Glyceollin　I,　an　induced　phytoalexin　isolated　from　soybean,　has　been　reported　to　have　various　bioactivities,　including　anti-bacterial,　anti-nematode,　anti-fungal,　anti-estrogenic　and　anti-cancer,　anti-oxidant,　anti-inflammatory,　insulin　sensitivity　enhancing,　and　attenuation　of　vascular　contractions.　Here　we　show　that　glyceollin　I　has　hormesis　and　extends　yeast　life　span　at　low　(nM)　doses　in　a　calorie　restriction　(CR)-dependent　manner,　while　it　reduces　life　span　and　inhibits　yeast　cell　proliferation　at　higher　(mu　M)　doses.　In　contrast,　the　other　two　isomers　(glyceollin　II　and　III)　cannot　extend　yeast　life　span　and　only　show　life　span　reduction　and　antiproliferation　at　higher　doses.　Our　results　in　anti-aging　activity　indicate　that　glyceollin　I　might　be　a　promising　calorie　restriction　mimetic　candidate,　and　the　high　content　of　glyceollins　could　improve　the　bioactivity　of　soybean　as　functional　food　ingredients.