Can regular dietary intake of a local spice, Tetrapleura tetraptera, reduce the risk of developing high blood pressure, heart disease, stroke and kidney failure' CHUKWUMA MUANYA writes.HYPERTENSION is on the prowl! Hypertension (HTN) or high blood pressure, sometimes referred to as arterial hypertension, is a chronic medical condition in which the blood pressure in the arteries is elevated. This requires the heart to work harder than normal to circulate blood through the blood vessels.Blood pressure involves two measurements, systolic and diastolic, which depend on whether the heart muscle is contracting (systole) or relaxed between beats (diastole). Normal blood pressure at rest is within the range of 100-140mmHg systolic (top reading) and 60-90mmHg diastolic (bottom reading). High blood pressure is said to be present if it is persistently at or above 140/90 mmHg.Several studies have shown that hypertension is the leading risk factor linked to increasing complications of cardiovascular diseases, coronary heart diseases, stroke and renal failure.It has also been shown that hypertension, which causes end organ damage to the heart, kidneys and the central nervous system has no conventional cure but can only be managed with drugs and lifestyle changes.But researchers have found that regular intake of the fruit and bark extracts of a local spice, Tetrapleura tetraptera, could prevent the development of hypertension and its complications.Tetrapleura tetraptera belongs to the mimosaceae family. It is referred locally to as Aridan in Yoruba and Oshosho in Ibo.Tetrpleura tetraptera is generally found in the lowland forest of tropical Africa. The fruit consist of a fleshy pulp with small, brownish-black seeds. The dry fruit has a pleasant aroma. It is therefore, used as a popular seasoning spice in southern and eastern Nigeria. The fruit is used to prepare soup for mothers from the first day of birth to prevent post partum contraction.Camerounian researchers in a study titled: 'Aqueous Extract of Tetrapleura tetraptera (Mimosaceae) prevents hypertension, dyslipidemia and oxidative stress in high salt-sucrose induced hypertensive rats' concluded: 'Present study showed that oral administration of Tetrapleura tetraptera aqueous extract exhibited an antihypertensive and anti-dyslipidemic (cholesterol lowering) effects on high salt-sucrose feeding rats. This effect might be related to its antioxidant potential and supports the traditional use of the stem bark of Tetrapleura tetraptera.'Dyslipidemia or dyslipidaemia is an abnormal amount of lipids (example cholesterol and/or fat) in the blood.Oxidative stress is caused by an imbalance between the production of reactive oxygen and a biological system's ability to readily detoxify the reactive intermediates or easily repair the resulting damage.The study published in Pharmacologia investigated the antihyperlipidemic and antioxidant effects of Tetrapleura tetraptera aqueous extract in high salt-sucrose-induced hypertensive rats.Antioxidants are substances that may protect cells from the damage caused by unstable molecules known as free radicals or Reactive Oxygen Species (ROS).The researchers include: Bella Ndzana Martin Thierry, Ngo Lemba Tom Esther, Aboubakar Oumarou Bibi Farouck, Tsala David Emery and Dimo Theophile.Hypertensive rats were obtained from normotensive Wistar rats by giving daily, 2 mL/100g salt solution (nine per cent) p.o., with free access to sucrose solution (10 per cent) as drinking water. Wistar rat is the albino laboratory rat with its red eyes and white fur is an iconic model organism for scientific research in a variety of fields. Another set of rats were divided into three groups of five rats each and treated respectively with salt-sucrose and the aqueous extract of Tetrapleura tetraptera (100 and 200mg kg-1) or captopril (20mg kg-1).The effects of plant extract were evaluated after three weeks on blood pressure, lipid profile, oxidative status and liver function of animals and compared to those of normotensive control rats. Blood pressure was evaluated by invasive method and biochemical parameters were evaluated by colorimetric and kinetic methods.The results of the study showed that chronic salt-sucrose consumption increased systolic arterial blood pressure (30.05 per cent) and heart rate (15.36 per cent) as compared to control. Tetrapleura tetraptera aqueous extract (100 and 200mg kg-1) or captopril significantly prevented the increase in blood pressure and heart rate and inhibited salt-sucrose-induced lipid peroxidation in the liver.Captopril is a conventional drug used for the treatment of hypertension and some types of congestive heart failure.Lipid peroxidation refers to the oxidative degradation of lipids. It is the process in which free radicals 'steal' electrons from the lipids in cell membranes, resulting in cell damage.Tetrapleura tetraptera countered salt-sucrose induced oxidative stress by enhancing the activity of antioxidant enzymes (catalase, superoxide dismutase) and glutathione content. Glutathione is an antioxidant, preventing damage to important cellular components caused by reactive oxygen species such as free radicals and peroxides.According to the study, the plant extract significantly reduced the