1. Institute of Tropical Agriculture and Forestry; Hainan University; 58 Renmin Avenue, Haikou 570228 P. R. China
2. Research Centers for Marine Drugs and Pharmaceutical Analysis, School of Pharmacy; Second Military Medical University; 325 Guo-He Road Shanghai 200433 P. R. China
3. Department of Oceanography; National Sun Yat-sen University, 70 Lien-Hai Road; Kaohsiung 80424 Taiwan, R. o. China