1. CAS Key Laboratory of Chemistry of Northwestern Plant Resources Key Laboratory for Natural Medicine of Gansu Province Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences (CAS) Lanzhou Gansu 730000 P. R. China
2. University of Chinese Academy of Sciences Beijing 100049 P. R. China
3. State Key Laboratory of Applied Organic Chemistry and Department of Chemistry Lanzhou University Lanzhou Gansu 730000 P. R. China
4. State Key Laboratory of Quality Research in Chinese Medicine, Macau Institute for Applied Research in Medicine and Health Macau University of Science and Technology Taipa Macau 999078 P. R. China