Anti-hypertensive medicinal plants and their mode of action

Study of the Antihypertensive and Vasorelaxant Activities of Haloxylon scoparium in Rats

AIMS

The work aimed to study the antihypertensive ability of Haloxylon scoparium.

BACKGROUND

Haloxylon scoparium Pomel is used to treat various diseases, including hypertension.

OBJECTIVE

This study aimed to evaluate the antihypertensive effect of Haloxylon scoparium (H. scoparium) in hypertensive rats, and to evaluate its probable vasorelaxant activity.

MATERIALS AND METHODS

The aqueous extract of Haloxylon scoparium (AEHS) was prepared and used to investigate its antihypertensive ability in L-NAME(Nω-L-arginine methyl ester)-induced hypertensive rats, and its vasorelaxant activity was studied on the isolated thoracic aorta of rats. The acute and subchronic effects of (AEHS) on blood pressure parameters were evaluated after oral administration of AEHS (60 and 100 mg/kg body weight) for 6 h for the acute experiment and for 7 days for the subchronic test.

RESULTS

The results indicated that AEHS decreased blood pressure parameters (systolic, mean, and diastolic blood pressure) after repeated oral administration in hypertensive rats without affecting normal rats. In addition, AEHS (375-1250 μg/mL) revealed a vasorelaxant effect in thoracic aortic rings precontracted with norepinephrine (NE) (10 μM) or KCl (80 mM). This effect was partially decreased in the presence of nifedipine by inhibition of the vascular calcium channel pathway in isolated rat thoracic aorta.

CONCLUSION

The study demonstrates the beneficial effect of Haloxylon scoparium as an antihypertensive agent. Moreover, this plant exerts vasorelaxant activity via the blockade of Ca²⁺ channels.

Cardiovascular Effects Induced by Fruit Peels from Passiflora edulis in Hypertensive Rats and Fingerprint Analysis by HPLC-ESI-MSn spectrometry

Hypertension is a chronic disease and a global health problem. Due to its high prevalence, it constitutes the most important risk factor for cardiovascular disease. Fruit peels from Passiflora edulis fo. flavicarpa are rich in bioactive natural compounds that may have action in hypertension. This study aimed to perform a fingerprinting analysis of Passiflora edulis fruit peel extract and evaluate its actions on the cardiovascular system in an in vivo model. The extract was obtained from the dried and powdered fruit peels of Passiflora edulis. Glycoside flavonoids were identified in the extract by HPLC-ESI-MSⁿ. The extract showed a significant hypotensive effect after 28 days of treatment and improved vascular function in the mesenteric artery. This effect was verified by decreased vascular hypercontractility and increased vasorelaxant in response to sodium nitroprusside and acetylcholine. There was also a decrease in endothelial dysfunction, which can be attributed to nitric oxide's increased bioavailability. Thus, we hypothesize that all these effects contributed to a reduction in peripheral vascular resistance, leading to a significant hypotensive effect. These results are novel for fruit peels from P. edulis. Also, there was a decrease in plasma and cardiac malondialdehyde levels and an increase in glutathione, suggesting a reduction in oxidative stress, as well as an increase of anti-inflammatory cytokines such as IL-10 in the plasma. This study demonstrated that the extract can be a new source of raw material to be applied as food or medicine adjuvant for treating hypertension.

Effect of Calamintha officinalis on Vascular Contractility and Angiotensinconverting Enzyme-2

AIMS

The study aimed to assess the antihypertensive activity of Calamintha officinalis.

BACKGROUND

Calamintha officinalis (CO) is a medicinal and aromatic herb as well as an antihypertensive plant that is widely used for its medicinal properties in several regions.

OBJECTIVE

This study aimed to evaluate the effect of the aqueous extract of Calamintha officinalis (AECO) on vasorelaxant activity and arterial blood pressure under normal and hypertensive states in rats. Additionally, the effect of AECO on vascular angiotensin-converting enzyme 2 (ACE-2) was assessed.

