Roselle is an erect, branched, nearly smooth annual herb, 1 to 2 meters in height. Stems are purplish. Leaves are 8 to 12 centimeters long, variable in shape, entire or deeply 3- or 5-lobed, the lobes oblong to oblong-lanceolate. Calyx is somewhat hairy, lobes are pointed, connate below the middle, forming a fleshy cup. Corolla is pink with a dark center, about 5 centimeters long. Fruit is ovoid, pointed, hairy, about 2.5 centimeters long, enclosed by a fleshy and enlarged calyx.
- Planted for ornamental purposes and its edible calyces.
- Not spontaneous.
- Introduce post-Spanish colonization.
- Native of tropical Africa.
• The dried calyces yield among others: cellulose, insoluble and soluble ash, tartaric acid, malic acid.
• Calyces are high in calcium, niacin, riboflavin, and iron.
• Food value per 100 g of fresh edible portion: Moisture 9.2 g, protein 1.145g. fat 2.61g, fiber 12 g, ash 6.9 g, calcium 1,263 mg, phosphorus 273.2 mg, iron 8.98 mg, carotene 0.029 mg, thiamine 0.117 mg, riboflavin 0.277 mg, niacin 3.765 mg, ascorbic acid 6.7 mg.
• The flowers yield a coloring matter that contain gossypetin, quercetin, hibiscetin and free protocatechuic acid.
• Bitter seeds contain 20% oil with 26% albuminoids.
• Leaves yield oxalic acid.
• Analysis of unextracted (UE) and extracted (E) roselle seeds showed 15.36% (UE) 27.50% (E) digestible crude protein, 75.81% (UE) 68.83% (E) total digestible nutrients, 84.06% (UE) 64.23% (E) starch value, and 3184 kcal/kg (UE) 2891 kcal/kg (E) calculated metabolizable energy.
• Nutritional analysis of the plant by proximate method yielded carbohydrate content of 68.7%, crude fiber 14.6%, and ash content of 12.2%. (38)
• Leaves considered emollient, stomachic, scorbutic and febrifuge.
• Seeds are diuretic and tonic.
• Flowers considered tonic and aperitive.
Leaves and flowers.
Culinary / Nutritional
• Cultivated ornamentally and for the red and fleshy calyces that surround the fruit used for making jellies, wine and other food products. The jam, jelly, and sauce are similar in appearance and taste to cranberries.
• Young leaves used as a substitute for spinach; used in cooking of curries, meat or fish, and the native dish "sinigang."
• In Myanmar, green leaves are the main ingredient in making chin baung kyaw curry.
• Calyces are high in calcium, niacin, riboflavin, and iron.
• In Nigeria, used for making refreshing beverage. (54)
• Leaves used as emollient.
• Lotion made from leaves used for sores.
• Decoction of seeds used for dysuria and strangury; for mild dyspepsia and debility.
• In Brazil, drink made from the plant, considered refrigerant and used for fevers.
• A boiled drink prepared from the fruit and calyx, dashed with salt, pepper, asafoetida and molasses, used for biliousness.
• Fruit used as antiscorbutic.
• Seeds are diuretic and tonic.
• In Chad, infusion of calyces used for plethora, bronchitis and coughs.
• Heated leaves applied to cracks in the feet; also, to boils and ulcers to hasten healing and maturation.
• In India seed decoction used for dysuria, strangury and mild dyspepsia.
• In Nigeria, seed decoction used to enhance or induce lactation in cases of poor milk production. (see study below) (27) Used as antihypertensive drug.
Plant yields bast fiber from the stems; used a jute substitute in making burlap.
Plant yields a coloring matter used for food coloring.
