Another excellent natural remedy for high blood pressure is eating a fruit called mangaba or drinking a mangaba bark tea.

This plant helps with vasodilation, lowering blood pressure. Add the bark to the boiling water and let the mixture soak for a few minutes.

Cover the pot, let the tea cool down and then strain. You can drink two to three cups per day. The DASH diet is widely recommended for the prevention and treatment of hypertension in adults.

This diet involves the reduction of saturated fat and cholesterol and emphasizes the importance of fruits, vegetables and low-fat dairy products in daily meals.

Patients should aim to incorporate dietary and soluble fiber, whole grains and protein from plant sources into every meal. Patients who have been diagnosed with high blood pressure may be advised to additionally reduce their potassium intake, as increased potassium levels and contribute to high blood pressure.

Horsetail tea is an excellent natural diuretic that increases the production of urine and eliminates excess fluid from the body. It can be a great tea for lowering blood pressure in people who have a lot of fluid retention, as the excess water in the body causes more stress on the heart, which can worsen hypertension.

Despite its benefits, this tea should only be taken occasionally, for instance, when it is harder to control blood pressure with other methods and when there is a lot of fluid retention. This tea must not be taken for more than one week, as it also leads to the elimination of important minerals through the urine.

Place the horsetail leaves in the boiling water and let the mixture sit for five to ten minutes. Then strain the mixture and drink the tea while it is warm. This tea can be taken two to three times a day. Valerian roots have excellent calming and relaxing properties that help improve blood circulation.

In addition, valerian tea acts directly on the GABA neurotransmitter, which can help those who suffer from frequent anxiety attacks and have high blood pressure as a result.

Place the valerian roots in a cup of boiling water and let the mixture soak for five to ten minutes. Then strain with a mesh sieve and drink two to three times a day. In some people, valerian tea can cause sleepiness during the day. If you experience any drowsiness, it should only be used at bedtime.

Some patients may benefit from relaxation techniques if stress or anxiety plays a role in elevated blood pressure readings. Individualized cognitive behavioral therapies are found to be effective, as well as meditation, yoga or acupuncture.

Learn more about soothing herbs that can be used to treat stress and anxiety naturally. Please follow the instructions in that email so that we can continue to contact you and respond to your inquiry.

Tea is a great natural diuretic that can help increase urine production and reduce water retention. They can also be a great option to Some home remedies, like lemon juice and honey, ginger syrup with cinnamon, or peppermint tea, contain substances with expectorant, To make yourself throw up, there are tips for reducing discomfort, like washing your hands and drinking water.

The vomit reflex should only Soursop is a fruit with a green peel and spikes on the outside, and a soft, white pulp on the inside. It tastes sweet and is slightly High creatinine levels in the blood can occur from normal occurrences, like mild dehydration or eating more protein, but it can also be a Some of the best home remedies to treat gastritis include teas such as maytenus ilicifolia tea or Brazilian peppertree tea and juices To detox the liver, you should prioritize food like fruits, vegetables and tea like green tea or artichoke tea.

You should try to avoid Detox drinks contain antioxidant and diuretic properties, which helps with weight loss and fluid retention. In addition, natural juices Tua Saúde Health A-Z Diseases and Conditions.

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Assuming a homeostatic imbalance, the following signaling molecular entities become integral to the pathogenesis of hypertension Ong and Whitworth, ; Montezano and Touyz, Fortunately, a diverse range of plant and herbal extracts and their individual metabolites can modulate signaling cascades implicated in the physiology of the cardiovascular system see Section Herbs and Spices Most Commonly Used for Treatment of Hypertension, below.

These herbs are not only vasculo-protective but they could also potentially reverse the changes in hypertension.

This particularly applies if the alterations in hypertensive patients are addressed prior to reaching a decompensated state. In good health, the activity of pro-oxidants is balanced by anti-oxidative agents.

However, when this equilibrium is disturbed, the un-orchestrated milieu leads to pathologic states, such as hypertension, atherosclerosis, and other vascular complications Figure 1 ; Montezano and Touyz, ROS are produced from the reactivity of nicotinamide-adenine dinucleotide phosphate NADPH oxidase and many other enzymatic reactions particularly ones related to the electron transport chain within the mitochondria Zeng et al.

The oxidant molecules are inactivated by antioxidant enzymes such as superoxide dismutase SOD , catalase CAT , glutathione peroxidase GPX , and non-enzymatic substances like reduced glutathione GSH; Song and Zou, Recent evidence suggests that AMPK can also suppress the activity of NADPH oxidase Song and Zou, An increase in the amount of ROS, and the corresponding fall in intracellular endothelial antioxidant levels Zeng et al.

The oxidative stress leads to endothelial cell dysfunction and vascular smooth muscle remodeling by reducing NO bioavailability Zeng et al.

ROS are also responsible for the oxidation of low-density lipoprotein LDL , which results in inflammation and increased proliferation of VSMCs Slevin et al.

Both inflammation and enhanced proliferation significantly trigger plaque formation Slevin et al. Interestingly, blocking ROS production by exposure to antioxidants has been shown to reduce blood pressure in rodents Zeng et al. A key molecule that regulates oxidative stress in VSMCs is the transcription factor erythroid 2-related factor 2 Nrf2, or nuclear factor erythroid 2-like 2.

