Mechanisms underlying the antihypertensive properties of Urtica dioica

Antidiabetic Properties of Caffeoylmalic Acid, a Bioactive Natural Compound Isolated from Urtica dioica

The uncontrolled hyperglycemia that characterizes diabetes mellitus (DM) causes several complications in the organism. DM is among the major causes of deaths, and the limited efficacy of current treatments push the search for novel drug candidates, also among natural compounds. We focused our attention on caffeoylmalic acid, a phenolic derivative extracted from Urtica dioica, a plant investigated for its potential against type 2 DM. This compound was tested for its antidiabetic activity in vitro through a glucose uptake assay, in vivo in a mouse DM model and through molecular docking towards α-amylase and α-glucosidase. The effects on glucose blood level, liver enzymes, insulin and creatinine levels as well as on lipid and blood parameters, considered biochemical markers of diabetes, were also evaluated. The results showed an antidiabetic activity in vitro and in vivo, as the compound stimulates glucose absorbtion and reduces blood glucose levels. Moreover, it ameliorates lipid profile, liver and blood parameters, with moderate effect on insulin secretion. Taken together, these findings pave the way for the compounds from this class of caffeoylmalic acid as potential antidiabetic compounds.

7-Hydroxy Frullanolide Ameliorates Isoproterenol-Induced Myocardial Injury through Modification of iNOS and Nrf2 Genes

Myocardial infarction (MI) is the principal cause of premature death. Protecting myocardium from ischemia is the main focus of intense research. 7-hydroxy frullanolide (7-HF) is a potent anti-inflammatory agent, showing its efficacy in different acute and chronic inflammatory disorders such as atherosclerosis, suggesting it can be a potential cardioprotective agent. For the induction of MI, Sprague-Dawley rats (n = 5) were administered isoproterenol (ISO) 85 mg/kg s.c at 24 h intervals for two days. The potential cardioprotective effect of 7-HF and its mechanisms were explored by in vivo and in vitro methods. 7-HF significantly prevented the extent of myocardial injury by decreasing the infarct size, preserving the histology of myocardial tissue, and reducing the release of cardiac biomarkers. Further, 7-HF increased the mRNA expression of cardioprotective gene Nrf2 and reduced the mRNA expression of iNOS. 7-HF also improved cardiac function by decreasing the cardiac workload through its negative chronotropic and negative ionotropic effect, as well as by reducing peripheral vascular resistance due to the inhibition of voltage-dependent calcium channels and the release of calcium from intracellular calcium stores. In conclusion, 7-HF showed cardioprotective effects in the MI model, which might be due to modulating the expression of iNOS and Nrf2 genes as well as improving cardiac functions.

Endophytic bacteria isolated from Urtica dioica L.- preliminary screening for enzyme and polyphenols production

Endophytes, especially those isolated from herbal plants, may act as a reservoir of a variety of secondary metabolites exhibiting biological activity. Some endophytes express the ability to produce the same bioactive compounds as their plant hosts, making them a more sustainable industrial supply of these substances. Urtica dioica L. (common stinging nettle) is a synanthropic plant that is widely used in herbal medicine due to the diversity of bioactive chemicals it contains, e.g., polyphenols, which demonstrate anti-inflammatory, antioxidant, and anti-cancerous capabilities. This study aimed at isolating endophytic bacteria from stinging nettles for their bioactive compounds. The endophytic isolates were identified by both biochemical and molecular methods (16S rRNA) and investigated for enzymes, biosurfactants, and polyphenols production. Each of the isolated bacterial strains was capable of producing biosurfactants and polyphenols. However, three of the isolated endophytes, identified as two strains of Bacillus cereus and one strain of Bacillus mycoides, possessed the greatest capacity to produce biosurfactants and polyphenols. The derivatized extracts from culture liquid showed the 1.633 mol l-1 (9.691 mg l-1) concentration of polyphenol compounds. Therefore, the present study signifies that endophytic B. cereus and B. mycoides isolated from Urtica dioica L. could be a potential source of biosurfactants and polyphenols. However, further study is required to understand the mechanism of the process and achieve efficient polyphenol production by endophytic bacteria.