• Antihypertensive: A study evaluating the effect of sour tea (H sabdariffa) on essential hypertension showed significant lowering of both systolic and diastolic blood pressure. (1) A randomized, double-blind, placebo-controlled study examined the anti-hypertensive effects of H. sabdariffa tisane (hibiscus tea) consumption in humans. Results suggest daily consumption of hibiscus tea, in an amount readily incorporated into the diet, lowers BP in pre- and mildly hypertensive adults. (22) Study evaluated the anti-hypertensive activity of aqueous calyx extract of H. sabdariffa on salt induced hypertensive albino rats. Extract and drug treated groups showed a significant reduction in diastolic and systolic blood pressure. (41)
• Antimutagenic: A study of an 80% ethanol extract of roselle showed antimutagenic activity against MAM acetate, a colon carcinogen. (2)
• Anti-Atherosclerotic / Hypolipidemic: A study of HB extract suggests it inhibits serum lipids and shows and anti-atherosclerotic activity. (3)
• Nephroprotective / Diabetic Nephropathy Amelioration: Study showed HS extract possesses potential effects to ameliorate diabetic nephropathy in STZ induced type 1 diabetic rats via improving oxidative status and regulating Akt/Bad/14-3-3 signaling.(4)
• Galactagogue / Lactogenic Effect: A study showed the seed extract of H sabdariffa possesses lactogenic activity, enhancing serum prolactin level which is the principal lactogenic hormone secreted by the anterior pituitary. Results establish the ethnomedical use of the seeds as a galactagogue. (•) Study showed the serum prolactin level of extract-treated rats showed a dose-dependent significant increase when compared to the control group. (5)
• Anti-Hyperammonemia: A study showed administration of extract of HS altered the activities of the liver marker enzymes in ammonium chloride-induced hyperammonemic rats. (7)
• Antihypertensive / Seed: Study showed the aqueous seed extract of HS produced a significant reduction in cat blood pressure. (8)
• Antioxidant: A study showed the protective role of extract of HS against lipid peroxidation and suggests an antioxidant potential to be used for therapeutic purposes.
• Hypolipidemic / Calyx / Leaves: A study of HS dried calyx ethanolic extract on the serum lipid profile of Sprague-Dawley rats showed triacylglycerols and LDL levels to be significantly less in all groups. All groups had lower cholesterol levels compared to control. No significant results were found on the HDL levels (10)
• Antiviral / Anti-Measles Virus: A study of leaf extracts of red and green leaved Hibiscus sabdariffa showed antiviral activities against the Measles Virus. (12)
• Hepatoprotective / Carbon Tetrachloride Hepatotoxicity: A study of the aqueous ethanol extract of the calyx of Hibiscus sabdariffa on carbon tetrachloride-induced liver damage showed healing of oxidative liver damage as determined by serum enzyme levels and liver thiobarbituric acid reactive substances levels. (13)
• Antioxidant / Seeds: Study investigated the antioxidant activity of an ethanolic seed extract of H sabdariffa in toxicity induced by chronic administration of sodium nitrate in wistar rats. Results showed alleviation of induced toxicity by the antioxidant effect of HS. Substantial amounts of Vitamin E and Vitamin C in the seed oil observed on preliminary phytochemical screening may be responsible for the antioxidant effect. (14)
• Anti-Obesity: Study investigated the effect of a calyx extract on fat absorption-excretion and body weight in rats. Results showed a significant increase in the amount of fatty acid in the feces. The components of the Hs extract at the intermediate and higher concentrations could be considered possible antiobesity agents. (15) Review focuses on the anti-obesity effect of H. sabdariffa. Studies have reported that HS modulates obesity through its antioxidant mechanism and reduction in adipogenesis, with a significant effect on lipid metabolism, fat absorption and excretion, and obesity related enzymes. (46) A previous study suggested H. sabdariffa extracts had a metabolic-regulating and liver protecting potential. This clinical trial showed consumption of HSE improved liver steatosis. There were no adverse effects, with no alteration in serum amylase and lipase. Results suggest HSE can be used as adjuvant for preventing obesity and non-alcoholic fatty liver. (61)
• Staining Effect: Roselle extract shows reasonable potential as a candidate nuclear stain especially when mordanted with iron alum or mordanted with potassium alum and acidified with acetic acid. (16)
• Safety Study: Study concludes Hibiscus sabdariffa is probably a safe medicinal plant, short-term administration of the HS did not show harmful effects on body water and electrolyte levels.