Under physiological conditions, Nrf2 activity is inhibited by its endogenous inhibitor Kelch-like ECH-associated inhibitor 1 Keap1; Villeneuve et al. On the other hand, when oxidative stress ensues, Keap1 releases Nrf2, which then translocates to the nucleus and promotes expression of different antioxidant enzymes such as CAT, GPX, heme oxygenase-1 HO-1 , SOD Kern et al.

Pertinently, various phytochemicals suppress oxidative stress by upregulating antioxidant enzymes through the Keap1—Nrf2 pathway Tao et al. Nitric oxide NO is often recognized as an important indicator of vascular health.

It plays an important role in blood pressure regulation due to its vasodilating potency Francis et al. NO is produced from L-arginine Francis et al. After its release, NO translocates into VSMCs and activates soluble guanylate cyclase sGC , which then catalyzes the conversion and cyclization of guanosine triphosphate GTP to cGMP Francis et al.

cGMP then binds to cGMP-dependent protein kinases PKGs; Francis et al. Within seconds of its production, NO reacts with superoxide anions Drummond et al. This in itself is a selective oxidant and can precipitate oxidative stress as well as diminish the vasodilatory effect of NO Drummond et al.

As such, the concentration of ROS has a direct impact on the bioavailability of NO. Interestingly, oxidative stress can also induce eNOS uncoupling, so that eNOS generates free radicals instead of NO.

This peroxynitrite then oxidatively degrades the eNOS cofactor tetrahydrobiopterin BH 4 to the inactive dihydrobiopterin BH 2.

Effectively, this yields more superoxide anion that eventually depletes BH 4. Therefore, a shift in balance from NO to superoxide formation ensues; this is referred to as uncoupling of NOS Michel and Vanhoutte, As such, the interplay between NO and the regulatory mechanisms governing its bioavailability are thus intimately intertwined with vascular tone and endothelial dysfunction Montezano and Touyz, Hydrogen sulfide H 2 S is an important biological mediator produced in VSMCs and potentially endothelial cells via the catalysis of L-cysteine by the enzyme cystathionine γ-lyase CSE; Calvert et al.

It has been reported that deficiency in H 2 S production is positively correlated with pathophysiology of hypertension in several animal models Benavides et al.

Indeed, CSE activity and H 2 S levels were notably decreased in the aorta and plasma of SHR, respectively Yan et al.

In addition, there was a significant increase in BP levels of Wistar Kyoto WKY rats treated with DL-propargylglycine PPG , a CSE inhibitor Yan et al. Furthermore, administration of H 2 S is sufficient to abolish the N ω -nitro-L-arginine methyl ester hydrochloride L-NAME, an inhibitor of nitric oxide synthase -induced hypertension in WKY rats Zhong et al.

At the molecular and cellular levels, H 2 S exhibits a vasorelaxant effect on VSMCs by increasing intracellular levels of cGMP Bucci et al.

Interestingly, H 2 S has also been reported to prevent vascular inflammation Calvert et al. The Renin—Angiotensin—Aldosterone RAA system plays a pivotal role in regulating blood pressure Nguyen Dinh Cat and Touyz, Activation of the RAA system in response to a decrease in cardiac output leads to the secretion of renin, which in turn catalyzes the conversion of angiotensinogen to angiotensin I Ang I.

Ang I is then cleaved by Angiotensin Converting Enzyme ACE -1 ACE-1 to form Angiotensin II Ang II. Ang II-mediated hypertension occurs by promotion of sodium and water retention as well as enhancement of vasoconstriction by binding to the angiotensin type 1 AT 1 receptor Morgan, ; Nguyen Dinh Cat and Touyz, ; Savoia et al.

Activation of AT 1 receptors is known to trigger the proliferation of VSMCs Castro et al. The fact that ACE is present in several tissues, including arteries, indicates that Ang II can be formed locally within the arteries themselves.

Indeed, there is a higher concentration of Ang II in the vasculature of hypertensive compared to normotensive rats Ma et al.

Taken together, these observations may explain why inhibiting ACE is an attractive approach for antihypertensive therapies Morgan, ; Bernstein et al. Ang II induces aldosterone production Oparil et al. Blockade of AT 1 receptors improves endothelial dysfunction Virdis et al.

Accumulating evidence demonstrates that Ang II also stimulates NADPH oxidase to generate ROS Ma et al. In addition, Ang II may increase the sympathetic nervous system SNS activity Manrique et al.

Inflammation is well-documented to contribute to vascular remodeling and consequent hypertension Vazquez-Prieto et al. Nuclear Factor kappa B NF-κB , a transcription factor, is known to partake in the pathology of hypertension. It induces endothelial cell dysfunction, oxidative stress, and inflammation Li and Zhuo, ; Kang et al.

It has been shown that increased expression and activation of NF-κB contributes to renal injury and hypertension Elks et al. Indeed, suppressing NF-κB with pyrrolidine dithiocarbamate PDTC decreased SBP in spontaneous hypertensive rats SHRs; Elks et al.

Interestingly, PDTC also suppressed the higher concentration of cytosolic and mitochondrial ROS in kidneys of these SHRs Elks et al. Activation of NF-κB could be induced by several factors such as Ang II Kang et al. Interestingly, TNF-α-induced ROS production, which drastically impacts endothelial dysfunction, is shown to be mediated by NF-κB Zhang et al.

