We had previously found that the motility of highly metastatic murine osteosarcoma FBJ-LL cells was decreased by a serum from a mouse orally given maoto and the spontaneous metastasis of FBJ-LL cells was suppressed by oral administration of maoto in vivo. Furthermore, we reported that the human serum-induced motility of human breast cancer MDA-MB-231 cell was prevented by the addition of maoto. In this study, we investigated the effect of human sera after intake of maoto on the motility of MDA-MB-231 cells as a first step to approach for clinical application of maoto as a metastatic inhibitor. Maoto was orally administered to 10 healthy male volunteers at usual dosage for 3.5 days and their bloods were collected before administration of maoto and at 0, 0.5, 1, 2 and 4 hours after intake of it. All of the sera after intake of maoto caused almost 30% reductions in the motility of MDA-MB-231 cells without cytotoxicity. These results suggest that maoto may be a novel inhibitor of cancer metastasis suitable for application in humans.