• Review / Hypertension Study / No Effect: Current trials of HS in reducing high blood pressure were poor. Four randomized controlled studies do not provide reliable evidence to support recommending HS for the treatment of primary hypertension in adults. (18)
• Lactogenic Study / Prolactin Effect: Study evaluated the effect of an ethyl acetate fraction of seed on pituitary prolactin and milk production in albino rats. Results showed a significant increase in prolactin level. Results infer the EA seed fraction has lactogenic activity, increasing pituitary prolactin level and milk production in lactating female albino rats. The LD50 of ethyl acetate fraction was above to be above 5000 mg/kg. (19)
• Review / Treatment of Hypertension and Hyperlipidemia / Animal and Human Studies: This review reports of a comprehensive body of evidence suggesting that HS extracts are promising as treatment of hypertension and hyperlipidemia. Of the potential hypolipidemic and hypotensive mechanisms, the most common explanation is the antioxidant effects of the anthocyanins inhibition of LDL-C oxidation, which impeded atherosclerosis, an important cardiovascular risk factor. Author suggests more high quality animal and human studies to provide recommendations for its potential public health benefit. (23)
• Toxicity Study: Study evaluated acute and chronic toxicities of water extract from calyces of Hibiscus sabariffa in male and female rats. A single oral administration of extract in the amount of 5,000 mg/kbw did not produce acute toxicity. A 270-day chronic toxicity evaluation at doses of 50, 100, and 200 mg/kbw did not cause chronic toxicity in rat. (25)
• Protective Against Oxidative Stress Induced Damage on RBC Membrane: Study evaluated the effect of an aqueous extract of H. sabdariffa calyx on hydrogen peroxide induced oxidative stress on rat RBC membranes. The extract showed a protective effect by reducing oxidative stress damage in vitro. Dose concentrations of 0.5 mg/ml Roselle extract reduced peroxidation on lipids by reducing the concentration of MDA and helped RBC membrane antioxidant defense system by increasing GSH and lowering SOD concentrations. (26)
• Safety Study During Pregnancy and Lactation: Study reviewed the literation on use, safety, efficacy, and pharmacology during pregnancy and lactation. Results showed no scientific evidence to support use of H. sabdariffa during pregnancy and lactation. In vitro studies of seeds in animals suggest a lactogenic effect. Animal studies have also shown delayed puberty, elevation of body weight and BMI in female rats. Authors advise caution with the use of HS during pregnancy and lactation until human research determines its safety. (27)
• Antifungal Synergism with Voriconazole in Fluconazole-Resistant Candida albicans: Study reports on the antimicrobial effect of H. sabdariffa extract, a common herbal drink, in combination with voriconazole or fluconazole against C. albicans isolates. Results showed a high degree of synergism of the extract with voriconazole against fluconazole-resistant C. albicans. The extract showed no effect with fluconazole. (28)
• Hypotensive Effect / Anthocyanins: Extraction study on H. sabdariffa analyzed total phenol content and antioxidant capacity using various assays. Highest concentration was through water extraction, providing the highest concentrations of cyanidin 3-sambubioside and delphinidin 3-sambubioside. Partition coefficients of anthocyanins showed aglycone and glucoside forms of hibiscus anthocyanins behave differently when in the presence of cell wall material, which could effect absorption and bioactiviy of the anthocyanins. A human crossover study on daily consumption of H. sabdariffa juice for 8 weeks showed a significant reduction in systolic blood pressure. Study suggests regular consumption of HS extracts may reduce cardiovascular risk. (29)
• Effect on Spermatogenesis / Fruit: Study evaluated the effect of aqueous fruit extract of Hibiscus sabdariffa on spermatogenesis and sperm of adult male mice. Results showed an adverse effect on spermatogenesis and sperm parameters in mice, with significant differences in FSH, LH, and testosterone hormones, with testes histology showing a significant decrease in lumina spermatozoa. (30)
