1. Shaanxi Key Laboratory of Natural Products & Chemical Biology
2. College of Chemistry & Pharmacy
3. Northwest A&F University
4. Yangling 712100
5. P. R. China
6. School of Chemical and Environmental Engineering
7. Sichuan University of Science and Engineering
8. Zigong 643000
9. School of Chemistry and Chemical Engineering
10. Shanxi University
11. Taiyuan 030006