1. State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Zu Chong Zhi Road 555, Zhangjiang Hi-Tech Park, Shanghai 201203, People's Republic of China,
2. Key Laboratory of Marine Drugs, School of Medicine and Pharmacy, Ocean University of China, Ministry of Education, People's Republic of China
3. South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510000, People's Republic of China
4. Istituto di Chimica Biomolecolare-CNR, Pozzuoli (Na) 80078, Italy