title: [Evaluation of crude drugs by means of colorimeter (I). Study on correlation between color and alkaloids content of coptidis rhizoma].
abstract: OBJECTIVE
  To examine the correlation between alkaloids content and L*, a* and b* color indices of Rhizoma Coptidis for quality control.
  
  
  METHODS
  A colorimeter was used for the measurement of reflected light from sieved powder samples using the CIE 1976 L* a* b* color system. The content of six alkaloids were determined by HPLC. The correlation between alkaloids content and color indices of Rhizoma Coptidis was analyzed.
  
  
  RESULTS
  When the particle size of Rhizoma Coptidis was less than 355 microm and the colorimeter parameters were set as measurement diameter of 3 mm, observation degree of 10, and light source of F2 and F7, the measured color was significantly correlated with total alkaloids content (r = 0.793, P < 0.05). As light source of F11, the measured color was significantly correlated with berberine content (r = 0.867, P < 0.01).
  
  
  CONCLUSIONS
  The correlation between the color of powdered Coptidis Rhizoma and its alkaloids contents was found in this study. Measurment of the color of Coptidis Rhizoma can be used to assess its quality.
authors.forename: Michiyo
authors.initials: M
authors.lastname: Yoshimitsu
authors.forename: Xian-You
authors.initials: XY
authors.lastname: Qu
authors.forename: Wei-Zao
authors.initials: WZ
authors.lastname: Luo
authors.forename: Song-Yun
authors.initials: SY
authors.lastname: Qin
mesh_terms: D000470:Alkaloids / Q000032:analysis*; D001599:Berberine / Q000032:analysis; D001600:Berberine Alkaloids / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D003116:Color; D003124:Colorimetry / Q000379:methods*; D039323:Coptis / Q000737:chemistry*; D011208:Powders; D011786:Quality Control; D027343:Rhizome / Q000737:chemistry
chemical_list: D000470:Alkaloids; D001600:Berberine Alkaloids; D011208:Powders; D001599:Berberine