1. National Research Institute of Chinese Medicine, No. 155-1, Li-Nong Street, Section 2, Shih-Pai, Taipei, 112, Taiwan, Republic of China, Department of Applied Chemistry, Chinese Culture University, Taipei, 113, Taiwan, Republic of China, Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, 807, Taiwan, Republic of China, and Department of Chemistry, National Cheng Kung University, Tainan, 701, Taiwan, Republic of China