The medicinal chemistry of Urtica dioica L.: from preliminary evidence to clinical studies supporting its neuroprotective activity

Urtica dioica is a perennial herb from the family of Urticaceae that is commonly known as stinging nettle. This plant is widespread in Europe, Africa, America, and a part of Asia, as it adapts to different environments and climatic conditions. The leaves, stalk, and bark of U. dioica found applications in the field of nutrition, cosmetics, textile, pest control and pharmacology. In this connection, bioactive chemical constituents such as flavonoids, phenolic acids, amino acids, carotenoids, and fatty acids have been isolated from the plant. With this review, we aim at providing an updated and comprehensive overview of the contributions in literature reporting computational, in vitro, pre-clinical and clinical data supporting the therapeutic applications of U. dioica. Experimental evidence shows that U. dioica constituents and extracts can provide neuroprotective effects by acting through a combination of different molecular mechanisms, that are discussed in the review. These findings could lay the basis for the identification and design of more effective tools against neurodegenerative diseases.

Vasorelaxant and Antihypertensive Effects of Bergenin on Isolated Rat Aorta and High Salt-Induced Hypertensive Rats

Bergenin is a phenolic glycoside that has been reported to be present in some medicinal plants which are traditionally used for their antihypertensive actions. So, bergenin was investigated for antihypertensive and vasorelaxant experiments in a rat model. Bergenin produced a significant fall in the mean arterial pressure (MAP) of rats. To explore the involvement of NO and muscarinic receptors, rats were pretreated with L-NAME and atropine in-vivo. The L-NAME did not change significantly the effect of bergenin on MAP excluding the involvement of NO. Unlike the L-NAME, atropine pretreatment reduced the effect of bergenin on MAP, indicating the role of muscarinic receptors. In in-vitro study, the bergenin produced endothelium-dependent (at lower concentrations) and independent (at higher concentrations) vasorelaxation, which was attenuated significantly in the presence of atropine and indomethacin but not with L-NAME. While a partial response was observed against K⁺-induced contractions. This was further confirmed when bergenin partly shifted the CaCl₂-CRCs toward right. Bergenin also suppressed the PE peak formation, indicating the antagonist effect against the release of Ca²⁺. Moreover, the bergenin-induced vasorelaxant response was not markedly attenuated with TEA, while significantly ablated with 4-AP and BaCl₂. In conclusion, the antihypertensive effects of bergenin are due to Ca²⁺ channel blockade, K⁺ channels activation, and muscarinic receptor-linked vasodilation.

Blood pressure-lowering and cardiovascular effects of plumbagin in rats: An insight into the underlying mechanisms

Background

Plumbagin, a natural phenolic compound is investigated for response against blood pressure and vascular reactivity.

Methodology

Blood pressure lowering effects were observed by in-vivo invasive evaluation in normotensive rats, and in-vitro experimentation to measure changes of tension in isolated rat aorta and contractility in atria.

Results

The percentage decrease in mean arterial pressure (MAP) observed with plumbagin intravenously at doses of 0.1, 0.5, 1, 5, 10 ​μg/kg in normotensive rats was 7.16 ​± ​2.35, 15.5 ​± ​5.62, 19.5 ​± ​5.27, 26 ​± ​6.67, 34.33 ​± ​8.80, respectively. Plumbagin exerted vasorelaxant effects in rat aorta, unaffected by the removal of vascular endothelium, and _L-NAME and methylene blue pretreatment. Plumbagin completely inhibited phenylephrine (1 ​μM) and High K⁺ (80 ​mM) induced contractions. Similar to a Ca⁺² channel antagonist, plumbagin caused a rightward shift in the Ca⁺² concentration-response-curves (CRCs), resembling nifedipine. Pre-incubation with plumbagin, significantly suppressed contractions induced by phenylephrine in Ca⁺²-free medium via disrupting Ca⁺² release from intracellular stores. No change in vasorelaxant response was observed with the addition of potassium channel blockers, TEA and BaCl₂. In rat atrial strips, plumbagin exerted significant negative inotropic and chronotropic effects. No significant change was observed with atropine and atenolol pretreatment, so the effect appeared independent of muscarinic and beta-adrenergic receptors.

