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Hibiscus Flower

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J Adv Pharm Technol Res. 2019 Jul-Sep; 10(3): 107–111. 

doi: 10.4103/japtr.JAPTR_402_18

PMCID: PMC6621350

PMID: 31334091

Effect of hibiscus sabdariffa on blood pressure in patients with stage 1 hypertension

Majid JalalyazdiJavad Ramezani,1 Azadeh Izadi-MoudFereshteh Madani-SaniShokufeh Shahlaei, and  Shirin Sadat Ghiasi

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Using different drug regimens has been proved to have effective effects on lowering blood pressure, but the adverse effects of long-term usage such medications is evident. According to recent trend in suing herbal and traditional medicines, researchers have been focused on evaluating the effect of different herbals on managing hypertension. The aim of the present study is the evaluation of the antihypertensive effect one of these herbs, sour tea (Hibiscus sabdariffa), on stage one hypertension. Patients with stage one hypertension who were diagnosed by a cardiologist has been included in the present clinical trial after giving informed consent. The patients were divided into two groups. The control and case group received the same lifestyle and dietary advices for controlling blood pressure. The case group received two standard cup of sour tea every morning for 1 month. The blood pressure of both groups was documented at baseline and at the end of the study and the results were analyzed using SPSS software. A total of 46 patients participated in this study and there was no significant difference in terms of age and body mass index between groups. There was a significant reduction in systolic blood pressure in both groups, but the mean reduction in systolic and diastolic blood pressure was significantly higher in the case group (P = 0.004 and P < 0.001, respectively). Using H. sabdariffa as sour tea two times a day can be effective in managing blood pressure in stage one hypertension along with lifestyle and dietary modification.

Key words: Diastolic pressure, Hibiscus sabdariffa, hypertension, systolic pressure

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Hypertension has been considered as a risk factor of various diseases including ischemic heart and cerebrovascular disease as well as chronic kidney disease. Hypertension also accounts for increases in disability-adjusted life years and deaths worldwide.[1,2,3] The global prevalence of hypertension among adults was 31.1% and its burden was higher in low- and middle-income countries.[4] In addition, 26.6% of the population of Iran are hypertensive.[5] It should be noted that in developing countries, insufficient treatment and unawareness, make the management of hypertensive individuals more challenging for healthcare systems.[6,7]

Good blood pressure control can prevent adverse cardiologic outcome including heart attacks and heart failures.[8] There are different classes of antihypertensive drugs such as thiazides, beta-blockers, calcium channel blockers, angiotensin II receptor blockers, and alpha-blockers which are used clinically to treat hypertension.[9] Based on 2017 American College of Cardiology/American Heart Association guideline, from 45.6% of hypertensive adults in united states, 36.2% were recommended to use antihypertensive medications which approximately half of them still had a higher blood pressure than the goal threshold.[10] Thus, there is an urgent need for developing management strategies for this physiological disorder. On the other hand, there is an emerging use of herbal medicine (HM) as an alternative to chemical medicine (CM) which could have many reasons including side effects of CM.[11] Putting these together with positive beliefs and experiences of HM among people and their traditions, makes them more eager to trust and use herbal medication.[11] Traditions suggested herbs such as garlic, onion, Chinese herbal medicine, black and green tea, and sour tea or Hibiscus sabdariffa. Some studies have proven some of these medications positive effects.[12,13,14,15,16,17,18,19,20,21,22,23,24] The latter one, which is our experimental agent, is a plant containing carbohydrates, proteins, fatty acids, flavonoid, minerals, and vitamins. Studies mentioned that this herb has anticancer, antibacterial, anti-oxidant, nephro- and hepato-protective, diuretic, anti-cholesterol, anti-diabetic, and anti-hypertensive properties.[25,26] Despite the frequent usage of this alternative medicine among people, there is not adequate evidence and enough knowledge about its effectiveness in different medical conditions. Thus, knowing more details about this plant and conducting scientific and evidence-based studies seems to be necessary. According to these facts, this study aimed to evaluate the effect of H. sabdariffa on blood pressure.

