1. Natural Products Research Laboratories and Division of Medicinal Chemistry and Natural Products, School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, AndroScience Corporation, 11175 Flintkote Ave., Suite F, San Diego, California 92121, National Research Institute of Chinese Medicine, Taipei, Taiwan, and Pharmacological Institute, College of Medicine, National Taiwan University, No. 1, Jen-Ai Road, Sec. 1, Taipei, Taiwan