METHODS

In the current study, AECO (100 mg/Kg) was prepared, and its antihypertensive ability was assessed in L-N^G-Nitro arginine methyl ester (L-NAME)-induced hypertensive rats. Blood pressure and heart rate were recorded for 6 h for the acute experiment and during seven days for the subchronic treatment.

RESULTS

The results indicated that AECO reduced the systolic, diastolic, and mean arterial blood pressure in hypertensive rats. In addition, the study showed that AECO exerts a vasorelaxant ability through the sGC-cGMP induction pathway, vascular cyclooxygenase pathway, and the opening of K+ channels. However, AECO had no inhibitory effect on aortic ACE-2.

CONCLUSION

The study illustrates the beneficial action of AECO as an antihypertensive and vasorelaxant agent.

Medicinal Plants in the Treatment of Hypertension: A Review

Traditional medicine is a comprehensive term for ancient, culture-bound health care practices that existed before the use of science in health matters and has been used for centuries. Medicinal plants are used to treat patients with cardiovascular diseases, which may occur due to ailments of the heart and blood vessels and comprise heart attacks, cerebrovascular diseases, hypertension, and heart failure. Hypertension causes difficulty in the functioning of the heart and is involved in atherosclerosis, raising the risk of heart attack and stroke. Many drugs are available for managing these diseases, though common antihypertensive drugs are generally accompanied by many side effects. Medicinal herbs have several active substances with pharmacological and prophylactic properties that can be used in the treatment of hypertension. This review presents an overview of some medicinal plants that have been shown to have hypotensive or antihypertensive properties.

Phytotherapy of Hypertension: An Updated Overview

BACKGROUND

Cardiovascular disorders are the leading cause of morbidity and mortality throughout the globe. Hypertension is the main risk factor that contributes to the development of many diseases. The use of herbal therapies, medicinal plants and their derivatives for the remedy and management of hypertension is well-recognized and popular among a wide part of the world population.

METHODS

The aim of the current review was to collect, treat, and critically analyze the published research studies relative to experimental and clinical investigations which have studied the blood pressure lowering abilities of medicinal plant derivatives in the last decade. This review was organized into three principal axes; the first axis was attributed to the in vivo and in vitro experimental studies; the second treated the clinical trials; while, the last one is devoted to analyze the mechanisms of action underlying the therapeutic antihypertensive effectiveness of phytochemicals.

RESULTS

Different types of extracts and isolated molecules obtained from a large variety of species demonstrated their efficiency in improving the increase of blood pressure either experimentally or clinically. Medicinal species such as garlic (Allium sativum), celery (Apium graveolens), Black Cumin (Nigella sativa) and Ginseng (Panax) are among the most common and therapeutically used plant derivatives for controlling hypertension while Asteraceae, Apiaceae and Rosaceae are among the botanical families which were frequently studied in the last decade. Isolated compounds such as allicin and apigenin have received more interest in this field. Recent evidence from clinical trials suggests that a wide variety of herbal preparations and plant extracts or natural isolated compounds have a favorable therapeutic impact on blood flow. Interestingly, phytochemicals can either act directly on blood vessels via a vasorelaxant effect involving a variety of signaling cascades or indirectly through inhibiting or stimulating diversity of systems such as angiotensin-converting enzyme (ACE), renin-angiotensin system (RAS) or the diuretic activity. Hence, based on the findings of the present review medicinal plant derivatives could be used as preventive and curative agents in the case of cardiovascular disorders, particularly hypertension and could play a promoting function for the discovery of new antihypertensive agents.

CONCLUSION

The analysis of the published data shows that a great effort remains to be done to investigate the medicinal plants cited as antihypertensive through published ethnopharmacological surveys. The analysis of the literature in this field shows the lack of standardization at the level of experimental study methods as well as the need to study purified molecules. Moreover, the mechanistic studies when they exist remain in the whole partial. On the other hand, few advanced clinical studies have been conducted. Finally, the determination of the efficacy/safety ratio remains absent in almost all studies.

