Current insights and future perspectives of flavonoids: A promising antihypertensive approach.

Hypertension, or high blood pressure (BP), is a complex disease influenced by various risk factors. It is characterized by persistent elevation of BP levels, typically exceeding 140/90 mmHg. Endothelial dysfunction and reduced nitric oxide (NO) bioavailability play crucial roles in hypertension development. L-NG-nitro arginine methyl ester (L-NAME), an analog of L-arginine, inhibits endothelial NO synthase (eNOS) enzymes, leading to decreased NO production and increased BP. Animal models exposed to L-NAME manifest hypertension, making it a useful design for studying the hypertension condition. Natural products have gained interest as alternative approaches for managing hypertension. Flavonoids, abundant in fruits, vegetables, and other plant sources, have potential cardiovascular benefits, including antihypertensive effects. Flavonoids have been extensively studied in cell cultures, animal models, and, to lesser extent, in human trials to evaluate their effectiveness against L-NAME-induced hypertension. This comprehensive review summarizes the antihypertensive activity of specific flavonoids, including quercetin, luteolin, rutin, troxerutin, apigenin, and chrysin, in L-NAME-induced hypertension models. Flavonoids possess antioxidant properties that mitigate oxidative stress, a major contributor to endothelial dysfunction and hypertension. They enhance endothelial function by promoting NO bioavailability, vasodilation, and the preservation of vascular homeostasis. Flavonoids also modulate vasoactive factors involved in BP regulation, such as angiotensin-converting enzyme (ACE) and endothelin-1. Moreover, they exhibit anti-inflammatory effects, attenuating inflammation-mediated hypertension. This review provides compelling evidence for the antihypertensive potential of flavonoids against L-NAME-induced hypertension. Their multifaceted mechanisms of action suggest their ability to target multiple pathways involved in hypertension development. Nonetheless, the reviewed studies contribute to the evidence supporting the useful of flavonoids for hypertension prevention and treatment. In conclusion, flavonoids represent a promising class of natural compounds for combating hypertension. This comprehensive review serves as a valuable resource summarizing the current knowledge on the antihypertensive effects of specific flavonoids, facilitating further investigation and guiding the development of novel therapeutic strategies for hypertension management.

Evaluation and estimation of diuretic activity of the linalyl acetate in the rats.

This study aimed to explore the diuretic activity of linalyl acetate (LA). LA is an essential oil, it is an integral phyto-constituent of various plants. In this study, acute and chronic diuretic activities were explored by measuring the levels of different electrolytes and pH in the urine of experimental rats. Rats were divided into five groups. The control group was given 10 mg/kg normal saline, the treated group was given 10 mg/kg furosemide, and the remaining 3 groups received different doses of LA including 25, 50, and 75 mg/kg through intraperitoneal route, to determine its diuretic potential. Urine volume for acute diuretic activity was measured for 6 hours however for chronic diuretic activity was measured for 6 days. For a comparative study of LA with a control group and treated group with reference drug, diuretic index was used. Moreover, the underlying mechanism of the diuretic activity was also explored by comparing atropine, L-NAME, and indomethacin. The results of each group with 6 rats in each group were obtained by ± standard error of the mean of every group. Analysis of Variance (ANOVA) was used for statistical analysis. Results revealed that the LA 75 mg/kg dose showed comparable results as of furosemide. Moreover, this study revealed the involvement of muscarinic receptors to produce diuresis in comparison with atropine with very little involvement of prostanoids and no effect on NO pathway induced by indomethacin and L-NAME respectively. It is concluded that LA possess anti-diuretic potential. Muscarinic receptors might be involved in producing diuretic effects.

Protective Effects of Aspirin Supplemented With Quercetin in L-NAME-Induced Preeclampsia-Like Rats.

Aspirin supplemented with quercetin was reported to enhance the therapeutic effects of aspirin in a rat model of preeclampsia. In this study, the underlying mechanisms were further explored. Preeclampsia was induced by L-NAME (50 mg/kg/day) via oral gavage from gestation day (GD)14 to GD19. Aspirin (1.5 mg/kg/day) administration was performed using aspirin mixed with rodent dough from GD0 to GD19. The administration of quercetin (2 mg/kg/day) was performed by intraperitoneal infusion from GD0 to GD19. Protein levels were evaluated using ELISA or Western blot, and microRNA (miRNA) level was evaluated by RT-PCR. Aspirin supplemented with quercetin ameliorated the increase of systolic blood pressure (SBP), proteinuria, tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) levels, and improved the pregnancy outcomes in preeclampsia rats. Aspirin supplemented with quercetin inhibited miR-155 expression in preeclampsia rats. The decreased miR-155 level in placenta further increased the protein level of SOCS1 and inhibited the phosphorylation of p65. In this study, we demonstrated that aspirin supplemented with quercetin enhanced the effects of aspirin for the treatment of preeclampsia.