Moreover, NF-κB plays an important role in attenuation of ANG II-induced pressor response Kang et al. Further, NF-κB can increase proliferation, decrease apoptosis of endothelial cells, as well as stimulate expression of vascular cell adhesion molecule-1 VCAM-1; Vazquez-Prieto et al.

Taken together, these NF-κB-induced changes can lead to the derangement of endothelial function and vascular tone. Secondary metabolites of herbs and spices exhibit anti-hypertensive effects.

Here, we present a comprehensive alphabetical list of herbs for which sound evidence suggests they could be beneficial in hypertension therapy Tables 1 — 6 ; Figure 1. Garlic's multi-fold therapeutic effects have been recognized for thousands of years amongst different cultures around the world, and continues to attract interest from pharmacologists and health practitioners Frishman et al.

This herb is not only known for its hypotensive capacity, but is also characterized by anti-inflammatory, antioxidant, antibacterial, hypocholesteremic, and anti-cancer properties Banerjee et al. For health benefits, garlic can be consumed in different forms, such as raw, aged, an aqueous extract, oil, and in powder form Banerjee et al.

Several mechanisms have been alluded to in the explanation of garlic's hypotensive effects Shouk et al. These are based on garlic's organo-sulfur constituents such as Allicin, S-allylcysteine SAC , diallyl disulfides DADS , diallyl trisulfides DATS , and methyl thiosulfonate Banerjee et al.

Many hypertensive patients use garlic to lower their blood pressure Qidwai and Ashfaq, The reported effects vary from significant reduction in mean arterial pressure, drop in either SBP or DBP only, to no alteration in blood pressure at all Banerjee et al.

However, most studies confirm the induction of hypotensive effects by garlic and its constituents. Banerjee and Maulik reviewed pertinent literature and concluded that different forms of garlic can reduce SBP, DBP, or both Banerjee et al. Interestingly, evidence from meta-analysis studies indicates that aged garlic extract AGE produces consistent lowering of blood pressure compared to other forms of garlic.

A recent meta-analysis of randomized, controlled trials concluded that garlic supplements induce a significant reduction in both SBP and DBP by 3.

Similarly, another meta-analysis on randomized, controlled trials also reported a significant decrease in SBP by 4. This effect appears to be due to the principle constituent S-allylcysteine, which is relatively more stable in relation to allicin Ried et al.

This study reported a significant decrease in SBP and DBP by a maximum of 9. Analysis of assays on antioxidant ability of different forms of garlic demonstrate far greater potency in aged extracts than other types of garlic clove derivatives Mathew and Biju, Indeed, AGE potently scavenges ROS Drobiova et al.

In comparable studies, Drobiova et al. The superoxide scavenging abilities of AGE have also been demonstrated in human neutrophils Morihara et al. The endogenous signaling gases, NO and H 2 S, are recognized as mediators of garlic's antihypertensive properties Banerjee et al. This is thought to occur through the reaction between NO and the sulfide components of garlic Ku et al.

An ethanolic extract of garlic 0. In addition, garlic does not merely increase H 2 S production, but induces its synthesis for vasorelaxant activity Benavides et al. In their study, Benavides et al. Moreover, treatment with 50 μM garlic-derived DADS induce an increase in expression of Connexin Cx43 , a gap junction protein whose expression is correlated with a reduced VSMC proliferation and DNA synthesis Joshi et al.

Garlic's ability to inhibit ACE activity has also been recognized Sendl et al. Constituents of Garlic dampen Ang II-induced vasoconstrictor responses, antagonize endothelin-1 induced vasoconstriction, inhibit VSMCs proliferation in smooth muscles isolated from SHR and abrogate the activation of NF-κB Banerjee et al.

These effects are modulated by Allicin after the reaction of Alliin with the enzyme Alliinase Frishman et al.

Despite having these multifarious therapeutic effects, garlic also produces a few minor side effects. Several articles report garlic's ability to cause abdominal swelling, heartburn, flatulence, and acid reflux Yang et al. Individuals under anticoagulant management are advised to avoid garlic consumption throughout the duration of treatment as the anti-hemostatic effect may be far more potent and detrimental Qidwai and Ashfaq, paniculata has been part of eastern and southeastern Asian traditional medicine as a treatment for cold, CVDs Awang et al.

It has been shown to possess anti-bacterial, anti-inflammatory Awang et al. Several hypotensive labdane-type diterpenoid compounds have been identified in Andrographis paniculatia extracts. These include andrographolide, deoxy,didehydroandrographolide and deoxyandrographolide Awang et al.

However, no clinical trials have yet been conducted using A. Treatments with extracts of A. paniculata decrease ACE and ROS activities in spontaneously hypertensive rats SHR leading to a decrease in BP Zhang and Tan, ; Table 1.

Moreover, crude extracts with high content of deoxy,didehydroandrographolide induced dramatic hypotensive effects Awang et al. This was apparently due to increased NO release which consequently induced vasodilation Awang et al. In addition to its antioxidant Lobo et al.

Other reports also indicate that A. paniculata exhibits anti-inflammatory activities in natriuretic peptide receptor-A Npr1 -gene knockout mice Das et al. The hypotensive effect of celery has been reported in in vivo animal studies.

