title: A universal quantitative ¹H nuclear magnetic resonance (qNMR) method for assessing the purity of dammarane-type ginsenosides.
abstract: BACKGROUND
  Quantitative (1)H-NMR (qNMR) is a well-established method for quantitative analysis and purity tests. Applications have been reported in many areas, such as natural products, foods and beverages, metabolites, pharmaceuticals and agriculture. The characteristics of quantitative estimation without relying on special target reference substances make qNMR especially suitable for purity tests of chemical compounds and natural products. Ginsenosides are a special group of natural products drawing broad attention, and are considered to be the main bioactive principles behind the claims of ginsengs efficacy. The purity of ginsenosides is usually determined by conventional chromatographic methods, although these may not be ideal due to the response of detectors to discriminate between analytes and impurities and the long run times involved.
  
  
  OBJECTIVE
  To establish a qNMR method for purity tests of six dammarane-type ginsenoside standards.
  
  
  METHODS
  Several experimental parameters were optimised for the quantification, including relaxation delay (D1), the transmitter frequency offset (O1P) and power level for pre-saturation (PL9). The method was validated and the purity of the six ginsenoside standards was tested. Also, the results of the qNMR method were further validated by comparison with those of high performance liquid chromatography.
  
  
  CONCLUSIONS
  The qNMR method was rapid, specific and accurate, thus providing a practical and reliable protocol for the purity analysis of ginsenoside standards.
authors.affiliation: School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China.
authors.forename: Ze Yun
authors.initials: ZY
authors.lastname: Li
authors.forename: Edward
authors.initials: E
authors.lastname: Welbeck
authors.forename: Ru Feng
authors.initials: RF
authors.lastname: Wang
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.forename: Ying Bo
authors.initials: YB
authors.lastname: Yang
authors.forename: Gui Xin
authors.initials: GX
authors.lastname: Chou
authors.forename: Kai Shun
authors.initials: KS
authors.lastname: Bi
authors.forename: Zheng Tao
authors.initials: ZT
authors.lastname: Wang
mesh_terms: D002851:Chromatography, High Pressure Liquid; D036145:Ginsenosides / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D015203:Reproducibility of Results; D014315:Triterpenes / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D000097669:Dammaranes
chemical_list: D036145:Ginsenosides; D014315:Triterpenes; D000097669:Dammaranes
keywords: HPLC/UV; ginsenosides; purity; qNMR