• Corrosion Inhibition: Study of calyx extract of H. sabdariffa on mild steel corrosion showed suppression corrosion in both acid media (2M HCl and 1M H2SO4) through mix-inhibition mechanism. Inhibition efficiency increase with increase in extract concentration and synergistically increased in the presence of halide ions. (31)
• Anthocyanins / Antioxidant / Petals: Study investigated the relationship between antioxidant activity and anthocyanin content in Roselle petals. Results showed the antioxidant capacity of Roselle extract increased when extraction time or weight of petals increased. FRAP showed a linear relationship with anthocyanin. Results showed anthocyanin is the major source of antioxidant capacity in Roselle extract. Study indicated the anthocyanin and a brown pigment in the extract accounted for about 51% and 24% of the antioxidant capacity, respectively. (33)
• Antioxidant / Anthocyanins / Flowers: Study evaluated the antioxidant potential of three fractions of ethanol crude extract from dried flowers of H. sabdariffa by DPPH and XO activity. The ethyl acetate fraction showed the highest capacity for scavenging free radical (EC50 0.017 mg/ml) and the chloroform soluble fraction showed strongest XO inhibitory effect (EC50 0.742 mg/ml). The dried flower extracts protected rat hepatocytes from t-BHP-induced cytotoxicity and genotoxicity b y different mechanisms. (34)
• Reduction of Serum Cholesterol in Men and Women: A clinical study investigated the cholesterol- lowering potential of HS extract in human subjects. Results showed a dosage of 2 capsules of HSE (with a meal) for 1 month significantly lowered the serum cholesterol level. (35)
• Inhibition of Angiotensin Converting Enzyme (ACE) Activity / Anthocyanins: Study evaluated the constituents responsible for the ACE inhibitory activity of aqueous extract of HS. Study isolated anthocyanins delphinidin-3-O-sambubioside (1) and cyanidin-3-O-sambubioside (2). The compounds showed competitive ACE inhibitor activity with IC50 of 84.5 and 68.4 µg/mL, respectively. Results support the folk medicine use of HS calyces as antihypertensive. (36)
• Effect of Sour Tea on Hypertension in T2 Diabetic Patients: A double-blind randomized controlled trial compared the antihypertensive effectiveness of sour tea (H. sabdariffa) with black tea infusion in diabetic patients. Results showed consuming ST infusion had positive effects on BP in T2DM patients with mild hypertension. (37)
• Minor Interaction with Acetaminophen:Drinking a hibiscus beverage before taking acetaminophen might increase how fast the body eliminates acetaminophen. (39)
• Therapeutic Effective in the Treatment of Hypertension: Randomized, double-blind, controlled clinical trial on the therapeutic effective of H. sabdariffa in hypertensive patients at 200 mg of anthocyanin daily for 16 weeks showed an effect less than that of lisinopril. However, the treatment significantly reduced systolic and diastolic blood pressure and showed 100% safety. Because of a diuretic effect, night administration was contraindicated. (40)
• Gastric Ulcer Protective: Study evaluated the anti-ulcerogenic activity of ethanolic extract of dried calyces in different ulcer models in Wistar albino rats i.e. cold restraint stress, pylorus ligation, necrotizing agents, and indomethacin induced gastric ulcer models. The extract showed an ability to significantly protect against gastric mucosal injury in all models used. Pharmacological and biochemical findings were supported by histological assessment in the stomach. (42)
• Clinical Trial on Hypolipidemic Effect / Leaves: Double-blind, placebo controlled, randomized trial evaluated the hypolipidemic effect of HS leaves extract in 50 patients. At 1 gm per day of the leaf extract, there was no discernible blood lipid lowering effect. The observed effects might have been the result of patients following standard dietary and physical activity advice. (43)
