title: LC-MS/MS determination and pharmacokinetic study of five flavone components after solvent extraction/acid hydrolysis in rat plasma after oral administration of Verbena officinalis L. extract.
abstract: BACKGROUND
  Traditional Chinese medicine (TCM) has been used in clinical practice for several thousand years. TCM has played an indispensable role in the prevention and treatment of diseases, especially the complicated and chronic ones. Pharmacokinetic study on active constituents in herbal preparations is a good way for us to explain and predict a variety of events related to the efficacy and toxicity of TCM.
  
  
  OBJECTIVE
  A selective and sensitive HPLC-MS/MS method was first developed and validated for the determination of luteolin, kaempferol, apigenin, quercetol, and isorhamnetin in rat plasma.
  
  
  METHODS
  The LC system consisted of an Agilent Technologies Series 1200 system (Agilent, USA) equipped with an automatic degasser, a quaternary pump, and an autosampler. Chromatographic separations were performed on a Waters SunFire™ C(18) column (150 mm × 4.6mm, 5 μm), and the column temperature was maintained at 25°C and the sample injection volume was 20 μL. The current LC-MS/MS assay was validated for linearity, intra-day and inter-day precisions, accuracy, extraction recovery and stability.
  
  
  RESULTS
  The validated method was successfully applied to monitoring the concentrations and pharmacokinetic studies of five flavone compounds in rat plasma after a single oral administration of Verbena officinalis L. extract with a dosage of 8.0 mL/kg. The time to reach the maximum plasma concentration (T(max1)) was 0.48 ± 2.14 h for luteolin, 0.25 ± 0.13 h for kaempferol, 0.97 ± 1.08 h for apigenin, 1.04 ± 4.25 h for quercetol and 0.25 ± 0.16 h for isorhamnetin, and the maximum plasma concentration (T(max2)) was 3.97 ± 1.48 h, 4.05 ± 0.46 h, 4.33 ± 0.58 h, 2.99 ± 0.48 h and 4.02 ± 0.34 h. The elimination half-time (t(1/2)) of luteolin, kaempferol, apigenin, quercetol and isorhamnetin was 4.02 ± 0.81, 7.65 ± 0.71, 3.30 ± 0.83, 4.55 ± 0.49 and 5.56 ± 1.32 h, respectively.
  
  
  CONCLUSIONS
  This paper described a simple, sensitive and validated LC-MS/MS method for simultaneous determination of luteolin, kaempferol, apigenin, quercetol and isorhamnetin in rat plasma after oral administration of V. officinalis L. extract, and investigated on their pharmacokinetic studies as well, with a short run time of 5 min.
authors.affiliation: Department of Pharmaceutical Analysis, School of Pharmacy, Hebei Medical University, Shijiazhuang 050017, China.
authors.forename: Kunfeng
authors.initials: K
authors.lastname: Duan
authors.forename: Zhifang
authors.initials: Z
authors.lastname: Yuan
authors.forename: Wei
authors.initials: W
authors.lastname: Guo
authors.forename: Yan
authors.initials: Y
authors.lastname: Meng
authors.forename: Yang
authors.initials: Y
authors.lastname: Cui
authors.forename: Dezhi
authors.initials: D
authors.lastname: Kong
authors.forename: Lantong
authors.initials: L
authors.lastname: Zhang
authors.forename: Na
authors.initials: N
authors.lastname: Wang
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D047309:Flavones / Q000032:analysis* / Q000493:pharmacokinetics; D008297:Male; D010936:Plant Extracts / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley; D053719:Tandem Mass Spectrometry / Q000379:methods*; D032412:Verbena / Q000737:chemistry*
chemical_list: D047309:Flavones; D010936:Plant Extracts