Indian-sorrel
StarHibiscus sabdariffa
Synonyms: Hibiscus sanguineus, Hibiscus acetosus, Sabdariffa rubra, Furcaria sabdariffa, Hibiscus palmatilobus, Hibiscus cruentus, Hibiscus digitatus, Hibiscus masuianus, Sabdariffa digitata, Abelmoschus cruentus, Hibiscus digitatus var. kerrianus, Hibiscus subdariffa, Hibiscus gossypifolius, Hibiscus fraternus, Hibiscus cuneatus
Traditionally used for
- Digestion
- Urinary & fluids
- Blood pressure
Cautions & contraindications
- Kidney conditions
Western Herbalism Properties
Traditional Uses
Roselle calyces are brewed into a tart, deep-red cooling beverage across many cultures, known as karkade in Egypt and Sudan, bissap in West Africa, and agua de Jamaica in Mexico, and are widely used in folk medicine for high blood pressure, as a mild diuretic, and to aid digestion (Morton, 1987; Da-Costa-Rocha et al., 2014). The young leaves and shoots are also eaten as a vegetable and the sour leaves used in sauces and folk remedies across tropical Africa, Latin America, and South Asia.
Gallery
Botanical Description
Hibiscus sabdariffa, known as roselle, is an annual or perennial herbaceous shrub in the family Malvaceae, growing up to about 2–2.5 m tall. The erect stems are often reddish and bear alternate leaves that are deeply three- to five-lobed on the upper part of the plant and simple and ovate near the base. The showy flowers have pale yellow to buff petals with a dark red centre, borne singly in the leaf axils. After flowering, the calyx and bracts (the epicalyx) enlarge and become fleshy, bright red, and succulent, surrounding the seed capsule; these red calyces are the most economically important part. Native to tropical Africa, roselle is now cultivated throughout the tropics and subtropics, including West Africa, the Caribbean, Mexico, India, and Southeast Asia. It thrives in warm climates with well-drained soils and is grown for its calyces, edible leaves, and fibre.
Active Constituents
Delphinidin-3-O-sambubioside
Anthocyanin (delphinidin diglycoside)Concentration: Predominant anthocyanin of the dried calyx; total calyx anthocyanins commonly 1-2.5% of dry weight, with delphinidin-3-sambubioside typically the largest single fraction
The principal red pigment of the roselle calyx and the marker compound to which standardised antihypertensive extracts are titrated. It is a strong radical scavenger in vitro and is the constituent most often used to normalise dosing across products, though it has not been shown on its own to reproduce the blood-pressure effect of the whole calyx.
Cyanidin-3-O-sambubioside
Anthocyanin (cyanidin diglycoside)Concentration: Second major calyx anthocyanin, usually a minority fraction of total anthocyanins alongside delphinidin-3-sambubioside
Co-occurs with delphinidin-3-sambubioside and contributes to the colour and antioxidant capacity of calyx infusions. Anthocyanin content is the usual basis for standardising roselle preparations, and clinical doses have been expressed in mg of anthocyanins rather than mg of extract.
Hibiscus acid
Organic acid (lactone of (+)-allo-hydroxycitric acid)Concentration: Characteristic calyx acid; total organic acids commonly 15-30% of the dry calyx
A species-characteristic organic acid of the roselle calyx and a chemotaxonomic marker distinguishing it from other Hibiscus drugs. It contributes much of the sourness of the infusion and is the constituent behind the marked acidity of the beverage.
Citric acid
Organic acid (tricarboxylic acid)Concentration: One of the dominant free acids of the calyx, together with malic, tartaric and hydroxycitric acids
Together with the other free acids it gives the calyx infusion a pH low enough to matter pharmaceutically: the acidity of the beverage is the most plausible explanation for the reduced absorption of pH-sensitive co-administered drugs such as chloroquine.
Chlorogenic acid
Hydroxycinnamic acid ester (caffeoylquinic acid)Concentration: Present in calyx and leaf extracts as a minor phenolic alongside protocatechuic and caffeic acids
A widely distributed dietary polyphenol present in roselle extracts; contributes to total phenolic content and antioxidant assays. It is not specific to this species and should not be treated as a roselle marker.
Hibiscitrin
Flavonol glycoside (gossypetin 3-glucoside)Concentration: Minor flavonoid constituent of the calyx
One of the gossypetin-derived flavonol glycosides reported from the calyx. Reported activity is limited to in vitro antioxidant and enzyme-inhibition work; no human data attach to this compound alone.
Calyx polysaccharides
Polysaccharide (pectic mucilage)Concentration: Substantial fraction of the dry calyx; pectin content of roselle calyx is high enough for the plant to be used commercially as a pectin source
The pectic mucilage gives infusions body and is a plausible contributor to any effect on the absorption of co-administered drugs through binding or delayed gastric emptying. Effects reported for polysaccharide fractions are preclinical only.
