1. Department of Chemistry, Rikkyo University, Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan
2. Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima 770–8514, Japan
3. Graduate School of Biomedical Sciences, Nagasaki University, Bunkyo-machi, Nagasaki 852-8521, Japan
4. Department of Life Science, Rikkyo University, Nishi-Ikebukuro, Toshima-ku, Tokyo 171–8501, Japan
5. Kunming Institute of Botany, Chinese Academy of Science, Kunming 650201, China