Pharmacological Mechanisms in the Pathogenesis of Arterial Hypertension and the Therapeutic Role of Phytotherapy

Бюллетень науки и практики / Bulletin of Science and Practice

UDC 616.2/.34:615.322                              

In modern medicine, synthetic antihypertensive drugs (diuretics, β-blockers, ACE inhibitors, etc.) are effective; however, long-term use may cause a number of side effects, including electrolyte imbalance, gastrointestinal disturbances, and liver or kidney damage [3].

Therefore, in recent years, there has been increasing interest in natural, less toxic, plantbased remedies that help normalize overall body functions. Medicinal plants exert both prophylactic and therapeutic effects on the human body [1-4]. The bioactive compounds they contain—flavonoids, phenolic compounds, essential oils, alkaloids, saponins, and tannins—help regulate blood pressure by providing vasodilatory, diuretic, antioxidant, sedative, and anti-stress effects.

The material of the study consisted of individuals suffering from arterial hypertension and the phytotherapeutic agents used in its treatment. The primary focus was on medicinal plants such as Crataegus oxyacantha (hawthorn), Allium sativum (garlic), Olea europaea (olive leaf), Valeriana officinalis (valerian), Leonurus cardiaca (motherwort), and Hibiscus sabdariffa (red hibiscus). The mechanisms of action of these plants, the composition of their bioactive compounds, and their effects on blood pressure in hypertensive patients were systematically analyzed.

Clinical and laboratory studies conducted over the last ten years were reviewed. Databases such as PubMed, Scopus, Web of Science, and Google Scholar were utilized. The mechanisms of action of bioactive compounds present in the plants—including flavonoids, phenolic compounds, saponins, alkaloids, and others—were evaluated. The effects of plant extracts on blood pressure were assessed based on randomized clinical trials and meta-analyses. The doses, duration of administration, and safety profiles of plant-based preparations were compared. Comparisons between plant extracts and synthetic antihypertensive drugs were conducted, and combined phytotherapeutic approaches (e.g., garlic and hibiscus) were evaluated against monotherapy. This study was based solely on scientific literature and did not involve direct experimental research or clinical trials. The increase in arterial blood pressure arises from the combined effects of several mechanisms: elevated peripheral vascular resistance, increased cardiac stroke volume, and hyperactivation of the renin–angiotensin–aldosterone system (RAAS) [5].

Activation of this system leads to elevated angiotensin II levels, which cause vasoconstriction and an increase in blood pressure. In addition, endothelial dysfunction and decreased nitric oxide (NO) synthesis result in reduced vascular elasticity. Oxidative stress and the overproduction of free radicals also play a significant role in the pathogenesis of hypertension [6].

Risk factors for hypertension include age, genetic predisposition, obesity and high body mass index, high intake of salty and saturated foods, smoking and alcohol consumption, chronic stress, and physical inactivity [7].

Phytotherapy plays a significant role in the treatment of hypertension. Phytotherapy involves the use of plant-based preparations for disease prevention and treatment. This method has been widely used in traditional medicine systems for millennia [7].

Modern scientific studies indicate that many medicinal plants regulate blood pressure, stabilize cardiovascular function, and enhance antioxidant defenses due to their content of flavonoids and phenolic compounds. Plant-based remedies exert a comprehensive effect on the body, simultaneously influencing vascular tone, cardiac function, and the nervous system. They reduce toxic effects during long-term use, stimulate the immune system, regulate metabolic processes, and can be used alongside conventional medications [8].

The mechanisms of action of the primary medicinal plants used in hypertension treatment are associated with their bioactive compounds: Crataegus oxyacantha (Hawthorn): The fruits and leaves of hawthorn contain flavonoids (hyperoside, vitexin), triterpene acids, and anthocyanins. These compounds improve myocardial nutrition, dilate blood vessels, and normalize heart rhythm. Clinical studies have shown that hawthorn extract (900 mg/day) can reduce systolic blood pressure by 10-12 mmHg and diastolic pressure by 6-8 mmHg after 8 weeks of administration [9].

Furthermore, hawthorn exhibits antioxidant activity, restores endothelial function, and decreases heart rate. Therefore, it is widely used in both early-stage hypertension and heart failure [10].

Allium sativum (Garlic): Garlic is considered a natural ACE inhibitor. Its bioactive compound allicin has vasodilatory and antithrombotic effects. A meta-analysis conducted in 2023 demonstrated that daily intake of garlic extract at 600-1200 mg reduces systolic blood pressure by an average of 8-10 mmHg [11].

Regular garlic consumption lowers cholesterol levels, improves vascular elasticity, and enhances antioxidant defenses [12].

Garlic can be consumed by chewing 1-2 cloves before or with meals to improve endothelial function, dilate blood vessels, and reduce both systolic and diastolic blood pressure. Drinking water immediately after chewing garlic may reduce its odor. Alternatively, 2 -3 cloves can be crushed or finely chopped, added to 250 ml of boiling water, steeped for 10-15 minutes, and consumed warm once daily, either on an empty stomach in the morning or after dinner. This decoction supports hypertension management and cardiovascular health [31].