Vasorelaxant effects of ellagitannins isolated from Cuphea carthagenensis.

Cuphea carthagenensis (Jacq.) J. F. Macbr. is a popular plant in Brazilian folk medicine owing to its hypotensive and central nervous system depressant effects. This study aimed to validate the hypotensive effect of the plant's aqueous extract (AE) in rats and examine the vascular actions of three hydrolyzable tannins, oenothein B, woodfordin C, and eucalbanin B, isolated from AE. Systolic blood pressure in unanesthetized rats was determined using the non-invasive tail-cuff method. Oral treatment of normotensive rats with 0.5 and 1.0 g/kg/day AE induced a dose-related hypotensive effect after 1 week. In rat aortic rings pre-contracted with noradrenaline, all ellagitannins (20 - 180 µM) induced a concentration-related vasorelaxation. This effect was blocked by either removing the endothelium or pre-incubating with NG-nitro-l-arginine methyl ester (10 µM), an inhibitor of nitric oxide (NO) synthase. In KCl-depolarized rat portal vein preparations, the investigated compounds did not affect significantly the maximal contractile responses and pD2 values of the concentration-response curves to CaCl2. Our results demonstrated the hypotensive effect of C. carthagenensis AE in unanesthetized rats. All isolated ellagitannins induced vasorelaxation in vitro via activating NO synthesis/NO release from endothelial cells, without altering the Ca2+ influx in vascular smooth muscle preparations. Considering the low oral bioavailability of ellagitannins, the determined in vitro actions of these compounds are unlikely to account for the hypotensive effect of AE in vivo. It remains to be determined the role of the bioactive ellagitannin-derived metabolites in the hypotensive effect observed after oral treatment of unanesthetized rats with the plant extract.

Potential Antihypertensive Activity of the Aqueous Extract of Ammi visnaga and its Effect on ACE-2 in Rats.

AIMS: This work aimed to investigate the antihypertensive activity of Ammi visnaga. BACKGROUND: The aqueous extract of Ammi visnaga has traditionally been used to treat hypertension in Morocco. OBJECTIVE: The objective of this investigation was to evaluate the effect of Ammi visnaga aqueous extract (AVAE) on arterial blood pressure, systolic blood pressure (SBP), mean blood pressure (MBP), diastolic blood pressure (DBP), and heart rate (HR) in normotensive and hypertensive rats. In addition, the effect of the aqueous extract of Ammi visnaga on vasodilatation was assessed in isolated rat aortic rings with functional endothelium pre-contracted with epinephrine EP or KCl. METHODS: AVAE was obtained, and its antihypertensive ability was pharmacologically investigated in L-NAME hypertensive and normotensive rats. The rats received oral AVAE at two selected doses of 70 and 140 mg/kg for six hours (acute experiment) and seven days (sub-chronic). Thereafter, systolic, diastolic, mean arterial blood pressure and heart rate were evaluated. Moreover, the vasorelaxant activity of AESA was performed in thoracic aortic ring rats. In addition, the mechanisms of action involved in the vasorelaxant effect were studied. RESULTS: AVAE lowered blood pressure only in L-Name-induced hypertensive rats. Furthermore, AVAE (0.375-1.375 mg/ml) showed a vasodilator effect in isolated aortic rats. In addition, not all of the medications used in our study were responsible for the signaling pathway. As a result, additional pharmaceuticals are required to confirm the mechanism of this signaling pathway. CONCLUSION: The aqueous extract of Ammi visnaga exerts an interesting antihypertensive activity, which could be mediated through its vasorelaxant activity. The study supports its use as a medicinal plant against hypertension in Morocco.

Correlational Study of Aminopeptidase Activities between Left or Right Frontal Cortex versus the Hypothalamus, Pituitary, Adrenal Axis of Spontaneously Hypertensive Rats Treated with Hypotensive or Hypertensive Agents.

