A multitarget semi-synthetic derivative of the flavonoid morin with improved in vitro vasorelaxant activity: Role of CaV1.2 and KCa1.1 channels.

[Display omitted] Ca V 1.2 channels play a fundamental role in the regulation of vascular smooth muscle tone. The aim of the present study was to synthesize morin derivatives bearing the nitrophenyl moiety of dihydropyridine Ca2+ antagonists to increase the flavonoid vasorelaxant activity. The effects of morin and its derivatives were assessed on Ca V 1.2 and K Ca 1.1 channels, both in vitro and in silico , as well as on the contractile responses of rat aorta rings. All compounds were effective Ca V 1.2 channel blockers, positioning in the α 1C subunit region where standard blockers bind. Among the four newly synthesized morin derivatives, the penta-acetylated morin-1 was the most efficacious Ca2+ antagonist, presenting a vasorelaxant profile superior to that of the parent compound and, contrary to morin, antagonized also the release of Ca2+ from the sarcoplasmic reticulum; surprisingly, it also stimulated K Ca 1.1 channel current. Computational analysis demonstrated that morin-1 bound close to the K Ca 1.1 channel S6 segment. In conclusion, these findings open a new avenue for the synthesis of valuable multi-functional, vasorelaxant morin derivatives capable to target several pathways underpinning the pathogenesis of hypertension. [ABSTRACT FROM AUTHOR]