Abstract

Twenty new ent -kaurane diterpenoids, wardiisins A-T ( 1 – 20 ), along with two previously undescribed artefactual compounds ( 21 and 22 ) and twelve known analogues ( 23 – 34 ), were isolated from the aerial part of Isodon wardii . Their structures were elucidated by comprehensive analysis of spectroscopic data and single-crystal X-ray diffraction, and most of them were found to bear unusual C-12 oxygenation. Compounds 4 , 7 , 8 , 19 , 20 , 21 exhibited remarkable cytotoxicity against the cancer cell lines HL-60, SMMC-7721, A-549, MDA-MB-231, and SW480, with IC 50 values ranging from 0.3 to 5.2  μ M. Moreover, 7 was found to induce G2/M cell cycle arrest and promote apoptosis in SW480 cell lines.