Does consumption of an aqueous extract of Hibscus sabdariffa affect renal function in subjects with mild to moderate hypertension?

Roselle (Hibiscus sabdariffa L.) extract as an adjunct to valsartan in patients with mild chronic kidney disease: A double-blind randomized controlled clinical trial

Objective

The objective of this study was to evaluate the effectiveness of Hibiscus sabdariffa L. extract (HS) as an adjunct to valsartan in the treatment of high blood pressure in patients with mild chronic kidney disease (CKD).

Materials and Methods

This trial was conducted in Gorgan, Iran. Seventy-two participants with CKD and high blood pressure were randomly assigned to either the HS group, receiving a 350 mg pill every 12 hr for 90 days along with 40 mg of valsartan every 12 hr, or the control group (40 mg valsartan + 12.5 mg hydrochlorothiazide). The primary objective was to assess the improvement of hypertension, while secondary objectives included the evaluation of proteinuria, albuminuria, kidney function, lipid profile, and electrolyte levels. Molecular docking analysis was performed to examine the mechanisms of action of the isolated components of HS.

Results

Out of 80 initial participants, 72 were included in the analysis. Both groups showed a significant reduction in blood pressure (p<0.001). The HS group demonstrated a statistically significant decrease in lipid profile (p<0.001). There were no statistically significant differences between the groups regarding the reduction of renal markers. Molecular docking analysis revealed that the compounds present in HS, particularly its anthocyanins and flavonoids, exhibited greater angiotensin-converting enzyme (ACE) inhibitory potential than hydrochlorothiazide in both domains. Moreover, the compounds met the criteria for drug likeness and Lipinski rules.

Conclusion

Adjunctive therapy with HS showed promising results in reducing hypertension and improving lipid profile in patients with CKD.

Physiological Effects and Human Health Benefits of Hibiscus sabdariffa: A Review of Clinical Trials

Hibiscus sabdariffa Linn. Malvaceae (HS) is characterized by its edible calyxes. The HS calyxes are widely used for cosmetic, food, and medicinal applications. According to ethnobotanical evidence, decoction, infusion, or maceration extracts from HS calyxes have been used in folk medicine to treat many ailments. Moreover, several in vitro and in vivo studies have demonstrated the pharmacological properties and potential human health benefits of HS consumption. On the other hand, the evaluation of the physiological effects and health benefits of HS in clinical studies is most challenging. Therefore, this narrative review summarizes and discusses the physiological effects and health benefits of HS calyxes reported in clinical trials. Preparations obtained from HS calyxes (extracts, infusions, decoction, teas, beverages, capsules, and pills) are used as non-pharmacological therapies to prevent/control diverse chronic non-communicable diseases. The most-reported HS health benefits are its antihypertensive, antidyslipidemic, hypoglycemic, body fat mass reduction, nephroprotective, antianemic, antioxidant, anti-inflammatory, and anti-xerostomic activities; these effects are associated with the phytochemicals found in HS. Moreover, no adverse effects were reported during the clinical trials. However, clinical studies exhibited some limitations; thus, further studies are required to validate the clinical efficacy of HS in large-scale studies with higher doses and a good experimental design

Efficacy of Hibiscus sabdariffa on Reducing Blood Pressure in Patients With Mild-to-Moderate Hypertension: A Systematic Review and Meta-Analysis of Published Randomized Controlled Trials

We aimed to assess the efficacy of Hibiscus sabdariffa in patients with mild-to-moderate hypertension or metabolic syndrome (MetS) by comparing it against placebo, antihypertensive drugs, or other herbal products. Four databases were searched for randomized clinical trials (RCTs) examining the efficacy of H. sabdariffa in patients with mild-to-moderate hypertension or hypertension associated with MetS. Data on the change in systolic blood pressure (SBP) and diastolic blood pressure (DBP) were extracted and analyzed using Review Manager Version 5.3. A total of 13 RCTs (1205 participants) were analyzed. Hibiscus sabdariffa significantly reduced both SBP and DBP compared with placebo (mean difference -6.67, P = 0.004 and -4.35 mm Hg, P = 0.02). Subgroup analysis showed that change in SBP and DBP was statistically significant in patients with only hypertension, whereas not significant in patients with hypertension associated with MetS. When H. sabdariffa was compared with active controls (antihypertensive drugs or other herbals), the change in SBP and DBP was not statistically significant (all P > 0.05). Hibiscus sabdariffa is effective in reducing the SBP and DBP in patients with mild-to-moderate hypertension, but was neither effective in those with MetS nor superior to antihypertensive drugs. Further RCTs are required to determine the long-term efficacy of H. sabdariffa and to describe patients who would benefit most from this treatment.

Roselle for hypertension in adults

BACKGROUND

Hypertension is considered to be a serious health problem worldwide. Controlling and lowering blood pressure are of significant benefit to people with hypertension because hypertension is a risk factor for stroke, heart disease, and cardiovascular disease. Roselle, the tropical plant Hibiscus sabdariffa, also commonly called sour tea or red tea, has been used as both a thirst-quenching drink and for medicinal purposes.

OBJECTIVES

To assess the effect of Roselle on blood pressure in people with primary hypertension.

SEARCH METHODS

For this update, the Cochrane Hypertension Information Specialist searched the following databases and trials registers for randomised controlled trials (RCTs): the Cochrane Hypertension Specialised Register (to 6 August 2021), Cochrane Central Register of Controlled Trials (CENTRAL; 2021, Issue 7), MEDLINE Ovid (1946 to 5 August 2021), Embase Ovid (1974 to 5 August 2021), ProQuest Dissertations & Theses (to 6 August 2021), Web of Science Clarivate (to 7 August 2021), Food Science and Technology Abstracts Clarivate (to 7 August 2021), the WHO International Clinical Trials Registry Platform (to 6 August 2021), and the US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov (to 6 August 2021). We searched Google Scholar and OpenSIGLE. We also handsearched local and regional Chinese databases: CBM, CMCC, TCMLARS, CNKI, CMAC, and the Index to Chinese Periodical Literature (to 14 September 2020), as well as Thai databases (ThaiJO, CUIR, TDC, CMU e-Theses, TCTR) (to 3 October 2020). There were no language or publication date restrictions.

SELECTION CRITERIA

We sought RCTs evaluating the use of any forms of Roselle with placebo or no treatment in adults with hypertension. Our primary outcome was change in trough and/or peak systolic and diastolic blood pressure (SBP, DBP). Secondary outcomes were withdrawals due to adverse effects, change in pulse pressure, and change in heart rate.

DATA COLLECTION AND ANALYSIS

All search results were managed using Covidence and re-checked for the number of records, inclusion and exclusion of studies with Mendeley reference management software. We used standard methodological procedures expected by Cochrane. Two review authors worked independently in parallel for screening (titles and abstracts, and full reports), data extraction, risk of bias assessment, and assessment of the certainty of the evidence using the GRADE approach. Any disagreements were resolved by discussion or by consultation with the third review author if necessary. We presented mean difference (MD) of change in SBP and DBP with their corresponding 95% confidence interval (CI).

MAIN RESULTS

For this update, only one RCT with a parallel-group design involving 60 participants with type 2 diabetes mellitus fulfilled the inclusion criteria. This study investigated the effect of Roselle extract capsules (total dose of 5600 mg) compared with placebo (lactose) at eight weeks. The study was at low risk of selection bias, performance bias, and detection bias. Conversely, it was at high risk of attrition bias, reporting bias, and other bias (baseline imbalance). We have very little confidence in the effect estimate of Roselle on change-from-baseline in both SBP and DBP between the two groups. The MD of change in SBP was 1.65, 95% CI -7.89 to 11.19 mmHg, 52 participants, very low-certainty evidence. The MD of change in DBP was 4.60, 95% CI -1.38 to 10.58 mmHg, 52 participants, very low-certainty evidence. Our secondary outcomes of withdrawals due to adverse effects, change in pulse pressure, and change in heart rate were not reported. Due to the limited available data, no secondary analyses were performed (subgroup and sensitivity analysis).

AUTHORS' CONCLUSIONS

The evidence is currently insufficient to determine the effectiveness of Roselle compared to placebo for controlling or lowering blood pressure in people with hypertension. The certainty of evidence was very low due to methodological limitations, imprecision, and indirectness. There is a need for rigorous RCTs that address the review question.

A systematic review with meta-analysis on the antihypertensive efficacy of Nigerian medicinal plants

ETHNOPHARMACOLOGICAL RELEVANCE

Despite the promising effects of herbal preparations in lowering blood pressure (BP), hypertension remains a major clinical challenge in Nigeria. The BP-lowering effects of medicinal plants are due to the presence of bioactive compounds.

AIM OF THE STUDY

This meta-analysis presents a precise estimate of the therapeutic benefits of medicinal plants utilized in Nigeria for the management of hypertension in animals and humans.

METHODS

A systematic literature search was performed through Cochrane, PubMed, Science Direct and Scopus databases from inception until February 28, 2021 using search terms related to randomized controlled trials of Nigerian medicinal plants for hypertension. Additional studies were identified through manual search. BP was the main outcome that was measured after the intervention. Meta-analysis was performed using the Review Manager and Meta-Essential.

RESULTS

Nineteen trials comprising of 16 preclinical and 3 clinical studies were enrolled for the meta-analysis. A total number of 16 plants was identified of which H. sabdariffa was the highest reported plant. The plant extracts significantly lowered the systolic blood pressure (SBP) and diastolic blood pressure (DBP) of the hypertensive subjects compared to control. Weighted mean difference (WMD) for SBP (-43.60 mmHg, 95% CI: -63.18, -24.01; p<0.0001) and DBP (-29.50 mmHg, 95 CI: -43.66, -15.34; p<0.0001) was observed for the preclinical studies. For clinical trials, the WMD was -13.98 mmHg, 95 CI: -19.08, -8.88; p<0.00001 for SBP and -10.00 mmHg, 95 CI: -12.22, -7.78; p<0.00001 for DBP. High heterogeneity was observed for the outcome measures of preclinical studies, but not for the clinical studies. The observed substantial heterogeneity in preclinical studies may be linked to methodological shortcomings as evidenced by the results of the risk of bias assessment. There was no evidence of publication bias in animal trials for BP using the funnel plot and Egger's regression test (SBP, p=0.239 and DBP, p=0.112).

CONCLUSIONS

This study provides evidence of medicinal preparations for the treatment of hypertension. A well-conducted trial with methodological rigour and a longer duration of follow-up is required for their effective clinical utilization.

Modulation of Renal Function in a Metabolic Syndrome Rat Model by Antioxidants in Hibiscus sabdariffa L

Metabolic syndrome (MS) is the association of three or more pathologies among which obesity, hypertension, insulin resistance, dyslipidemia, and diabetes are included. It causes oxidative stress (OS) and renal dysfunction. Hibiscus sabdariffa L. (HSL) is a source of natural antioxidants that may control the renal damage caused by the MS. The objective of this work was to evaluate the effect of a 2% HSL infusion on renal function in a MS rat model induced by the administration of 30% sucrose in drinking water. 24 male Wistar rats were divided into 3 groups: Control rats, MS rats and MS + HSL rats. MS rats had increased body weight, systolic blood pressure, triglycerides, insulin, HOMA index, and leptin (p ≤ 0.04). Renal function was impaired by an increase in perfusion pressure in the isolated and perfused kidney, albuminuria (p ≤ 0.03), and by a decrease in clearance of creatinine (p ≤ 0.04). The activity of some antioxidant enzymes including the superoxide dismutase isoforms, peroxidases, glutathione peroxidase, glutathione-S-transferase was decreased (p ≤ 0.05). Lipoperoxidation and carbonylation were increased (p ≤ 0.001). The nitrates/nitrites ratio, total antioxidant capacity, glutathione levels and vitamin C were decreased (p ≤ 0.03). The treatment with 2% HSL reversed these alterations. The results suggest that the treatment with 2% HSL infusion protects renal function through its natural antioxidants which favor an improved renal vascular response. The infusion contributes to the increase in the glomerular filtration rate, by promoting an increase in the enzymatic and non-enzymatic antioxidant systems leading to a decrease in OS and reestablishing the normal renal function.

Nutraceuticals and blood pressure control: a European Society of Hypertension position document

: High-normal blood pressure (BP) is associated with an increased risk of cardiovascular disease, however the cost-benefit ratio of the use of antihypertensive treatment in these patients is not yet clear. Some dietary components and natural products seems to be able to significantly lower BP without significant side effects. The aim of this position document is to highlight which of these products have the most clinically significant antihypertensive action and wheter they could be suggested to patients with high-normal BP. Among foods, beetroot juice has the most covincing evidence of antihypertensive effect. Antioxidant-rich beverages (teas, coffee) could be considered. Among nutrients, magnesium, potassium and vitamin C supplements could improve BP. Among nonnutrient-nutraceuticals, soy isoflavones could be suggested in perimenopausal women, resveratrol in insulin-resistant patients, melatonin in study participants with night hypertension. In any case, the nutracutical approach has never to substitute the drug treatment, when needed.

Antihypertensive phytocomplexes of proven efficacy and well-established use: Mode of action and individual characterization of the active constituents

Hypertension has become the leading risk factor for worldwide cardiovascular diseases. Conventional pharmacological treatment, after both dietary and lifestyle changes, is generally proposed. In this review, we present the antihypertensive properties of phytocomplexes from thirteen plants, long ago widely employed in ethnomedicines and, in recent years, increasingly evaluated for their activity in vitro and in vivo, also in humans, in comparison with synthetic drugs acting on the same systems. Here, we focus on the demonstrated or proposed mechanisms of action of such phytocomplexes and of their constituents proven to exert cardiovascular effects. Almost seventy phytochemicals are described and scientifically sound pertinent literature, published up to now, is summarized. The review emphasizes the therapeutic potential of these natural substances in the treatment of the 'high normal blood pressure' or 'stage 1 hypertension', so-named according to the most recent European and U.S. guidelines, and as a supplementation in more advanced stages of hypertension, however needing further validation by clinical trial intensification.

Effect of aqueous extract and anthocyanins of calyces of Hibiscus sabdariffa (Malvaceae) in rats with adenine-induced chronic kidney disease

OBJECTIVES

The aim of this work was to assess the possible beneficial effects of aqueous extracts of Hibiscus sabdariffa L. calyces and anthocyanins isolated therefrom in an adenine-induced chronic kidney disease (CKD) model.

METHODS

Rats were orally given, for 28 consecutive days, either adenine alone or together with either aqueous extract of H. sabdariffa calyces (5 and 10%) or anthocyanins (50, 100 and 200 mg/kg of anthocyanin concentrate). For comparative purposes, two groups of rats were given lisinopril (10 mg/kg).

KEY FINDINGS

When either H. sabdariffa aqueous extract or the anthocyanins isolated from it was administered along with adenine, the adverse effects of adenine-induced CKD were significantly lessened, mostly in a dose-dependent manner. The positive effects were similar to those obtained by administration of lisinopril.

CONCLUSIONS

The results obtained show that both H. sabdariffa and its anthocyanins could be considered as possible promising safe dietary agents that could be used to attenuate the progression of human CKD. This could have added significance as H. sabdariffa tea is widely consumed in many parts of Africa and Asia and is thus readily available.

Roselle for hypertension in adults

BACKGROUND

Hypertension is considered a serious health problem worldwide. Controlling and lowering blood pressure have a significant benefit to the hypertensive patients because hypertension is a risk factor for stroke, heart disease and cardiovascular disease. A tropical plant called Roselle, or Red Sorrel in English-speaking countries, has been used both as a thirst-quenching drink and for medical purposes.

OBJECTIVES

To explore the effect of Roselle on blood pressure in hypertensive adult patients.

SEARCH STRATEGY

The following databases were searched (Date of most recent search was September 2009): - Cochrane Database of Systematic Reviews (2nd Quarter 2009) - DARE (2nd Quarter 2009) - Ovid MEDLINE (1950 to Present with Daily Update) - EMBASE (1980 to 2009 Week 22) - AMED (1985 to May 2009) - EBSCO CINAHL - BIOSIS (1969 to 2008) - AGRICOLA (1970 to May 2009) - Food Science and Technology Abstract (1969 to 2009 June Week 1) - International Pharmaceutical Abstracts - International Bibliographic Information on Dietary Supplements - Clinical Trials.gov and Current Controlled Trials - OpenSIGLE - Hand searching of journals - ISI Web of Knowledge

SELECTION CRITERIA

We sought randomised control trials (RCTs) evaluating use of any forms of Roselle with placebo or no treatment in hypertensive patients. Change in trough and/or peak systolic and diastolic blood pressure were primary outcomes. Secondary outcomes were withdrawals due to adverse effects, change of pulse pressure and change of heart rate.

DATA COLLECTION AND ANALYSIS

Two review authors (C Ngamjarus, CN and P Pattanittum, PP) independently scanned titles and abstracts, as well as independently screened the full reports of the potentially relevant studies. At each stage, the results were compared and disagreements were solved by discussion.

MAIN RESULTS

No studies were identified that met the inclusion criteria. However, one abstract of an ongoing study is likely to meet the inclusion criteria, when completed.

AUTHORS' CONCLUSIONS

There is insufficient evidence to support the benefit of Roselle for either controlling or lowering blood pressure in patients with hypertension. Based on the information of this review, there is a clear need to develop well-designed studies to assess the efficacy of Roselle on hypertensive patients.