1. Key Laboratory of Tropical Medicinal Plant Chemistry of Ministry of Education, Hainan Normal University, Haikou, P.R.China;
2. Key Laboratory of Tropical Medicinal Plant Chemistry of Hainan Province College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou, P.R. China;
3. Key Laboratory of Ethnomedicine (Minzu University of China) Ministry of Education, Beijing, P. R. China