1. Li Dak Sum Marine Biopharmaceutical Research Center Department of Marine Pharmacy College of Food and Pharmaceutical Sciences Ningbo University Ningbo 315832 P. R. China
2. Key Laboratory of Marine Biogenetic Resources Third Institute of Oceanography Ministry of Natural Resources of P. R. China Xiamen 361005 P. R. China
3. Ningbo Institute of Marine Medicine Peking University Ningbo 315832 P. R. China