A Standardized Lindera obtusiloba Extract Improves Endothelial Dysfunction and Attenuates Plaque Development in Hyperlipidemic ApoE-Knockout Mice.

Lindera obtusiloba extract (LOE), a traditional herbal medicine used to enhance blood circulation and to reduce inflammation, induced NO-mediated endothelium-dependent relaxation, and reduced the formation of reactive oxygen species (ROS). The study investigated whether LOE improves endothelial dysfunction and reduces plaque inflammation and progression by inhibiting ROS generation in a mouse model of atherosclerosis. Eight-week-old apolipoprotein E-deficient (apoE-/-) mice fed with a western diet (WD) were randomized into different groups by administering vehicle (0.5% carboxymethylcellulose (CMC)), LOE (100 mg/kg/day), or losartan (30 mg/kg/day) by gavage until the age of 28 weeks. Fourteen male C57BL/6 mice that were fed normal chow and treated with CMC were used as negative controls. Similar to losartan treatment, LOE treatment induced the concentration-dependent relaxation of aorta rings in WD-fed apoE-/- mice. LOE treatment significantly reduced the vascular ROS formation and expression of NADPH oxidase subunits, including p22phox and p47phox. Compared with WD-fed apoE-/- mice, mice exposed to chronic LOE treatment exhibited reductions in plaque inflammation-related fluorescence signals and atherosclerotic lesions. These effects were greater than those of losartan treatment. In conclusion, LOE treatment improves endothelial dysfunction and reduces plaque inflammation as well as lesion areas by reducing vascular NADPH oxidase-induced ROS generation in a mouse model of atherosclerosis.

Vasorelaxant Effect of Boesenbergia rotunda and Its Active Ingredients on an Isolated Coronary Artery.

Cardiovascular diseases are a major cause of death in developed countries. The regulation of vascular tone is a major approach to prevent and ameliorate vascular diseases. As part of our ongoing screening for cardioprotective natural compounds, we investigated the vasorelaxant effect of rhizomes from Boesenbergia rotunda (L.) Mansf. [Boesenbergia pandurata (Roxb.) Schltr.] used as a spice and herbal medicine in Asian countries. The methanol extract of B. rotunda rhizomes (BRE) exhibited significant vasorelaxation effects ex vivo at EC50 values of 13.4 ± 6.1 µg/mL and 40.9 ± 7.9 µg/mL, respectively, with and without endothelium in the porcine coronary artery ring. The intrinsic mechanism was evaluated by treating with specific inhibitors or activators that typically affect vascular reactivity. The results suggested that BRE induced relaxation in the coronary artery rings via an endothelium-dependent pathway involving NO-cGMP, and also via an endothelium-independent pathway involving the blockade of Ca2+ channels. Vasorelaxant principles in BRE were identified by subsequent chromatographic methods, which revealed that flavonoids regulate vasorelaxant activity in BRE. One of the flavonoids was a Diels-Alder type adduct, 4-hydroxypanduratin A, which showed the most potent vasorelaxant effect on porcine coronary artery with an EC50 of 17.8 ± 2.5 µM. Our results suggest that rhizomes of B. rotunda might be of interest as herbal medicine against cardiovascular diseases.

Endothelium-Dependent Relaxation Effects of Actinidia arguta Extracts in Coronary Artery: Involvement of eNOS/Akt Pathway.

Cardiovascular diseases (CVD) are the major cause of death globally. Bioavailability of nitric oxide, antioxidative activity, and regulation of ionic homeostasis are the key targets for prevention of CVD. Actinidia arguta (AA) has shown promising effect for anticancer, anti-hypercholesterolemia, and antioxidant agents. However, the vascular effect of AA remains unclear. Therefore, we investigated the vascular relaxation of AA extract as well as the underlying mechanisms. Vascular reactivity was assessed in organ baths using porcine coronary arteries and antioxidant properties were assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH). Methanol extract of AA stem (AASE) induced significantly vasorelaxation of porcine coronary artery and its effects is endothelium-dependent without cytotoxicity effects. In addition, ASSE scavenged reactive oxygen species (ROS) in vitro and strongly inhibited NADPH-oxidase activity, which is major source of ROS in vasculature. AASE strongly and dose-dependently activate endothelial nitric oxide synthase (eNOS), the major vascular protective enzyme, and Akt, the upstream signaling protein of eNOS, in porcine coronary artery endothelial cell. Altogether, these results have demonstrated that AASE is a potent endotheliumdependent vasodilator and this effect was involved in, at least in part, Akt/eNOS/NO pathway with strong anti-oxidant properties. The present findings indicate that AA stem could be a valuable candidate of herbal medicine for cardiovascular diseases associated with endothelial dysfunction and atherosclerosis.

