NEW SESQUITERPENES FROM THE ROOTS OF LIGULARIA-DENTATA

Phytochemical investigation of the roots of Ligularia dentata has resu lted in the isolation of three new bisabolane sesquiterpenes: 1 alpha, 3 beta P,10,11-tetrahydroxy-2 alpha,5 alpha,8-triangeloyloxybisabola-( 7)1 4-en-4-one (1), 1 alpha,3 beta,10-trihydroxy-11-methoxy-2 alpha,5 alpha,8-triangeloyloxybisabola-7(14) (2), and 1 alpha, 3 beta,10-trihy droxy-2 alpha,5 a,8-triangeloyloxybisabola-7(14),11(12)-dien-4-one (3) . Their structures were elucidated with spectroscopic methods and 2D-N MR techniques as well as chemical transformations. In addition, three known phenolic norsesquiterpenes, liguhodgsonal (4), ligujapone (5), a nd 2-hydroxyplatyphyllide (6) have also been obtained.