Another traditional preparation involves crushing 5 cloves of garlic and mixing them with 3 tablespoons of natural honey. The mixture should be stored in a sealed glass container and taken at 1 tablespoon per day. This combination helps normalize blood pressure and strengthen the immune system. It is necessary to consult a physician when using these remedies alongside antihypertensive drugs. They may cause digestive disturbances and, in some individuals, allergic reactions. Continuous use for at least 4-6 weeks in hypertension has shown favorable effects [13].

Olea europaea (Olive leaf): Olive leaves contain polyphenols such as oleuropein and hydroxytyrosol. These compounds reduce the activity of the angiotensin-converting enzyme (ACE), contributing to the regulation of the RAAS system [13].

Clinical studies have reported that administration of 500 mg of olive leaf extract for six weeks resulted in an average reduction of arterial blood pressure by 9/5 mmHg [14].

Valeriana officinalis (Valerian): Valerian contains valeric acids and essential oils [15].

These compounds calm the central nervous system, reduce the effects of stress, and lower sympathetic tone [16].

Preparations made from the valerian root have long been used as sedatives in traditional and folk medicine to treat headaches, migraines, irritability, neurosis, hysteria, and insomnia. They are also beneficial for women during menopause. Studies have shown that valerian extract reduces stress-related blood pressure increases by 15-20% [17].

Despite its benefits, valerian may have adverse effects in certain individuals. In very elderly patients, it may increase blood clotting, raising the risk of stroke, myocardial infarction, or thrombosis. Hypertensive patients who use valerian regularly may experience heightened nervous system activity and insomnia. Its use is contraindicated in individuals with liver disease, enterocolitis, nephritis, or kidney disorders. Patients with severe depression, sexual dysfunction, erectile dysfunction, or psychiatric disorders should only use valerian under medical supervision, and it should not be combined with other medications. Uncontrolled, long-term, or excessive use in individuals with allergies or pregnant women may cause poisoning, leading to headaches, dizziness, hypotension, drowsiness, hypothermia, nausea, and difficulty breathing .

Leonurus cardiaca (Motherwort): Motherwort contains leonurine, stachydrine, and alkaloids, which help stabilize heart rhythm and improve circulation [18].

Clinical trials have shown that motherwort extract reduces blood pressure by an average of 7-10 mmHg over four weeks [19].

The aerial parts of the plant are collected during the flowering period, approximately 30 -40 cm above the ground, dried in shaded areas, and used for medicinal purposes. In scientific medicine, aqueous decoctions and alcoholic extracts are used as sedative agents in cardiovascular and nervous system disorders. Pharmacologically, motherwort resembles valerian preparations. For hypotensive and cardiotonic purposes, 30-40 drops of the alcoholic extract can be taken orally .

Motherwort has several potentially harmful effects. Its use is prohibited during pregnancy and breastfeeding. It should also be avoided in individuals with depression or hypersensitivity. Patients with bradycardia, thrombosis, thrombophlebitis, or hypotension must consult a physician before use. Excessive use can lead to loss of consciousness and cardiac arrest .

Hibiscus sabdariffa (Red Hibiscus): Hibiscus flowers are rich in anthocyanins, which enhance vascular elasticity and reduce renin activity [20].

A randomized study conducted in 2022 reported that participants who consumed hibiscus tea for four weeks experienced an average reduction in blood pressure of 11/7 mmHg [21].

To prepare the tea, 1-2 teaspoons of dried hibiscus flowers are added to 200 ml of boiling water and steeped for 5-10 minutes. For improved taste, additives such as honey, sugar, mint, lemon, or cinnamon may be used. Hibiscus tea can be consumed either hot or cold (iced). In some countries, lemon and mint are added to hibiscus tea, while in others, vanilla, ginger, or cloves are used, enhancing the flavor and variety of the infusion. Despite its multiple benefits, hibiscus tea should be used with caution [22-23].

Individuals with low blood pressure, pregnant or breastfeeding women, those prone to allergies, and those regularly taking medications should consult a physician before use. Excessive consumption may disrupt fluid balance in the body, and there is a potential risk of interaction with certain drugs .

2023 study published in the Journal of Ethnopharmacology reported that a combination of garlic and hibiscus extracts produced a greater antihypertensive effect compared to monotherapy [24].

Another study found that a three-month regimen combining hawthorn, valerian, and motherwort stabilized blood pressure and improved sleep quality in 68% of patients [25].

Long-term use of phytotherapy has not been associated with significant toxic or hepatotoxic effects, supporting the safety of plant-based treatments [26].

Scientific studies indicate that phytotherapy plays a significant role in the comprehensive management of hypertension. Plant-based preparations gradually and steadily normalize blood pressure, exert a positive effect on the nervous system, and enhance antioxidant defense [27].

Hawthorn, garlic, olive leaf, valerian, motherwort, and hibiscus are among the most studied and effective medicinal plants [28].

However, phytotherapy should be conducted under medical supervision with an individualized approach. High doses and long-term use of plant extracts may, in some cases, lead to interactions with other medications [29].