It has been suggested that the neuro-visceral integration works asymmetrically and that this asymmetry is dynamic and modifiable by physio-pathological influences. Aminopeptidases of the renin-angiotensin system (angiotensinases) have been shown to be modifiable under such conditions. This article analyzes the interactions of these angiotensinases between the left or right frontal cortex (FC) and the same enzymes in the hypothalamus (HT), pituitary (PT), adrenal (AD) axis (HPA) in control spontaneously hypertensive rats (SHR), in SHR treated with a hypotensive agent in the form of captopril (an angiotensin-converting enzyme inhibitor), and in SHR treated with a hypertensive agent in the form of the L-Arginine hypertensive analogue L-NG-Nitroarginine Methyl Ester (L-NAME). In the control SHR, there were significant negative correlations between the right FC with HPA and positive correlations between the left FC and HPA. In the captopril group, the predominance of negative correlations between the right FC and HPA and positive correlations between the HPA and left FC was maintained. In the L-NAME group, a radical change in all types of interactions was observed; particularly, there was an inversion in the predominance of negative correlations between the HPA and left FC. These results indicated a better balance of neuro-visceral interactions after captopril treatment and an increase in these interactions in the hypertensive animals, especially in those treated with L-NAME.

Assessment of In Vitro Airway Smooth Muscle Relaxant Activity of Rhus coriaria L. Fruit Ethanolic Extract and Its Possible Mechanisms.

Rhus coriaria L. (Anacardiaceae), also known as Sumac, is commonly used as a spice, flavoring agent, and as a traditional medicinal herb. This includes also the traditional use for treating asthma, catarrh, and common colds. The accumulating evidence supports its cardioprotective, antidiabetic, neuroprotective, anticancer, gastroprotective, antibacterial, anti-inflammatory, antiviral, antioxidant, and respiratory effects. However, there are no previous studies that have shown its effects and mechanism in the airway smooth muscle tone, and therefore, the aim of our study was to investigate the in vitro pharmacological action of R. coriaria L. extract (RCE) on the rat isolated tracheal and bronchial preparations by exploring its relaxant activity and mechanism of action. The direct relaxant effect of RCE (0.1-0.7 mg/mL) was tested in the rat bronchi and trachea rings precontracted by carbachol (CCh). In addition, the pretreatment with RCE (1 mg/mL) was tested on the bronchial and tracheal reactivity induced by CCh, potassium chloride (KCl), or CaCl2. In addition, the cyclooxygenase inhibitor indomethacin and the nitric oxide synthase inhibitor N(G)-nitro-l-arginine methyl ester (L-NAME), respectively, were used for exploring the mechanisms of RCE-induced relaxation and reduction of reactivity. Our findings demonstrated that RCE induced a concentration-dependent relaxation and a significant reduction of reactivity, significantly reduced with either indomethacin or L-NAME. In addition, RCE decreased the responsiveness to KCl and affected the extracellular Ca2+-induced contraction in the tissues with added CCh or KCl in Ca2+-free Krebs-Henseleit solution. In summary, we have shown that RCE displayed relaxant activities in the in vitro airway smooth muscles, and the possible mechanisms seems to involve the prostaglandin, nitric oxide, and Ca2+ pathways. Taken together, our findings indicate the potential role of RCE in the treatment of respiratory diseases with limited airflow, or obstructive respiratory diseases, and could justify its traditional use in the respiratory diseases.

Quercetin supplementation attenuates airway hyperreactivity and restores airway relaxation in rat pups exposed to hyperoxia.

Hyperoxia exposure of immature lungs contributes to lung injury and airway hyperreactivity. Up to now, treatments of airway hyperreactivity induced by hyperoxia exposure have been ineffective. The aim of this study was to investigate the effects of quercetin on hyperoxia-induced airway hyperreactivity, impaired relaxation, and lung inflammation. Newborn rats were exposed to hyperoxia (FiO2 > 95%) or ambient air (AA) for seven days. Subgroups were injected with quercetin (10 mg·kg-1·day-1). After exposures, tracheal cylinders were prepared for in vitro wire myography. Contraction to methacholine was measured in the presence or absence of organ bath quercetin and/or Nω-nitro-L-arginine methyl ester (L-NAME). Relaxation responses were evoked in preconstricted tissues using electrical field stimulation (EFS). Lung tumor necrosis factor-alpha (TNF-α) and interleukin-1ß (IL-1ß) levels were measured by enzyme-linked immunosorbent assay (ELISA). A P < 0.05 was considered statistically significant. Contractile responses of tracheal smooth muscle (TSM) of hyperoxic animals were significantly increased compared with AA animals (P < 0.001). Treatment with quercetin significantly reduced contraction in hyperoxic groups compared with hyperoxic control (P < 0.01), but did not have any effect in AA groups. In hyperoxic animals, relaxation of TSM was significantly reduced compared with AA animals (P < 0.001), while supplementation of quercetin restored the lost relaxation in hyperoxic groups. Incubation of preparations in L-NAME significantly reduced the quercetin effects on both contraction and relaxation (P < 0.01). Treatment of hyperoxic animals with quercetin significantly decreased the expression of TNF-α and IL-1ß compared with hyperoxic controls (P < 0.001 and P < 0.01, respectively).The findings of this study demonstrate the protective effect of quercetin on airway hyperreactivity and suggest that quercetin might serve as a novel therapy to prevent and treat neonatal hyperoxia-induced airway hyperreactivity and inflammation.