⚠ Drug Interactions
Chloroquine
In a controlled crossover study in healthy Sudanese men, a single 600 mg oral dose of chloroquine taken with karkadi (Hibiscus sabdariffa calyx beverage) instead of water reduced mean chloroquine AUC from 7.52 to 2.16 mg.h/L and mean Cmax from 553 to 148 mg/L, both statistically significant. Tamarindus indica and Citrus limetta beverages produced comparable reductions, which points to the shared acidity and complexation capacity of these drinks rather than to anything specific to roselle. The authors concluded that a parallel loss of antimalarial efficacy might be expected.
Clinical note: Do not take chloroquine (or, by extension, structurally related 4-aminoquinolines) with roselle infusions. Separate the drug from the beverage by several hours and use plain water for dosing, particularly where treatment failure would be dangerous.
Diclofenac
In a controlled study in healthy volunteers, 300 mL of roselle calyx beverage (equivalent to 8.18 mg anthocyanins) daily for three days significantly reduced the amount of diclofenac recovered in 8 h urine (p < 0.05). The study measured urinary excretion only, not plasma pharmacokinetics, so it establishes that the beverage changes diclofenac handling but not whether systemic exposure rises or falls.
Clinical note: Treat concurrent daily roselle beverage use as a reason to review NSAID response and renal function rather than as an absolute contraindication. Advise patients not to take diclofenac washed down with hibiscus drinks.
Hydrochlorothiazide
In rats and rabbits, co-administration of Hibiscus sabdariffa extract 20-40 mg/kg with hydrochlorothiazide 10 mg/kg increased and prolonged plasma hydrochlorothiazide concentrations, raised mean AUC and volume of distribution, and reduced plasma clearance and elimination rate constant in a dose-dependent way. Urine volume rose while urinary pH and sodium, bicarbonate and chloride concentrations fell. This is an animal study; there is no equivalent human pharmacokinetic dataset.
Clinical note: In patients on thiazides who drink roselle regularly, monitor blood pressure, volume status and serum electrolytes. The pharmacodynamic overlap (both are diuretic and hypotensive) is the more immediately relevant half of this interaction.
Antihypertensive drugs (ACE inhibitors, calcium channel blockers, diuretics)
Roselle calyx has a genuine, replicated antihypertensive effect in humans: a meta-analysis of randomised controlled trials found significant reductions in systolic and diastolic blood pressure, and controlled trials have compared standardised calyx extracts directly against captopril and lisinopril in hypertensive patients. Adding roselle to an existing antihypertensive regimen is therefore an additive pharmacodynamic effect with real magnitude, not a theoretical one.
Clinical note: Expect a further fall in blood pressure. Ask hypertensive patients how much roselle tea they drink before adjusting drug doses, and monitor for symptomatic hypotension when roselle is started or stopped.
Acetaminophen (paracetamol)
In six healthy male volunteers given 1 g acetaminophen 1.5 h after a roselle (zobo) drink, absorption parameters (t1/2a, Ka, Tmax, Cmax, AUC) were unchanged, but the terminal elimination rate constant and terminal half-life changed significantly and total clearance rose by 11.69%. The sample was very small and the assay spectrophotometric rather than chromatographic, so the finding is suggestive rather than definitive.
Clinical note: No dose change is warranted on this evidence. Mention it only where acetaminophen efficacy is unexpectedly poor in a heavy roselle drinker.
Other Hibiscus species substituted for roselle
Essentially all of the published human hibiscus pharmacology, including the antihypertensive trials and every interaction above, was generated with the dried calyx of Hibiscus sabdariffa. Other members of the genus used medicinally (for example Hibiscus rosa-sinensis and Hibiscus mutabilis) have different constituent profiles and no comparable human data, and products labelled only as hibiscus may not be roselle calyx at all.
Clinical note: Confirm that a hibiscus product is Hibiscus sabdariffa calyx before applying any of this evidence, and do not transfer roselle data onto other Hibiscus species or onto roselle leaf or seed.
Dosage Calculator
⚖ Dosage Calculator
A weight-based mathematical estimate for Indian-sorrel. Not a prescription.
Evidence Tier
Strong evidence · 8 studiesRecorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.
Systematic review / meta-analysis
1
1 verified · 0 unverified
Randomized controlled trial
6
3 verified · 3 unverified
Show 6 studies
- Hibiscus Sabdariffa L. Tea (Tisane) Lowers Blood Pressure in Prehypertensive and Mildly Hypertensive Adults
- Effectiveness and tolerability of a standardized extract from Hibiscus sabdariffa in patients with mild to moderate hypertension: a controlled and randomized clinical trial
- Clinical Effects Produced by a Standardized Herbal Medicinal Product of Hibiscus sabdariffa on Patients with Hypertension. A Randomized, Double-blind, Lisinopril-Controlled Clinical Trial
- Significant reduction in chloroquine bioavailability following coadministration with the Sudanese beverages Aradaib, Karkadi and Lemon
- Effects of water extract of Hibiscus sabdariffa, Linn (Malvaceae) 'Roselle' on excretion of a diclofenac formulation
- Effect of zobo drink (Hibiscus sabdariffa water extract) on the pharmacokinetics of acetaminophen in human volunteers
Other clinical trial
0
Observational / case report
0
In vitro / animal
1
0 verified · 1 unverified
Other / unclassified
0
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Hibiscus Sabdariffa L. Tea (Tisane) Lowers Blood Pressure in Prehypertensive and Mildly Hypertensive Adults
Randomised, double-blind, placebo-controlled trial in prehypertensive and mildly hypertensive adults drinking three 240 mL servings of Hibiscus sabdariffa calyx tisane daily for six weeks. Systolic blood pressure fell significantly relative to placebo, with the largest effect in participants who started with the highest systolic pressure. This is one of the anchor human trials for the roselle calyx.