Hexanic extract was by far the more potent in lowering BP in comparison to other solvent extracts. This was explained by greater retention of n-butylphthalide, which has been identified as the source of celery's flavor and aromatic odor Moghadam et al.

Similarly, this phthalide was reported to decrease BP in another animal model of hypertension SHRs; Tsi and Tan, Apigenin, a flavone isolate of A.

The inhibition of calcium entry from extracellular sources was also responsible for apigenin-dependent relaxation of noradrenaline-preconstricted rat isolated aorta. This action was not influenced by either methylene blue, endothelial denudation, indomethacin, nifedipine, or caffeine, and the concentration of intracellular signaling molecules cAMP, cGMP, and inositol monophosphate were unaltered Ko et al.

Importantly, extracts and constituents of celery have been reported to lower arterial pressure in humans, possibly by lowering levels of circulating catecholamines and decreasing vascular resistance Houston, Interestingly, this herb can reduce oxidative stress by virtue of its flavonoid content that potentiates antioxidant mechanisms Popovic et al.

This plant belongs to the family Asteraceae and has several common names: beggar's tick, black-jack, and broom stick. In addition to exhibiting antihypertensive effects, B. pilosa also possesses anti-cancer, anti-bacterial, anti-malarial, and anti-obesity properties Bartolome et al.

As of yet, no clinical trials have determined the potential effect of this plant on hypertension. However, extracts of its leaves were able to prevent and attenuate high blood pressure in different hypertensive rat models SHRs and fructose-fed hypertensive rats as well as normotensive Wistar rats Dimo et al.

Using the same animal model, it was also shown that a 3-week treatment with aqueous and methylene chloride extracts of B.

pilosa can prevent fructose-induced hypertension Dimo et al. There are conflicting reports regarding B. piloas 's effect on insulin sensitivity, with some studies showing improvement in insulin sensitivity Dimo et al.

However, there is a definite agreement on its vasorelaxant responses Dimo et al. Cumulative doses of a neutral extract of B. pilosa with an optimum concentration of 0. The mechanism of vasodilation has not been completely deciphered.

It appears to be independent of ATP-sensitive potassium channels, but possibly involves a calcium channel antagonism and cyclooxygenase metabolite Nguelefack et al. Importantly, the crude extract, its fractions or the isolated phytochemicals of B. pilosa have been reported to display radical scavenging ability Bartolome et al.

Two of these compounds, luteolin a flavonoid and ethyl caffeate ester of hydroxycinnamic acid , exhibit potent anti-inflammatory activities. For example, luteolin blocked the effects of inflammatory cytokines, TNF-α, and IL-6 Xagorari et al.

Moreover, both luteolin Xagorari et al. Collectively, the teas prepared from Camellia sinensis are the most frequently consumed beverages and are second only to water, worldwide Faria et al.

Tea has pleiotropic effects including antibacterial, anti-inflammatory Deka and Vita, , anti-cancer, anti-diabetic, as well as antihypertensive actions Deka and Vita, ; Table 1.

The data on the hypotensive effect of tea are not concrete. Hodgson et al. reported increases in BP after 30 min of consuming tea, with the BP returning to its baseline value after 60 min Hodgson et al. Another study suggested that green tea causes a decrease in SBP for participants with BP of mmHg or higher Nagao et al.

A meta-analysis of five trials came to conclusion of no change in blood pressure subsequent to drinking tea Taubert et al. However, a more recent meta-analysis study of randomized controlled trials demonstrated that green tea reduces both SBP and DBP by 1.

Likewise, other meta-analysis of randomized controlled trials came to the same conclusion that green tea reduces SBP and DBP by 1. Interestingly, it was reported that green tea evoked a more powerful hypotensive effect compared to black tea, and that long-term tea consumption produced a more significant SBP and DBP reduction.

Moreover, in a double-blind, placebo-controlled trial, obese hypertensive patients who received mg green tea extract for 12 weeks exhibited a significant decrease in SBP and DBP by 4 mmHg each Bogdanski et al. It is important to note here that ingestion of green or black tea 7.

EGCG constitutes the primary component of tea's total catechins Babu and Liu, ; Faria et al. Constituents of tea lessen the risk of hypertension through several mechanisms, such as attenuation of oxidative stress Table 1. Green tea has been reported to increase CAT antioxidant enzyme while simultaneously blocking AT 1 receptors in streptozotocin-treated rats Thomson et al.

Another mechanism for oxidative stress reduction by tea is the inhibition of eNOS uncoupling Faria et al. In addition, green tea has the capacity to scavenge superoxides Nakagawa and Yokozawa, in vitro as well as attenuate NAPDH oxidase production Ribaldo et al.

Flavonoids are noted for their vasorelaxant responses, including flow-mediated Ras et al. Black tea catechins are converted by an enzymatic polyphenol oxidase and peroxidase oxidative polymerization reaction to tannins: theaflavins benztropolone ring and thearubigins, both of which are orange-red colored polyphenolic pigments that are also potent vasodilators Yang et al.

A couple of clinical studies have reported black tea's positive effect on flow-mediated dilation FMD , an index of endothelial function Duffy et al.

