Antiproliferative and apoptotic effects of butyrolactone lignans from Arctium lappa on leukemic cells

In the course of screening for pharmacologically active substances from extracts of crude drugs used traditionally in Sino-Japanese herbal medicines, it was found that the 70% ethanol extract from the fruits of Arctium lappa L. (Compositae) showed potent antiproliferative activity against B cell hybridoma cell, MH60. By bioassay-guided purification, a new lignan, (+)-7,8-didehydroarctigenin, together with the known lignans (-)-arctigenin and (-)-matairesinol were isolated as the active ingredients from an aqueous ethanolic extract of the fruits of A. lappa. Of these active compounds, (-)-arctigenin showed the most potent anti proliferative activity against MH60 cells (IC50: 1.0 mu M), and the activity was suggested to be due to apoptosis.