Vasodilatory effects of flavonoids in rat aortic smooth muscle. Structure-activity relationships

Abstract

Abstract--1. Flavonoids relaxed the contractions induced by noradrenaline, KCI or phorbol 12-myristate,13-acetate in rat aortic strips, the order of potency being: flavonols (quercetin, kaempferol, pentamethylquereetin)>flavones(luteolin, apigenin)>flavanols((+)-catechin, (-)-epicatechin) which correlates with the reported order of potency to inhibit protein kinase C.2. The relaxant effects of kaempferol and luteolin were slightly potentiated by isoprenaline and those of pentamethylquercetin, kaempferol and apigenin by sodium nitroprusside.3. It is concluded that the main vasodilatory mechanism of flavonoids seems to be the inhibition of protein kinase C. Inhibition of cyclic nucleotide phosphodiesterases or decreased Ca 2+ uptake may also contribute to their vasodilatory effects.

The Flavanol (−)-Epicatechin Prevents Stroke Damage through the Nrf2/HO1 Pathway

“…Mounting evidence suggests a protective role for various polyphenols and flavonoids in cerebral ischemia (Lee et al, 2004;Lee et al, 2000;Shah et al, 2005;Shin et al, 2006;Simonyi et al, 2005). It is noteworthy also that flavanols have been shown to improve vasorelaxation (Duarte et al, 1993;Karim et al, 2000). The simple chemical structure of flavanols may interact with specific cellular and molecular targets, thereby mediating a wide range of biologic activities.…”

Variation of Phenolic Compounds Contents in Cultivated Astragalus membranaceus

“…Flavonoids constitute a large class of ubiquitous compounds in plants, and they contain a number of phenolic hydroxyl groups attached to their ring structure, conferring antioxidant activity (Harborne et al, 1986). Flavonoids and other plant phenolics have been reported to have multiple biological activities (Ho et al, 1992;Kinsella et al, 1993) in addition to their free radical scavenging activities (Kandaswami and Middleton, 1994), including vasodilatory (Duarte et al, 1993), anticarcinogenic, antiinflammatory, antibacterial, immuno-stimulating, antiallergic, antiviral, and estrogenic effects, as well as being inhibitors of phospholipase A2, cyclooxygenase, and lipoxygenase (Brown, 1980). As mentioned above, herbal medicines possess biologically functional substances.…”

Effects of flavonoids on rat aortic smooth muscle contractility: Structure-activity relationships

“…Flavonoids are natural substances which display a broad range of pharmacological actions (Middleton, 1984;Gabor, 1986;Pathak et al, 1991) with most exhibiting vasodilatory effects (Beretz et al, 1980;Ubeda et a/., 1991;Ko et al, 1991;Duarte et al, 1993a;Duarte et al, 1993bDuarte et al, , 1994. This vascular smooth muscle relaxation has been attributed to several mechanisms including decreased transmembrane 4SCa2÷ uptake (Ko et al, 1991;Duarte et al, 1993a) and inhibitory effects on cAMPand cGMP-phosphodiesterases (PDE; Beretz et al, 1980) or on protein kinase C (PKC) (Duarte et al, 1993a(Duarte et al, , 1993b.…”