Ethnomedicinal Plants Used for the Treatment of Cardiovascular Diseases by Healers in the Southwestern State of Paraná, Brazil, and Their Validation Based on Scientific Pharmacological Data

Cardiovascular diseases are responsible for high morbidity and mortality rates worldwide. Among treatment options, medicinal plants are frequently used, especially in developing countries, such as Brazil. Despite social development that has been observed in the last decades, the use of medicinal plants is still driven by popular knowledge, especially by healers. The present study sought to identify medicinal species that are used for the treatment of cardiovascular diseases by healers in the microregion of Francisco Beltrão, Paraná, Brazil. The snowball technique was used to select informants, and data were collected through interviews. The research was performed in two stages: (1) a structured interview and (2) the collection and botanical identification of the species that were mentioned by the healers. Medicinal plants were classified into the following categories of cardiovascular agents: hypotensive and antihypertensive agents, lipid-lowering agents, diuretic agents, and cardiotonic agents. To analyze the data, the frequency was determined, Spearman correlations were calculated, and the informant consensus factor (ICF) and use value were obtained. Some characteristics, such as female gender and old age, were associated with knowledge about medicinal plants. Overall, 77 different species and 149 medicinal uses were cited by the healers. With regard to categories of use, the highest number of species was found among lipid-lowering plants, and the highest ICF was found for species that are used as cardiotonics. Moreover, a literature review indicated that among the cited species, several still lack studies that have proven their effects on the cardiovascular system. The traditional use of medicinal plants for the treatment of cardiovascular diseases is broad in the study regions. The present results are important for clarifying popular knowledge in this region and providing a framework for selecting species with potential for the development of new pharmacological studies.

Ruta Montana Evokes Antihypertensive Activity Through an Increase of Prostaglandins Release in L-NAME-Induced Hypertensive Rats

AIMS

The aim of the study was to experimentally investigate the antihypertensive effect of Ruta Montana.

BACKGROUND

Ruta montana L. is traditionally used in Moroccan herbal medicine to treat hypertension. This study aimed to experimentally evaluate the hypotensive and vasoactive properties of this plant.

OBJECTIVE

The objective of the study was to evaluate the effect of the aqueous extract of Ruta Montana on blood pressure parameters in LNAME-induced hypertensive rats and to determine the vasorelaxant activity of this aqueous extract.

METHODS

The antihypertensive effect of the aqueous extract obtained from Ruta montana aerial parts (RMAPAE) (200 mg/kg) was evaluated in normal and anesthetized hypertensive rats. Blood pressure parameters (systolic blood pressure (SBP), mean blood pressure (MBP) and diastolic blood pressure (DBP)) and heart rate were measured using a tail-cuff and a computer-assisted monitoring device. The acute and chronic effect of RMAPAE was recorded for 6 hours for the acute experiment and for 7 days for the sub-chronic test. In the other set, the vasorelaxant effect of RMAPAE on the contractile response was observed in the isolated thoracic aorta.

RESULTS

The results indicated that the RMAPAE extract significantly decreased SBP, MBP, DBP and heart rate in L-NAME-induced hypertensive rats. Furthermore, RMAPAE was demonstrated to induce a dose-dependent relaxation in the aorta precontracted with Epinephrine or KCl. More interestingly, this vasorelaxant activity of RMAPAE seems to be probably mediated through the prostaglandins pathway.

CONCLUSION

The present study illustrates the beneficial action of Ruta montana on hypertension and supports its use as an antihypertensive agent.

