1. State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing 210009, P. R. China
2. School of Pharmacy, The University of Nottingham, University Park Campus, Nottingham NG7 2RD, U.K.
3. School of Pharmacy, University of College London, London WC1N 1AX, U.K.