Hibiscus

Scientific names: Hibiscus sabdariffa

Common names: Hibiscus also is known as karkade, red tea, red sorrel, Jamaica sorrel, rosella, soborodo (Zobo drink), Karkadi, roselle, and sour tea.

Efficacy-safety rating:

ÒÒ...Ethno or other evidence of efficacy.

Safety rating:

...Little exposure or very minor concerns.

What is Hibiscus?

Roselle is native to tropical Africa, but today grows throughout many tropical areas. This annual herb produces elegant red flowers. The flowers (calyx and bract portions) are collected when slightly immature. The major producing countries are Jamaica and Mexico.

What is Hibiscus used for?

Traditional/Ethnobotanical uses

The hibiscus has had a lengthy history of use in Africa and neighboring tropical countries. Its fragrant flowers have been used in sachets and perfumes. In areas of northern Nigeria, this plant has been used to treat constipation. Fiber from H. sabdariffa has been used to fashion rope as a jute substitute. The fleshy red calyx is used in the preparation of jams, jellies, and cold and warm teas and drinks. The leaves have been used like spinach. The plant is used widely in Egypt for the treatment of cardiac and nerve diseases and has been described as a diuretic. In Iran, drinking sour tea for the treatment of hypertension is a popular practice. It has been used in the treatment of cancers. Research reveals little or no evidence of these medicinal uses of hibiscus. The mucilaginous leaves are used as a topical emollient in Africa. In Western countries, hibiscus flowers often are found as components of herbal tea mixtures. In Thailand, people consume roselle juice to quench thirst. Karkade seed products (ie, karkade defatted flour, protein concentrate, protein isolate) have been studied for their nutritional and functional value.

Hypertension

A randomized clinical trial evaluated the effect of sour tea available commercially in Iran on essential hypertension in otherwise healthy volunteers. A decrease in blood pressure was seen. However, after cessation of drinking the sour tea, a rise in blood pressure occurred. Although no adverse effects were seen in this study, the use of sour tea for treating hypertension requires further study.

Antibacterial/Vermifuge

Aqueous extracts of hibiscus appear to exert a slight antibacterial effect. In laboratory and animal studies, worms were killed by hibiscus extracts. Research reveals little or no clinical data regarding the use of hibiscus as an antibacterial or vermifuge (kill worms).

Chemopreventive effects

Components of hibiscus have shown potential as a chemopreventative agent against tumor promotion in laboratory and animal studies. These components also possess anti-inflammatory properties. Research reveals little or no clinical data regarding the use of hibiscus as a chemopreventive agent.

Laxative effects

The plant has been used as a mild laxative. While animal studies show a mild cathartic effect, research reveals little or no human clinical data regarding the use of hibiscus as a laxative.

Other uses

Hibiscus has been studied for its use in preventing renal stone formation, as well as its respiratory and sedative effects. To date there is no clinical evidence to prove any of these beneficial medical effects. Additionally, hibiscus anthocyanins have shown antioxidant activity in protecting against hepatotoxicity in rats. Application and action in humans has yet to be investigated.

What is the dosage of Hibiscus?

There is no clinical evidence on which dosage recommendations can be based. Roselle has generally recognized as safe (GRAS) status as a foodstuff. A typical dose as a tea is 1.5 g.

Is Hibiscus safe?

Contraindications

Contraindications have not yet been identified.

Pregnancy/nursing

Documented adverse effects. Avoid use. Roselle has emmenagogue (to stimulate menstrual flow) effects.

Interactions

Hibiscus beverages may reduce chloroquine plasma levels, decreasing the effectiveness.

Side Effects

No data.

Toxicities

The flowers are considered relatively nontoxic. However, high doses have caused death in mice within 24 hours.

Copyright © 2006 Wolters Kluwer Health

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