Conclusion

This study suggests the blood pressure lowering effects of plumbagin. That could be contributed by a decrease in vascular resistance via calcium antagonism, interferences in calcium efflux, and depressive effects on the rate and force of cardiac contraction. Further studies would be necessary to probe deeper into the underlying mechanisms.

The Effects of Nettle Extract Consumption on Liver PPARs, SIRT1, ACOX1 and Blood Lipid Levels in Male and Female C57Bl6 Mice

The aim of this study was to evaluate how nettle (Urtica dioica L.) water extract consumption would interact with regulators of peroxysomal lipid oxidation, histone deacetylase, and markers of oxidative stress in the liver and blood lipid levels in male and female C57Bl6 mice. Metabolically unchallenged (healthy) mice (n = 5 per sex) were treated with a nettle extract in a dose of 40 mg of total polyphenols in the extract per kg mice body weight. The nettle extract was applied daily along with normal diet for 15 days. The serum triglycerides, cholesterol, HDL, LDL, and liver PPAR-α, PPAR-γ, PGC-1-α, ACOX1, SIRT1, MDA, SOD, CAT, and GSH were compared between exposed and unexposed (control) animals. In males, the PPAR-α, PGC1-α, and ACOX1 levels together with systemic HDL cholesterol were significantly (p ≤ 0.05) increased while the LDL cholesterol decreased (p ≤ 0.05). In females, no changes in PPAR-α and PGC1-α or serum lipids were noted, but the ACOX1 content in the liver was significantly (p ≤ 0.05) increased. The SIRT1 activity increased (p ≤ 0.05) only in females. In both sexes, the PPAR-γ levels were not significantly (p ≤ 0.05) affected in either sex. The results indicate that nettle plant extract has the potential to modulate selected transcriptional factors and histone deacetylase in vivo, with certain sex differences, which should be studied further in similar models.

Stinging Nettle (Urtica dioica L.): Nutritional Composition, Bioactive Compounds, and Food Functional Properties

Stinging nettle (Urtica dioica L., Urticaceae) is commonly found in Asia, Africa, and Europe and has a long history of being used as food and traditional medicine. Recently, this plant is gaining attention as a highly nutritious food, where fresh leaves are dried and used as powder or in other forms. Leaves are rich in many bioactive compounds. This review aims to cover the traditional uses in food and medicine, as well as its nutritional composition, including its bioactive chemical constituents and reported food functional activities. Various bioactive chemical constituents have been isolated from stinging nettle to date, such as flavonoids, phenolic acids, amino acid, carotenoids, and fatty acids. Stinging nettle extracts and its compounds, such as rutin, kaempferol, and vitamin A, are also used for their nutritional properties and as anti-inflammatory and antioxidant agents. Future studies should focus on the proper formulation and stability testing of the functional foods containing stinging nettle and their detailed activities in clinical studies.

Investigation into the Antihypertensive Effects of Diosmetin and Its Underlying Vascular Mechanisms Using Rat Model