An Overview of the Potential Use of Ethno-Medicinal Plants Targeting the Renin-Angiotensin System in the Treatment of Hypertension

The development of risk factors associated with cardiovascular disorders present a major public health challenge in both developed countries and countries with emerging economies. Hypertension and associated complications including stroke and myocardial infarction have reached pandemic levels. Current management strategies of hypertension predominantly include the utilization of pharmaceutical drugs which are often associated with undesirable side effects. Moreover, the drugs are often too expensive for populations from resource-limited Southern African rural, and some urban, communities. As a result, most patients rely on ethno-medicinal plants for the treatment of a variety of diseases including cardiovascular and metabolic disorders. The effectiveness of these plants in managing several cardiovascular diseases has been attributed to the presence of bioactive phytochemical constituents. In this review, the treatment options that target the renin-angiotensin system (RAS) in the management of hypertension were summarized, with special emphasis on ethno-medicinal plants and their influence on the ACE1 RAS pathway. The dearth of knowledge regarding the effect of ethno-medicinal plants on the ACE2 pathway was also highlighted.

Cardiovascular Effects of Micromeria graeca (L.) Benth. ex Rchb in Normotensive and Hypertensive Rats

AIMS

The present study was performed in order to analyze the antihypertensive activity of Micromeria graeca (L.) Benth. ex Rchb.

BACKGROUND

Micromeria graeca (L.) Benth. ex Rchb is an aromatic and medicinal plant belonging to the Lamiaceae family. This herb is used to treat various pathologies such as cardiovascular disorders. Meanwhile, its pharmacological effects on the cardiovascular system have not been studied.

OBJECTIVE

The present study aimed to evaluate the effect of aqueous extract of aerial parts of Micromeria graeca (AEMG) on the cardiovascular system in normotensive and hypertensive rats.

METHODS

In this study, the cardiovascular effect of AEMG was evaluated using in vivo and in vitro investigations. In order to assess the acute effect of AEMG on the cardiovascular system, anesthetized L-NAME-hypertensive and normotensive rats received AEMG (100 mg/kg) orally and arterial blood pressure parameters were monitored during six hours. In the sub-chronic study, rats were orally treated for one week, followed by blood pressure assessment during one week of treatment. Blood pressure was measured using a tail-cuff and a computer-assisted monitoring device. In the second experiment, isolated rat aortic ring pre-contracted with Epinephrine (EP) or KCl was used to assess the vasorelaxant effect of AEMG.

RESULTS

Oral administration of AEMG (100 mg/kg) provoked a decrease of arterial blood pressure parameters in hypertensive rats. In addition, AEMG induced a vasorelaxant effect in thoracic aortic rings pre-contracted with EP (10 μM) or KCl (80 mM). This effect was attenuated in the presence of propranolol and methylene blue. While in the presence of glibenclamide, L-NAME, nifedipine or Indomethacin, the vasorelaxant effect was not affected.

CONCLUSION

This study showed that Micromeria graeca possesses a potent antihypertensive effect and relaxes the vascular smooth muscle through β-adrenergic and cGMP pathways.

Study of Antihypertensive Activity of Anvillea radiata in L-Name-Induced Hypertensive Rats and HPLC-ESI-MS Analysis

OBJECTIVE

This study aimed to evaluate the effect of the aqueous extract of Anvillea radiate (A. radiata) aerial parts (AEAR) on arterial blood pressure in normotensive and hypertensive rats.

METHODS

The effect of the acute and sub-chronic administration of AEAR on the following blood pressure parameters: systolic blood pressure (SBP), mean blood pressure (MBP), diastolic blood pressure (DBP), and heart rate (HR) was evaluated in normotensive and L-NAME induced hypertensive rats. In the second experiment, the vasorelaxant effect of AEAR was assessed in isolated aortic rings from rats with functional endothelium pre-contracted with epinephrine (EP) or KCl, and six antagonists/ inhibitors were used to explore the mechanisms of action involved in the vasorelaxant effect. In order to determine the phytochemical contents of Anvillea radiata, HPLC-ESI-MS analysis was conducted.

RESULTS

Daily oral administration of AEAR (100 mg/kg) provoked a significant decrease in SBP, MBP, and DBP without affecting HR in hypertensive rats. In addition, AEAR (0.08-0.64 mg/ml) revealed a vasorelaxant effect in thoracic aortic rings pre-contracted by EP (10 μM) or KCl (80 mM). This effect was reduced in the presence of Nifedipine, L-Name or Methylene blue. The polyphenolic compounds of AEAR were determined.

