Polygonum viviparum L. induces vasorelaxation in the rat thoracic aorta via activation of nitric oxide synthase in endothelial cells

Abstract

BackgroundIn the past several decades, Polygonum viviparum L. (PV) was reported to have antibacterial, antiulcer, antioxidant, antitumor, anti-inflammatory, and antiarthritic properties. The anti-inflammatory pathway was recently elucidated through cytosolic nuclear factor E2-related factor 2 (Nrf2) activation and heme oxygenase (HO)-1 protein expression. PV is a perennial herb and widely distributed in high-elevation mountain regions, such as the Tibetan Plateau. In Tibetan traditional medicine, PV is usually used to boost the blood circulation to dissipate blood stasis. Therefore, this study focused on how PV improves the vascular circulation and acts on vascular tissues.MethodsIn this study, we isolated aortas from Sprague-Dawley rats (male, weight about 250 ~ 350 g), and detected the effects of PV on phenylephrine (PE)-induced contraction and cyclic guanosine 3′,5′-monophosphate (cGMP) formation using aortic rings. In addition, human umbilical vein endothelial cells (HUVECs) were used to exam nitric oxygen (NO) synthase (NOS) activity by directly measuring NO production in the culture medium. Endothelial (e) NOS phosphorylation, and cytosolic Nrf2 and HO-1 expressions were measured using a Western blot analysis.ResultsPV dose-dependently relaxed PE-induced contractions in endothelial-intact but not -denuded aorta. The concentration to produce 50% relaxation was 22.04 ± 1.77 μg/ml. PV-induced vasorelaxation was markedly blocked by pretreatment with NG-nitro-L-arginine methyl ester (L-NAME), an NOS inhibitor, methylene blue (MB), a guanylyl cyclase inhibitor, and hemoglobin, an NO scavenger. PV increased cGMP formation; however, this effect was also suppressed by co-pretreatment with l-NAME, MB, hemoglobin, and Ca2+-free medium. In HUVECs, PV increased NO formation, which was greatly attenuated by NOS inhibitors (L-NAME and L-NMMA) and by removing extracellular Ca2+ and chelating intracellular Ca2+ with BAPTA-AM. In addition, PV promoted eNOS phosphorylation, Nrf2 degradation, and HO-1 protein expression according to a Western blot analysis.ConclusionsThe results suggest that PV possesses vasorelaxing action in an endothelium-dependent manner and works through activating Ca2+/calmodulin- dependent NO synthesis; when NO is released and then transferred to smooth muscle cells, NO activates guanylyl cyclase and increases cGMP formation, ultimately resulting in vasorelaxation. Thus, PV can be considered for application as a potential therapeutic approach for vascular-associated disorders.

Rosmarinic Acid Alleviates the Endothelial Dysfunction Induced by Hydrogen Peroxide in Rat Aortic Rings via Activation of AMPK

“…Given that NO is the most potent vasodilator and the modulator of intracellular oxidative status, and it is produced by the eNOS in endothelium [ 19 ], we explored the effect of eNOS activation in RA's protection against the endothelial dysfunction induced by H 2 O 2 . The pretreatment with the NOS inhibitor L-NAME alone significantly decreased the vasodilation induced by ACh ( Figure 3(a) ), while increased the NBT reduction ( Figure 3(b) ) in rat aortic rings.…”

Role of Nitric Oxide and Hydrogen Sulfide in the Vasodilator Effect of Ursolic Acid and Uvaol from Black Cherry Prunus serotina Fruits

“…After the incubation time, 50 µL of 1% sulfanilic acid and 50 µL of 0.2% N -naphthyl ethylenediamine were added to induce formation of a colored azo compound. Absorbance was measured at 540 nm and samples concentrations were calculated with a linear equation based on a NO 2 − calibration curve [66,67].…”

Observations on traditional usage of ethnomedicinal plants in humans and animals of Kangra and Chamba districts of Himachal Pradesh in North-Western Himalaya, India

“…Polygonaceae Dysentery, heart problems, fever, menstruation irregularities, leucorrhoea, ulcer, cold, fever, headache, joint pain, indigestion, stomach pain and eye wound (Matin et al, 2001;Uniyal et al, 2006;Gairola et al, 2014;Kayani et al, 2015) Cardiac glycosides, saponin glycosides, alkaloids, anthraquinones, flavonoids, phenols, tannins, steroids and terpenoids Persicaria nepalensis (Meisn. ), Miyabe Polygonaceae Abortive, diuretic, anti-inflammatory, antiviral, hypotensive, antipyretic, fungitoxic, cure cold, influenza, swelling, hemorrhoids, diarrhea and rheumatism (Alves et al, 2000;Maria et al, 2001) Tannins, phenols, flavonoids and steroids (Garg et al, 2011) Persicaria vivipara (L.) Ronse Decr., Polygonaceae Anti-inflammatory, antibacterial, antiulcer, antioxidant, antitumor, antiarthritic, cure bronchitis, piles, wounds, ulcers, vomiting and biliousness (Hui et al, 2013;Chang et al, 2014) Volatile oil, flavonoids, flavone glycosides, gallic acid, saponins and tannins (Chang et al, 2014) Plantago lanceolata L., Plantaginaceae Febrifuge, demulcent, treat diarrhea, dysentery, piles, constipation, whooping cough, bronchitis, neck rashes, sores, boils, blisters, jaundice and inflammation (Singh and Kumar, 2000;Prajapati et al, 2003;Kayani et al, 2014;Rana and Masoodi, 2014;Abbasi et al, 2015) Iridoid glucoside aucubin, phenylpropanoid glycoside verbascoside and tannins (Stewart, 1996).…”