Citrus junos Fruit Extract Facilitates Anti-Adipogenic Activity of Garcinia cambogia Extract in 3T3-L1 Adipocytes by Reducing Oxidative Stress.

Obesity is a metabolic disorder associated with chronic oxidative stress and inflammation. Recruitment of inflammatory cells to adipose tissue and subsequent production of a large amount of reactive oxygen species (ROS) facilitates adipocyte differentiation and promotes lipid accumulation. The removal of ROS with anti-oxidants appeared an effective strategy against lipid accumulation. Here, we chose Citrus junos, a good dietary source of anti-oxidants and tested the anti-adipogenic potential of Citrus junos extract (CE). CE effectively suppressed the ROS production and lipid accumulation in H2O2-stimulated 3T3-L1 cells. CE also inhibited the expression of CEBP-α and PPAR-γ, the transcription regulators of adipocyte differentiation. These data suggest that CE might suppress the adipocyte differentiation through ROS scavenging action. Also, CE and Garcinia cambogia extract (GE) appeared act additively in reducing ROS and in inhibiting lipid accumulation. It implied a potential usefulness of this combination in the management of obesity related disorders.

The Vasorelaxatory Effect of Nelumbo nucifera Spornioderm on Porcine Coronary Artery.

Endothelium dysfunction is a hallmark of cardiovascular disease (CVD) and is characterized by loss of homeostasis. Nitric oxide deprivation, unbalanced production of vasoactive factors such as thromboxane, endothelium-derived hyperpolarizing factor (EDHF) and production of reactive oxygen species are known as early indicators of CVD. Bioavailability of nitric oxide, antioxidative activity, and regulation of ionic homeostasis are the key targets for prevention of CVD. In this study, we investigated the vasorelaxant action of Nelumbo nucifera extract as well as the underlying mechanism using porcine coronary artery. Vasorelaxant effect of extracts from four different parts of Nelumbo nucifera (flower, leaf, seed, and spornioderm) was tested. Among them, extracts from Nelumbo nucifera spornioderm (NNS) showed the strongest endothelium-dependent vasorelaxation. Vasorelaxation effect of NNS was markedly reduced by inhibitor of endothelial nitric oxide synthase (eNOS), inhibitor of Phosphoinositide 3 kinase (PI3K) and inhibitor of soluble guanylyl cyclase (sGC), but unaffected by inhibitor of cyclooxygenase and EDHF. NNS induced concentration-dependent phosphorylation of eNOS in endothelial cells. Altogether, our study demonstrated that NNS is a potent endothelium-dependent vasodilator, mediated by PI3K-eNOS-sGC pathway. Our present findings showed NNS as a potential herbal candidate for the therapy of cardiovascular diseases associated with endothelial dysfunction and atherosclerosis.

Vascular Protection by Ethanol Extract of Morus alba Root Bark: Endothelium-Dependent Relaxation of Rat Aorta and Decrease of Smooth Muscle Cell Migration and Proliferation.

Morus alba (white mulberry) is native to the northern part of Korea and popularly used as a traditional medicine due to its numerous health benefits against human's disease. However, the possibility that M. alba may also affect the cardiovascular system remains unexplored. This study sought to investigate the vascular protective effects of the root bark extract of M. alba (MAE). Vascular reactivity was performed in organ baths using isolated rat thoracic aorta, while platelet derived growth factor (PDGF) induced proliferation and migration of vascular smooth muscle cells (VSMCs) were studied by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) and wound healing assay, respectively. MAE evoked a concentration dependent vasorelaxation following endothelium-dependent pathway. However, vessel relaxations in response to MAE were markedly reduced after endothelium removal; treatment of endothelial nitric oxide synthase inhibitor, guanylyl cyclase inhibitor, and nonspecific potassium channel inhibitor, however, was not altered by cyclooxygenase inhibitor. Furthermore, MAE also significantly blunted contractile response to vasoconstrictor agent, phenylephrine. Taken together, the current evidence revealed that MAE is a potent endothelium-dependent vasodilator and this effect was involved in, at least in part, nitric oxide cyclic-guanosine monophosphate (NO-cGMP) pathway in combination with potassium (K+) channel activation. Moreover, MAE inhibited proliferation and migration of VSMCs induced by PDGF. Therefore, MAE could be a promising candidate of natural medicine for preventing and controlling cardiovascular diseases linked with endothelial dysfunction.