[Mechanism of Jiming Powder in ameliorating heart failure with preserved ejection fraction based on metabolomics].

In this study, untargeted metabolomics was conducted using the liquid chromatography-tandem mass spectrometry(LC-MS/MS) technique to analyze the potential biomarkers in the plasma of mice with heart failure with preserved ejection fraction(HFpEF) induced by a high-fat diet(HFD) and nitric oxide synthase inhibitor(Nω-nitro-L-arginine methyl ester hydrochloride, L-NAME) and explore the pharmacological effects and mechanism of Jiming Powder in improving HFpEF. Male C57BL/6N mice aged eight weeks were randomly assigned to a control group, a model group, an empagliflozin(10 mg·kg~(-1)·d~(-1)) group, and high-and low-dose Jiming Powder(14.3 and 7.15 g·kg~(-1)·d~(-1)) groups. Mice in the control group were fed on a low-fat diet, and mice in the model group and groups with drug intervention were fed on a high-fat diet. All mice had free access to water, with water in the model group and Jiming Powder groups being supplemented with L-NAME(0.5 g·L~(-1)). Drugs were administered on the first day of modeling, and 15 weeks later, blood pressure and cardiac function of the mice in each group were measured. Heart tissues were collected for hematoxylin-eosin(HE) staining to observe pathological changes and Masson's staining to observe myocardial collagen deposition. Untargeted metabolomics analysis was performed on the plasma collected from mice in each group, and metabolic pathway analysis was conducted using MetaboAnalyst 5.0. The results showed that the blood pressure was significantly lower and the myocardial concentric hypertrophy and left ventricular diastolic dysfunction were significantly improved in both the high-dose and low-dose Jiming Powder groups as compared with those in the model group. HE and Masson staining showed that both high-dose and low-dose Jiming Powder significantly alleviated myocardial fibrosis. In the metabolomics experiment, 23 potential biomarkers were identified and eight strongly correlated metabolic pathways were enriched, including linoleic acid metabolism, histidine metabolism, alpha-linolenic acid metabolism, glycerophospholipid metabolism, purine metabolism, porphyrin and chlorophyll metabolism, arachidonic acid metabolism, and pyrimidine metabolism. The study confirmed the pharmacological effects of Jiming Powder in lowering blood pressure and ameliorating HFpEF and revealed the mechanism of Jiming Powder using the metabolomics technique, providing experimental evidence for the clinical application of Jiming Powder in treating HFpEF and a new perspective for advancing and developing TCM therapy for HFpEF.

Cardiomodulatory and Antioxidative Potentials of Almond-Citrus Peel Fortified Shortbread in High Fat Diet/L-NAME-Induced Hyperlipidemic-Hypertensive Rats.

In folk medicine, the almond nut (Terminalia catappa) and orange peel (Citrus sinensis) are cost-effective sources of nutraceutical utilized in the treatment of degenerative diseases. Hyperlipidemia and hypertension are two pathological conditions implicated in cardiovascular disorders. This study sought to evaluate the cardiomodulatory effect of almond-citrus peel fortified shortbread in hyperlipidemic-hypertensive rats induced by high fat diet and Nω-nitro-l-arginine methyl ester. The experimental animals were divided into eight groups. The experimental rats were fed with shortbread supplemented with almond and citrus peel at varying inclusions of 0.2% citrus, 50% almond, and almond (50%)- citrus (0.2%) for 21 days. The mean arterial blood pressure (MABP), systolic blood pressure (SBP), and lipid profile of the experimental rats were measured. Thereafter, the activities of angiotensin-1-converting enzyme (ACE), arginase, malondialdehyde (MDA), phosphodiesterase-5, nitric oxide (NO), and antioxidant indices were evaluated. The result showed significant elevation in SBP, MABP, blood cholesterol, triglyceride, ACE, arginase, activities, and MDA levels in the heart tissue of the untreated rats. In contrast, the antioxidant status and NO level were significantly decreased in the untreated groups. Remarkably, the treatment with almond-citrus peel fortified shortbread and the individual effect of almond (50%) and citrus peel (0.2%) all reversed these trends in the hyperlipidemic-hypertensive rats. Intriguingly, the blend of almond (50%)-citrus peel (0.2%) fortified shortbread showed the best antioxidative and cardioprotective effect. The results suggest that almond and citrus peel offer potentials as therapeutic agent in the prevention and management of hyperlipidemia and hypertension.

