1. Marine Drugs Research Center, College of Pharmacy, Jinan University, 601 Huangpu Avenue West, Guangzhou 510632, P. R. China
2. School of Pharmaceutical Sciences, Southern Medical University, 1838 Guangzhou Avenue North, Guangzhou 510515, P. R. China
3. Department of Organic Chemistry, University of Debrecen, P.O. Box 400, 4002 Debrecen, Hungary
4. School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, P. R. China