Potential mechanisms underlying cardiovascular protection by polyphenols: Role of the endothelium.

Epidemiological studies have indicated that regular intake of polyphenol-rich diets such as red wine and tea, are associated with a reduced risk of cardiovascular diseases. The beneficial effect of polyphenol-rich products has been attributable, at least in part, to their direct action on the endothelial function. Indeed, polyphenols from tea, grapes, cacao, berries, and plants have been shown to activate endothelial cells to increase the formation of potent vasoprotective factors including nitric oxide (NO) and to delay endothelial ageing. Moreover, intake of such polyphenol-rich products has been associated with the prevention and/or the improvement of an established endothelial dysfunction in several experimental models of cardiovascular diseases and in Humans with cardiovascular diseases. This review will discuss both experimental and clinical evidences indicating that polyphenols are able to promote endothelial and vascular health, as well as the underlying mechanisms.

Melatonin supplementation plus exercise behavior ameliorate insulin resistance, hypertension and fatigue in a rat model of type 2 diabetes mellitus.

INTRODUCTION: The objective was to investigate the effects of melatonin and exercise on insulin resistance (IR), hypertension and fatigue syndrome in a rat model of type 2 diabetes mellitus (T2DM). MATERIALS AND METHODS: Rats were divided into 5 groups namely normal control (NC), T2DM control group (DC), diabetes plus exercise (DE), diabetes plus oral melatonin supplement (DM) and diabetes plus melatonin and exercise (DME) groups. Melatonin was administered orally 5mg/kg twice daily and 40min swimming/day 5days/week were regimented after diabetes induction. RESULTS: Blood pressure, fasting blood glucose, insulin, IR, serum leptin, lipid profiles, inflammatory cytokines, lipid peroxidation increased significantly (P<0.01) while serum adiponectin, antioxidant activities (superoxide dismutase, glutathione), exercise performance significantly decreased (P<0.001) in the DC group compared with the control group. Combined effects of exercise and melatonin ameliorated markedly hypertension, IR, biochemical alteration induced by diabetes and significantly increased exercise performance (P<0.01). The expression glucose transporter type 4 (GLUT4) mitochondrial biogenesis related proteins such as peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1 α), nuclear respiratory factor (NRFs) and mitochondrial transcription factor-A were up-regulated skeletal and cardiac muscle in the DME group. CONCLUSION: Melatonin supplementation in combination with exercise behavior may ameliorate IR, hypertension and exercise performance or fatigue possibly by improving antioxidative activities, hyperlipidemia, inflammatory cytokines via up-regulation of GLUT4, PGC-1 α and mitochondrial biogenesis in T2DM rats.

Rice Bran Extract Inhibits TMEM16A-Involved Activity in the Neonatal Rat Cochlea.

TMEM16A is a Ca²âº-activated Cl⁻ channel found in secretory glands, GI and respiratory tracts, and sensory organs, playing a major physiological role in fluid secretion, autonomous GI motility, and sensory transduction. In addition, overexpression of TMEM16A has been associated with cancer cell proliferation and invasion. Suppression of upregulated TMEM16A has been proposed as an effective anti-cancer strategy. While searching for a potential TMEM16A inhibitor, components of rice bran attracted our attention due to their anti-cancer potential in colon cancer cells, a type of cells known to overexpressing TMEM16A. Here, it was tested whether rice bran extract exhibits anti-TMEM16A activity. Rice bran extract was tested in the neonatal rat cochlear tissues where TMEM16A-involved spontaneous activity is generated as a part of normal development of the auditory pathway. Rice bran extract readily inhibited the TMEM16A-involved activity in the cochlear tissues and the effect was reversible upon washout. Taken together, rice bran extract appears to contain a putative TMEM16A inhibitor and the rice byproduct might serve as a source of a new anti-cancer agent.

