1. a College of Life Science of Northwest Normal University , 967, Anning Dong Road, Lanzhou 730070 , China
2. b Bioactive Products Engineering Research Center for Gansu Distinctive Plants , Lanzhou 730070 , China
3. c Lanzhou Industry Research Institute , Lanzhou 730070 , China
4. d Gansu Key Laboratory of Polymer Material , Lanzhou 730070 , China