1. Niigata College of Pharmacy, Kamishin'ei-cho 5-13-2, Niigata 950-2081, Japan, National Institute of Health Sciences, Setagaya-ku, Tokyo 158-8501, Japan, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan, and Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan