Hibiscus

Common names: Hibiscus, roselle, karkade, sour tea

Botanical names: Hibiscus sabdariffa, H. rosa

Parts used and where grown

Members of the Malvaceae family, various species of hibiscus are shrubs found practically around the globe. The flower of hibiscus is the part used as medicine. The most widely known and best-studied species tend to be annuals from the tropics, such as the two that are focused on here. There are, however, hardy perennial species that survive in colder climates. Another hibiscus not discussed here is Hibiscus esculenta, or okra.

Hibiscus has been used in connection with the following conditions (refer to the individual health concern for complete information):

Rating	Health Concerns
	Hypertension Lice
	Fever Type 1 diabetes Type 2 diabetes
Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit. For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Historical or traditional use (may or may not be supported by scientific studies)

Teas made from hibiscus flowers and, occasionally, leaves are a very common drink in tropical regions where they grow. The cool, astringent, acidic flavour is widely recognized and has made it a staple of “zinger” type teas in the United States. All parts of hibiscus plants are used traditionally. Due to their soothing (demulcent) and astringent properties, the flowers and leaves have been traditionally used to treat conditions such as cancer and gallbladder attacks, to lower blood pressure, to relieve dry coughs, and topically to treat skin afflictions.¹ The root has been used as a tonic. The stems yield fibres that can be used to make rope or burlap.

Active constituents

The flowers contain substantial quantities of flavonoids and proanthocyanidins,² which are associated with anti-oxidant, fever-reducing (antipyretic), pain-relieving (analgesic), and spasm-inhibiting (spasmolytic) activities.³ ⁴ Of the many polysaccharides, the acidic polysaccharides show the most interesting properties. For example, they stimulate specialized skin cells which would presumably promote wound healing and these polysaccharides are also immune-modulating.⁵ ⁶ There is also a high concentration (15 to 30%) of simple organic acids such as citric and malic acids.⁷

Complex extracts of hibiscus have shown other properties in the test tube and in animal studies, such as reducing skin cancer promoted by ultraviolet light, inhibiting herpes simplex virus, and lowering cholesterol levels.⁸ ⁹ ¹⁰ A variety of studies have looked at the potential use of hibiscus for male and female fertility regulation with mixed results.¹¹ ¹² ¹³

How much is usually taken?

Hibiscus is usually taken as tea. Clinical trials have used 1 to 2 tsp (3 to 6 grams) of dried flower infused in to 1 cup (250 ml) three times per day.¹⁴ One study used 500 ml of tea once a day before breakfast.¹⁵

Are there any side effects or interactions?

There are no known side effects from reasonable amounts of hibiscus.

Are there any drug interactions?
Certain medicines may interact with hibiscus. Refer to drug interactions for a list of those medicines.

References

1. Duke JA. CRC Handbook of Medicinal Herbs. Boca Raton, FL: CRC Press, 1985:228–9.

2. Bruneton J. Pharmacognosy Phytochemistry Medicinal Plants, 2nd ed. London: Intercept, 1999:24.

3. Dafallah AA, al-Mustafa Z. Investigation of the anti-inflammatory activity of Acacia nilotica and Hibiscus sabdariffa. Am J Chin Med 1996;24:263–9.

4. Salah AM, Gathumbi J, Vierling W. Inhibition of intestinal motility by methanol extracts of Hibiscus sabdariffa L. (Malvaceae) in rats. Phytother Res 2002;16:283–5.

5. Brunold C, Deters A, Knoepfel-Sidler F, et al. Polysaccharides from Hibiscus sabdariffa flowers stimulate proliferation and differentiation of human keratinocytes. Planta Med 2004;70:370–3.

6. Muller BM, Franz G. Chemical structure and biological activity of polysaccharides from Hibiscus sabdariffa. Planta Med 1992;58:60–7.

7. Bruneton J. Pharmacognosy Phytochemistry Medicinal Plants, 2nd ed. London: Lavoisier, 1999:24.

8. Sharma S, Sultana S. Effect of Hibiscus rosa sinensis extract on hyperproliferation and oxidative damage caused by benzoyl peroxide and ultraviolet radiations in mouse skin. Basic Clin Pharmacol Toxicol 2004;95:220–5.

9. Zheng MS. An experimental study of the anti-HSV-II action of 500 herbal drugs. J Tradit Chin Med 1989;9:113–6.

10. El-Saadany SS, Sitohy MZ, Labib SM, el-Massry RA. Biochemical dynamics and hypocholesterolemic action of Hibiscus sabdariffa (Karkade). Nahrung 1991;35:567-76.

11. Pal AK, Bhattacharya K, Kabir SN, Pakrashi A. Flowers of Hibiscus rosa-sinensis, a potential source of contragestative agent: II. Possible mode of action with reference to anti-implantation effect of the benzene extract. Contraception 1985;32:517–29.

12. Tan CH. Is Hibiscus rosa sinensis Linn. a potential source of antifertility agents for males? Int J Fertil 1983;28:247–8.

13. Kholkute SD, Mudgal V, Udupa KN. Studies on the antifertility potentiality of Hibiscus rosa sinensis. Parts of medicinal value; selection of species and seasonal variations. Planta Med 1977;31:35–9.

14. Herrera-Arellano A, Flores-Romero S, Chavez-Soto MA, Tortoriello J. Effectiveness and tolerability of a standardized extract from Hibiscus sabdariffa in patients with mild to moderate hypertension: a controlled and randomized clinical trial. Phytomedicine 2004;11:375–82.

15. Herrera-Arellano A, Flores-Romero S, Chavez-Soto MA, Tortoriello J. Effectiveness and tolerability of a standardized extract from Hibiscus sabdariffa in patients with mild to moderate hypertension: a controlled and randomized clinical trial. Phytomedicine 2004;11:375–82.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or chemist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires September 2008.

2007-09-01