Structure and Cytotoxicity of Novel Lignans and Lignan Glycosides from the Aerial Parts of Larrea tridentata

Chemical Constituents of the Leaves of Thujopsis dolabrata and Their Cytotoxicity

Five podophyllotoxin derivatives (1-5), two diterpenoids (6 and 7), three diterpenoid xylosides (8-10), a flavanonol glycoside (11), flavonol (12), and biflavonoid (13) were isolated from the leaves of Thujopsis dolabrata (Cupressaceae). Compounds 1, 6, and 8 were named (-)-β-isopeltatin, epi-nootkastatin 2, and acetoxyanticopalol 15-O-β-D-xylopyranoside, respectively. The structures of the isolated compounds were determined based on a detailed analysis of NMR spectroscopic data and through chromatographic and spectroscopic analyses following specific chemical transformations. The isolated compounds (1-5 and 7-11) were evaluated for their cytotoxicity toward HL-60 human promyelocytic leukemia cells and Caki-1 human kidney carcinoma cells. The podophyllotoxin derivatives (1-5) exhibited cytotoxicity against both HL-60 and Caki-1 cells with IC₅₀ values ranging from 0.00069 to 5.4 µM, and the diterpenoid derivatives (7-10) demonstrated cytotoxicity against HL-60 cells with IC₅₀ values ranging from 4.5 to 11 µM. HL-60 cells treated with 8 exhibited apoptosis characteristics, such as accumulation of sub-G₁ cells and nuclear chromatin condensation.