1. Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, People's Republic of China, Institute of Materia Medica, Chinese Academy of Medical Science, Beijing 100050, People's Republic of China, and the Program for Collaborative Research in the Pharmaceutical Sciences, Department of Medicinal Chemistry and Pharmacognosy, Center for Pharmaceutical Biotechnology, College of Pharmacy, University of Illinois at Chicago, 833 Wood Street, Chicago, Illinois 60612