• Antioxidant / Polyphenolic Rich Extract: Study evaluated the scavenging abilities of Hibiscus polyphenolic rich extract against superoxide ions generated during XO mediated breakdown of xanthine to uric acid. Results showed the 1.0% and 2.5% (v/v) diethyl ether extract significantly inhibited superoxide ions by 42.35 and 100.00% respectively. Results suggest HS may be beneficial in reducing oxidative damage to lipid and prevent or reduced development or progression of free radical mediated diseases. (44)
• Anti-Inflammatory:Study evaluated the anti-inflammatory activity of methanolic extract of H. sabdariffa in adult wistar rat. Results showed anti-inflammatory activity against carrageenan induced inflammation with decrease in paw diameter. Results were similar to the action of diclofenac. (45)
• Biochemical Effect on Reproductive Hormones / Calyx: Study evaluated the biochemical effect of H. sabdariffa calyx extract on male rat reproductive hormones. A 28-day administration of aqueous extract of H. sabdariffa is associated with decreased circulating plasma levels of follicle stimulating hormone, testosterone, luteinizing hormone and prolactin in male wistar rats. (47)
• Antihypertensive / Leaves: Study investigated the antihypertensive effects of methanolic extract of HS leaves in rats with hypertension induced by a salt-loading diet for 6 weeks. Result showed significant reduction (p<0.05) of blood pressure and heart rate in hypertensive rats in a dose-dependent manner. Effects were similar to that of captopril. The antihypertensive effect may be mediated by a reduction in serum oxidative stress. (48)
• Cytotoxic / Antioxidative / Breast Cancer Cell Lines: Study evaluated the cytotoxic and antioxidant effects of water and methanolic extracts of H. sabdariffa on cancerous MCF7 and non-cancerous MCF12Aa breast cell lines. The ORAC assay of the methanolic extract demonstrated a higher total antioxidant capacity than the water extract. The HS extracts selectively induced apoptosis via ROS generation and the mitochondrial dysfunctional pathway in MCF cells. Results suggest the extracts contain compounds that selectively confer pro-oxidant and cytotoxic effects on MCF7 cancer cells. (49)
• Hepatoprotective / Antioxidant / Petals: Study evaluated an aqueous petal extracts of H. sabdariffa for hepatoprotective and antioxidant properties in Wistar rats with DNPH induced hepatotoxicity. The hepatoprotective and antioxidant properties were statistically identical (p<0.05) for markers of hepatotoxicity and oxidative stress. (50)
• Meta-Analysis / Effect on Arterial Hypertension: Meta-analysis assessed the potential antihypertensive effects of H. sabdariffa. Fixed-effect meta-regression indicated a significant effect of H. sabdariffa supplementation in lowering both systolic and diastolic blood pressure. (51)
• Synergism with Antibiotics Against Helicobacter pylori: Study evaluated the in vitro antimicrobial combinatory effect of aqueous extract of H. sabdariffa with antibiotics (clarithromycin, amoxicillin, metronidazole) against H. pylori strains. The aqueous extract exhibited remarkable bacteriostatic effect against all HP strains tested with MICs ranging from 9.18 to 16.68 µg/mL. Results showed a potential for AEHS as a therapeutic candidate alone or in combination with antibiotics for the treatment of HP infection. (52)
• Antibacterial:Study of H. sabdariffa extracts sowed antibacterial activity. The 96% alcohol extract yielded a higher amount of bioactive compounds. The most sensitive strains were Escherichia coli ATCC 25922 and Enterobacter cloacae ATCC 13047. Antibacterial activity depended on concentration, on solvent used, as well as resistance of the bacteria under study to the bioactive compounds. (53)
• Effect on Blood Pressure and Electrolyte Profile / Comparative Study with Hydrochlorothiazide: Study evaluated the effect of HS consumption on blood pressure and electrolytes of Nigerians with mild to moderate hypertension and compared it with hydrochlorothiazide, a widely used antihypertensive drug. Hibiscus sabdariffa was a more effective antihypertensive agent than HCTZ in mild to moderate hypertension, showing a longer duration of action, and did not cause electrolyte imbalance. (54)
