title: Quantification of phenylpropanoids in commercial Echinacea products using TLC with video densitometry as detection technique and ANN for data modelling.
abstract: BACKGROUND
  Echinacea preparations are among the most popular herbal remedies worldwide. Although it is generally assigned immune enhancement activities, the effectiveness of Echinacea is highly dependent on the Echinacea species, part of the plant used, the age of the plant, its location and the method of extraction.
  
  
  OBJECTIVE
  The aim of this study was to investigate the capacity of an artificial neural network (ANN) to analyse thin-layer chromatography (TLC) chromatograms as fingerprint patterns for quantitative estimation of three phenylpropanoid markers (chicoric acid, chlorogenic acid and echinacoside) in commercial Echinacea products.
  
  
  METHODS
  By applying samples with different weight ratios of marker compounds to the system, a database of chromatograms was constructed. One hundred and one signal intensities in each of the TLC chromatograms were correlated to the amounts of applied echinacoside, chlorogenic acid and chicoric acid using an ANN.
  
  
  RESULTS
  The developed ANN correlation was used to quantify the amounts of three marker compounds in Echinacea commercial formulations. The minimum quantifiable level of 63, 154 and 98 ng and the limit of detection of 19, 46 and 29 ng were established for echinacoside, chlorogenic acid and chicoric acid respectively.
  
  
  CONCLUSIONS
  A novel method for quality control of herbal products, based on TLC separation, high-resolution digital plate imaging and ANN data analysis has been developed. The method proposed can be adopted for routine evaluation of the phytochemical variability in Echinacea formulations available in the market.
authors.affiliation: School of Pharmacy and Applied Science, La Trobe University, Edwards Rd, Bendigo, Victoria 3550, Australia. s.kustrin@latrobe.edu.au
authors.forename: S
authors.initials: S
authors.lastname: Agatonovic-Kustrin
authors.forename: Christine M
authors.initials: CM
authors.lastname: Loescher
authors.forename: Ragini
authors.initials: R
authors.lastname: Singh
mesh_terms: D002109:Caffeic Acids / Q000032:analysis; D002726:Chlorogenic Acid / Q000032:analysis; D002855:Chromatography, Thin Layer / Q000379:methods*; D003720:Densitometry / Q000379:methods*; D020900:Echinacea / Q000737:chemistry*; D006027:Glycosides / Q000032:analysis; D007091:Image Processing, Computer-Assisted / Q000379:methods; D057230:Limit of Detection; D016571:Neural Networks, Computer; D010666:Phenylpropionates / Q000032:analysis* / Q000737:chemistry; D028321:Plant Preparations / Q000592:standards*; D011786:Quality Control; D013386:Succinates / Q000032:analysis
chemical_list: D002109:Caffeic Acids; D006027:Glycosides; D010666:Phenylpropionates; D028321:Plant Preparations; D013386:Succinates; D002726:Chlorogenic Acid; C060297:echinacoside; C100435:chicoric acid