Progranulin Maintains Blood Pressure and Vascular Tone Dependent on EphrinA2 and Sortilin1 Receptors and Endothelial Nitric Oxide Synthase Activation.

Background The mechanisms determining vascular tone are still not completely understood, even though it is a significant factor in blood pressure management. Many circulating proteins have a significant impact on controlling vascular tone. Progranulin displays anti-inflammatory effects and has been extensively studied in neurodegenerative illnesses. We investigated whether progranulin sustains the vascular tone that helps regulate blood pressure. Methods and Results We used male and female C57BL6/J wild type (progranulin+/+) and B6(Cg)-Grntm1.1Aidi/J (progranulin-/-) to understand the impact of progranulin on vascular contractility and blood pressure. We found that progranulin-/- mice display elevated blood pressure followed by hypercontractility to noradrenaline in mesenteric arteries, which is restored by supplementing the mice with recombinant progranulin. In ex vivo experiments, recombinant progranulin attenuated the vascular contractility to noradrenaline in male and female progranulin+/+ arteries, which was blunted by blocking EphrinA2 or Sortilin1. To understand the mechanisms whereby progranulin evokes anticontractile effects, we inhibited endothelial factors. N(gamma)-nitro-L-arginine methyl ester (nitric oxide synthase inhibitor) prevented the progranulin effects, whereas indomethacin (cyclooxygenase inhibitor) affected only the contractility in arteries incubated with vehicle, indicating that progranulin increases nitric oxide and decreases contractile prostanoids. Finally, recombinant progranulin induced endothelial nitric oxide synthase phosphorylation and nitric oxide production in isolated mesenteric endothelial cells. Conclusions Circulating progranulin regulates vascular tone and blood pressure via EphrinA2 and Sortilin1 receptors and endothelial nitric oxide synthase activation. Collectively, our data suggest that deficiency in progranulin is a cardiovascular risk factor and that progranulin might be a new therapeutic avenue to treat high blood pressure.

Antiulcer mechanisms of the hydroalcoholic extract from Aztec marigolds' medicinal and edible flowers (Tagetes erecta L.).

The antiulcer mechanisms of the dry extract of T. erecta flowers (DETe) were studied here. The acute ulcers induced by acidified ethanol or indomethacin were reproduced in mice pretreated with DETe (3 - 300 mg/kg). The antiulcer activity of DETe was also verified in mice pretreated with NEM, L-NAME, indomethacin, or yohimbine. The antisecretory effect of DETe was verified in rats, and its anti-Helicobacter pylori activity was determined in vitro. DETe (300 mg/kg, p.o) reduced the ethanol- or indomethacin-induced ulcer by 49 and 93%, respectively. The pre-treatment with L-NAME, NEM or yohimbine abolished the gastroprotective effect of DETe. However, DETe did not change the volume, acidity, or peptic activity in rats and did not affect H. pylori. This study expands knowledge about the antiulcerogenic potential of DETe, evidencing the role of nitric oxide, non-protein sulfhydryl groups, α2 adrenergic receptors, and prostaglandins, but not antisecretory or anti-H. pylori properties.

Vasorelaxant effect of Alpinia zerumbet's essential oil on rat resistance artery involves blocking of calcium mobilization.

Alpinia zerumbet is a plant from the Zingiberaceae family, popularly used for hypertension treatment. Several studies have demonstrated Alpinia zerumbet vasodilator effect on conductance vessels but not on resistance vessels. Thereby, the aim of this study was to verify the vasodilator effect of the essential oil of Alpinia zerumbet (EOAz) on isolated rat resistance arteries and characterize its mechanism of action. Therefore, the effect of EOAz (3 to 3000 µg/mL) was verified in second-order branches of the mesenteric artery (SOBMA) pre-contracted by KCl and U46619. To study the mechanism of action, the influence of several inhibitors (TEA, 4-AP, Glibenclamide, Atropine, L-NAME, ODQ and indomethacin) on the vasodilator effect of EOAz was evaluated. Some protocols were also performed aiming to study the effect of EOAz on Ca2+ influx and release from intracellular storage. Furthermore, the binding energy of the main constituents with calcium channels were evaluated by molecular docking. Results showed an endothelium-independent vasorelaxant effect of EOAz on SOBMA, and only ODQ and L-NAME produced significant alteration on its pEC50. Regarding the calcium assays, contraction reduction caused by incubation with EOAz was observed in all three protocols. Hence, our results suggest that EOAz has a vasodilator effect mediated by inhibition of Ca2+ influx and release from intracellular storage, as well as an activation of the NOS/sGC pathway.

