1. Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung 804, Taiwan, Republic of China, School of Pharmacy, College of Medicine, National Taiwan University, Jen-Ai Rd. Sec. 1, Taipei 100, Taiwan, Republic of China, National Research Institute of Chinese Medicine, Taipei 112, Taiwan, Republic of China, and Graduate Institute of Natural Products, Chang Gung University, Taoyuan 333, Taiwan, Republic of China