1. Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan, Republic of China
2. Department of Biotechnology, National Formosa University, Yunlin 632, Taiwan, Republic of China
3. Graduate Institute of Natural Products, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan, Republic of China
4. Department of Pharmacy and Chinese Medicine Research and Development Center, China Medical University, Taichung 401, Taiwan, Republic of China