1. Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, Innovative Drug Research Center School of Pharmaceutical Sciences Chongqing University Chongqing 401331 P. R. China
2. Pharmaceutical Department of Chongqing, Three Gorges Central Hospital Chongqing University Chongqing 401331 P. R. China
3. Chemical Biology Research Center School of Pharmaceutical Sciences Chongqing University Chongqing 401331 P. R. China