1. College of Life Science, Qinghai Normal University, Xining, China;
2. State Key Laboratory of Phytochemistry and Plant Resources of West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China;
3. University of Chinese Academy of Sciences, Beijing, People's Republic of China;
4. Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China