1. Institute of Chinese Medicine, Department of Biology and Department of Biochemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, People's Republic of China, Hong Kong Jockey Club Institute of Chinese Medicine, Hong Kong Science Park, Shatin, New Territories, Hong Kong, People's Republic of China, and Comparative and Ecological Phytochemistry Section, Department of Systematic and Evolutionary Botany, University of Vienna, Vienna, Austria