Hydrogen sulfide alleviates heart failure with preserved ejection fraction in mice by targeting mitochondrial abnormalities via PGC-1α.

AIM: Increasing evidence has proposed that mitochondrial abnormalities may be an important factor contributing to the development of heart failure with preserved ejection fraction (HFpEF). Hydrogen sulfide (H2S) has been suggested to play a pivotal role in regulating mitochondrial function. Therefore, the present study was designed to explore the protective effect of H2S on mitochondrial dysfunction in a multifactorial mouse model of HFpEF. METHODS: Wild type, 8-week-old, male C57BL/6J mice or cardiomyocyte specific-Cse (Cystathionine γ-lyase, a major H2S-producing enzyme) knockout mice (CSEcko) were given high-fat diet (HFD) and l-NAME (an inhibitor of constitutive nitric oxide synthases) or standardized chow. After 4 weeks, mice were randomly administered with NaHS (a conventional H2S donor), ZLN005 (a potent transcriptional activator of PGC-1α) or vehicle. After additional 4 weeks, echocardiogram and mitochondrial function were evaluated. Expression of PGC-1α, NRF1 and TFAM in cardiomyocytes was assayed by Western blot. RESULTS: Challenging with HFD and l-NAME in mice not only caused HFpEF but also inhibited the production of endogenous H2S in a time-dependent manner. Meanwhile the expression of PGC-1α and mitochondrial function in cardiomyocytes were impaired. Supplementation with NaHS not only upregulated the expression of PGC-1α, NRF1 and TFAM in cardiomyocytes but also restored mitochondrial function and ultrastructure, conferring an obvious improvement in cardiac diastolic function. In contrast, cardiac deletion of CSE gene aggravated the inhibition of PGC-1α-NRF1-TFAM pathway, mitochondrial abnormalities and diastolic dysfunction. The deleterious effect observed in CSEcko HFpEF mice was partially counteracted by pre-treatment with ZLN005 or supplementation with NaHS. CONCLUSION: Our findings have demonstrated that H2S ameliorates left ventricular diastolic dysfunction by restoring mitochondrial abnormalities via upregulating PGC-1α and its downstream targets NRF1 and TFAM, suggesting the therapeutic potential of H2S supplementation in multifactorial HFpEF.

Antioxidant-rich Terminalia catappa fruit exerts antihypertensive effect via modulation of angiotensin-1-converting enzyme activity and H2S/NO/cGMP signalling pathway in Wistar rats.

INTRODUCTION: The present study aimed at investigating the effect of Terminalia catappa fruits on blood pressure, NO/cGMP signalling pathway, angiotensin-1-converting enzyme and arginase activity, and oxidative stress biomarkers in L-NAME-induced hypertensive rats. MATERIALS AND METHODS: Forty-two Wistar rats were divided into seven groups. Hypertension was induced via oral administration of 40 mg/kg of L-NAME for 21 days. Thereafter, the hypertensive rats were treated with Terminalia catappa fruit-supplemented diet and sildenafil citrate for 21 days. The blood pressure was measured and cardiac homogenate was prepared for biochemical analyses. RESULTS: The results showed that L-NAME caused a significant (p < 0.05) increase in systolic and diastolic blood pressure, and heart rate as well as ACE, arginase and PDE-5 activity, with a simultaneous decrease in NO and H2S levels as well as increased oxidative stress biomarkers. However, treatment with Terminalia catappa fruits-supplemented diets and sildenafil citrate lowered blood pressure and modulated ACE, arginase, and PDE-5 activity, improved NO and H2S levels, as well as antioxidant status. CONCLUSION: Findings presented in this study provide useful information on the antihypertensive property of Terminalia catappa fruits, alongside some possible mechanisms. Hence, Terminalia catappa fruits could be considered a dietary regimen and functional food in alleviating hypertension.

Angelica decursiva exerts antihypertensive activity by inhibiting L-type calcium channel.

