1. Faculty of Pharmaceutical Sciences, Hokuriku University, Ho-3 Kanagawa-machi, Kanazawa 920-1181, Japan, Department of Pharmaceutical Botany, Faculty of Pharmacy, Mahidol University, Thailand, The Food Chemistry Division, Institute of Nutrition, Mahidol University, Thailand, and Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Kobe 651-2180, Japan