[Studies on the chemical constituents of Arctium lappa L].

Six compounds were isolated from the seeds of Arctium lappa L. One of them is a new lignan named neoarctin B(VI). The structure has been elucidated on the basis of spectral (UV, IR, 1H-NMR, 13C-NMR, DEPT, 2D-NMR and MS) analysis. The other five compounds were identified as daucosterol (I), arctigenin (II), arctiin (III), matairesinol (IV) and lappaol F (V).