ETHNOPHARMACOLOGICAL RELEVANCE: Angelica decursiva is a perennial herb that belongs to the Umbelliferae family. It is traditionally used to treat fever, upper respiratory tract infections, bleeding and hypertension. However, despite its extensive pharmacological potential, literature reports on its antihypertensive pharmacological properties are scarce. AIM OF THE STUDY: In the study, crude extract from A. decursiva roots was examined for its antihypertensive activity and its molecular basis was explored. MATERIALS AND METHODS: A. decursiva roots were extracted with ethanol, and isolated with silica gel normal-phase chromatography and reverse-phase high performance liquid chromatography. L-NAME-induced hypertensive mouse model was used to detect in vivo hypertensive activity. Thoracic aorta ring contraction activity and electrophysiology recordings were employed to evaluate in vitro antihypertensive activity and revealed an antihypertensive target, which was transiently expressed in HEK293T cells. RESULTS: Angelica decursiva ethanol decoction (ADED) exhibited significant antihypertensive effects in L-NAME-induced hypertension models and phenylephrine-induced vasoconstriction. Further screening revealed that demethylsuberosin is an essential component accounting for the antihypertension effects of A. decursiva. Voltage-gated calcium channel CaV1.2 is the likely target of A. decursiva for its antihypertension effects. CONCLUSION: The study suggests that A. decursiva and demethylsuberosin may be effective antihypertensive agents in preclinical studies. It appears that A. decursiva and demethylsuberosin exert antihypertensive effects by inhibiting the CaV1.2 channel, which contributes to the vasodilatory effect. The present study provides experimental evidence that A. decursiva is an effective remedy for hypertension in folklore. Demethylsuberosin could be a lead molecule for antihypertension drug development.

The Angiogenesis Inhibitor Isthmin-1 (ISM1) Is Overexpressed in Experimental Models of Glomerulopathy and Impairs the Viability of Podocytes.

Focal segmental glomerulosclerosis (FSGS) is a major cause of end-stage renal disease and remains without specific treatment. To identify new events during FSGS progression, we used an experimental model of FSGS associated with nephroangiosclerosis in rats injected with L-NAME (Nω-nitro-L-arginine methyl ester). After transcriptomic analysis we focused our study on the role of Isthmin-1 (ISM1, an anti-angiogenic protein involved in endothelial cell apoptosis. We studied the renal expression of ISM1 in L-NAME rats and other models of proteinuria, particularly at the glomerular level. In the L-NAME model, withdrawal of the stimulus partially restored basal ISM1 levels, along with an improvement in renal function. In other four animal models of proteinuria, ISM1 was overexpressed and localized in podocytes while the renal function was degraded. Together these facts suggest that the glomerular expression of ISM1 correlates directly with the progression-recovery of the disease. Further in vitro experiments demonstrated that ISM1 co-localized with its receptors GRP78 and integrin αvß5 on podocytes. Treatment of human podocytes with low doses of recombinant ISM1 decreased cell viability and induced caspase activation. Stronger ISM1 stimuli in podocytes dropped mitochondrial membrane potential and induced nuclear translocation of apoptosis-inducing factor (AIF). Our results suggest that ISM1 participates in the progression of glomerular diseases and promotes podocyte apoptosis in two different complementary ways: one caspase-dependent and one caspase-independent associated with mitochondrial destabilization.

Combination Sodium Nitrite and Hydralazine Therapy Attenuates Heart Failure With Preserved Ejection Fraction Severity in a "2-Hit" Murine Model.