In a clinical trial, Oyama et al. The data revealed a significant increase in blood flow due to an augmented release of NO with a concomitant decrease in levels of both asymmetrical dimethylarginine an endogenous inhibitor of eNOS and oxidative stress Oyama et al.

The bioactive components of tea are reported to express anti-inflammatory properties Table 3 , reflected by mitigated expression and release of different cytokines.

In other studies, EGCG Ludwig et al. In addition, EGCG was able to inhibit NF-κB activation in human endothelial cells Hong et al. Interestingly, EGCG derived from green tea also elicited a concentration-dependent inhibition of proliferation in human aortic VSMCs by increasing HO-1 enzyme expression Liu et al.

Coptis chinensis , commonly known as Chinese goldthread, is widely used in Chinese folk medicine Affuso et al. Evidence indicates that goldthread, and its main component Berberine BBR , have the ability to lower blood pressure Affuso et al.

Indeed, a recent meta-analysis of twenty-seven randomized controlled trials involving patients reported that BBR can cause a significant hypotensive effect Lan et al. In addition, this meta-analysis concluded that combined with an oral hypotensor, BBR can significantly reduce BP more than the hypotensor alone can do.

The magnitude of the decrease was determined to be an average of 4. Several mechanisms have been proposed for Chinese goldthread's antihypertensive effect.

One mechanism appears to be via amelioration of oxidative stress Zhang et al. Constituents of goldthread also act by relaxing arterial tissues through endothelial-dependent and independent routes Affuso et al.

In chronic intermittent hypobaric hypoxic and normoxic animal models, goldthread has been shown to relax NE-induced contractions in rat isolated thoracic aortic rings Zhang et al. The same authors also reported BBR's vasorelaxant activity on KCl-induced contractions using the same models Zhang et al.

Apparently, BBR elevates the expression of eNOS with a concomitant rise in NO release that leads to enhanced flow-mediated vasodilation Affuso et al.

In a clinical study, BBR 1. In addition, BBR isolate of Chinese goldthread inhibits endothelial injury Wang et al. It also improves lipid profile by reducing total and LDL cholesterol, and cardiac muscle hypertrophy Zhang et al.

Table 4. Commonly used antihypertensive plants with anti-proliferative activity. In several countries, coriander also known as cilantro or dhania is not only used as a culinary ingredient Anilakumar et al.

To the best of our knowledge, no clinical trials have been conducted to assess coriander's effects on BP. However, coriander has been reported to exhibit antioxidant properties Sreelatha et al. Coriander leaves' extracts also increased antioxidants enzymes Sreelatha et al.

Other studies have also reported similar antioxidant activities of coriander Cioanca et al. Vasodilatory effects of coriander are well-established. The same report also showed that coriander fruit extracts produced dose-dependent relaxation of pre-constricted phenylephrine and potassium chloride rabbit aortas, and this response was atropine and calcium-channel dependent Jabeen et al.

Further, the same extracts showed diuretic affects as well. The active component of which should act synergistically with the vasoactive constituent to complement the treatment and management of hypertension Jabeen et al. Moreover, coriander acts as an inhibitory agent to reduce the activities of NF-κB and iNOS Wu et al.

Hawthorns hawberry or thorn apple plants are shrubs that belong to a genus comprising almost species Tassell et al. Hawthorns have been used for treatment of CVDs since the seventeenth century Asher et al. Modest decreases in blood pressure have been observed in a few human-based studies with a demographic of hypertensive patients Walker et al.

In a randomized, double-blind, placebo-controlled study where mildly hypertensive subjects were treated with mg of hawthorn extract for 10 weeks, a promising tendency for a reduction in DBP by It is argued that the dose and duration were not sufficient for a more effective result to be noted.

Indeed, in phytotherapy practice, a significant decrease in BP is only noted after a longer duration and higher doses Bone and Mills, , In another randomized, double-blind, placebo-controlled clinical study, administration of hydro-alcoholic extracts of Crataegus curvisepala Lind flowers to hypertensive patients age range 40—60 years for 3 months induced a decrease in both SBP and DBP by around 13 and 8 mmHg, respectively Asgary et al.

The aforemnetioned antihypertensive actions are credited to the plant's multiple components: flavonoids hyperoside, quercetin, rutin, and vitexin and oligomeric proanthocyanidins OPCs, epicatechin, procyanidin, and procyanidin B-2; Valli and Giardina, ; Houston, ; Asher et al.

Quercetin, a major polyphenolic flavonoid in hawthorn shrubs, expresses numerous bioactive functions including anti-oxidant, anti-inflammatory, and vasorelaxant effects. Quercetin supplement intervention studies have demonstrated a reduction in blood pressure of hypertensive subjects Larson et al.

Interestingly, hawthorn extracts have an effect on both VSMCs and endothelial cells Tassell et al. The latter interaction is attributable to increased NOS activity and hence NO release Brixius et al.

In porcine isolated coronary arterial rings, WS an extract of Crataegus leaves with flowers induced endothelium-dependent relaxation through the activation of multiple signaling pathways, including ROS, Src, PI 3 -kinase, Akt, and eNOS Anselm et al. Moreover, WS caused endothelium-dependent and NO-mediated vasorelaxation of phenylephrine-preconstricted rings of rat aorta as well as human internal mammaria Brixius et al.