• Enhancement of Myocardial Capillarization in Spontaneous Hypertension: Study investigated the effect of water extract of dried calyx of HS and Hibiscus anthocyanins on left ventricular myocardial capillary length and surface are in spontaneously hypertensivre rats. HS ingestion significantly reduced SBP, DBP, and LV mass in a dose-dependent fashion but did affect HR. HS significantly increased surface area and length density of myocardial capillaries and length density. The effects may be beneficial in restoring myocyte nutritional status compromised by the hypertrophic state of hypertension. (55)
• Phenolic and Flavonoid Content / Antioxidant / Antitumoral / Leaf and Calyx: Study evaluated the phenolic and flavonoid contents and antioxidant and antitumoral activity of leaf and calyx extracts of H. sabdariffa cultivated with poultry litter and organosuper®. Highest phenolic and flavonoid contents were seen in the leaf extracts. Both exhibited free radical scavenging action. The methanol extract from calyces showed significant selective activity against leukemia cell line (K-562), with concentration dependent cytotoxic and cytocidal effects. (56)
• Anthocyanin / Inhibition of N-Nitrosomethylurea-Induced Leukemia: Study previously reported anthocyanins from roselle that showed significant anticancer activity in promyelocytic leukemia cells. This study explored the antitumor effect of anthocyanin, a bioactive polyphenol of roselle in a rat model of chemically induced leukemia. The oral administration of Hibiscus anthocyanin (0.2%) significantly inhibited progression of NMU-induced leukemia by approximately 33% in rats. (57)
• Effect on the Renin-Angiotensin-Aldosterone System / Clinical Study: A double-blind controlled randomized clinical study evaluated the effects of aqueous extract of Hibiscus sabdariffa on three basic components of the renin-angiotensin-aldosterone system: plasma renin, serum angiotension-converting enzyme (ACE), and plasma aldosterone (PA) in Nigerians with mild to moderate hypertension. HS reduced serum ACE and PA in mild to moderate patients with equal efficacy as lisinopril. Activity are possibly due to the presence of anthocyanins in the extract. (58)
• Prevention of Insulin Resistance: Study evaluated the effect of HS extract on fasting blood glucose level, fasting blood insulin level, and insulin resistance index (HOMA-IR)in high-fructose fed Sprague-Dawley rats. At dose of 400 mg/kbw, the blood glucose, insulin and HOMA-IR were significantly lower. (59)
Against Glucose Deprivation Induced PC12 Cells Injury: Serum/glucose deprivation (SGD) is a model for the understanding of the molecular mechanisms of neuronal damage during ischemia in vitro and the search for neuroprotective drugs against ischemia-induced brain injury. Study showed HS extract has protective effects of HS against SGD-induced PC12 cells injury. Results suggest a potential as a therapeutic option for neurodegenerative disorders. (62)
• Phytoestrogens / Estrogenic Activity:Study evaluated 10 widely used herbs in the Middle East for quantification of five known phytoestrogens. Some of the plants were devoid of tested phytoestrogens i.e., genistein, biochanin A, daidzein, quercetin, and kaempferol. Hibiscus sabdariffa was found to be richest in quercetin and daidzein, 3.70 ± 0.02 and 49.3 ± 0.05 µg/g of dried plant, respectively, with 13.5 ± 0.2 µg/g of kaempferol. H. sabdariffa also showed modest and significant proliferative effect on MCF-7 cells. (63)
• Corolla as Acid-Base Indicator: Acid-base titration requires indicators that show color change at each pH interval. Study yielded an anthocyanin from Roselle's corolla which was used for extraction of the indicator. Roselle's corolla indicator gave red color in acidic solution and green in basic solution, results similar to that of methyl orange. (64)
