1. Faculty of Pharmacy, Meijo University, Tempaku, Nagoya 468-8503, Japan, Tokai Gakuen University, Miyoshi, Aichi 470-0207, Japan, Laboratoire des Plantes Medicinales, CNRS, BP643, Noumea, New Caledonia, and Department of Biochemistry, Kyoto Prefectural University of Medicine, Kamigyou-ku, Kyoto 602-0841, Japan