Effect of sour tea (Hibiscus sabdariffa L.) on arterial hypertension
Systematic review and meta-analysis of randomised controlled trials of sour tea in hypertensive and prehypertensive adults. Pooled analysis found significant reductions in both systolic and diastolic blood pressure versus control. It is the most useful single summary of the human antihypertensive evidence for the Hibiscus sabdariffa calyx and should be read as applying to that species and plant part only.
Effectiveness and tolerability of a standardized extract from Hibiscus sabdariffa in patients with mild to moderate hypertension: a controlled and randomized clinical trial
Randomised controlled trial comparing a standardised Hibiscus sabdariffa calyx extract with captopril in patients with mild to moderate hypertension. The roselle extract produced clinically meaningful blood-pressure reduction with good tolerability over the trial period. Because the comparator is an active antihypertensive drug rather than placebo, the trial supports additive effect when roselle is combined with conventional therapy.
Clinical Effects Produced by a Standardized Herbal Medicinal Product of Hibiscus sabdariffa on Patients with Hypertension. A Randomized, Double-blind, Lisinopril-Controlled Clinical Trial
Randomised, double-blind trial of a standardised Hibiscus sabdariffa calyx product against lisinopril in hypertensive patients, with dosing expressed in anthocyanin content. Roselle lowered blood pressure and was well tolerated, although it did not match the ACE inhibitor on every endpoint. Confirms that the calyx has drug-comparable antihypertensive activity and therefore drug-comparable additive potential.
Significant reduction in chloroquine bioavailability following coadministration with the Sudanese beverages Aradaib, Karkadi and Lemon
Crossover pharmacokinetic study in healthy men comparing a 600 mg oral chloroquine dose taken with water against the same dose taken with karkadi (Hibiscus sabdariffa), aradaib (Tamarindus indica) or lemon (Citrus limetta). Karkadi cut mean AUC from 7.52 to 2.16 mg.h/L and mean Cmax from 553 to 148 mg/L. The authors warned that a parallel reduction in antimalarial efficacy might be expected.
Effects of water extract of Hibiscus sabdariffa, Linn (Malvaceae) 'Roselle' on excretion of a diclofenac formulation
Controlled study in healthy human volunteers measuring 8 h urinary diclofenac by HPLC before and after three days of 300 mL daily roselle calyx beverage (8.18 mg anthocyanins per serving). The amount of diclofenac excreted was significantly reduced (p < 0.05). The authors framed the result as a reason to counsel patients against taking plant beverages with medicines.
Herb-drug interaction between the extract of Hibiscus sabdariffa L. and hydrochlorothiazide in experimental animals
Pharmacokinetic and pharmacodynamic study in rats and rabbits. Roselle extract 20-40 mg/kg given with hydrochlorothiazide 10 mg/kg raised and prolonged plasma hydrochlorothiazide concentrations, increased AUC and volume of distribution, and reduced clearance and elimination rate constant dose-dependently, while urine volume increased and urinary pH, sodium, bicarbonate and chloride fell. An animal study, not a human one.
Effect of zobo drink (Hibiscus sabdariffa water extract) on the pharmacokinetics of acetaminophen in human volunteers
Two-phase study in six healthy male volunteers given 1 g oral acetaminophen with and without a preceding roselle (zobo) drink. Absorption parameters were unchanged, but the terminal elimination rate constant and terminal half-life changed significantly and total clearance rose by 11.69%. A very small study with a spectrophotometric assay, so the effect size should not be over-read.
Historical Texts
Species Plantarum, vol. 2, p. 695 (Carl Linnaeus)
1753References
- Da-Costa-Rocha I; Bonnlaender B; Sievers H; Pischel I; Heinrich M. Hibiscus sabdariffa L. - A phytochemical and pharmacological review . Food Chemistry (2014) [DOI]
- Haji Faraji M; Haji Tarkhani AH. The effect of sour tea (Hibiscus sabdariffa) on essential hypertension . Journal of Ethnopharmacology (1999) [DOI]
- Shafiee M; Mohammadi V; Kazemi A; Davarpanah H; Tabibzadeh SM; Babajafari S; Rostami H; Mazloomi SM. The effect of Hibiscus sabdariffa (sour tea) compared to other herbal teas and antihypertension drugs on cardiometabolic risk factors: Result from a systematic review and meta-analysis . Journal of Herbal Medicine (2021) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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