Cacao Polyphenols Potentiate Anti-Platelet Effect of Endothelial Cells and Ameliorate Hypercoagulatory States Associated with Hypercholesterolemia.

Platelets are related to the formation of blood clots that play a crucial role in thrombosis and other cardiovascular diseases. Cocoa, derived from Theobroma cocoa, has been widely used as functional food for improving cardiovascular health. In the present study, the direct and indirect effects of cacao polyphenols (CPs) were investigated on human platelet aggregation associated with endothelial cells (ECs) senescence. In addition, the effect of CPs on high-fat diet- (HFD-) induced hypercoagulatory states in rats was evaluated. CPs directly inhibited the human platelet aggregation induced by thromboxane analogue, U46619, and treatment of CPs on senescent endothelial cells markedly restored inhibitory effect of ECs on platelet aggregation. Nitric oxide (NO) from ECs is known as modulator of platelet aggregation and CPs increased eNOS activity in ECs and coronary artery. In animal model, increased TG level induced by high fat diet (HFD) was significantly decreased by CPs administration. In addition, the HFD animal had shorter bleeding time, and CPs administration attenuated the HFD-induced changes. Taken together, the present study indicates that CPs have potent anti-platelet effects most likely by direct and indirect effect via ECs and have the potential for lowering the risk of cardiovascular disease-related hypercoagulation due to hypercholesterolemia.

The Effect of Quercus salicina Leaf Extracts on Vascular Endothelial Function: Role of Nitric Oxide.

Dysfunction of the vascular endothelium is reported as a hallmark of cardiovascular diseases. Many evidences suggest that polyphenols are associated with a decreased global mortality and might be involved in protection against cardiovascular risk. This beneficial effect of polyphenol may be due to many actions as antioxidant that increases bioavailability of nitric oxide, vasodilation or anti-hypertensive properties. To identify new natural medicine candidate for cardiovascular protection, plant extracts used in traditional medicine were evaluated by vascular reactivity system. Porcine coronary artery rings were suspended in organ chambers for the measurement of changes in isometric tension. Screening results indicated that the ethanolic extract of leaf from Quercus salicina (QSE) has been found to exhibit potent vasorelaxant activity. QSE dose-dependently induced endothelium-dependent relaxations, which were abolished by inhibitors of nitric oxide synthase (Nomega-nitro-L-arginine). In addition, QSE strongly and dose-dependently activate endothelial nitric oxide synthase (eNOS) in porcine coronary artery endothelial cell. Taken together, the present study has demonstrated that QSE is a powerful endothelium-dependentvasodilator and that this effect involves increased nitric oxide bioavailability. In conclusion, QSE could be a cardiovascular protective herbal medicine candidate associated with cardiovascular diseases and endothelial dysfunction.

Protective Effect of Salicornia europaea Extracts on High Salt Intake-Induced Vascular Dysfunction and Hypertension.

High salt intake causes and aggravates arterial hypertension and vascular dysfunction. We investigated the effect of Salicornia europaea extracts (SE) on vascular function and blood pressure. SE constituents were analyzed using high performance liquid chromatography, and SE's effect on vascular function was evaluated in isolated porcine coronary arteries. SE's vascular protective effect was also evaluated in vivo using normotensive and spontaneous hypertensive rats (SHRs). SE mainly contained sodium chloride (55.6%), 5-(hydroxymethyl)furfural, p-coumaric acid, and trans-ferulic acid. High sodium (160 mmol/L) induced vascular dysfunction; however, SE containing the same quantity of sodium did not cause vascular dysfunction. Among the compounds in SE, trans-ferulic acid accounts for the vascular protective effect. Normotensive rats fed a high-salt diet showed significantly increased systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP), which decreased significantly in the SE-treated groups. In SHRs, high edible salt intake significantly increased SBP, DBP, and MAP, but SE intake was associated with a significantly lower MAP. Thus, SE did not induce vascular dysfunction, and trans-ferulic acid might be at least partly responsible for the vasoprotective effect of SE. Taken together, SE could be used as an alternative to purified salt to prevent and ameliorate hypertension.

Antiatherogenic Effect of Camellia japonica Fruit Extract in High Fat Diet-Fed Rats.