• Cyclooxygenase Inhibitory Activity / Antioxidant: In vitro study evaluated the antioxidant activity of various extracts of three varieties of sorrel as well as their potential for reducing blood viscosity. Cyclooxygenase inhibitory activity was measured using COX-1 and COX-2 enzymes rate of oxygen uptake in prostaglandin synthesis. Antioxidant activity was highest in the red variety, with the methanol extract showing highest activity. There was higher COX-1 inhibition than COX-2 inhibition, with a high potential to decrease blood viscosity. Results support the ethnomedicinal use of HS for the treatment of cardiovascular disease and hypertension. (65)
• Antihepatotoxic / STZ Diabetic-Induced Liver Damage: Study evaluated the anti-hepatotoxic activities of a flavonoid-rich aqueous fraction of methanolic extract in STZ-induced diabetic Wistar rats, Hepatoprotective effects were evident from amelioration of hepatic fibrosis and excessive glycogen deposition along with restoration of elevated liver enzymes. The anti-hepatotoxic activity could be partly attributed to antioxidant activity and the presence of flavonoids. (66)
• Hepatoprotective / Acetaminophen Induced Liver Injury / Leaves: Study of H. sabdariffa aqueous extract of leaves showed hepatoprotective activity against acetaminophen induced hepatocellular injury, along with reduction of blood cholesterol levels. Activity could be attributed to it free radical scavenging property and presence of natural antioxidants. (67)
• Hepatoprotective / DMBA-Induced Toxicity: Study showed Roselle possess significant hepato- protective effect against hepatic injury induced by DMBA treatment. Results showed potential for use of Roselle in the prevention of oxidative stress caused by free radicals from pollutants and foods. (68)
• Antigenotoxic / Free Radical Scavenging / Flowers: Study evaluated fractions of ethanolic extract of flowers for antioxidant and free radical scavenging activity. Results showed HS flower extracts possess strong antimutagenic activity and free radical scavenging effects of active oxygen species. (69)
• Hematopoetic Potential / Anthocyanin-Rich Red Dye: Study evaluated the protective efficacy of anthocyanin-rich dye of H. sabdariffa against cadmium chloride (CdCl2)-induced hypochromic microcytic anemia and oxidative stress in rat blood cells. Results showed supplementation of anthocyanin-rich red dye of HS counteracted the toxic effects of cadmium chloride on hematological and oxidative stress parameters. (70)
• Comparison with Enalapril on Effect in Bleomycin-Induced Lung Fibrosis Model: Study evaluated the inhibitory effect of H. sabdariffa extract on angiotensin-converting enzyme (ACE) compared to enalapril in a rat model of bleomycin-induced pulmonary fibrosis. There was a significant increase in lung index and levels of MDA, HP, ANG II and pro-inflammatory cytokines after bleomycin administration. Pre-treatment with with enalapril, PCA, and HS extract resulted in reduction of above factors. Enalapril and HS extract could mitigate the progression of fibrosis viz ACE blocking and a decrease in level of oxidative stress, and prevent the formation of fibroblasts, inflammatory cells and alveolar thickening caused by bleomycin. (71)
• Radioprotective / Radiation-Induced Liver Damage: Study of the methanolic extract of leaves of Vernonia amygdalina and Hibiscus sabdariffa, and vitamin C suggest that, taken together together, they could increase the antioxidant defense systems and may protect animals from gamma-induced radiation liver damage in male Wistar albino rats. (72)
Interactions / Toxicology
• Studies in healthy volunteers showed altered chloroquine, acetaminophen and diclofenac pharmacokinetics. (32) Hypotensive effects might be of concern in patients on antihypertensives.
• The LD50 of ethyl acetate fraction of seed was above to be above 5000 mg/kg. (19) The median lethal dose of the calyx extract in rats is estimated to be higher than 5 g/kg. (Ali BH, Al Wabel N, Blunden G. Phytochemical, pharmacological and toxicological aspects of Hibiscus sabdariffa L.: a review. Phytother Res. 2005;19(5):369-375.) (32)
- Teas and extracts in the cybermarket.