[Objectives] To establish a method for the determination of tannin in Sanguisorba officinalis L.,and provide guarantee for further control over quality of semi-finished tannin products from Sanguisorba officinalis L. ...[Objectives] To establish a method for the determination of tannin in Sanguisorba officinalis L.,and provide guarantee for further control over quality of semi-finished tannin products from Sanguisorba officinalis L. [Methods] With gallic acid as reference substance,the UV method was used to determine the content of tannin in Sanguisorba officinalis L.,and the methodological examination was done. [Results]With gallic acid as standard,when the concentration of tannin in Sanguisorba officinalis L. was 1. 02-10. 14 μg·m L^(-1),there was a good linear relationship with absorbance,the precision,reproducibility and recovery were in line with the requirements,and the absorbance value was stable within 40 min after coloration. [Conclusions] The method was simple,rapid and accurate in determining the content of tannin in Sanguisorba officinalis L.展开更多
Objective:To investigate the antioxidant activity,total phenolic and total tannin content of the pericarp and the seed of Coffea benghalensis(C.benghalensis) and Coffea liberica compared to Coffea arabica(C.arabica).M...Objective:To investigate the antioxidant activity,total phenolic and total tannin content of the pericarp and the seed of Coffea benghalensis(C.benghalensis) and Coffea liberica compared to Coffea arabica(C.arabica).Methods:The antioxidant potential,total tannin and polyphenol contents of the immature and mature seed and pericarp of C.benghalensis and Coffea liberica were quantified and compared to C.arabica.Enhanced chemiluminescence(ECL).2,2-diphenyl-1-picrylhydruzyl(DPPH).oxygen radical absorbance capacity,Folin-Ciocaltcau method and total tannin content assays were used.Results:Trolox equivalent(TE/g plant material) values obtained by ECL and DPPH methods showed loose correlation(r^2=0.587)while those measured by oxygen radical absorbance capacity assay were higher without correlation in each plant.A closer correlation was detected between the ECL method and the percentage antioxidant activity of the DPPH technique(r^2=0.610 7) in each species,however the immature pericarp of C.benghalensis showed much higher DPPH scavenging potential than was seen in the ECL assay.The immature pericarp of C.benghalensis expressed the highest tannin and polyphenol content,and a high polyphenol level was also detected in the immature seed of C.arabica.The immature pericarp of Bengal and Liberian coffees showed the largest amount of phenolic contents.Conclusions:The obtained data highlight the potential role of C.benghalensis as a new source of natural antioxidants and polyphenols compared to C.arabica.展开更多
The stepwise stability constants of coordination compounds from sulfonatedsheoak tannin with metal ions have been determined by pH potential method with catechol asmodel compounds at 20℃and constant ionic strength.
文摘[Objectives] To establish a method for the determination of tannin in Sanguisorba officinalis L.,and provide guarantee for further control over quality of semi-finished tannin products from Sanguisorba officinalis L. [Methods] With gallic acid as reference substance,the UV method was used to determine the content of tannin in Sanguisorba officinalis L.,and the methodological examination was done. [Results]With gallic acid as standard,when the concentration of tannin in Sanguisorba officinalis L. was 1. 02-10. 14 μg·m L^(-1),there was a good linear relationship with absorbance,the precision,reproducibility and recovery were in line with the requirements,and the absorbance value was stable within 40 min after coloration. [Conclusions] The method was simple,rapid and accurate in determining the content of tannin in Sanguisorba officinalis L.
文摘Objective:To investigate the antioxidant activity,total phenolic and total tannin content of the pericarp and the seed of Coffea benghalensis(C.benghalensis) and Coffea liberica compared to Coffea arabica(C.arabica).Methods:The antioxidant potential,total tannin and polyphenol contents of the immature and mature seed and pericarp of C.benghalensis and Coffea liberica were quantified and compared to C.arabica.Enhanced chemiluminescence(ECL).2,2-diphenyl-1-picrylhydruzyl(DPPH).oxygen radical absorbance capacity,Folin-Ciocaltcau method and total tannin content assays were used.Results:Trolox equivalent(TE/g plant material) values obtained by ECL and DPPH methods showed loose correlation(r^2=0.587)while those measured by oxygen radical absorbance capacity assay were higher without correlation in each plant.A closer correlation was detected between the ECL method and the percentage antioxidant activity of the DPPH technique(r^2=0.610 7) in each species,however the immature pericarp of C.benghalensis showed much higher DPPH scavenging potential than was seen in the ECL assay.The immature pericarp of C.benghalensis expressed the highest tannin and polyphenol content,and a high polyphenol level was also detected in the immature seed of C.arabica.The immature pericarp of Bengal and Liberian coffees showed the largest amount of phenolic contents.Conclusions:The obtained data highlight the potential role of C.benghalensis as a new source of natural antioxidants and polyphenols compared to C.arabica.
文摘The stepwise stability constants of coordination compounds from sulfonatedsheoak tannin with metal ions have been determined by pH potential method with catechol asmodel compounds at 20℃and constant ionic strength.
