PURPOSE: To provide a new lignan derivative having bronchodilative activity, thus serviceable as a useful medicine for chronic airway-obstructive respiratory diseases.

CONSTITUTION: The objective lignan derivative of the formula. This compound can be obtained by a process wherein: a cucumber tree is immersed in a lower alcohol or halogen-based solvent; the resulting extract is successively put to transfer dissolution in a low-polar organic solvent (e.g. n-hexane, petroleum ether), medium-polar organic solvent (e.g. diethyl ether, ethyl acetate), high-polar organic solvent (e.g. n-butanol, DMF), and water; the fraction for the medium- polar organic solvent is subjected to a silica gel column chromatography; of the compounds obtained from n-hexane-diethyl ether mixed solvent-eluted fractions, such a compound as to give an Rf value of 0.6 when developed on a silica get thin layer plate using an acetone/chloroform (1/9) mixed solvent is purified through silica gel chromatography or dispensing liquid chromatography.