Inhibitors of DNA Topoisomerase I and II Isolated from the Coptis Rhizomes - Kobayashi, Yoshinori; Yamashita, Yoshinori; Fujii, Noboru; Takaboshi, Kouji; Kawakami, Toshiyuki; Kawamura, Michio; Mizukami, Tamio; Nakano, Hirofumi (Planta Medica, 1995)