Scientific name : Hibiscus Sabdariffa

Common name : Hibiscus, Karkade, Red Tea

Botany

Hibiscus is native to tropical Africa but today ,throughout many tropical climates. This strong herb grows to 5 feet or more and produces elegant 'wers. The flowers (calyx and bract portions) are ed when slightly immature. The major producing hes are Jamaica and Mexico.

History

The hibiscus has had a long history of use in and neighboring tropical countries. Its fragrant have been used in sachets and perfumes. Fiber "sabdariffa has been used to fashion rope as a jute ute and the fleshy red calyx is used in the prepaof teas, drinks, jams and jellies, and the leaves een used like spinach.2 The plant is used widely in ", lor the treatment of cardiac and nerve diseases

ias been described as a diuretic. It has been used in~atment of cancers. The mucilagenous leaves are as a topical emollient in Africa. In western coun[bibiscus flowers are often found as components of tea mixtures.

Chemistry

A variety of compounds have been isoam the hibiscus plant. As expected from their vivid hibiscus flowers contain various anthocyanins 1,5%) and other pigments. Oxalic, malic, citric and acids have been identified. These, along with 15% of hibiscic acid (the lactone of a hydroxycitric acid) !Iy contribute to the tartness of the herb and its e flowers contain beta-sitosterol, traces of an and sitosterol-beta-D-glucoside.

Pharmacology

The plant has been used as a mild t&9, an effect that may be in part due to the acids d above. However, the pharmacologic evaluation extract suggests that hibiscus is not an effective Ne, A 5% solution caused a slight increase in intes tinal motility in vitro, while higher concentrations reduced it. Complete inhibition of intestinal motility was observed in vitro with more concentrated water extracts.

When injected intravenously in dogs, a 10% aqueous extract of the flowers caused a rapid but short-lived dose-dependent decrease in mean blood pressure. The extract reduced uterine motility in vitro and had essentially no effect on respiratory rate.

There is no evidence that doses of hibiscus from teas have a sedative effect. Aqueous extracts of hibiscus appear to exert a slight antibacterial effect. Extracts have been found to inhibit the movement of human and canine taenias and a 4% solution killed the worms in about one-half hour in vitro.5 A 15% aqueous extract prevented the growth of Mycobacterium tuberculosis in vitro, and 10 ml doses of a 20% extract prevented growth of the bacillus in infected rabbits? However, these data require confirmation and the antibacterial effect of the plant should not be considered to be clinically relevant.

Toxicology

Hibiscus flowers are generally considered to be relatively non-toxic. However, a 30% aqueous extract of the flowers had an LD-50 of 0.4 to 0.6 ml in mice following intraperitoneal injection.5 Animals injected with this toxic dose were dull and apathetic and died within 24 hours.

Summary

Hibiscus is a popular plant whose flowers are found in numerous herbal tea preparations. The flowers contribute color and a pleasant taste to beverages. In normal concentrations, the teas would not be expected to exert any pharmacologic action.

Patient information - Hibiscus

Uses

The leaves and calyxes have been used as food and the flowers steeped for tea. Hibiscus has been used medicine as a diuretic, mild laxative and treatment for cardiac and nerve diseases and cancer.

ous leaves have been used as topical emollient.

side effects

The flowers are considered relatively non-toxic, although an injected extract killed mice within 24 hours.