title: [Determination of effective time of Schizonepeta tenuifalia pieces by classical constant temperature acceleration experiment].
abstract: OBJECTIVE
  To study the validity of Schizonepeta tenuifalia pieces.
  
  
  METHODS
  The change principle for the contents of essential oil and pulegone was determined by the way of classical constant temperature acceleration experiment, and the reacting speed at 20 degrees C was calculated according to Arrhenius index law and effective time was calculated.
  
  
  RESULTS
  In classical constant temperature experiment, the content change of essential oil with the regular pattern of one level. The effective time of S. tenuifalia pieces stored in 20 degrees C was 2.08 years and the constant of speed is 8.453 4 x 10(-6) carried out by essentialoil, 190 days with the constant of speed is 3.39 x 10(-5) carried out by pulegone.
  
  
  CONCLUSIONS
  The effective time of S. tenuifalia pieces was about 2 years carried out by essential oil and 190 days carried out by pulegone by the way of classical constant temperature experiment.
authors: Institute of Chinese Materia Medica, Henan University, Kaifeng 475004, China.
authors: Chang-Qin
authors: CQ
authors: Li
authors: Jin-Mei
authors: JM
authors: Wang
authors: Wen-Yi
authors: WY
authors: Kang
mesh_terms: D000081005:Cyclohexane Monoterpenes; D004355:Drug Stability; D019686:Lamiaceae / Q000737:chemistry*; D039821:Monoterpenes / Q000032:analysis*; D009822:Oils, Volatile / Q000032:analysis*; D013696:Temperature; D013997:Time Factors
chemical_list: D000081005:Cyclohexane Monoterpenes; D039821:Monoterpenes; D009822:Oils, Volatile; C039648:pulegone