title: Determination of berberine and the study of fluorescence quenching mechanism between berberine and enzyme-catalyzed product.
abstract: 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.
authors.affiliation: College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, PR China. wanghuaiyou@sdnu.edu.cn
authors.forename: Huaiyou
authors.initials: H
authors.lastname: Wang
authors.forename: Miao
authors.initials: M
authors.lastname: Zhang
authors.forename: Qingluan
authors.initials: Q
authors.lastname: Lv
authors.forename: Ningning
authors.initials: N
authors.lastname: Yue
authors.forename: Bin
authors.initials: B
authors.lastname: Gong
mesh_terms: 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
chemical_list: D010940:Plant Proteins; D001599:Berberine; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase