1. Department of Synthetic Natural Products Chemistry; School of Pharmacy; Kitasato University; 5-9-1 Shirokane Minato-ku Tokyo 108-8641 Japan
2. Department of Microbial Chemistry; School of Pharmacy; Kitasato University; 5-9-1 Shirokane Minato-ku Tokyo 108-8641 Japan
3. School of Pharmacy; Kitasato University; 5-9-1 Shirokane Minato-ku Tokyo 108-8641 Japan
4. Kitasato Institute for Life Sciences and Graduate School of Infection Control Sciences; Kitasato University; 5-9-1 Shirokane Minato-ku Tokyo 108-8641 Japan