title: [Simultaneous determination of formononetin, calycosin and isorhamnetin from Astragalus mongholicus in rat plasma by LC-MS/MS and application to pharmacokinetic study].
abstract: OBJECTIVE
  To establish a method to determine the concentration of formononetin, calycosin and isorhamnetin from Astragalus mongholicus in rats' plasma using LC-MS/MS and calculate their pharmacokinetic parameters.
  
  
  METHODS
  The contents of formononetin, calycosin and isorhamnetin in plasma were detected before and 24 h after 10 rats were treated with 10 g/kg Astragalus mongholicus. Rutin was used as internal standard. Agilent 1 200 HPLC system with Alltima C18 (150 mm x 2.1 mm, 5 microm) was used. Mobile phase was methanol-water solution with gradient elute at a flow rate of 0.3 mL/min. The column temperature was 40 degrees C. The LC-MS/ MS system was operated using an electrospray ionization probe in negative ion mode; Scan mode: multiple reaction ion monitoring (MRM) mode. The ion of monitor: m/z 267.0 --> 251.9 for formononetin, m/z 283.1 --> 268.2 for calycosin, m/z 315.4 --> 300.1 for isorhamnetin and m/z 609.4 --> 300.1 for rutin (internal standard), respectively.
  
  
  RESULTS
  The linear range of formononetin, calycosin and isorhamnetin was 5 - 1 000 (r = 0.9996), 3.91 - 500 (r = 0.9989) and 0.5 - 100 ng/mL (r = 0.9992), respectively. The lowest limit of quantification (LLOQ) of formononetin, calycosin and isorhamnetin was 0.625, 0.5 and 0.1 ng/mL, respectively. The pharmacokinetic parameter, t(1/2beta), of formononetin, calycosin and isorhamnetin was (10.43 +/- 2.94), (6.91 +/- 1.33) and (5.07 +/- 1.21) h, respectively. The C(max) of formononetin, calycosin and isorhamnetin was (398.5 +/- 103.7), (138.7 +/- 32.8) and (58.3 +/- 14.5) ng/mL, respectively. The AUC(0 -> 12h), of formononetin, calycosin and isorhamnetin was (1238.8 +/- 311.3), (669.5 +/- 159.7) and (274.1 +/- 83.9)ng x h/mL, respectively.
  
  
  CONCLUSIONS
  A sensitive, accuracy and suitable LC-MS/MS method for determination of formononetin, calycosin and isorhamnetin is developed and successfully applied to the pharmacokinetic study of 10 g/kg Astragalus mongholicus after oral administration in rats.
authors.affiliation: Huangpu District of the First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510700, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Lin
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.forename: Xiao-Mei
authors.initials: XM
authors.lastname: Tan
authors.forename: Xiang-Chao
authors.initials: XC
authors.lastname: Yao
mesh_terms: D000284:Administration, Oral; D000818:Animals; D027883:Astragalus Plant / Q000737:chemistry*; D002853:Chromatography, Liquid; D007529:Isoflavones / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D008297:Male; D011794:Quercetin / Q000031:analogs & derivatives* / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry
chemical_list: D007529:Isoflavones; C047368:3-methylquercetin; C121707:7,3'-dihydroxy-4'-methoxyisoflavone; C007768:formononetin; D011794:Quercetin