1. State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu 211198, P. R. China
2. State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093, P. R. China
3. Division of Molecular Therapeutics & Formulation, School of Pharmacy, The University of Nottingham, Nottingham NG7 2RD, U.K.