Objective:Tea polyphenols are natural extracts used widely throughout the world.However,the severe astringency of tea polyphenols has reduced patient compliance.Based on the analysis of the formation mechanism of astr...Objective:Tea polyphenols are natural extracts used widely throughout the world.However,the severe astringency of tea polyphenols has reduced patient compliance.Based on the analysis of the formation mechanism of astringency,this paper hopes to propose a new method to control the astringency of tea polyphenols and improve patient compliance without changing its effect.Methods:Artificial saliva was used to prepare the tea polyphenols solution with different p H,using bcasein to imitate salivary protein,and preparing 1.2 mg/m L b-casein solution.A fluorescence quenching test was used to study the interaction between tea polyphenols and b-casein,combined with the stability test results of the compound,we can choose the p H with weak binding but good stability as the best p H for masking astringency.The taste-masking tablets were prepared under the best p H conditions,and the Xinnaojian Original Tablets were prepared according to the conventional preparation method.The disintegration time limit and solubility were tested respectively.The astringency of Xinnaojian original tablets and taste-masking tablets was evaluated by visual analogue scale(VAS).Results:The result of the fluorescence quenching test prompted that the combination force was the weakest when the p H was 4.9.Further synchronous fluorescence analysis showed that an increase in p H resulted in a decrease of the binding sites between tea polyphenols and b-casein,and this decrease was closely related to changes in tryptophan residues in b-casein.Both original and taste-masking Xinnaojian Tablets were prepared.Volunteers’VAS scores illustrated that the astringency improved significantly with the masking tablets(P<0.05).Conclusion:This p H-adjusting masking treatment had little effect on the recovery of polyphenols from the tablets or the dissolution of the tablets.This study provides a novel and feasible astringency masking technology for tea polyphenols and its preparation.展开更多
A novel chemiluminescence（CL） performance of CdTe/CdS/ZnS quantum dots（QDs） with periodate（KIO_4） was studied.Effects of concentration and pH on the CL system were investigated.Electron spin resonance（ESR） and...A novel chemiluminescence（CL） performance of CdTe/CdS/ZnS quantum dots（QDs） with periodate（KIO_4） was studied.Effects of concentration and pH on the CL system were investigated.Electron spin resonance（ESR） and the effects of radical scavenger analysis were employed for identification of intermediate species.The CL spectra for this system showed only one maximum emission peak centered around 620 nm,which was similar with photoluminescence（PL） spectra of CdTe/CdS/ZnS QDs.The CL of CdTe/CdS/ZnS QDs was induced by direct chemical oxidation and the possible mechanism could be explained by radiative recombination of injected holes and electrons.This investigation not only provided new sight into the optical characteristics of CdTe/CdS/ZnS QDs,but also broadened their potential optical utilizations.展开更多
Objective Currently, powdered Chinese herbal medicines （CHMs） were mainly evaluated through physical property, chemical dissolution, and bioactivity independently. It could not reflect the quality comprehensively. T...Objective Currently, powdered Chinese herbal medicines （CHMs） were mainly evaluated through physical property, chemical dissolution, and bioactivity independently. It could not reflect the quality comprehensively. This paper was to explore and establish a comprehensive evaluation method for powdered CHMs. Methods Isatidis Radixwas chosen as an exemple. Firstly, powdered Isatidis Radixin different particle size was prepared. Then, their physical properties were characterized. The dissolution of index component epigoitrin was determined, and their antiviral activities were evaluated by neuraminidase-based bioassay. Results As the particle size decreased, powder distribution tended to be uniform, and the dissolution of epigoitrin increased, antiviral activity enhanced. According to cluster analysis of above results, the sequence of evaluation consequence was ultrafine powder S2 （D90：32.80± 0.29） 〉 ultrafine powder S1 （D90：52.08 ± 0.53） 〉 fine powder SO （D90：118.16± 0.76） （from the superior to the inferior）. Conclusion Overall, the comprehensive evaluation for powdered CHMs based on the physical characterization, chemical dissolution, and bioassay could not only be used to evaluate powdered herbs, but also guide the screening and optimization of the particle size of powder.展开更多
