Aiphanol (1), a novel stilbenolignan, which has recently been isolated from the seeds of Aiphanes aculeata Willd (Are- caceae) possesses significant inhibitory activity toward cyclooxygenases-1 and -2.1 Compound 1 demonstrated the IC50 value of 1.9 mM toward cyclooxyganase-1 and of 9.9 mM toward cyclooxyganase-2. Compound 1 has a stilbenolignan skeleton in which a stilbene unit is bridged with a phenylpro- pane moiety by 1,4-dioxane. ...