Structure‑activity associations in novel farrerol derivatives with vasorelaxant properties

To detect the structure‑activity associations of farrerol derivatives, the relaxation activity of farrerol derivatives was observed in isolated aortic rings pre‑contracted using phenylephrine in Sprague‑Dawley rats. All compounds tested in the present study produced a relaxation effect, which was significantly affected by the molecular structure. Using a collagen gel contraction assay, the present study further evaluated the inhibitiory effect of farrerol derivatives in a decreased collagen gel area, induced by Angiotensin II. The results indicated that farrerol derivatives could inhibit collagen contraction, and that the inhibitory effect was associated with the molecular structure of the compounds. Furthermore, the inhibitory strength of the different compounds was consistent with the results of vascular tension detection. The activity of the farrerol derivatives was closely associated with the molecular structure. The analysis indicated that an electron‑withdrawing substituent in the ortho position of the phenyl group (ring B) was crucial in order to observe improved vasorelaxation activity, whereas a hydroxyl or methoxy group was unfavorable. A para electron‑donating group was oberved to increase compound activity. In addition, when the B ring was heterocycle rather than a phenyl ring, the vasorelaxation ability was weakened.