title: [Simultaneous determination of ergosterol, nucleosides and their bases from natural and cultured Cordyceps by pressurized solvent extraction and high performance liquid chromatography].
abstract: OBJECTIVE
  To establish a simple method for simultaneous determination of ergosterol, nucleosides and their bases in Cordyceps by HPLC coupled with pressurized solvent extraction (PSE).
  
  
  METHODS
  The extraction was performed by using PSE and the PSE condition was optimized by using orthogonal test, the contents of ergosterol, nucleosides and their bases in Cordyceps were determined by HPLC.
  
  
  RESULTS
  The optimized condition of PSE extraction for ergosterol, nucleosides and their bases in Cordyceps was obtained as follow: solvent, methanol; temperature, 160 degrees C; static extraction time, 5 min; pressure, 10 MPa and one extraction cycle and one time. A ZORBAX NH2 column (250 mm x 4.6 mm ID, 5 microm) and a ZORBAX NH2 guard column (12.5 mm x 4.6 mm ID, 5 microm) were used for simultaneous determination of ergosterol, nucleosides and their bases. Solvents that constituted the mobile phase were A (acetonitrile) and B (10 mmol x L(-1) ammonium acetate in water). The elution conditions applied were: 0 -5.0 min, linear gradient 0 --> 15% B; 5.0-25.0 min, linear gradient 15% --> 20% B; 25.0 - 35.0 min, linear gradient 20% --> 40% B; 35.0 - 45.0 min, linear gradient 40% --> 80% B; 45.0 -50.0 min, 80% B isocratic. The flow-rate was 0. 6 mL x min(-1) and the injection volume was 20 microL. The system operated at 25 degrees C. Ergosterol was monitored and quantified at 275 nm, nucleosides and their bases at 254 nm.
  
  
  CONCLUSIONS
  High performance liquid chromatography coupled with pressurized solvent extraction is a rapid and simple method for simultaneous determination of ergosterol, nucleosides and their bases in Cordyceps.
authors.affiliation: Institute of Chinese Medical Sciences, University of Macau, Macau, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Li
authors.forename: Shao-Ping
authors.initials: SP
authors.lastname: Li
authors.forename: Yuan-Xiang
authors.initials: YX
authors.lastname: Gong
authors.forename: Yi-Tao
authors.initials: YT
authors.lastname: Wang
mesh_terms: D000241:Adenosine / Q000032:analysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D032661:Cordyceps / Q000737:chemistry*; D003596:Cytosine / Q000032:analysis; D004875:Ergosterol / Q000032:analysis*; D006147:Guanine / Q000032:analysis; D009705:Nucleosides / Q000032:analysis*
chemical_list: D009705:Nucleosides; D006147:Guanine; D003596:Cytosine; D000241:Adenosine; D004875:Ergosterol