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The present randomized controlled clinical trial was conducted to evaluate the effectiveness of sour tea (H. sabdariffa) on patients with stage one hypertension referred to an outpatient cardiology clinic in Imam Reza Hospital in Mashhad, Iran. Every patient who was aged between 18 and 70 years with stage 1 hypertension who were diagnosed by the same cardiologist were enrolled in the present study. These patients had systolic and diastolic blood pressure ranging from 130 to 139 and 80–89 mmHg, respectively. These patients did not have any previous medical illness, and none of them were pregnant or breastfeeding. According to this criterion, 46 patients were divided into two experimental and control group. After taking the informed consent and according to the declaration of Helsinki, patients' demographic information including age, gender, and body mass index was recorded. Blood pressure was taken by Riester minimums II Aneroid Sphygmomanometer under the consideration of a specialist by the same researcher which was not aware of the present study. The manometer cuff was putted on brachial artery as its edge was 2 cm upper the elbow brachial artery pulse. Blood pressure was taken in sited position for three times with 5 min' intervals. The average of three attempts was recorded. Twenty-three patients in experimental group received nonmedical treatment advices and two standard cup of sour tea (each cup with one sour tea bag containing 1.25 g H. sabdariffa (480 mL/d)) every day morning and night for 1 month (they did not use any other kind of teas). The instructions for using tea bags were given to the participants by the same researcher. All the tea bags were purchased from same reliable herbal shop and prescribed freely for the study participants. The other group only received the same nonmedical treatment advices as the control group. These advices included lowering weight under the consideration of a nutrition specialist, recommendation to have Dietary Approaches to Stop Hypertension (DASH), decreasing sodium and increasing potassium under the consideration of a nutrition specialist, and doing aerobic exercises at list 5 days a week for 30 min. The patients were visited by a cardiologist before and after the treatment, and their blood pressure was taken.

Ethical consideration

The proposal of our study was approved by the Institutional Ethics Committee of Mashhad University of Medical Sciences.

Statistical analysis

Data were analyzed using the statistical package for social sciences software version 22 (IBM Inc. Chicago, IL, USA). Continuous variables were checked for normality using the Shapiro–Wilk test. As all the continuous variables were normally distributed, the mean and standard deviation were used to present data. Categorical variables were presented using frequency and percentage. Comparison of continuous variables between groups was performed using the independent Student's t-test, whereas categorical variables were compared using the Chi-square test. Repeated measures analysis of variance (ANOVA) was Performed to assess the time and group effects. The statistical significance was defined as P < 0.05, and the confidence level was 0.95.

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A total of 46 participants (23, 50% in the tea group and 23, 50% in control group) participated in this study. The mean age of study participants was 49.83 ± 3.38 years. The mean body mass index (BMI) of the participants was 28.74 ± 3.50 kg/m2. There was no significant difference in terms of age and BMI between groups [Table 1]. Among the study participants, 25 (54.3%) were male and 21 (45.7%) were female. Among the intervention group, 12 participants (48.0%) were male and 11 participants (52.4%) were female, while in the control group, 13 participants (52.0%) were male and 10 participants (47.6%) were female. There was no significant difference in gender distribution pattern between the study groups (χ(df = 1) =0.09, P = 0.77).


Using antihypertensive chemical medication has its own side effects and limitations. However, using herbal medicine could be a considerable choice with lesser adverse effects if used within appropriate amounts. In our population, positive beliefs about herbal medicine among people make them more eager to trust and use herbal medication. According to the current study results, consumption of sour tea (H. sabdariffa) could effectively lower blood pressure in patients with stage 1 hypertension. Thus, concerning this herb as a medicine for hypertensive people seems beneficial. However, further investigation is needed to clear its mechanisms and effectiveness details in longer follow ups.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

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