Three new butanolides, 2-(1-methoxy-11-dodecenyl)-penta-2,4-dien-4-olide (1
), (2Z,3S,4S)-2-(11-dodecenylidene)-3-hydroxy-4-methylbutanolide (2) and (2
E,3R,4R)-2-(11-dodecenylidene)-3-hydroxy-4-methoxy-4-methylbutanolide (3),
were isolated from the stems of Lindera obtusiloba BLUME. Their chemical st
ructures were assigned by spectroscopic evidence. They exhibited cytotoxici
ty against cultured human tumor cell lines with their ED50 values ranging f
rom 3.19 to 14.63 mu g/ml.