title: Online near-infrared analysis coupled with MWPLS and SiPLS models for the multi-ingredient and multi-phase extraction of licorice (Gancao).
abstract: BACKGROUND
  This study aims to analyze the active pharmaceutical ingredients (APIs) of licorice (Radix Glycyrrhizae; gancao), including glycyrrhizic acid, liquiritin, isoliquiritin and total flavonoids, in multi-ingredient and multi-phase extraction by online near-infrared technology with fiber optic probes and chemometric analysis.
  
  
  METHODS
  High-performance liquid chromatography and ultraviolet spectrophotometry determined the APIs content in different extraction phases by online near-infrared analysis, which included sample set selection by the Kennard-Stone algorithm, optimization of spectral pretreatment methods (i.e., orthogonal signal correction and wavelet denoising spectral correction), and model calibration by the partial least-squares algorithm, moving-window partial least-squares algorithm and synergy interval partial least-squares (SiPLS) algorithm. The relative errors and F values were used to assess the models in different extraction phases.
  
  
  RESULTS
  The root-mean-square error of correction, root-mean-square error of cross-validation and root-mean-square error of prediction of APIs in the SiPLS model was less than 0.07. The F values of glycyrrhizic acid, liquiritin, isoliquiritin and total flavonoids were 10,765, 32,431, 649 and 6080, respectively, which were larger than 6.90 (P < 0.01).
  
  
  CONCLUSIONS
  The study demonstrated the feasibility of online NIR analysis in the multi-ingredient and multi-phase extraction of APIs from licorice.
authors.affiliation: School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, China ; Pharmaceutical Engineering and New Drug Development of Traditional Chinese Medicine, Ministry of Education, Beijing, China ; Key Laboratory of Traditional Chinese Medicine-Information Engineering, State Administration of Traditional Chinese Medicine, Beijing, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, China.
authors.forename: Mingye
authors.initials: M
authors.lastname: Guo
authors.affiliation: School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, China ; Pharmaceutical Engineering and New Drug Development of Traditional Chinese Medicine, Ministry of Education, Beijing, China ; Key Laboratory of Traditional Chinese Medicine-Information Engineering, State Administration of Traditional Chinese Medicine, Beijing, China.
authors.forename: Xinyuan
authors.initials: X
authors.lastname: Shi
authors.affiliation: School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, China ; Pharmaceutical Engineering and New Drug Development of Traditional Chinese Medicine, Ministry of Education, Beijing, China ; Key Laboratory of Traditional Chinese Medicine-Information Engineering, State Administration of Traditional Chinese Medicine, Beijing, China.
authors.forename: Zhisheng
authors.initials: Z
authors.lastname: Wu
authors.affiliation: School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, China ; Pharmaceutical Engineering and New Drug Development of Traditional Chinese Medicine, Ministry of Education, Beijing, China ; Key Laboratory of Traditional Chinese Medicine-Information Engineering, State Administration of Traditional Chinese Medicine, Beijing, China.
authors.forename: Jianyu
authors.initials: J
authors.lastname: Li
authors.affiliation: School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, China ; Beijing Key Laboratory for Basic and Development Research on Chinese Medicine, Beijing, China.
authors.forename: Qun
authors.initials: Q
authors.lastname: Ma
authors.affiliation: School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, China ; Pharmaceutical Engineering and New Drug Development of Traditional Chinese Medicine, Ministry of Education, Beijing, China ; Key Laboratory of Traditional Chinese Medicine-Information Engineering, State Administration of Traditional Chinese Medicine, Beijing, China.
authors.forename: Yanjiang
authors.initials: Y
authors.lastname: Qiao