Comparative analysis of four terpenoids in root and cortex of Tripterygium wilfordii Radix by different drying methods.

Background: Tripterygium wilfordii Radix, a well-known traditional medicine in china which is used for treatment of inflammation, pain, tumor and immune regulation for centuries in china, accompany with the serious toxic side effects. This study was carried out for simultaneously analyzing the four main components (triptolide, triptophenolide, demethylzeylasteral and celastrol) in Tripterygium wilfordii Radix under different drying processes, which was important for reducing the toxicity and quality control of Tripterygium wilfordii Radix in future.

Methods: The terpenes were extracted by using ultrasonic method with ethyl acetate from root or cortex of Tripterygium wilfordii Radix, and the sensitive and rapid HPLC-PDA method was developed for simultaneous quantification of triptolide, triptophenolide, demethylzeylasteral and celastrol in root and cortex of Tripterygium wilfordii Radix for evaluation of the impacts by different drying processes.

Results: The four compounds in their respective determined arrange had good linearity of 0.9998≦R≦0.9999 and the average recoveries were range from 94.69 to 100.28%, RSDs were within 0.27 to 2.42%, respectively. The contents of triptolide, triptophenolide, demethylzeylasteral and celastrol in different Tripterygium wilfordii Radix individuals were varied greatly at different drying temperatures. Under different temperatures, the contents of triptolide, triptophenolide, demethylzeylasteral, and celastrol were 37.94-70.31 mg/g, 0-1.807 mg/g, 0.3513-9.205 mg/g, 3.202-15.31 mg/g, respectively. The suitable drying temperature of terpenoids in root of wild and cultivate are 80 °C and 60 °C, the suitable drying temperature of terpenoids in cortex is 40 °C.

Conclusions: The method established is high sensitivity, accuracy, reliability and suitable for the simultaneous analysis of terpenoids in Tripterygium wilfordii Radix. The data provide a scientific basis and reference for the quality control of herb and preparations related to Tripterygium wilfordii Radix.