Journal of Ethnopharmacology 89 (2003) 161–164 Toxicological investigation of aqueous-methanolic extract of the calyces of Hibiscus sabdariffa L. A.A. Akindahunsi ∗ , M.T. Olaleye Department of Biochemistry, Federal University of Technology, Akure, Nigeria Received 2 April 2003; received in revised form 10 July 2003; accepted 25 July 2003 Abstract The aqueous fraction of an aqueous-alcoholic extract of Hibiscus sabdariffa L. calyces was given to Wistar albino rats (150–200 g) orally as drugs to study the toxicity of the extract. The rats, which were fed with commercial diet and water ad libitum, were divided into six groups of four rats each. Treatments 1 through 6 received 0, 1, 3, 5, 10 and 15 doses of 250mg/kg each, respectively; the control group received physiological saline (0.9% NaCl). Results of the studies showed that the levels of serum aspartate aminotransferase (AST) and alanine amino transferase (ALT) were significantly (P< 0.05) increased in all the treatments compared with the control group. However, the serum levels of alkaline phosphatase, and lactate dehydrogenase were not significantly (P> 0.05) affected. Only the group with 15 doses had their serum level of albumin significantly (P< 0.05) increased. However, the results of histopathological studies showed that both the livers and hearts gave no pathological features for all the treatments. The results showed that prolong usage of this extract at 15-dose level could cause liver injury while the effect was mild at small dose levels (1–10). Though the average consumption of 150–180mg/kg per day appears safe, the extract should be taken with caution bearing in mind that higher doses could affect the liver. © 2003 Elsevier Ireland Ltd. All rights reserved. Keywords: Hibiscus sabdariffa L.; Toxicological; Aspartate amino transferase; Alanine amino transferase; Alkaline phosphatase; Lactate dehydrogenase 1. Introduction In recent times, focus on plant research has increased all over the world and a large body of evidence has col- lected to show immense potentials of medicinal plants used in various traditional systems. Various medicinal plants have been studied using modern scientific approaches. The results from these plants have revealed the potentials of medici- nal plants in the area of pharmacology (Dahanukar et al., 2000; Auddy et al., 2003; Somova et al., 2003; Fatehi et al., 2003). Hibiscus sabdariffa L., a member of the Malvaceae fam- ily, is an annual herb that grows to 180cm or more; stems are globorous, while the lower leaves are ovate with the up- per leaves being 3–5 palmately lobed. The flowers are auxil- iary or in terminal racemes, the petals are white with reddish centre at the base of the staminal column, the calyx enlarges ∗ Corresponding author. Present address: Department of Biochemistry, Biophysics and Macromolecular Chemistry, University of Trieste, Via Giorgieri, 1, Trieste I-34127, Italy. Tel.: +39-334-3510944; fax: +39-040-5583691. E-mail addresses: aakin@ictp.trieste.it, aaakindahunsi@yahoo.co.uk (A.A. Akindahunsi). at maturity and the fruit is fleshy and bright red. It is known as roselle (English), l’Oiselle (French), spanish (Jamaica), karkade (Arabic) and bissap (Wolof). The calyces are used to make cold and hot beverages in many of the world’s trop- ical and sub-tropical countries. The average consumption of these beverages in Nigeria is 150–180mg/kg per day. Ca- lyces are used in the West Indies to colour and flavour rum. Seeds have been used as an aphrodisiac coffee substitute, and the fruits are edible too (Watt and Breyer-Bradndwijk, 1962). Folk medicine has reported Hibiscus sabdariffa to be an- tiseptic, aphrodisiac, astringent, resolvent, cholagogue, di- gestive, diuretic and stomachic (Perry, 1980). Roselle is a folk remedy for abscesses, heart ailments and hypertension. Hibiscus tea has been shown to lower blood pressure in patients with essential hypertension (Farayi and Tarkhani, 1999). The bitter root is used as an aperitive and tonic (Perry, 1980). Anna Pavala Sindhooram used for atherosclerosis, is a polyherb drug having flowers of Hibiscus rosasinensis as one of its constituents. Despite the popular use of this plant in the area of pharmacology, little or no information has been given about its toxicity. This work was carried out to evaluate the toxicity of the extract of the plant calyces on albino rats. 0378-8741/$ – see front matter © 2003 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/S0378-8741(03)00276-9