Phytochemical, pharmacological and toxicological aspects ofHibiscus sabdariffa L.: a review

Abstract

This article reviews the reported phytochemical, pharmacological and toxicological properties of Hibiscus sabdariffa L. (English: roselle, red sorrel; Arabic: karkade), the calyces of which are used in many parts of the world to make cold and hot drinks. Nutritionally, these contain ascorbic acid (vitamin C). In folk medicine, the calyx extracts are used for the treatment of several complaints, including high blood pressure, liver diseases and fever. The pharmacological actions of the calyx extracts include strong in vitro and in vivo antioxidant activity. In rats and rabbits, the extract showed antihypercholesterolaemic, antinociceptive and antipyretic, but not antiinflammatory activities. In rat and man a strong antihypertensive action has been demonstrated. The effects of the calyx extracts on smooth muscles in vitro are variable, but they mostly inhibit the tone of the isolated muscles. In healthy men, consumption of H. sabdariffa has resulted in significant decreases in the urinary concentrations of creatinine, uric acid, citrate, tartrate, calcium, sodium, potassium and phosphate, but not oxalate. Oil extracted from the plant's seeds has been shown to have an inhibitory effect on some bacteria and fungi in vitro. The plant extracts are characterized by a very low degree of toxicity. The LD50 of H. sabdariffa calyx extract in rats was found to be above 5000 mg/kg. A single report has suggested that excessive doses for relatively long periods could have a deleterious effect on the testes of rats. In view of its reported nutritional and pharmacological properties and relative safety, H. sabdariffa and compounds isolated from it (for example, anthocyanins and Hibiscus protocatechuic acid) could be a source of therapeutically useful products.

Effect of Sowing Time and Plant Density on the Growth and Production of Roselle (Hibiscus sabdariffa)

“…Extracts of roselle calyces are used for liver diseases, fever and high blood pressure. The calyx extracts are found to have strong in vitro and in vivo antioxidant activity (Ali et al, 2005).…”

Selected physiological responses of roselle (Hibiscus sabdariffa) to drought stress

“…2012). The antimicrobial properties of roselle were attributed to the presence of an abundance of secondary metabolites including a wide range of phenolic compounds (Ali et al, 2005). Additionally, some of these naturally occurring phenolic compounds have shown anti-carcinogenic, anti-hypertensive, anti-microbial, anti-mutagenic, anti-oxidative, and antiinflammatory properties (Kim & Lee 2003;Mckay et al, 2009).…”

The effects of sour tea (Hibiscus sabdariffa) on hypertension in patients with type II diabetes

“…In view of its reported nutritional and pharmacological properties and relative safety, H. sabdariffa and compounds isolated from it could be a source of therapeutically useful products. 9,10 Different studies, both in animal [11][12][13][14] and human models, 15,16 have shown that an extract or infusion of ST influences the atherosclerosis process, blood sugar and lipids, and BP. Lin et al 17 reported that ST infusion reduces cholesterol by 8.3-14.4% after 4 weeks.…”