Aim: To present a theory bases for Chinese traditional medicine extraction process.
Methods: A kinetic equation for Chinese traditional medicine extraction process was presented based on Fick's second law of diffusion. Experiments for extracting tanshinone from Salvia miltiorrhiza Bge with ethanol under different particle sizes and temperatures were studied. In addition, the data of extraction process of three kinds of herbs, including Glycyrrhiza uralensis Fisch, Schisandra chinesis and Ophiopogon japonicus (Thunb.) Ker-Gawl were introduced to evaluate the kinetic equation.
Results: The kinetic of Chinese traditional medicine extraction process agreed with the first-order rate equation. Experiment data of active components extracted from the herbs above could perfectly match with the kinetic equation. The rate-determining step for extracting tanshinone from Salvia miltiorrhiza Bge was the diffusion of tanshinone through the herb particles. The apparent activation energy for tanshinone diffusion process was 20.26 kJ.mol-1.
Conclusion: The relation between the concentration of active component and extraction time, size of herb particles and temperature could be got from this kinetic equation. The extraction process of other herbs besides the above could be described by this equation.