1. College of Pharmacy Jinhua Polytechnic 888 West Hai Tang Road Jinhua 321007 P. R. China
2. Department of Preparation Center General Hospital of Ningxia Medical University Yinchuan 750004 P. R. China
3. Jinhua Branch Sichuan Industrial Institute of Antibiotics School of Pharmacy Chengdu University 888 West Hai Tang Road Jinhua 321007 P. R. China
4. State Key Laboratory of Drug Research Shanghai Institute of Materia Medica Chinese Academy of Sciences 555 Zu Chong Zhi Road Shanghai 201203 P. R. China