Objective: Diosmetin is a flavonoid that is found in many important medicinal plants that have antihypertensive therapeutic potential. Diosmetin has been shown to have antiplatelet, anti-inflammatory and antioxidant properties, which suggests that it could be a potential candidate for use in antihypertensive therapy. Methods: In vivo and in vitro methods were used for our investigation into the antihypertensive effects of diosmetin. Results: Diosmetin significantly decreased the mean arterial pressure (MAP). The effects of diosmetin on the MAP and heart rate were more pronounced in hypertensive rats. To explore the involvement of the muscarinic receptors-linked NO pathway, Nω-nitro-L-arginine methyl ester (L-NAME) and atropine were pre-administered in vivo. The pretreatment with L-NAME did not significantly change the effects of diosmetin on the MAP by excluding the involvement of NO. Unlike L-NAME, the atropine pretreatment reduced the effects of diosmetin on the MAP, which demonstrated the role of the muscarinic receptors. In the in vitro study, diosmetin at lower concentrations produced endothelium-dependent and -independent (at higher concentrations) vasorelaxation, which was attenuated significantly by the presence of atropine and indomethacin but not L-NAME. Diosmetin was also tested for high K+-induced contractions. Diosmetin induced significant relaxation (similar to verapamil), which indicated its Ca2+ antagonistic effects. This was further confirmed by diosmetin shifting the CaCl₂ CRCs toward the right due to its suppression of the maximum response. Diosmetin also suppressed phenylephrine peak formation, which indicated its antagonist effects on the release of Ca2+. Moreover, BaCl₂ significantly inhibited the effects of diosmetin, followed by 4-AP and TEA, which suggested that the K+ channels had a role as well. Conclusions: The obtained data showed the Ca2+ channel antagonism, potassium channel activation and antimuscarinic receptor-linked vasodilatory effects of diosmetin, which demonstrated its antihypertensive potential.

Antihypertensive Activity in High Salt-Induced Hypertensive Rats and LC-MS/MS-Based Phytochemical Profiling of Melia azedarach L. (Meliaceae) Leaves

Melia azedarach L. leaves have been traditionally used but not scientifically evaluated for antihypertensive activity. The focus of the present work was to carry out the detailed phytochemical profiling and antihypertensive potential of methanolic extract and subsequent fractions of this plant. The tandem mass spectrometry-based phytochemical profiling of M. azedarach extract (Ma.Cr) and fractions was determined in negative ionization mode while molecular networking was executed using the Global Natural Product Social (GNPS) molecular networking platform. This study resulted in the identification of 29 compounds including flavonoid O-glycosides, simple flavonoids, triterpenoidal saponins, and cardenolides as the major constituents. Ma.Cr at the concentration of 300 mg/kg resulted in a fall in blood pressure (BP), i.e., 81.44 ± 2.1 mmHg in high salt-induced hypertensive rats in vivo, in comparison to normotensive group, i.e., 65.36 ± 1.8 mmHg at the same dose. A decrease in blood pressure was observed in anaesthetized normotensive and hypertensive rats treated with extract and various fractions of M. azedarach. A reasonable activity was observed for all fractions except the aqueous fraction. The highest efficacy was shown by the ethyl acetate fraction, i.e., 77.06 ± 3.77 mmHg in normotensive and 88.96 ± 1.3 mmHg in hypertensive anaesthetized rats. Ma.Cr and fractions showed comparatively better efficacy towards hypertensive rats as compared to rats with normal blood pressure. Blood pressure-lowering effects did not change upon prior incubation with atropine. In vitro testing of Ma.Cr and polarity-based fractions resulted in L-NAME sensitive, endothelium-dependent vasodilator effects on aortic tissues. Pretreatment of aorta preparations with Ma.Cr and its fractions also blocked K+-induced precontractions indicating Ca2+ channel blocking activity comparable to verapamil. The extract and polarity-based fractions did not reveal a vasoconstrictor response in spontaneously beating isolated rat aorta. Ma.Cr and fractions when used in atrial preparations resulted in negative inotropic and chronotropic effects. These effects in atrial preparations did not change in the presence of atropine. These effects of extract and fractions explained the antihypertensive potential of M. azedarach and thus provided a scientific basis for its ethnopharmacological use in the treatment of hypertension. Among the constituents observed, flavonoids and flavonoid O-glycosides were previously reported for antihypertensive potential.

A review of the effects of Urtica dioica (nettle) in metabolic syndrome

Metabolic syndrome is a serious health condition, yet a common worldwide disorder. It includes several risk factors such as hypertension, dyslipidemia, and high glucose levels which lead the patients to higher risks of cardiovascular diseases, diabetes, and stroke. Phytotherapy plays an important role in treating components of metabolic syndrome. Nettle (Urtica dioica) is considered a valuable plant due to bioactive compounds such as formic acid and rich sources of flavonoids. To acknowledge the role of nettle in metabolic syndrome, several mechanisms have been suggested such as alterations in potassium and calcium channels which improve hypertension. Antihyperlipidemic properties of nettle are mediated by inhibition of HMGCoA reductase and amelioration of lipid peroxidation via antioxidant effects. Also, one of the flavonoids in nettle, quercetin, is responsible for decreasing total cholesterol. Moreover, nettle is responsible for anti-diabetic effects through processes such as increasing insulin secretion and proliferation of pancreatic β-cells. This review aims to gather different studies to confirm the potential efficacy of nettle in metabolic syndrome.

