Anticancer effects of the flavonoid diosmetin on cell cycle progression and proliferation of MDA-MB 468 breast cancer cells due to CYP1 activation

Flavonoids constitute a large class of polyphenolic compounds with cancer preventative properties. We have examined the ability of the natural flavone diosmetin to inhibit proliferation of breast adenocarcinoma MDA-MB 468 and normal breast MCF-10A cells and found that this compound is selective for the cancer cells with slight toxicity in the normal breast cells. Diosmetin was inetabolised to the structurally similar flavone luteolin in MDA-MB 468 cells, whereas no metabolism was seen in MCF-10A cells. Diosmetin caused G, arrest at 10 mu M in MDA-MB 468 cells after 48-h treatment whereas this effect was not observed in MCF-10A cells. We suggest that diosmetin exerts cytostatic effects in MDA-MB 468 cells, due to CYP1A1 and CYP1B1 catalyzed conversion to the flavone luteolin.