New sesquiterpenes from the roots of Ligularia dentata

Phytochemical investigation of the roots of Ligularia dentata has resulted in the isolation of three new bisabolane sesquiterpenes: 1alpha,3beta,10,11 -tetrahydroxy-2alpha,5alpha,8-triangeloyl-oxybisabola-(7)14-en-4-one, 1alpha,3beta,10-trihydroxy-11 -methoxy-2alpha,5alpha,8-triangeloyloxybisabola-7(14)-en-4-one, and lalpha, 3beta,10-trihydroxy-2alpha,5alpha,8-triangeloyloxybisabola-7(14),11(12)-dien-4-one. Their structures were elucidated with spectro-scopic methods and 2D-NMR techniques as well as chemical transformations. In addition, three known phenolic norsesquiterpenes, liguhodgsonal, ligujapone, and 2-hydroxy-platyphyllide have also been obtained.