Prenylated flavonoids are mainly distributed in Leguminosae and Moraceae plants, and they have been reported to possess various biological activities. Previously, we have reported a prenylated isoflavonoid, isoangustone A（IAA） from licorice（Glycyrrhiza uralensis）, which induces apoptosis in colorectal cancer cells by disrupting mitochondrial functions. In the present study, we compared a group of flavonoids from licorice with IAA for their anti-proliferation activities and effects on intracellular signaling. The results indicated that the isoprenyl groups on the A and B rings, the hydroxyl groups at the ortho position of isoprenyl on A ring and the conjugated plane of C ring might contribute to the anti-cancer activity of prenylated flavonoids. Based on the above structure-activity relationship, we further identified four prenylated flavonoids with similar anti-cancer activities from licorice. Taken together, our present study established a preliminary structure-activity relationship of anti-cancer prenylated flavonoids, and our data provided important leading compounds from licorice, which deserved further research and development.
