1. Key Laboratory of Marine Drugs, Chinese; Ministry of Education; School of Medicine and Pharmacy; Ocean University of China; Qingdao 266003 P. R. China
2. Laboratory for Marine Drugs and Bioproducts; Qingdao National Laboratory for Marine Science and Technology; Qingdao 266237 P. R. China
3. Institute of Cerebrovascular Diseases; Affiliated Hospital of Qingdao University Medical College; Qingdao 266500 P. R. China