1. Hainan Key Laboratory for Research and Development of Natural Products from Li Folk Medicine, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agriculture Sciences, Haikou 571101, People’s Republic of China
2. College of Tropical Crop, Hainan University, Haikou 570228, People’s Republic of China
3. Department of Organic Chemistry, University of Debrecen, P.O.B. 400, 4002 Debrecen, Hungary