Hypercholesterolemia is a well-known etiological factor for cardiovascular disease and a common symptom of most types of metabolic disorders. Camellia japonica is a traditional garden plant, and its flower and seed have been used as a base oil of traditional cosmetics in East Asia. The present study was carried out to evaluate the effect of C. japonica fruit extracts (CJF) in a high fat diet- (HFD-) induced hypercholesterolemic rat model. CJF was administered orally at three different doses: 100, 400, and 800 mg·kg(-1)·day(-1) (CJF 100, 400, and 800, resp.). Our results showed that CJF possessed strong cholesterol-lowering potency as indicated by the decrease in serum total cholesterol (TC), triglyceride (TG), and low-density lipoprotein (LDL), accompanied by an increase in serum high-density lipoprotein (HDL). Furthermore, CJF reduced serum lipid peroxidation by suppressing the formation of thiobarbituric acid reactive substance. In addition, oil red O (ORO) staining of rat arteries showed decreased lipid-positive staining in the CJF-treated groups compared to the control HFD group. Taken together, these results suggest that CJF could be a potent herbal therapeutic option and source of a functional food for the prevention and treatment of atherosclerosis and other diseases associated with hypercholesterolemia.

Vascular Protective Effect of an Ethanol Extract of Camellia japonica Fruit: Endothelium-Dependent Relaxation of Coronary Artery and Reduction of Smooth Muscle Cell Migration.

Camellia japonica is a popular garden plant in Asia and widely used as cosmetic sources and traditional medicine. However, the possibility that C. japonica affects cardiovascular system remains unclear. The aim of the present study was to evaluate vascular effects of an extract of C. japonica. Vascular reactivity was assessed in organ baths using porcine coronary arteries and inhibition of proliferation and migration were assessed using human vascular smooth muscle cells (VSMCs). All four different parts, leaf, stem, flower, and fruits, caused concentration-dependent relaxations and C. japonica fruit (CJF) extract showed the strongest vasorelaxation and its effect was endothelium dependent. Relaxations to CJF were markedly reduced by inhibitor of endothelial nitric oxide synthase (eNOS) and inhibitor of PI3-kinase, but not affected by inhibitor of cyclooxygenase and endothelium-derived hyperpolarizing factor-mediated response. CJF induced activated a time- and concentration-dependent phosphorylation of eNOS in endothelial cells. Altogether, these studies have demonstrated that CJF is a potent endothelium-dependent vasodilator and this effect was involved in, at least in part, PI3K-eNOS-NO pathway. Moreover, CJF attenuated TNF-α induced proliferation and PDGF-BB induced migration of VSMCs. The present findings indicate that CJF could be a valuable candidate of herbal medicine for cardiovascular diseases associated with endothelial dysfunction and atherosclerosis.

An ethanolic extract of Lindera obtusiloba stems, YJP-14, improves endothelial dysfunction, metabolic parameters and physical performance in diabetic db/db mice.

Lindera obtusiloba is a medicinal herb traditionally used in Asia for improvement of blood circulation, treatment of inflammation, and prevention of liver damage. A previous study has shown that an ethanolic extract of Lindera obtusiloba stems (LOE) has vasoprotective and antihypertensive effects. The possibility that Lindera obtusiloba improves endothelial function and metabolic parameters in type 2 diabetes mellitus (T2DM) remains to be examined. Therefore, the aim of the present study was to determine the potential of LOE to prevent the development of an endothelial dysfunction, and improve metabolic parameters including hyperglycemia, albuminuria and physical exercise capacity in db/db mice, an experimental model of T2DM. The effect of LOE (100 mg/kg/day by gavage for 8 weeks) on these parameters was compared to that of an oral antidiabetic drug, pioglitazone (30 mg/kg/day by gavage). Reduced blood glucose level, body weight and albumin-creatinine ratio were observed in the group receiving LOE compared to the control db/db group. The LOE treatment improved endothelium-dependent relaxations, abolished endothelium-dependent contractions to acetylcholine in the aorta, and normalized the increased vascular oxidative stress and expression of NADPH oxidase, cyclooxygenases, angiotensin II, angiotensin type 1 receptors and peroxynitrite and the decreased expression of endothelial NO synthase in db/db mice. The angiotensin-converting enzyme (ACE) activity was reduced in the LOE group compared to that in the control db/db group. LOE also inhibited the activity of purified ACE, COX-1 and COX-2 in a dose-dependent manner. In addition, LOE improved physical exercise capacity. Thus, the present findings indicate that LOE has a beneficial effect on the vascular system in db/db mice by improving endothelium-dependent relaxations and vascular oxidative stress most likely by normalizing the angiotensin system, and also on metabolic parameters, and these effects are associated with an enhanced physical exercise capacity.