Background Recent studies have suggested that cardiac nitrosative stress mediated by pathological overproduction of nitric oxide (NO) via inducible NO synthase (iNOS) contributes to the pathogenesis of heart failure with preserved ejection fraction (HFpEF). Other studies have suggested that endothelial NO synthase (eNOS) dysfunction and attenuated NO bioavailability contribute to HFpEF morbidity and mortality. We sought to further investigate dysregulated NO signaling and to examine the effects of a NO-based dual therapy (sodium nitrite+hydralazine) following the onset of HFpEF using a "2-hit" murine model. Methods and Results Nine-week-old male C57BL/6 N mice (n=15 per group) were treated concurrently with high-fat diet and N(ω)-nitro-L-arginine methyl ester (L-NAME) (0.5 g/L per day) via drinking water for 10 weeks. At week 5, mice were randomized into either vehicle (normal saline) or combination treatment with sodium nitrite (75 mg/L in the drinking water) and hydralazine (2.0 mg/kg IP, BID). Cardiac structure and function were monitored with echocardiography and invasive hemodynamic measurements. Cardiac mitochondrial respiration, aortic vascular function, and exercise performance were also evaluated. Circulating and myocardial nitrite were measured to determine the bioavailability of NO. Circulating markers of oxidative or nitrosative stress as well as systemic inflammation were also determined. Severe HFpEF was evident by significantly elevated E/E', LVEDP, and Tau in mice treated with L-NAME and HFD, which was associated with impaired NO bioavailability, mitochondrial respiration, aortic vascular function, and exercise capacity. Treatment with sodium nitrite and hydralazine restored NO bioavailability, reduced oxidative and nitrosative stress, preserved endothelial function and mitochondrial respiration, limited the fibrotic response, and improved exercise capacity, ultimately attenuating the severity of "two-hit" HFpEF. Conclusions Our data demonstrate that nitrite, a well-established biomarker of NO bioavailability and a physiological source of NO, is significantly reduced in the heart and circulation in the "2-hit" mouse HFpEF model. Furthermore, sodium nitrite+hydralazine combined therapy significantly attenuated the severity of HFpEF in the "2-hit" cardiometabolic HFpEF. These data suggest that supplementing NO-based therapeutics with a potent antioxidant and vasodilator agent may result in synergistic benefits for the treatment of HFpEF.

Antihypertensive Effect of Euphorbia cheiradenia in Rats.

AIMS: The study aimed to investigate the effect of Euphorbia cheiradenia on blood pressure. BACKGROUND: Euphorbia cheiradenia is a medicinal plant with several medicinal properties. OBJECTIVE: This study aimed to study the vasorelaxant and antihypertensive capacity of the aqueous extract of Euphorbia cheiradenia (E. cheiradenia), and to evaluate its effect on angiotensinconverting enzyme 2 (ACE2). METHODS: The antihypertensive ability of aerial parts of the aqueous extract of E. cheiradenia (AEEC) was investigated in L-NAME-induced hypertensive rats, and its vasorelaxant effect was performed on the isolated thoracic rat aorta. In addition, the possible inhibitory effect of AEEC on ACE2 was also studied. RESULTS: AEEC lowered blood pressure parameters in hypertensive rats. The study of the vasorelaxant activity revealed that AEEC partially relaxed the aortic rings through activation of the KATP channel and inhibition of the ß-adrenergic pathway. Whereas pretreatment of aortic rings with nifedipine, indomethacin, L-NAME, and methylene blue did not attenuate AEEC-induced vasorelaxation. However, AEEC did not affect ACE2 in isolated rat aortas. CONCLUSION: The study showed that aqueous E. cheiradenia extract exhibits significant antihypertensive activity in hypertensive rats.

Optimized addition of nitric oxide compounds in semen extender improves post-thaw seminal attributes of Murrah buffaloes.

Semen dilution and cryopreservation alter the homogeneity of seminal plasma, resulting in a non-physiological redox milieu and consequently poor sperm functionality. Considering the concentration-specific bimodal action of nitric oxide (NO) in the regulation of sperm functions, cryopreservation media supplemented with optimized concentrations can improve the semen attributes. The present study aimed to evaluate the effect of adding an optimized concentration of sodium nitroprusside (SNP) and N-nitro-L-arginine methyl ester (L-NAME) in an extender on in vitro semen quality. An aliquot of semen samples (n = 32) from Murrah buffalo bulls (n = 8) was divided into control (C) and treatment (T-I: SNP in extender at 1 µmol/L; T-II: L-NAME in extender at 10 µmol/L). Fresh semen quality parameters showed no significant difference at 0 h except for the structural integrity in the T-II group. Post-thaw semen quality parameters and sperm kinematics using computer-aided sperm analysis (CASA) revealed significantly higher (p < 0.05) cryoresistance in the treatment groups. Viability, acrosome integrity, and membrane integrity were significantly higher (p < 0.05) in both treatment groups; however, the results were pervasive in T-II. Lower abnormal spermatozoa were observed in both T-I and T-II. SNP supplementation led to a significant rise (p < 0.05) in NO, whereas L-NAME reduced the NO concentration in post-thawed samples, which was directly correlated with different sperm functionality and associated biomarkers viz. total antioxidant capacity (TAC) and thiobarbituric acid reactive substance (TBARS). It was concluded that the cryopreservation media supplemented with SNP and L-NAME at 1 µmol/L and 10 µmol/L, respectively, lower the cryo-damage and improve post-thaw seminal attributes.