Microwave-assisted extraction of tanshinones from Salvia miltiorrhiza bunge with analysis by high-performance liquid chromatography

A novel microwave-assisted extraction (MAE) method has been developed for t he extraction and determination of tanshinones (tanshinone IIA, cryptotansh inone and tanshinone I) from the root of Salvia miltiorrhiza bunge with ana lysis by HPLC. Various experimental conditions were investigated to optimiz e the percentage extraction. Under appropriate MAE conditions, such as etha nol concentrations of 95% (v/v), MAE for 2 min, liquid/solid ratio of 10:1 (ml/g), the percentage extraction can reach high in a short time. The perce ntage extraction (tanshinone EA: 0.29%; cryptotanshinone: 0.23%; tanshinone I: 0.11%) by MAE was the same or even higher than conventional extraction methods. MAE only needs 2 min, but extraction at room temperature, heat ref lux extraction, ultrasonic extraction and Soxhlet extraction need 24 h, 45 min, 75 min and 90 min, respectively. MAE was also available in pilot plant form for larger scale extraction. (C) 2001 Published by Elsevier Science B .V.