In the L-NAME-induced hypertension model, the blood pressure decreased after the administration of Crataegus tanacetifolia leaf extract or its isolate, hyperoside. Both C. tanacetifolia extract and hyperoside display protective effects at multiple levels.

These include improving hyperlipidemia, decreasing body weight, resolving hyperplasia, reducing thickness of the vascular medial layer as well as improving kidney function.

Such effects appear to be mediated by an increase in diuretic activity, efflux of water and sodium, as well as expression of NOS enzyme.

Together, all of these mechanistic actions contribute to the amelioration of hypertensive outcome Koçyildiz et al. As part of the integrated cardiovascular beneficial bioprocesses, hawthorn has the capacity to scavenge ROS Tassell et al.

Moreover, hawthorn extracts express anti-inflammatory activity, which is mirrored by the decline in concentrations of NF-κB, TNF-α Topal et al. Saffron common name , a plant indigenous to Southwest Asia Iran, Pakistan, and India , Spain, Greece, and Morocco, is a stemless herb whose medicinal values have been sought for over years Srivastava et al.

Saffron's main components include crocin, picrocrocin, safranal, and crocetin Srivastava et al. Several reports support the use of saffron for anti-hypertensive benefits.

A clinical study reported that mg of saffron tablets administered for 7 days were able to significantly reduce the SBP and mean arterial pressure in healthy humans by 11 and 5 mmHg, respectively Modaghegh et al. Saffron demonstrates vasorelaxant activities in different animal models.

Extracts of C. sativus petals rich in flavonoids and anthocyanins dose-dependently reduced the BP of male Sprague-Dawley rats, possibly by modulating peripheral vascular resistance Fatehi et al. Moreover, extract of C. Saffron relaxes non-vascular muscles as well.

In addition, safranal 0. Saffron's antioxidant ability has also been widely reported. It was shown to reduce oxidative stress El-Beshbishy et al. Moreover, saffron and its constituents also possess an inherent ability to inhibit inflammatory pathways, including NF-κB Nam et al.

Lemongrass common name has been widely used in traditional medicine of Brazil, China, and Southern Asia Devi et al. It has been reported to possess antihypertensive properties, which have been attributed to its active phytochemicals, the principle of which being Citral Devi et al.

However, no clinical trials have yet investigated the effect of Lemongrass on BP. The relaxant effect of lemongrass has been demonstrated in several different tissues, including the rabbit ileum Devi et al. For instance, Citral or crude extracts of C. citratus leaves, stems, or roots generated a dose-dependent vasorelaxation in phenylephrine pre-constricted aortic rings from male WKRs or SHRs Devi et al.

Likewise, administration of an intravenous bolus of Citronellol, an acyclic monoterpenoid isolated from lemongrass, to male Wistar rats produced a hypotensive response. This hypotensive effect was not affected by L-NAME, indomethacin, atropine, or hexamethonium Bastos et al. Citronellol also induced relaxation of rat superior mesenteric artery via an endothelium-independent mechanism.

Moreover, arteries denuded of endothelium were not reliant on tetraethylammonium-dependent potassium channels. Lemongrass is known to display moderate antioxidant activity. Results from another study showed an increase in antioxidant enzymes and molecules such as SOD and GSH in murine lungs after administering 5 and 10 μg of lemongrass' extracts Tiwari et al.

Lemongrass was reported to suppress ROS molecular activity Tiwari et al. In addition, lemongrass' Citral contributes to the anti-inflammatory pathways by inhibiting NF-κB Lee et al.

Hibiscus, widely known as roselle, is used for hypertension, fever, and other diseases in folk medicine. Different parts of this plant buds, calyx, flowers, leaves, and petals—fresh or dried are used for health purposes and as refreshing beverages, food items jams, preserves , or lotions.

Roselle's blood pressure lowering effects have been extensively reported in both animal Odigie et al. In a randomized, double-blind, Lisinopril-controlled clinical trial, antihypertensive effects were notable subsequent to treatment with dried extract of calyx mg for 4 weeks in patients with stage 1 or 2 hypertension Herrera-Arellano et al.

Indeed, a drop of BP from After 4 weeks, a significant decrease in SBP and DBP by Additional support for hibiscus' therapeutic role in ameliorating hypertension is provided by a report which shows that in mild and pre-hypertensive patients 65 subjects—30—70 years old , consuming roselle's tea ml—three times a day for 6 weeks significantly reduces SBP, DBP, and MAP by 7.

Different mechanisms for roselle's antihypertensive effect have been reported. Roselle primes the vasorelaxant pathways of both endothelial cells Ajay et al. Its relaxant effect is mediated through an increased production of NO Ajay et al.

Additionally, it has been shown to inhibit cardiac hypertrophy Odigie et al. A strong body of evidence is reported to support roselle's ability as a diuretic agent Onyenekwe et al.

One clinical study detected a lower concentration of uric acid in urine of healthy humans consuming roselle Ali et al. Another clinical study reflected the decrease in blood sodium content of stage 1 and 2 hypertensive humans after 4 weeks administration of mg of roselle's extracts Herrera-Arellano et al.

This diuretic activity is related to the vasorelaxant effect, as NO elevation is positively correlated with increases in renal filtration rates Alarcon-Alonso et al. Roselle exhibits potent antioxidant function Ali et al. In a clinical study, roselle's aqueous extracts enhanced the concentration of cellular antioxidants in healthy humans Frank et al.

