Abstract | Four sesquiterpene lactones including an eremophilenolide dimer, named as biligulaplenolide, 1, 8β-hydroxy-1-oxo-(14α,15α eremophil-7(11),9(10)-dien-12,8α-olide, 2, 1-hydroxy-2-oxo-(14α,15α eremophil-1(10),7(11),8(9)-trien-12,8-olide, 3, 4α,8β,9α-trihydroxy- 5αΗ-7(11)-eudesmen-12,8α-olide, 4, along with two known ones, 10α-hydroxy-1-oxo-eremophil-7(11),8(9)-dien-12,8-olide, 5, and furanoeremophil-1(10)-ene-2,9-dione, 6, were isolated from the underground organs of Ligularia platyglossa (Franch.) Hand.-Mazz. Their structures were elucidated by spectroscopic methods including single-crystal X-ray diffraction analysis (2 and 3). Their in vitro cytotoxicities against seven cancer cell lines (BGC-823, A549, HL-60, B16, SMMC-7721, BEL7402, Hela) were evaluated. Compounds 2, 3, 5 showed cytotoxic activities on HL-60 cancer cells with IC50 in the range of 24.0 to 51.1 μM, whereas compound 3 exhibited only weak cytotoxic activity against the B16, BEL7402 and Hela cancer cells. Flow cytometric analysis indicated that compound 3 induces Hela cells to apoptotic death after 48 h treatment with 0.38 mM of this compound. |
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