Anti-diabetic potential of Urtica Dioica: current knowledge and future direction

Aim

This review summarizes studies on the anti-diabetic effect of Urtica Dioica (UD) in Type-2-diabetes.

Materials and methods

We studied worldwide traditional medicines, old texts, and published literature for anti-diabetic effect of UD. Electronic databases comprising PubMed, Web of Science, Science Direct, Scopus and Google Scholar were searched to collect articles published between 1990 and 2021 years.

Results

Our literature investigation suggests UD as a glucose lowering, blood lipid regulating, anti-inflammatory and anti-oxidation plant.

Conclusions

UD's anti-diabetic properties make it potential traditional therapeutics for lowering the clinical manifestations of T2DM through affecting hyperglycemia and therefore suggest it as a proper medication with no or limited side effects.

Disruption of microbial cell morphology by Buxus macowanii

Background

Microbial infections are one of the major causes of death globally. This is attributed to the rising costs of primary healthcare and its inaccessibility especially in developing countries. Moreover, there has been an increase in microbial strains that have reduced susceptibility to antimicrobial drugs. Research on the antimicrobial properties of medicinal plants, which could address these problems, has become more important as they present fewer side effects when compared to the antibiotics currently in use. This study evaluated the antimicrobial properties of a methanolic extract from Buxus macowanii in order to assess its potential in the development of novel antimicrobial drugs.

Methods

Antimicrobial activity of the extract was evaluated using the broth microdilution method. The effects of B. macowanii on the morphology of B. cereus were observed using Scanning and Transmission electron microscopy. Chemical profiling of the plant extract was performed using the GCMS.

Results

The extract showed antimicrobial activity against all the microbial species used. Microscopic examination of the cells of B. cereus cells treated with Buxus macowanii showed some changes in morphology such as damage of the cell wall, swelling of the cells and incomplete cell division that eventually resulted in cell death. Neophytadiene, an antimicrobial compound was detected in the extract using GCMS.

Conclusion

The morphological disruptions of the cell wall of Bacillus cereus explain the antimicrobial properties of B. macowanii and indicate its possible application in the development of natural antimicrobial drugs.

Juglone as antihypertensive agent acts through multiple vascular mechanisms

Background: Juglone, a natural phenolic compound obtained from the walnut tree, is known for its wide range of biological activities. However, it has yet to be tested for its effects on hypertension and vascular tone. This investigation was aimed to explore the antihypertensive effect and the nature of vascular reactivity of juglone in rat models.Methods: Juglone was tested in in vivo and in vitro experiments in rats. The responses were analyzed and recorded through a PowerLab data acquisition system.Results: Intravenous injection of juglone significantly decreased the mean arterial blood pressure (MAP) in normotensive and hypertensive rats (Max. fall, 43.50 ± 2.96 vs 49.66 ± 3.28 mmHg). In rats pretreated with Nω-Nitro l-arginine methyl ester (_L-NAME), the effect of juglone on MAP was reduced as compared to the control. However, in rats pretreated with atropine the fall in MAP by juglone was not altered. Juglone induced relaxation in the phenylephrine, K⁺ (80 mM), and angiotensin II pretreated isolated rat aortic rings. This vasorelaxant effect was reduced with _L-NAME pretreatment. Atropine pretreatment did not modify the vasorelaxant effect of juglone. Pre-incubation with juglone attenuated the intracellular Ca²⁺ release by suppressing phenylephrine peak formation and also shifted CaCl₂ concentration-response curves (CRCs) to the right. Of note, combined treatment with 4-aminopyridine and barium chloride also reduced juglone-mediated vasorelaxation suggesting a role of K⁺-channels as well.Conclusion: In conclusion, juglone exerts its antihypertensive effect through vasorelaxation, which is mediated by nitric oxide, inhibition of intracellular calcium release and opening of K⁺-channels.

