1. State Key Laboratory of Natural Medicines (SKLNM) and Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, P. R. China
2. Faculty of Pharmacy Kinki University, 3-4-1 Kowakae, Higashiosaka, Osaka 577-8502, Japan
3. Department of Chemical and Material Science, Nanjing Normal University, Nanjing 210009, P. R. China
4. Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing 210009, P. R. China