1. State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100083, People's Republic of China, Analytical and Testing Center, Beijing Normal University, Beijing 100073, People's Republic of China, Institute for Systematics and Ecology, University of Amsterdam, P.O. Box 94766, 1090 GT Amsterdam, The Netherlands, and Institute of Pharmaceutical Biology, Heinrich-Heine University, Universitaetsstrasse 1, D-40225 Duesseldorf, Germany