ISOLATION AND BIOLOGICAL EFFECTS OF 7-O-METHYLERIODICTYOL, A FLAVANONE ISOLATED FROM ARTEMISIA-MONOSPERMA, ON RAT ISOLATED SMOOTH MUSCLES

The isolation for the first time from the genus Artemisia (Compositae) of the known flavanone, 7-O-methyleriodictyol (7-methoxy-5,3',4'-trihydroxyflavanone), its identification, and its biological effects on rat isolated smooth muscles are described. 7-0-Methyleriodictyol (10(-7) M to 3 X 10(-4) M) caused concentration-dependent inhibition of the amplitude of the phasic contractions and reduced the tone of the ileum, the uterus, and the urinary bladder. It also caused relaxation of the phenylephrine-precontracted pulmonary artery and the acetylcholine-precontracted trachea. The flavanone also shifted to the right the acetylcholine concentration-effect curve on the ileum and the oxytocin concentration-effect curve on the uterus. The maximum contractions induced by acetylcholine or oxytocin were also inhibited by 7-O-methyleriodictyol. These antispasmodic effects are partly consistent with the use of A. monosperma in folk medicine for certain gastrointestinal disorders.