Antitumor actions of a chromone glucoside cnidimoside A isolated from Cnidium japonicum.

In a series of studies on the search for new antitumor and antimetastatic substances from the natural medicinal plants of the Umbelliferae family, we previously reported that chalcone derivatives isolated from Angelica keisekei roots have antitumor and antimetastatic activities. In the present study, we examined the effects of a chromone glucoside cnidimoside A isolated from Cnidium japonicum whole plants on tumor growth and tumor metastasis in colon 26-bearing mice. Cnidimoside A (50 mg/kg, twice daily) significantly inhibited tumor growth and final tumor weight compared to the growth in vehicle-treated colon 26-bearing mice (control). Furthermore, the number of mice with abdominal invasion of tumors was also reduced by orally administered cnidimoside A (50 mg/kg, twice daily). In this study, the CD8(+) T Cell- and interferon (IFN)-gamma-positive cell numbers in the small intestine in the colon 26-bearing mice were significantly reduced compared with those in the normal mice, but the natural killer (NK)-positive cell number did not differ significantly between the normal and colon 26-bearing mice. The CD8(+) T-, NK and IFN-gamma-positive cell numbers in the small intestine were significantly increased by orally administered cnidimoside A (50 mg/kg, twice daily) compared to those in vehicle-treated colon 26-bearing mice. In conclusion, it seems likely that the antitumor and antimetastatic actions of cnidimoside A may be partly associated with the stimulation of immune response in the small intestine.