1. Department of Chemical Biology and Joint Laboratory of Peking University and The Hong Kong Polytechnic University, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100083, People's Republic of China, National Research Laboratories of Natural and Biomimetic Drugs, Peking University Health Science Center, Beijing 100083, People's Republic of China, and Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong