Abstract: OBJECTIVE: To study the effects of the drying processing in terms operational parameters on the bioactive constituents of six Yuanzhi(Radix Palygalae)samples across China.METHODS: Six Yuanzhi(Radix Palygalae) samples were investigated using thermogravimetry analysis. The heating courses were set in two ways: thetemperature-programmed process from room temperature to 150℃,and the constant-temperature course at 50℃, 70℃ and 90℃.RESULTS: The peak temperature of six Yuanzhi(Radix Palygalae) samples ranged from 78℃ to 88℃.The mass loss rate ofYuanzhi(Radix Palygalae) alcohol-soluble extract was significantly increased when heated at 90℃. Four types of bioactive ingredients were detected in volatile oils of Yuanzhi(Radix Palygalae) sample from Shanxi province by Gas Chromatography-mass spectrometry analysis. Fourier Transform Infrared Spectroscopy results showed that the drying temperature exerted a great influence on types and amount of ingredients of Yuanzhi(Radix Palygalae). The kinetic study showed that the constant-temperature drying process ofYuanzhi Radix Palygalae) samples could be well described by the Page Model, especially for the drying process at 50℃, in which R2and SD values were more than 0.98 and less than 0.04, respectively. The drying constant k of three Yuanzhi(Radix Palygalae) samples from Shanxi, Gansu and Shaanxi provinces in China was corresponding to the Arrhenius equation, and their activation energies were28.07, 25.38 and 21.48 kJ/mol, respectively.CONCLUSION: The drying process of Yuanzhi(Radix Palygalae) was very important for bioactive ingredients improvement in Yuanzhi(Radix Palygalae). Temperature was a thermodynamic property significantly affecting the process.

Key words: Yuanzhi(Radix Palygalae), Chromatography,supercritical fluid, Drying process, Thermogravimetric analysis, Alcohol soluble extract, Bioactive ingredients