New Sesquiterpene Glycosides from the Flowers of Aster koraiensis and Their Inhibition Activities on EGF- and TPA-Induced Cell Transformation.

In total, four new eudesmane-type sesquiterpene glycosides, askoseosides A-D ( 1 - 4 ), and 18 known compounds ( 5 - 22 ) were isolated from the flowers of Aster koraiensis via chromatographic techniques. Chemical structures of the isolated compounds were identified by spectroscopic/spectrometric methods, including NMR and HRESIMS, and the absolute configuration of the new compounds ( 1 and 2 ) was performed by electronic circular dichroism (ECD) studies. Further, the anticancer activities of the isolated compounds ( 1 - 22 ) were evaluated using the epidermal growth factor (EGF)-induced as well as the 12- O -tetradecanoylphorbol 13-acetate (TPA)-induced cell transformation assay. Among the 22 compounds, compounds 4 , 9 , 11 , 13 - 15 , 17 , 18 , and 22 significantly inhibited both EGF- and TPA-induced colony growth. In particular, askoseoside D ( 4 , EGF: 57.8%; TPA: 67.1%), apigenin ( 9 , EGF: 88.6%; TPA: 80.2%), apigenin-7- O - β -d-glucuronopyranoside ( 14 , EGF: 79.2%; TPA: 70.7%), and 1-(3',4'-dihydroxycinnamoyl) cyclopentane-2,3-diol ( 22 , EGF: 60.0%; TPA: 72.1%) showed higher potent activities.