The effect of nettle (Urtica dioica) supplementation on the glycemic control of patients with type 2 diabetes mellitus: A systematic review and meta-analysis

Type 2 diabetes mellitus (T2DM) is a major health problem, worldwide, that is associated with increased morbidity and mortality. Several randomized controlled clinical trials (RCTs) have investigated the effect of nettle (Urtica dioica) supplementation on markers of glycemic status in patients with T2DM, with conflicting results. Therefore, the present study assessed the effect of nettle on some glycemic parameters in patients with T2DM. A comprehensive search was conducted in PubMed, Scopus, Cochrane Library, and Web of Science, from database inception up to June 2019, to identify RCTs investigating the effect of nettle supplementation on glycemic markers, including fasting blood sugar (FBS) concentrations, insulin levels, homeostasis model assessment-estimated insulin resistance index, and glycosylated hemoglobin percentage in adults with T2DM. The Cochrane Collaboration tool was used to assess the methodological quality of the included studies. Results of this meta-analysis were reported based on the random effects model. Eight RCTs, comprising 401 participants, were included in the present systematic review and meta-analysis. Based on the Cochrane Collaboration risk of bias tool, five studies were considered as good quality, one was fair, and two studies were poor, respectively. The results of the meta-analysis revealed a significant reduction in FBS concentrations (weighted mean difference [WMD]: -18.01 mg/dl, 95% confidence interval [CI]: -30.04 to -5.97, p < .001, I² = 94.6%) following nettle supplementation. However, no significant reduction was observed in insulin levels (WMD: 0.83 Hedges' g, 95% CI: -0.26 to 1.92, p = .13, I² = 89.4%), homeostasis model assessment-estimated insulin resistance index (WMD: -0.22, 95% CI: -0.83 to 0.40, p = .49, I² = 69.2%), or glycosylated hemoglobin percentage (WMD: -0.77%, 95% CI: -1.77 to 0.22, p = .12, I² = 83.0%). The findings of the present study suggest that nettle supplementation may be effective in controlling FBS for T2DM patients. However, further studies are needed to confirm the veracity of these results.

Expression of antioxidant genes in broiler chickens fed nettle (Urtica dioica) and its link with pulmonary hypertension

Nettle (Urtica dioica) contains a wide range of chemical constituents that confer a strong antioxidant capacity to the plant. The present study was to investigate the antioxidant gene expression and pulmonary hypertensive responses of broiler chickens to U. dioica. A total of 240 one-d-old broilers (Ross 308) were randomly assigned to 4 dietary levels of U. dioica (0, 0.5%, 1% and 1.5%). Birds were reared for 6 wk in a high altitude region (2,100 m). The results showed a significant relative overexpression (target gene/β-actin as the arbitrary unit) of catalase (CAT) and superoxide dismutase 1 (SOD1) in the liver and lung of the chickens fed U. dioica. Lipid peroxidation was significantly suppressed, as reflected in reduced circulatory concentrations of malondialdehyde (MDA) in the birds fed U. dioica. These birds also had significantly (P < 0.05) higher serum nitric oxide (NO) concentrations than those in the control group. Feeding U. dioica at 1% and 1.5% also attenuated the right ventricular hypertrophy (reflected in the lower right to total ventricular weight ratio), which was associated with a significant lower rate of mortality from pulmonary hypertension syndrome. Feeding U. dioica led to an upregulation of hepatic and pulmonary antioxidant genes.