Vasorelaxant prenylated flavonoids from the roots of Sophora flavescens.

Bioassay-guided fractionation of the methanol extract from the root of Sophora flavescens led to the isolation of eight known prenylated flavonoids responsible for the vasorelaxation activity in porcine coronary arteries. Among them, kushenol N and 5-methylsophoraflavanone B strongly induced the relaxation of porcine coronary arteries with respective ED(50) values of 8.6 and 12.4 µM. This activity and the results of a high-performance liquid chromatographic analysis suggest that kushenol N and 5-methylsophoraflavanone B could be active markers in the S. flavescens extract for vasorelaxation activity.

Decaffeinated green tea extract improves hypertension and insulin resistance in a rat model of metabolic syndrome.

BACKGROUND: Oxidative stress and endothelial dysfunction are closely associated with hypertension and insulin resistance (IR) in metabolic syndrome (MetS). It is still controversial whether green tea extract (GTE) may have blood pressure (BP) lowering effect. Decaffeinated GTE might be presumed to have strong antioxidative effect and BP-lowering effect as compared with catechins. Thus we investigated whether decaffeinated-GTE could attenuate hypertension and IR by improving endothelial dysfunction and reducing oxidative stress in a rat model of MetS. METHODS AND RESULTS: 20 Otsuka Long-Evans Tokushima Fatty (OLETF) rats at 13 weeks old, MetS rats, were randomized into a saline treated group (OLETF; n = 10) and a group treated with decaffeinated-GTE (25 mg/kg/day) (GTE-OLETF; n = 10). Intraperitoneal glucose tolerance tests and BP measurements were performed at 13 and 25 weeks. Decaffeinated-GTE significantly reduced BP (OLETF vs. GTE-OLETF; 130 ± 7 vs. 121 ± 3 mmHg, p = 0.01), fasting/postprandial 2 h glucose (141 ± 18/159 ± 13 vs. 115 ± 7/132 ± 16 mg/dL, p = 0.009/0.002) and insulin levels (4.8 ± 2.3 vs. 2.4 ± 1.3 ng/mL, p < 0.001). Decaffeinated-GTE significantly reduced vascular reactive oxygen species (ROS) formation and NADPH oxidase activity, and improved endothelium dependent relaxation in the thoracic aorta of OLETF rats. Decaffeinated-GTE also suppressed the expression of p47 and p22phox (NADPH oxidase subunits) in the immunohistochemical staining, and stimulated phosphorylation of endothelial nitric oxide synthase (eNOS) and Akt in the immunoblotting of aortas. CONCLUSIONS: Decaffeinated-GTE reduced the formation of ROS and NADPH oxidase activity and stimulated phosphorylation of eNOS and Akt in the aorta of a rat model of MetS, which resulted in improved endothelial dysfunction and IR, and eventually lowered BP.

An ethanolic extract of Lindera obtusiloba stems causes NO-mediated endothelium-dependent relaxations in rat aortic rings and prevents angiotensin II-induced hypertension and endothelial dysfunction in rats.

Lindera obtusiloba is a medical herb traditionally used in Asia for the improvement of blood circulation, treatment of inflammation, and prevention of liver damage. The possibility that L. obtusiloba affects vascular reactivity remains to be examined. Therefore, the aim of the present study was to evaluate both the in vitro and in vivo vascular effects of an ethanolic extract of L. obtusiloba stems (LOE). Vascular reactivity was assessed in organ chambers using rat aortic rings and the activation of endothelial NO synthase (eNOS) in cultured bovine aortic endothelial cells. LOE induced endothelium-dependent relaxations, which were abolished by inhibitors of nitric oxide synthase (N (ω)-nitro-L: -arginine) and guanylyl cyclase (1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-L-one), significantly reduced by inhibitors of PI3 kinase (wortmannin and LY294002), and not affected by inhibitors of cyclooxygenase (indomethacin) and endothelium-derived hyperpolarizing factor-mediated responses (charybdotoxin plus apamin). LOE prevented contractile responses to phenylephrine and angiotensin II in rings with endothelium, but not in those without endothelium. LOE caused a concentration-dependent phosphorylation of Akt at Serine473 and eNOS at Serine1177 in endothelial cells. Thereafter, the vasoprotective effect of LOE was investigated in an experimental model of hypertension in rats. Intake of LOE prevented the angiotensin II-induced increase in systolic blood pressure, and endothelial dysfunction to acetylcholine and oxidative stress as assessed using dihydroethidine in aortic rings. The present findings indicate that LOE has vasoprotective and antihypertensive properties most likely by stimulating the endothelial formation of NO and inhibiting oxidative stress.

