title: A novel protocol for the preparation of sodium tanshinone sulphonates by direct ultrasound-assisted sulphonation of the crude extract of the roots of Salvia miltiorrhiza Bunge and following counter-current chromatography purification.
abstract: BACKGROUND
  Sodium tanshinone sulphonates are water-soluble derivatives of tanshinones originated from Tanshen (or Danshen, Salvia miltiorrhiza Bunge), a famous Traditional Chinese Medicine, which have potent biological activities, especially in the treatment of cardiovascular disorders. However, the classical preparation processes of sodium tanshinone sulphonates often involve multiple time- and solvent-consuming steps after purification of tanshinones, resulting in relatively low yields.
  
  
  OBJECTIVE
  To develop a simple protocol for direct preparation of sodium tanshinone sulphonates from the complex crude extract of the roots of S. miltiorrhiza without pre-purification of tanshinones.
  
  
  METHODS
  The 100 mg crude tanshinone extract of S. miltiorrhiza was first sulphonated in a ultrasound bath with glacial acetic acid, acetic anhydride and concentrated sulphuric acid for 20 min, and then subjected to counter-current chromatography (CCC) separation using a optimum two-phase solvent system composed of n-hexane:ethylacetate:ethanol:5% sodium chloride aqueous solution (1:8:4:10, v/v). Based on the UV detection and HPLC analyses, the sulphonated fractions were collected.
  
  
  RESULTS
  Sodium tanshinone IIA sulphonate (7.1 mg) and sodium tanshinone I sulphonate (2.8 mg) with over 95% purity were obtained successfully for the first time by ultrasound-assisted sulphonation and following CCC purification.
  
  
  CONCLUSIONS
  The study has shown that the method combining ultrasound-assisted sulphonation and CCC purification is an efficient way to prepare tanshinone sulphonates without pre-purification of tanshinones from the complex extracts of Tanshen, and can be explored as a new protocol for wide natural product modification directly from a crude complex extracts without pre-purification.
authors.affiliation: Research Center of Siyuan Natural Pharmacy and Biotoxicology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang Province 310058, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Zeng
authors.forename: Dingfang
authors.initials: D
authors.lastname: Wu
authors.forename: Shihua
authors.initials: S
authors.lastname: Wu
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003377:Countercurrent Distribution / Q000379:methods; D010616:Phenanthrenes / Q000138:chemical synthesis* / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry*; D027343:Rhizome / Q000737:chemistry; D027561:Salvia miltiorrhiza / Q000737:chemistry*; D014465:Ultrasonics
chemical_list: D010616:Phenanthrenes; D010936:Plant Extracts; C024894:tanshinone II A sodium sulfonate