1. Chongqing Key Laboratory of Natural Product Synthesis and Drug Research School of Pharmaceutical Sciences Chongqing University Chongqing 401331 P. R. China
2. Key Laboratory of Tropical Plant Resource and Sustainable Use Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Menglun Yunnan 666303 P. R. China
3. School of Pharmaceutical Engineering Shenyang Pharmaceutical University Shenyang 110016 P. R. China
4. State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia Medica Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100050 P. R. China