1. Graduate Institute of Pharmaceutical Sciences, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan 807, Republic of China, Graduate Institute of Pharmaceutical Technology, Tajen University, Pingtung, Taiwan 907, Republic of China, Division of Biotechnology, Pharmaceutical Research, National Health Research Institute, Miaoli, Taiwan 350, Republic of China, and Department of Chemistry, National Sun Yat-sen University, Kaohsiung, Taiwan 804, Republic of China