1. State Key Laboratory Natural Medicines; China Pharmaceutical University; Nanjing 210009 P. R. China
2. Department of Natural Medicinal Chemistry; China Pharmaceutical University; Nanjing 210009 P. R. China
3. Key Laboratory of Drug Quality Control and Pharmacovigilance (China Pharmaceutical University); Ministry of Education; China Pharmaceutical University; Nanjing 210009 P. R. China