title: Cluster analysis of commercial samples of Bauhinia spp. using HPLC-UV/PDA and MCR-ALS/PCA without peak alignment procedure.
abstract: BACKGROUND
  Bauhinia forficata Link. is recognised by the Brazilian Health Ministry as a treatment of hypoglycemia and diabetes. Analytical methods are useful to assess the plant identity due the similarities found in plants from Bauhinia spp. HPLC-UV/PDA in combination with chemometric tools is an alternative widely used and suitable for authentication of plant material, however, the shifts of retention times for similar compounds in different samples is a problem.
  
  
  OBJECTIVE
  To perform comparisons between the authentic medicinal plant (Bauhinia forficata Link.) and samples commercially available in drugstores claiming to be "Bauhinia spp. to treat diabetes" and to evaluate the performance of multivariate curve resolution - alternating least squares (MCR-ALS) associated to principal component analysis (PCA) when compared to pure PCA.
  
  
  METHODS
  HPLC-UV/PDA data obtained from extracts of leaves were evaluated employing a combination of MCR-ALS and PCA, which allowed the use of the full chromatographic and spectrometric information without the need of peak alignment procedures.
  
  
  RESULTS
  The use of MCR-ALS/PCA showed better results than the conventional PCA using only one wavelength. Only two of nine commercial samples presented characteristics similar to the authentic Bauhinia forficata spp., considering the full HPLC-UV/PDA data.
  
  
  CONCLUSIONS
  The combination of MCR-ALS and PCA is very useful when applied to a group of samples where a general alignment procedure could not be applied due to the different chromatographic profiles. This work also demonstrates the need of more strict control from the health authorities regarding herbal products available on the market.
authors.affiliation: Department of Chemistry, Federal University of São Carlos, 13565-905, São Carlos, São Paulo, Brazil.
authors.forename: Jorge Armando
authors.initials: JA
authors.lastname: Ardila
authors.affiliation: Australian Centre for Research on Separation Science (ACROSS), School of Chemistry, University of Tasmania, Tasmania, Australia.|Instituto de Química, Universidade Estadual Paulista, 14800-900, Araraquara, São Paulo, Brazil.|Faculdade de Ciências Agronômicas, Universidade Estadual Paulista, 18610-307, Botucatu, São Paulo, Brazil.
authors.forename: Cristiano Soleo
authors.initials: CS
authors.lastname: Funari
authors.affiliation: Instituto de Química, Universidade Estadual Paulista, 14800-900, Araraquara, São Paulo, Brazil.
authors.forename: André Marques
authors.initials: AM
authors.lastname: Andrade
authors.affiliation: Instituto de Química, Universidade Estadual Paulista, 14800-900, Araraquara, São Paulo, Brazil.
authors.forename: Alberto José
authors.initials: AJ
authors.lastname: Cavalheiro
authors.affiliation: Department of Chemistry, Federal University of São Carlos, 13565-905, São Carlos, São Paulo, Brazil.
authors.forename: Renato Lajarim
authors.initials: RL
authors.lastname: Carneiro
mesh_terms: D036481:Bauhinia / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D016000:Cluster Analysis; D016018:Least-Squares Analysis; D015999:Multivariate Analysis; D018515:Plant Leaves / Q000737:chemistry; D028321:Plant Preparations / Q000032:analysis* / Q000145:classification / Q000592:standards; D025341:Principal Component Analysis / Q000379:methods*; D011358:Product Surveillance, Postmarketing / Q000379:methods / Q000592:standards; D012015:Reference Standards; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*
chemical_list: D028321:Plant Preparations
keywords: Bauhinia forficata; chromatographic fingerprint; multivariate curve resolution; natural products