1. Natural
Products Center, School of Natural Resources and the Environment,
College of Agriculture and Life Sciences, University of Arizona, 250 E. Valencia Road, Tucson, Arizona 85706, United States
2. Basic
Research Program, Leidos Biomedical Research, Inc., Frederick National
Laboratory for Cancer Research, and Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, United States
3. State
Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Zhangjiang Hi-Tech Park, Shanghai 201203, People’s Republic of China