Moreover, it blocks the oxidation of LDL, indicating its role as an anti-atherogenic Lin et al. Roselle also shows anti-inflammatory capacity by inhibiting not only ACE activity Herrera-Arellano et al.

The effect of roselle on ACE activity was confirmed in a Lisinopril-controlled clinical trial, where mg of its extract was administered to patients with stage 1 or 2 hypertension Herrera-Arellano et al.

Black cumin, also known as Habbatul barakah seed of blessing , has been used in the kitchens of Europe, the Middle East, Africa, and South and Southwest Asia for centuries Ahmad et al.

In addition to its antihypertensive role, black cumin is also effective against diabetes and gastrointestinal diseases Leong et al. Thymoquinone TQ , one of the most abundant and bioactive components in Nigella sativa 's seeds, has been identified as the major element in its healing effects Ahmad et al.

sativa , and its constituents, have been reported to lower blood pressure in humans and in different animal models of hypertension Zaoui et al. For example, L-NAME-induced hypertension in rats was ameliorated by concomitant treatment with thymoquinone 0. Improvement in renal function and antioxidant activity were also noted, evident by the reduced serum creatinine or increased glutathione in control vs.

L-NAME treated rats, respectively Khattab and Nagi, Likewise, in SHRs, an oral dose of dichloromethane extract of black cumin seeds 0.

A randomized, double-blind placebo-controlled clinical trial of the effects of N. sativa 's seed extract administrated orally either or mg, two times per 24 h for 8 weeks to mild hypertensive male patients recorded a dose-dependent fall in both SBP and DBP, in the two treated groups compared to placebo Dehkordi and Kamkhah, ; Table 6.

For the mg dose, there was a decrease of around 2. Moreover, the NS 's extract reduced total cholesterol as well as low density lipoprotein LDL -cholesterol relative to pretreatment concentrations Dehkordi and Kamkhah, Again, in a randomized, placebo-controlled, double-blind study with 70 healthy subjects, N.

sativa oil caused a significant decrease of Table 6. Commonly used plants that were studied in clinical trials, and details of these trials. Another route by which black cumin attenuates hypertension is by vasorelaxant means. Moreover, TQ is reported to inhibit the release of vasoconstrictor metabolites of COX-1 Ahmad et al.

TQ's antihypertensive effects are partly due to its antioxidant activities as it lowers oxidative stress Khattab and Nagi, ; Ahmad et al. Another mechanism that may explain the hypotensive effect of black cumin pertains to its diuretic action Zaoui et al.

This has been highlighted by the ability of black cumin seeds to increase urea, calcium, sodium, and potassium in urine of rats Zaoui et al.

Yet another mechanism that underlies black cumin's actions is its anti-inflammatory property since it inhibits the generation of TNF-α and NF-κB Kundu et al. For centuries, the species Panax , especially the Asian variety, has been used in folk medicine Jang et al.

Ginseng is prepared and administered in various forms, either as a solid: tablets, capsules, dried roots; or as a liquid: oil, extracts or tea Valli and Giardina, ginseng Asian or Korean ginseng , P.

quinquefolius American ginseng , P. japonicas Japanese ginseng and P. notoginseng Chinese ginseng are the four most common species of ginseng Valli and Giardina, ; Kim, Interestingly, these—as a group—have the most reported hypotensive effects. Heterogeneous triterpenoid saponins and steroid glycosides or ginsenosides or panaxosides are the active principle components of ginseng Valli and Giardina, ; Kim, In addition to anti-hypertensive effects, ginseng also plays anti-carcinogenic and antidiabetic roles Choi et al.

Although ginseng 's blood pressure lowering effect is widely reported Jeon et al. Contextually, low doses of ginseng raise BP, while higher concentrations are hypotensive Jang et al. A probable explanation for this phenomenon is the varied action of different ginsenosides Valli and Giardina, Therefore, these studies suggest that ginseng rheostatically adjusts the BP level in hypotensive patients Kim, , possibly by tuning vascular function, modulating the autonomic nervous system, or regulating the arterial baroreflex.

Several clinical trials have been conducted to assess the efficacy of ginseng in modulating BP Table 6. In one trial, P. Along the same line, another randomized, double-blind, crossover trial reported that central SBP and DBP of healthy subjects was significantly reduced by 4.

ginseng mg; Jovanovski et al. The primary mechanism associated with ginseng -induced hypotensive effect is attributed to an improvement in arterial function. Indeed, ginseng causes a dramatic increase in eNOS expression and NO production Valli and Giardina, ; Jang et al.

Ginsenoside Rg3 red ginseng is known to activate eNOS Valli and Giardina, ; Jang et al. Ginsenosides mediate vasorelaxation of different vessels in different animals: rat aortas Kim et al. In the same context, this relaxation may be aided by ginseng's ability to diminish secretion of adrenal catecholamines in hypertensive rats Jang et al.

