1. Faculty of Pharmacy, Meijo University, Tempaku, Nagoya 468-8503, Japan, Tokai Gakuen University, Miyoshi, Aichi 470-0207, Japan, Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok 10330, Thailand, and Department of Biochemistry, Kyoto Prefectural University of Medicine, Kamigyou-ku, Kyoto 602-0841, Japan