Flavonoids as vasorelaxant agents: synthesis, biological evaluation and quantitative structure activities relationship (QSAR) studies.

A series of 2-(2-diethylamino)-ethoxychalcone and 6-prenyl(or its isomers)-flavanones 10a,b and 11a-g were synthesized and evaluated for their vasorelaxant activities against rat aorta rings pretreated with 1 μM phenylephrine (PE). Several compounds showed potent vasorelaxant activities. Compound 10a (EC(50) = 7.6 μM, E(max) = 93.1%), the most potent one, would be a promising structural template for development of novel and more efficient vasodilators. Further, 2D-QSAR analysis of compounds 10a,b and 11c-e as well as thirty previously synthesized flavonoids 1-3 and 12-38 using Enhanced Replacement Method-Multiple Linear Regression (ERM-MLR) was further performed based on an optimal set of molecular descriptors (H5m, SIC2, DISPe, Mor03u and L3m), leading to a reliable model with good predictive ability (R(train)(2) = 0.839, Q(loo)(2) = 0.733 and R(test)(2) = 0.804). The results provide good insights into the structure- activity relationships of the target compounds.