CONCLUSION

This study revealed that AEAR possesses a potent antihypertensive activity and its vasorelaxant activity seems to be mediated through Ca2+ channels, direct nitric oxide (NO), and NO/cGMP pathways. Chlorogenic acid and caffeic acid identified in A. radiata could be at least partially responsible for the antihypertensive activity of this extract.

Antihypertensive activity of Petroselinum crispum through inhibition of vascular calcium channels in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Parsley (Petroselinum crispum; P. crispum) is among the popular aromatic vegetables and a part of the daily diet in the Mediterranean area. This plant is widely used in alternative medicine as a remedy against hypertension.

THE AIM OF THE STUDY

The aim of the study was to evaluate the antihypertensive activity of the aqueous extract of this plant.

MATERIAL AND METHODS

In the current study, the aqueous extract of the aerial parts of parsley (AEPC) was prepared and its antihypertensive activity was evaluated using in vivo and in vitro studies. In the in vivo investigation, anesthetized L-NAME-hypertensive and normotensive rats received orally AEPC (160 mg/kg) during 6 h for the acute experiment and during seven days for the sub-chronic treatment. Thereafter, systolic, diastolic, mean arterial blood pressure and heart rate were recorded using a tail cuff and a computer-assisted monitoring device. Concerning the in vitro investigation, isolated thoracic aortic rings were suspended in a tissue bath and the tension changes were recorded to a data acquisition system.

RESULTS

The results indicated that AEPC extract decreased the systolic, diastolic, mean arterial blood pressure in normotensive and hypertensive rats. The data revealed that parsley extract exerts its hypotensive effects through vasodilatory properties via an endothelium-independent pathway. More interestingly, the study demonstrated here that the vasorelaxing ability of AEPC is exerted through both Voltage Operated and Receptor Operated Calcium Channels (VOCC and ROCC).

CONCLUSION

The study illustrates the beneficial action of P. crispum as an antihypertensive agent.

Medicinal plants used for hypertension treatment by folk healers in Songkhla province, Thailand

ETHNOPHARMACOLOGICAL RELEVANCE

Hypertension is the most dominant risk factor for the development of cardiovascular, kidney, and eye diseases. In Thailand, illness and hospitalisation in the modern public health system due to high blood pressure is increasing. However, some Thai people have turned their attention to the use of herbal medicines for healthcare. Therefore, this study aimed (1) to study the folk knowledge of hypertension treatment and (2) to study plant utilisation in the treatment of high blood pressure by Songkhla folk healers.

MATERIALS AND METHODS

Field surveys and semi-structured interviews about theories of disease, principles of healing, and herbal usage (plant species, parts used, preparation, and application methods) were gathered. The data were analysed by descriptive statistics. The literatures regarding medicinal plants used in any traditional medicine, antihypertension activity, and toxicity was reviewed.

RESULTS

Most healers believed that hypertension was caused by the disorder of fire and wind elements in the body. The medicinal plants containing hot and mild tastes, which had the potential for treating problems in the wind element, were applied. A total of 62 species were used for hypertension treatment. Most plants were in the Asteraceae, Piperaceae, Rutaceae, or Zingiberaceae family (4 species each). Herbal medicines were preferred to be prepared by boiling (78%) and consumed by drinking 1 teacup before 3 meals each day (26%). Piper retrofractum and Cleome viscosa had the greatest Frequency of Citation (FC = 6, n = 14). Thirty-seven species have been reported for use in traditional medicine. Twenty-four and 46 species have already been investigated for antihypertension activity and toxicity, respectively.

CONCLUSION

Identifying medicinal plants that have been tested by experienced folk doctors would provide an opportunity for people to choose and consume local herbs that are easy to access in their local area. However, the remaining plants that have not been studied for antihypertension activity and toxicity should be further analysed to confirm their efficacy.