1. Department of Botany, National Museum of Nature and Science, Amakubo 4-1-1, Tsukuba, Ibaraki 305-0005, Japan
2. Department of Chemistry, Hiyoshi Campus, Keio University, Hiyoshi 4-1-1, Kohoku-ku, Yokohama 223-8521, Japan
3. Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan
4. Laboratory of Pharmacognosy, Showa Pharmaceutical University, Higashi-tamagawagakuen 4, Machida, Tokyo 194-8543, Japan