Enhancement of NK cytotoxicity, antimetastasis and elongation effect of survival time in B16-F10 melanoma cells by oregonin.

We investigated the antitumor activity of oregonin, a diarylheptanoid derivative purified from Alnus hirsuta Turcz, Betulaceae. Oregonin is a potential novel immunomodulator, which augments the activation of natural killer (NK) cells, and thereby leads to a powerful antitumor activity. To evaluate the cytotoxicity of oregonin against tumor cells, we examined the effectiveness of NK cells and determined that oregonin could increase NK cell cytotoxicity.