Ginseng also elicits an anti-proliferative effect on VSMCs, and hence, it can be expected to possess antihypertensive and anti-atherosclerotic capacities Table 4.

quinquefolius for 12 weeks improves arterial stiffness in hypertensive patients Mucalo et al. Further support for this beneficial effect of ginseng comes from another clinical trial, where taking mg of P.

ginseng caused a significant reduction in aortic Alx, a marker of arterial stiffness Jovanovski et al. It has been reported that Chinese ginseng blocks the activation of extracellular signal-regulated protein kinases ERK pathway, and therefore inhibits PDGF-induced VSMCs proliferation Zhang et al.

Moreover, Chinese and other ginsengs reduced vascular aging of SHRs compared to WKY rats; this was reflected by inhibition of proliferation of VSMCs isolated from both WKY and SHRs. The mechanistic pathway for the effect of ginseng on SHR VSMCs entailed the decrease in the number of senescence-associated β-galactosidase SA-β-gal positive cells.

In the SHR, expression of p16, and retinoblastoma protein Rb was elevated whereas that of cyclin D1 and cyclin-dependent kinase 4 CDK4 was decreased Tao and Lei, Further, red ginseng also attenuated Ang II-induced VSMC growth Kim, Amongst ginseng 's other hypotensive mechanisms is its antioxidant ability Table 1.

In this regard, it has been reported that ginsenoside Rg1 60— μM inhibits oxidative stress Doh et al. In addition to its antioxidant effect, ginseng exhibits anti-inflammatory properties.

Indeed, Asian ginseng red inhibits the release of TNF-α Kim, as well as attenuates NF-κB and p38 mitogen activated protein kinase MAPK pathways Bak et al. It has been suggested that the consequence of this effect is a reduction in the vasoconstrictor activity of COX-2 enzyme Bak et al.

Danshen's most effective components include: salvianolic acid A SalA , salvianolic acid B SalB , danshensu, and tanshinones Ng et al. Danshen relaxes the vasculature via endothelium-dependent and endothelium-independent mechanisms. A combination treatment of danshen and gegen Pueraria lobata was shown to lower blood pressure in SHRs Ng et al.

Similarly, dihydrotanshinone lipophilic constituent of danshen is a vasorelaxant of rat coronary arteries Lam et al. Danshen's endothelium-dependent relaxations occur via an NO-dependent mechanism Chan et al.

SalB-derived vasodilation in rabbit aorta is mediated by the NO-sGC-cGMP pathway Shou et al. Other studies have also demonstrated that L-NAME inhibits eNOS and blocks the activity of danshen Chan et al. In VSMCs, danshen exhibits its vasodilating effect by opening of K ATP , K ir , and K v channels Ng et al.

Apart from its vasodilatory capacity, danshen expresses additional anti-hypertensive parameters such as antioxidative, anti-proliferative, and anti-inflammatory activities.

Its extracts have been shown to decrease ROS production in rat thoracic aorta Cho et al. Danshen was also reported to inhibit PDGF-induced proliferation of VSMCs Cho et al.

The anti-inflammatory capacity of danshen was demonstrated by virtue of its ability to inhibit TNF-α, NF-κB production, and VCAM-1 expression Cho et al. Taken together, these results illustrate the underlying molecular mechanism for danshen's antihypertensive effect. Ginger, a very common culinary ingredient, is reported to possess hypotensive properties.

Indeed, [6]-gingerol is now considered a novel angiotensin II type 1 receptor antagonist with an IC 50 of 8. The aqueous extract of ginger 0. In addition, zingerone, another active compound in ginger, can potently scavenge oxidant molecules like peroxynitrite Shin et al.

Recently, it was found that ginger not only reduces levels of total cholesterol, triglyceride, LDL, and vLDL, but it can also inhibit ACE-1 activity Akinyemi et al. With CVD remaining as a leading cause of worldwide mortality, the search for more effective treatments ought to be of prime importance.

An approach that appears promising is CAM Frishman et al. Not surprisingly, of all small-molecule new chemical entities introduced as drugs during the last three decades, a significant fraction were either obtained from or inspired by nature Newman and Cragg, Of relevant interest, it is important to note that herbal consumption appear to be the most common type of CAM among CVD patients Yeh et al.

In this first part of our review, we discussed the mechanisms of action of several plants that are most commonly used in the treatment or management of hypertension.

The pharmacological actions of herbs or herbal isolates appear to favorably modulate several parameters implicated in the pathogenesis of blood pressure, including but not limited to ROS production, VSMC phenotype, endothelial function, platelet activation, pro-inflammatory signaling, and gene expression.

With such a broad spectrum of actions, one may predict that herbal remedies will receive even more attention in the coming years, perhaps accentuating the need for further experimentations and clinical trials. Indeed, the lack of sufficient clinical trials constitutes a significant limitation on their use at the present time.

Of equal importance, it may be advisable that patients be appropriately educated, particularly in relation to herbs whose consumption has been considered safe for thousands of years black cumin, Chinese sage, coriander, garlic, ginger, ginseng, and tea , and has been supported by sound scientific evidence such as one based on clinical trials with large population groups.

It is important to note that there are herbs and plants that could actually raise blood pressure and thus should be avoided by hypertensive patients. There are also other limitations for herbal therapy of hypertension. These limitations would be discussed in the second part of this review.

All authors contributed to the writing. AE conceived, designed and revised the manuscript. This publication was made possible by grant NPRP from the Qatar National Research Fund a member of Qatar Foundation.

The Statements made herein are solely the responsibility of the authors. This grant was awarded to AE. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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