Possible mechanisms of vasorelaxation for 5,7‐dimethoxyflavone from Kaempferia parviflora in the rat aorta

Abstract

The present study investigated the vascular effects of 5,7-dimethoxyflavone (DMF), isolated from the rhizomes of Kaempferia parviflora (KP), on rat isolated aortic rings and its possible mechanisms. DMF (1-100 μM) caused concentration-dependent relaxations in aortic rings precontracted with methoxamine. This effect was significantly reduced by removal of the endothelium, and after pretreatment with N(G)-nitro-L-arginine methyl ester (L-NAME, 300 μM), indomethacin (10 μM) and 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ, 10 μM), but not 9-(tetrahydro-2-furanyl)-9H-purine-6-amine (SQ22536, 100 μM). Relaxant responses to DMF were significantly inhibited by high KCl (60 mM) in both endothelium-intact and -denuded rings. In addition, the relaxations to DMF were significantly reduced by pretreatment with tetraethylammonium (TEA, 5 mM), glibenclamide (10 μM), 4-aminopyridine (1 mM) or barium chloride (10 μM). Preincubation with DMF (10 and 100 μM) for 30 min significantly inhibited the contractile responses to CaCl(2) in a Ca(2+)-free, high K(+) buffer. The present study demonstrated that DMF causes endothelium-dependent relaxation that is partly mediated by NO-cGMP and cyclooxygenase pathways. Interestingly, DMF-induced responses are mainly due to increasing K(+) efflux, and inhibition of Ca(2+) influx from the extracellular space. The vasodilator effects of DMF provide experimental support for the potential use of KP as a medical plant in the treatment of cardiovascular diseases.

Vasodilatory Effect of Wogonin on the Rat Aorta and Its Mechanism Study

“…26) Several flavonoids have been developed as vasodilator drugs, some with and others without an endothelium-dependent vasodilation effect. 18,27) Our previous study reported that oroxylin A, a flavone isolated from the bark of Eucommia ulmoides OLIV. could relax rat thoracic aorta and the effect was endothelium and NO dependent.…”

“…Then the following experiments were done. [15][16][17][18][19][20][21] 1) To investigate the vasodilatory effect of wogonin, NE (1 µM) or KCl (60 mM) was used to contract the aortic rings. Once a stable contraction was achieved, wogonin (0.1-100 µM) was added cumulatively.…”

Enhancement of physical fitness by black ginger extract rich in polymethoxyflavones: a double-blind randomized crossover trial

“…anti-inflammatory, antioxidant [18][19][20][21], anticancer [22,23], muscular metabolismenhancing [24], anti-photoaging [25], phosphodiesterase (PDE)5 inhibitory [26], anti-cardiovascular disease [27], and viral protease inhibitory [28] activities). A large number of studies have investigated the bioactivities of black ginger extract (KPE), which is rich in PMFs [24,[29][30][31][32][33][34][35][36][37].…”

Structures of Two New Phenolic Glycosides, Kaempferiaosides A and B, and Hepatoprotective Constituents from the Rhizomes of <i>Kaempferia parviflora</i>

“…1,2) The rhizomes of this plant are tinged with-dark purple to black, and have traditionally been used for the treatment of hypertension, [3][4][5] allergy, 6) gastrointestinal disorders, 7) and impotence. 8,9) The extract of the rhizomes of K. parviflora and its constituents were revealed to exhibit several pharmacological activities, such as antiplasmoidal, antifungal, 2) antiinflammatory, [10][11][12] α-glucosidase inhibitory, 13) and xanthine oxidase inhibitory 1) activities and cytotoxicity of several tumor cell lines 14,15) as well as effect of P-glycoprotein function 16) and modulation of multi-drug resistance in cancer cells.…”

“…18) By a previous chemical study on K. parviflora, presence of several methoxyflavones and related phenolic constituents have been revealed. 2,5,6,[10][11][12][13][14][15]17,[19][20][21][22] During the course of our characterization studies on Thai natural medicines, [23][24][25][26][27][28][29][30][31][32] two new phenolic glycosides named kaempferiaosides A (1) and B (2) were isolated from the rhizomes of K. parviflora together with 24 known compounds. This paper deals with the structure elucidation of 1 and 2, as well as hepatoprotective effect of the constituents from the rhizomes of K. parviflora on D-galactosamine (D-GalN)-induced cytotoxicity in primary cultured mouse hepatocytes.…”