Determination of berberine and the study of fluorescence quenching mechanism between berberine and enzyme-catalyzed product.
A new method for determining berberine has been established based on the principle of fluorescence quenching. The calibration curve was found to be linear between F(0)/F and the concentration of berberine with the range of 3.00-20.0 microg mL(-1). The detection limit was 0.51 microg mL(-1) and the relative standard derivative was 0.18%. Effects of pH, foreign ions and the optimization of variables on the determination of berberine have been examined. The mechanism of the fluorescence quenching has been discussed. The binding constant and the number of binding sites were 1.70x10(6) L mol(-1) and 1.14, respectively. The data, DeltaH = 42.71 kJ mol(-1), DeltaS = 264.3 J K(-1) mol(-1) and the mean value DeltaG = -39.65 kJ mol(-1) were estimated which showed that the reaction was spontaneous and endothermic. The main binding force was hydrophobic force because both DeltaH and DeltaS were positive.
Wang
Huaiyou
H
College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, PR China. wanghuaiyou@sdnu.edu.cn
Zhang
Miao
M
Lv
Qingluan
Q
Yue
Ningning
N
Gong
Bin
B
D031215:Armoracia / Q000737:chemistry; D001599:Berberine / Q000032:analysis* / Q000378:metabolism; D001665:Binding Sites; D002138:Calibration; D006735:Horseradish Peroxidase / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D010940:Plant Proteins / Q000378:metabolism*; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013816:Thermodynamics
D010940:Plant Proteins; D001599:Berberine; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase