The characterization, binding ability and inclusion complexation behavior of the inclusion complexes of norathyriol with beta-cyclodextrin (beta-CD) and its derivatives such as hydroxypropy1-beta-cyclodextrin (HP beta CD), sulfobutyl ether beta-cyclodextrin (SBE beta CD) and mono (6-ethylene-diamino-6-deoxy)-beta-cyclodextrin (EN beta CD) were investigated in both solution and solid state by means of femtosecond spectroscopy, H-1 and 2D nuclear magnetic resonance, powder X-ray diffraction. The results showed that the aqueous solubility of the complexes was much higher than that of norathyriol. The cytotoxicity of complexes on human colon cancer cell lines HT-29, SW480, Lovo and HCT116 indicated that the antitumor activities of the complexes were better than that of norathyriol. This high antitumor activity, along with the satisfactory aqueous solubility of the complexes, will be potentially useful for their application on cancer chemotherapies. (C) 2013, The Society for Biotechnology, Japan. All rights reserved.