Lysimachia clethroides extract promote vascular relaxation via endothelium-dependent mechanism.

Lysimachia clethroides is widely used in traditional herbal medicine for many purposes, especially for blood vessel-related diseases in Korea and East Asia. Experiments were undertaken to determine whether hydro-alcoholic extract obtained from L. clethroides (LCE) has vasorelaxant activity in the rat aorta rings and, if so, to elucidate the underlying mechanism. Rat aorta rings were suspended in organ chambers for the measurement of changes in isometric tension in the presence or absence of several inhibitors. LCE induced endothelium-dependent vasodilation (ED50 = 6.1 mug/mL) and that was abolished by nitric oxide synthase inhibitor, N-nitro-L-arginine, and guanylyl cyclase inhibitor, 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one, PI3-kinase inhibitor, wortmannin, and cell permeable superoxide dismutase. In addition, LCE decreased vessels contraction by phenylephrine. Prostaglandin synthesis inhibitor, indometacin, and inhibitors of endothelium-derived hyperpolarizing factor, charybdotoxin plus apamin, did not affect vasodilatory effect of LCE. In cultured endothelial cells, LCE-induced phosphorylation of serine 1177-endothelial nitric oxide synthase and serine 473-Akt. LCE inhibited strongly nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity in smooth muscle cells and angiotensin II-induced contraction of rat aorta. Finally, increased oxidative stress in rat aorta-induced by angiotensin II is ameliorated by LCE. Taken together, LCE induces an endothelium-dependent vasodilation and might be involved, at least in part, the activation of the nitric oxide-cyclic guanosine monophosphate pathway. In addition, LCE decreases oxidative stress in aorta by inhibition of NADPH oxidase activity. The present findings indicate that LCE could be a candidate of herbal medicine for cardiovascular diseases associated with disturbed NO production and endothelial dysfunction.

Cocoa procyanidins inhibit expression and activation of MMP-2 in vascular smooth muscle cells by direct inhibition of MEK and MT1-MMP activities.

AIMS: Expression and activation of matrix metalloproteinase (MMP)-2 play pivotal roles in the migration and invasion of human aortic vascular smooth muscle cells (VSMC) originating from normal human tissue, which is strongly linked to atherosclerosis. The present study investigated the possible inhibitory effects of cocoa procyanidin on thrombin-induced expression and activation of MMP-2 in VSMC. METHODS AND RESULTS: Cocoa procyanidin fraction (CPF) and procyanidin B2, one of major procyanidins in cocoa (3 microg/mL and 5 microM, respectively), strongly inhibited thrombin-induced activation and expression of pro-MMP-2 in VSMC, as determined by zymography. The thrombin-induced invasion and migration of VSMC were inhibited by CPF or procyanidin B2 (P < 0.05), as assessed by a modified Boyden chamber and wound healing assays, respectively. An enzymatic assay data demonstrated that CPF and procyanidin B2 directly inhibited membrane type-1 (MT1)-MMP activity (P < 0.05), and this inhibition of CPF was greater than those of red wine polyphenols. Western blot data showed that CPF and procyanidin B2 inhibited thrombin-induced phosphorylation of extracellular signal-regulated protein kinase but not mitogen-activated protein kinase kinase (MEK) in VSMC. Kinase and pull-down data revealed that CPF and procyanidin B2 inhibited MEK1 activity and directly bound with glutathione-S-transferase-MEK1. In addition, the thrombin-induced invasion and migration and the activation and expression of pro-MMP-2 in VSMC were attenuated by U0126 (a well-known inhibitor of MEK1). CONCLUSION: Cocoa procyanidins are potent inhibitors of MEK and MT1-MMP, and subsequently inhibit the expression and activation of pro-MMP-2, and also the invasion and migration of VSMC, which may in part explain the molecular action of antiatherosclerotic effects of cocoa.