈光开关on/off行为。展开更多
Despite the breadth of knowledge about malaria, its transmission, preventive measures and available treatments and its difficulty in controlling the vector and the rapid spread of resistance to current drugs, there is...Despite the breadth of knowledge about malaria, its transmission, preventive measures and available treatments and its difficulty in controlling the vector and the rapid spread of resistance to current drugs, there is a stimulus to develop new research looking for active molecules. The phytochemical studies of the active extract confirmed the presence of alkaloids, flavonoids, coumarins, tannins, reducing compounds, anthocyanins, terpenes, triterpenes and steroids. In the present work, it was possible to isolate a mixture of isoquinolinic alkaloids from the tender leaves of Nectandra membranacea （Laureaceae） with antimalarial activity. The mixture composed of （-） - gliazovine and （＋） - aplogliazovine showed an IC50 value of 32.18 μg/mL against the P. berghei NK65 strain. It is important to continue with these studies and their chemical components isolated from N. membranacea that could be used as an alternative the treatment of malaria.展开更多
This work focuses the effect of alkali-NaOH solution on the nature of synthesized zeolite from 2：1 Tunisian clays. This study was achieved using correlation between results obtained from X-ray diffraction （XRD） and...This work focuses the effect of alkali-NaOH solution on the nature of synthesized zeolite from 2：1 Tunisian clays. This study was achieved using correlation between results obtained from X-ray diffraction （XRD） and MAS-NMR analysis. Preliminary treatment was adopted to prepare the starting sample that is placed in contact with NaOH solution at variable concentration. A specific hydrothermal reactor, allowing the control ofpH 〉 9, temperature and a continuous stirring of the sample in the NaOH solution; was used to achieve these syntheses. The obtained results showed that, for concentration value ~IN, the final complex presented characteristic XRD and MAS-NMR line of zeolite P. For 3N solution concentration we obtained zeolite HS. All synthesize process are controlled by XRD and MAS-NMR investigation.展开更多
A reversed-phase high-performance liquid chromatography （RP-HPLC） method was established for the simultaneous determination of three major constituents,/-calycanthine, quercetin, and kaempferol, in Chimonanthi Niten...A reversed-phase high-performance liquid chromatography （RP-HPLC） method was established for the simultaneous determination of three major constituents,/-calycanthine, quercetin, and kaempferol, in Chimonanthi Nitentis Folium. The RP-HPLC analysis was carried out using an Agilent HC-C18 （4.6 mm×250 mm, 5 μm） column and a gradient mobile phase consisting of methanol and phosphate buffer （10：90→90：10, v/v） at a flow rate of 1.0 mL/min. The column temperature was 25 ℃ and the detection wavelength was set at 239 nm from 0 to 15 min and 365 nm from 16 to 45 min. All calibration curves showed good linearity （R2〉0.9991） within test ranges. Relative standard deviations of repeated analyses were less than 2.64% （n = 6）, and the recovery of this method was 97.47%-98.26%. The contents of these three analytes were determined for the samples from different harvest times. The results showed that the/-calycanthine content in herbs increases from 99.94 μg/g to 468.0μg/g from April to July, whereas the content of quercetin and kaempferol was higher in April and May than that in June and July, which were consistent with the Chinese traditional medicine＇s use of Chimonanthi Nitentis Folium in Spring. Herein, a simple, rapid and accurate analytical method is presented and successfully applied for the simultaneous quantitative analysis of alkaloids and flavones from Chimonanthus nitens Oliv.展开更多
文摘通过Curtius重排反应,将高荧光量子产率的蒽基团通过脲基连接在N,N-二甲基苯胺单元上,合成了二元给受电子体系9-(4-N,N-二甲胺基苯基)脲基蒽(DMA-An)。选择性激发蒽单元,该二元体系发生从N,N-二甲基苯胺到蒽的光诱导电子转移反应(photoinduced electron transfer PET),导致蒽荧光猝灭。酸化使N,N-二甲基苯胺基质子化,PET过程受阻,DMA-An的荧光恢复。此时,向该体系中加入三乙胺可使DMA-An的荧光恢复至初始的猝灭状态。多次实验证明此荧光猝灭-增大过程是可逆的,即DMA-An的荧光随酸碱变化呈光开关on/off行为。
文摘Despite the breadth of knowledge about malaria, its transmission, preventive measures and available treatments and its difficulty in controlling the vector and the rapid spread of resistance to current drugs, there is a stimulus to develop new research looking for active molecules. The phytochemical studies of the active extract confirmed the presence of alkaloids, flavonoids, coumarins, tannins, reducing compounds, anthocyanins, terpenes, triterpenes and steroids. In the present work, it was possible to isolate a mixture of isoquinolinic alkaloids from the tender leaves of Nectandra membranacea （Laureaceae） with antimalarial activity. The mixture composed of （-） - gliazovine and （＋） - aplogliazovine showed an IC50 value of 32.18 μg/mL against the P. berghei NK65 strain. It is important to continue with these studies and their chemical components isolated from N. membranacea that could be used as an alternative the treatment of malaria.
文摘This work focuses the effect of alkali-NaOH solution on the nature of synthesized zeolite from 2：1 Tunisian clays. This study was achieved using correlation between results obtained from X-ray diffraction （XRD） and MAS-NMR analysis. Preliminary treatment was adopted to prepare the starting sample that is placed in contact with NaOH solution at variable concentration. A specific hydrothermal reactor, allowing the control ofpH 〉 9, temperature and a continuous stirring of the sample in the NaOH solution; was used to achieve these syntheses. The obtained results showed that, for concentration value ~IN, the final complex presented characteristic XRD and MAS-NMR line of zeolite P. For 3N solution concentration we obtained zeolite HS. All synthesize process are controlled by XRD and MAS-NMR investigation.
基金National Natural Science Foundation of China(Grant No.81360631)
文摘A reversed-phase high-performance liquid chromatography （RP-HPLC） method was established for the simultaneous determination of three major constituents,/-calycanthine, quercetin, and kaempferol, in Chimonanthi Nitentis Folium. The RP-HPLC analysis was carried out using an Agilent HC-C18 （4.6 mm×250 mm, 5 μm） column and a gradient mobile phase consisting of methanol and phosphate buffer （10：90→90：10, v/v） at a flow rate of 1.0 mL/min. The column temperature was 25 ℃ and the detection wavelength was set at 239 nm from 0 to 15 min and 365 nm from 16 to 45 min. All calibration curves showed good linearity （R2〉0.9991） within test ranges. Relative standard deviations of repeated analyses were less than 2.64% （n = 6）, and the recovery of this method was 97.47%-98.26%. The contents of these three analytes were determined for the samples from different harvest times. The results showed that the/-calycanthine content in herbs increases from 99.94 μg/g to 468.0μg/g from April to July, whereas the content of quercetin and kaempferol was higher in April and May than that in June and July, which were consistent with the Chinese traditional medicine＇s use of Chimonanthi Nitentis Folium in Spring. Herein, a simple, rapid and accurate analytical method is presented and successfully applied for the simultaneous quantitative analysis of alkaloids and flavones from Chimonanthus nitens Oliv.
