Roselle (Hibiscus sabdariffa Linn.)
Reduces High Blood Pressure in Persons with Type 2 Diabetes
Nov 13, 2009
High blood pressure (hypertension) often accompanies diabetes which compounds the risk for heart disease. In developing countries, Hibiscus sabdariffa Linn., or roselle, has been historically used to treat high blood pressure. To determine the validity of this folk remedy on hypertension among persons with type 2 diabetes, Mozaffari-Khosrav and his colleagues conducted a double-blind, randomized controlled trial involving 68 diabetic persons with mild hypertension. The subjects in the study were not taking anti-hypertensive or anti-lipidemic medication.
The participants were randomly assigned to the "sour tea" (ST) group and "black tea" (BT) group. The subjects were instructed to drink ST or BT infusions twice a day for one month. Their blood pressures (BPs) were measured on days: 0,15, and 30 of the study. The sour tea was made from the calyces of H. sabdariffa.
The findings showed that the average systolic blood pressure (SBP) in the ST group decreased from 134 mm Hg at the beginning of the study to 113 mm Hg after one month. By comparison, the mean systolic blood pressure in the BT group rose from 119 mm Hg to 127 mm Hg at month's end. The systolic blood pressure is the blood pressure created when the heart contracts.
The average pulse pressure (PP) of the patients in the ST group decreased from 52 mm Hg to 35 mm Hg. In comparison, the average PP in the BT group increased from 42 mm Hg to 47 mm Hg. The pulse pressure is the difference between the systolic blood pressure and diastolic blood pressure. A high pulse pressure is an independent marker for atherosclerosis - stiffening of the arteries. Atherosclerosis is a risk factor for heart disease and premature death.
ST and BT had no statistically significant effect on the diastolic blood pressure of both groups. The diastolic blood pressure is the pressure created between heartbeats, while the blood is flowing. This study shows that infusions of H. sabdariffa Linn. has positive effects on blood pressure in type 2 diabetics with mild hypertension. The study appeared in the 2009 issue of the Journal of Human Hypertension.
The Importance of Controlling Hypertension in the Treatment of Diabetes Mellitus
High blood pressure is one of the attendant disorders of diabetes. It occurs twice as frequently in persons with diabetes as in non-diabetics. It also accounts for 75% of added heart disease risks in this population. Hypertension is of the most treatable risk elements for cardiovascular disease because of its prevalence and lethal outcomes.
Several investigations have reported that the rate of hypertension among adults is about 3.4 % to 72.5%. Forecasts show that by 2025, 333 million people will have hypertension in the Western countries, while 639 million people will be suffering from high blood pressure in the developing nations.
Sour Tea - Infusions of Hibiscus sabdariffa: An Alternative Medicine for Hypertension
People in non-Western countries have used "sour" tea to treat a myriad of ailments, including hypertension, for centuries. Sour tea is made from the dried and fresh calyces (sepals) of Hibiscus sabdariffa, a plant from the Malvaceae/Mallow family. Sepals are the "leaflike" parts found in the base of the flowers. In English-speaking regions, H. sabdariffa is called "roselle", "red sorrel" or "Indian sorrel," In Spanish it is called "Acedera de Guinea," and in Arabic, it is called "kharkadi."
Health-Giving Compounds in Sour Tea
The plant chemicals, pharmacological, and toxicological properties of H.sabdariffa have been investigated in many studies. Consequently, many of its constituents are well known, some with multiple health-promoting properties in humans. They include the following biologically active compounds:
- antioxidants, including anthocyanins, ascorbic acid, beta carotene, beta-sitosterol, campestrol, citric acid, delphinidium, delphinidium-3-glucoside,myristic acid, procatechuic acid, selenium, and tartaric acid;
- hypotensive or blood pressure lowering agents including ascorbic acid, calcium, chromium, fiber, magnesium, manganese, potassium, zinc;
- antioxidant synergist (enhances the work of antioxidants) including citric acid and tartaric acid;
- vasodilators (dilates blood vessels, enhancing blood blow) including anthocyanins, potassium;
- heart protective compounds, including chromium, niacin, and procatechuic acid.
Sour tea has a long history of medicinal use. While Its efficacy is well established in some populations, Western medicine has yet to acknowledge that teas made from H. sabdariffa are effective against essential hypertension. This most recent study affirms its value as an alternative remedy for high blood pressure.
References:
Mozaffari - Khosrav H et al. "The effects of sour tea (H.sabdariffa) on hypertension in patients with type 2 diabetes" J of Human Hypertension 2009;23:48-54
Herrera-Arellano A et al. "Clinical effects of standardized herbal medicinal products of H. sabdariffa on patients with high blood pressure: A randomized, double-blind LISINOPRIL- controlled trial" Planta Med 2007;73-76
Kearney PM et al. "Global burden of hypertension; analysis of worldwide data" Lancet 2005;365:217-223
Ali BH et al. "Phytochemical, pharmocological, and toxicological aspects of H. sabdariffa L: a review" Phytother Research 2005;19:369-375
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