high concentration of serum Total Cholesterol (TC), glucose, triglyceride (TG) and low-density lipoprotein (LDL-C/ 'bad' cholesterol) and increased high-density lipoprotein (HDL-C/ 'good' cholesterol) observed in salt-sucrose hypertensive rats. Tetrapleura tetraptera also prevented the increase in atherogenic (deposition of fats on arterial walls) index.Atherosclerosis (also known as arteriosclerotic vascular disease or ASVD) is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol.The researchers said these finding supports the traditional use of Tetrapleura tetraptera extract and suggested that the bark of this plant could protect from salt-sucrose damage by enhancing activities of enzymes and holding up the increase of lipid markers and membrane peroxidation.Until now, the fruits of Tetrapleura tetraptera are used for the management of convulsions, leprosy, inflammation, rheumatism, flatulence, jaundice and fevers.The anticonvulsant activity of the volatile oil from fresh fruits of T. tetraptera in mice has been reported. Its leaves are essential for the treatment of epilepsy and present strong molluscicidal (mollusk killing) activity. The aqueous fruit extract has also been shown to possess hypoglycaemic (sugar/glucose lowering) properties. The root extract has also been used for the treatment of gastrointestinal related clinical problems.Tetrapleura tetraptera has been used in folk medicine in the treatment of hypertensive disorders, inflammation and several women's diseases such as breast and uterus cancers.Tetrapleura tetraptera has also been used in diabetics and cardiovascular affections treatment. Cardiovascular and neuromuscular actions of scopeletin from Tetrapleura tetraptera fruits have been described. This plant is also frequently used in Tropical African traditional medicine for the management and/or control of an array of human ailments, including arthritis and other inflammatory conditions, asthma, diabetes mellitus, hypertension, epilepsy and schistosomiasis.Meanwhile, according to the World Health Organisation (WHO), atherosclerosis occurs in 30 per cent of the cases and congestive heart failure, stroke, renal failure and retinopathy in more than half of the cases.According to the WHO, cardiovascular disease is the leading cause of death and a major cause of disability not only in the United States but also worldwide. The WHO indicates that total cholesterol concentrations superior at 147 mg dL-1 (3.8 mmol L-1) account for 18 per cent of cerebrovascular disease and 56 per cent of coronary heart disease on a global basis.There is also a powerful association between hypertension and cardiovascular disease, with approximately two thirds of strokes and one half of coronary heart disease cases worldwide occurring in the setting of systolic blood pressure superior at 115mmHg.ROS has also been shown to play a central role in the pathogenesis of metabolic disorders such as dyslipidemia and hypertension. Various preclinical and clinical studies have shown that high salt-sucrose is associated with an increased formation of free radicals along with an imbalance in antioxidant status, which leads to increase in oxidative damage of cellular components and oxide nitrite.Antioxidative substances or antioxidants are believed to suppress the onset and development of atherosclerosis and in addition, flavonoids and phenolic compounds have been proved to have antioxidative effects. Thus, substances with both antioxidative and hypocholesterolemic (cholesterol lowering) properties are expected to be effective in preventing the formation and/or progression of atherosclerosis.The researchers wrote: 'The present study showed that hypertension and dyslipidemia induced by high salt-sucrose in rats was associated with an oxidative stress characterized by a decrease in superoxide dismutase production, in tissue liver, leading to elevated plasma concentrations of MDA.'In fact, it has been reported that addition of high salt to a high sucrose diet causes even more marked elevation in blood pressure in Wistar rats. High sucrose intake appears also to elevate blood pressure only with normal or high dietary salt intake. The plant extract caused a significant and dose-dependent decrease arterial blood pressure in salt-sucrose-induced hypertensive rats. antioxidative, effect on heart function and lipid parameters.'Results of our study clearly demonstrated the role of Tetrapleura tetraptera in countering the lipidemic-oxidative alterations accompanying salt-sucrose-induced hypertension in rats. In the human body, high levels of triglycerides in the bloodstream have been linked to atherosclerosis and, by extension, the risk of heart disease and stroke.'The relationship of dietary carbohydrates to cardiovascular diseases appears to be mediated through indirect mechanisms, contribution to total energy and its effect on overweight and obesity; influence on central obesity; effects on plasma lipids, especially triglycerides and effects on glycaemic control. Triglycerides level was significantly (p<0.001) decreased in Tetrapleura tetraptera (100 and 200mgkg-1) or captopril treated groups as compared to untreated salt-sucrose hypertensive animals.
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