基金supported by the National Natural Science Foundation of China.(Nos.81673615,81403115)。
文摘Objective:Tea polyphenols are natural extracts used widely throughout the world.However,the severe astringency of tea polyphenols has reduced patient compliance.Based on the analysis of the formation mechanism of astringency,this paper hopes to propose a new method to control the astringency of tea polyphenols and improve patient compliance without changing its effect.Methods:Artificial saliva was used to prepare the tea polyphenols solution with different p H,using bcasein to imitate salivary protein,and preparing 1.2 mg/m L b-casein solution.A fluorescence quenching test was used to study the interaction between tea polyphenols and b-casein,combined with the stability test results of the compound,we can choose the p H with weak binding but good stability as the best p H for masking astringency.The taste-masking tablets were prepared under the best p H conditions,and the Xinnaojian Original Tablets were prepared according to the conventional preparation method.The disintegration time limit and solubility were tested respectively.The astringency of Xinnaojian original tablets and taste-masking tablets was evaluated by visual analogue scale(VAS).Results:The result of the fluorescence quenching test prompted that the combination force was the weakest when the p H was 4.9.Further synchronous fluorescence analysis showed that an increase in p H resulted in a decrease of the binding sites between tea polyphenols and b-casein,and this decrease was closely related to changes in tryptophan residues in b-casein.Both original and taste-masking Xinnaojian Tablets were prepared.Volunteers’VAS scores illustrated that the astringency improved significantly with the masking tablets(P<0.05).Conclusion:This p H-adjusting masking treatment had little effect on the recovery of polyphenols from the tablets or the dissolution of the tablets.This study provides a novel and feasible astringency masking technology for tea polyphenols and its preparation.
基金supported by the National Natural Science Foundation of China(Nos.81373373,21435002,21227006)
文摘A novel chemiluminescence（CL） performance of CdTe/CdS/ZnS quantum dots（QDs） with periodate（KIO_4） was studied.Effects of concentration and pH on the CL system were investigated.Electron spin resonance（ESR） and the effects of radical scavenger analysis were employed for identification of intermediate species.The CL spectra for this system showed only one maximum emission peak centered around 620 nm,which was similar with photoluminescence（PL） spectra of CdTe/CdS/ZnS QDs.The CL of CdTe/CdS/ZnS QDs was induced by direct chemical oxidation and the possible mechanism could be explained by radiative recombination of injected holes and electrons.This investigation not only provided new sight into the optical characteristics of CdTe/CdS/ZnS QDs,but also broadened their potential optical utilizations.
基金National Natural Science Foundation of China(81473316)
文摘Objective Currently, powdered Chinese herbal medicines （CHMs） were mainly evaluated through physical property, chemical dissolution, and bioactivity independently. It could not reflect the quality comprehensively. This paper was to explore and establish a comprehensive evaluation method for powdered CHMs. Methods Isatidis Radixwas chosen as an exemple. Firstly, powdered Isatidis Radixin different particle size was prepared. Then, their physical properties were characterized. The dissolution of index component epigoitrin was determined, and their antiviral activities were evaluated by neuraminidase-based bioassay. Results As the particle size decreased, powder distribution tended to be uniform, and the dissolution of epigoitrin increased, antiviral activity enhanced. According to cluster analysis of above results, the sequence of evaluation consequence was ultrafine powder S2 （D90：32.80± 0.29） 〉 ultrafine powder S1 （D90：52.08 ± 0.53） 〉 fine powder SO （D90：118.16± 0.76） （from the superior to the inferior）. Conclusion Overall, the comprehensive evaluation for powdered CHMs based on the physical characterization, chemical dissolution, and bioassay could not only be used to evaluate powdered herbs, but also guide the screening and optimization of the particle size of powder.
