1. School of Chemical Engineering and Technology Hainan University Haikou 570228 P. R. China
2. Hainan Branch Institute of Medicinal Plant Development (Hainan Provincial Key Laboratory of Resources Conservation and Development of Southern Medicine) Chinese Academy of Medical Sciences & Peking Union Medical College Haikou 570311 P. R. China
3. Institute of Medicinal Plant Development Chinese Academy of Medical Sciences & Peking Union Medical College Beijing 100193 P. R. China
4. Key Laboratory of Tropical Translational Medicine of the Ministry of Education Hainan Key Laboratory for Research and Development of Tropical Herbs School of Pharmacy Hainan Medical University Haikou 571199 P. R. China