1. a Institute of Chinese Materia Medica , China Academy of Traditional Chinese Medicine , 18 Beixincang, Dongcheng, Beijing , P.R. China
2. b Department of Analytical Chemistry, School of Pharmacy , Tokyo University of Pharmacy and Life Science , Tokyo , Japan
3. c Laboratory of Biophysical Chemistry, National Heart, Lung, and Blood Institute , National Institutes of Health , Bethesda , Maryland , USA