1. Graduate School of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan, Temko Corporation, 4-27-4 Honcho, Nakano, Tokyo 164-0012, Japan, Department of Horticulture, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand, and The Kitasato Institute, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8642, Japan