1. Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan 807, Republic of China
2. Department of Biomedical Laboratory Science and Biotechnology, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan 807, Republic of China
3. School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan 807, Republic of China