Antihypertensive Indigenous Lebanese Plants: Ethnopharmacology and a Clinical Trial

Hypertension is highly prevalent among the Lebanese adult population and is indeed the major cause of mortality in Lebanon. Traditional use of antihypertensive medicinal plants has long been practiced. The aim of this study is to document this traditional knowledge and clinically test the antihypertensive capacity of three of the most commonly used wild plant species Mentha longifolia, Viola odorata and Urtica dioica. Ethno-pharmacological data was collected by personal interviews with herbalists and traditional healers using a semi structured survey questionnaire and assessing relative frequency of citation (RFC). The clinical study was conducted by a randomized, blind, placebo-controlled trial in 29 subjects with mild hypertension distributed in four groups, three plant extract treatments and one placebo. Systolic (SBP) and diastolic blood pressures (DBP) as well as mean arterial blood pressures (MAP) were monitored at weeks 4, 8, 12 and 16 during the treatment with 300 mL/day of plant extract. Results showed that M. longifolia, U. dioica and V. odorata exhibited the highest values of RCF (0.95) followed by Allium ampeloprasum (0.94), Apium graveolens (0.92) and Crataegus azarolus (0.90). The clinical trial revealed dose- and duration-dependent significant reductions in SBP, DBP and MAP of subjects treated with M. longifolia, U. dioica or V. odorata. Our findings indicate that extracts of these plants present an effective, safe and promising potential as a phyto-therapuetical approach for the treatment of mild hypertension. More research on the phytochemistry, pharmacological effects and the underlying mechanisms is necessary.

Urtica dioica L. leaf extract modulates blood pressure and oxidative stress in spontaneously hypertensive rats

BACKGROUND

Urtica dioica L. (Stinging nettle) has been used for centuries for the treatment of numerous health issues.

PURPOSE

This study investigates the antioxidant capacity and the most abundant phenolic compounds of Urtica dioica L. leaf extract (UE), and its antihypertensive and antioxidative effects in vivo.

STUDY DESIGN

Spontaneously hypertensive rats were supplemented with 10, 50, and 200 mg/kg/day of UE and 10 mg/kg/day of losartan during 4-week period.

METHODS

In this study, HPLC analysis of UE was performed, as well as the determination of antioxidant capacity, superoxide radical scavenging activity, and metal chelating ability. Hemodynamic parameters were measured directly in anesthetized rats. Also, antioxidant enzyme activity and concentration in erythrocytes were determined, as well as systemic oxidative stress and plasma antioxidant status.

RESULTS

UE showed higher ferric reducing antioxidant power and Trolox equivalent antioxidant capacity than BHT, but lower than vitamin C. Furthermore, UE showed good metal chelating ability, but weak superoxide radical scavenging activity. All three tested UE doses managed to reduce systolic and diastolic blood pressure, as well as cardiac index, and to improve the antioxidative defense by increasing the activity of superoxide dismutase and catalase, without changing the concentration of the enzymes. Moreover, UE supplementation increased plasma antioxidant capacity and reduced systemic oxidative stress.

CONCLUSION

Chronic UE dietary supplementation had beneficial effects in the experimental model of essential hypertension.

Effects of standardized extracts of Lamium album and Urtica dioica on rat tracheal smooth muscle contraction

Objective

Diseases of the respiratory system are one of the main causes of death and include situation such as chronic obstructive pulmonary disease, pneumonia or asthma. Medicinal plants have beneficial effects on multiple diseases include respiratory disorders like asthma and bronchitis. The aim of this study was to evaluate the effects of U. dioica and L. Album on tracheal smooth muscle contraction.

Material and methods

Hydroalcoholic extracts of L. Album and U. Dioica aerial parts were prepared by maceration method and standardized based on their total phenol content. The effect of the extracts on the KCl-induced contraction of rat trachea was examined in an organ bath chamber. Data was analyzed with spss software 22.

Results

The extract of L. Album (5 mg/ml), similar to theophylline (20 mM), significantly reduced the KCl-induced tracheal contraction. On the other hand, U. Dioica (1 mg/ml and 5 mg/ml) augmented the KCl-induced contraction.

Conclusion

The relaxant effect of L. Album on the trachea makes it as a candidate for the managing patients with asthma and obstructive pulmonary diseases. But because of U. Dioica potential constrictive effect on the trachea it is suggested that patients avoid consuming it.