1. CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province
2. Lanzhou Institute of Chemical Physics
3. Chinese Academy of Sciences (CAS)
4. Lanzhou 730000
5. People's Republic of China
6. Shaanxi Key Laboratory of Natural Products & Chemical Biology
7. College of Chemistry and Pharmacy
8. Northwest A&F University
9. Yangling