More tban 300 species of hibiscus can be found around the world, growing in both Tropical and Subtropical regions. Most varieties are used as ornamentals. However, there are two main types of Hibiscus sabdariffaL.(family Malvaceae), these are H. sabdariffa var. altissima, cultivated for its jute like fibre and H sabdariffa var. sabdariffa, cultivated for its edible calyces.2a The latter has many common names including roselle, sorrel, red sorrel, Jamaican sorrel, Indian sorrel, Guinea sorrel, sour- sour, jelly okra, lemon bush, karkade, Florida cranberry and many others.
H sabdariffa var. sabdariffa is an annual, erect, bushy, herbaceous, sub shrub, 5-7ftin height with smooth or nearly smooth, cylindrical, typically red stems. The leaves are alternate, 7.5 - 12.5 cm long, green with reddish veins and long or short petioles.
Flowers are borne singly in the leaf axils and are up to 12.5 cm wide, yellow or buff with arose or maroon eye and turn pink as they wither at the end of each day. The main edible part, the bright red calyx, surrounds the seed boll and consists of five large sepals with a collar or epicalyx of 8 -12 bracteoles around the base. The seed boll is a velvety capsule; 1.25 :-:- 2.0 cm long and is five-valved, with each valve containing three to four kidney-sh3:ped, light brown seeds. The seeds are usually 3 - 5 mm long and minutely downy. The capsule, which is usually green when immature turns brown and splits open when mature and dry. The calyces, stems and leaves are acid and closely resemble the cranberry (Vaccinium spp.) in flavour.
Hibiscus sabdariffa or sorrel as it is commonly called in Jamaica, is native from India to Malaysia, where it is commonly cultivated. It has been widely distributed in the Tropics and Subtropics of both hemispheres and has become naturalized in many areas of the West Indies and Central America. There are over one hundred cultivars or seed varieties of Hibiscus sabdariffa, with the major commercial varieties being grown in China, Thailand, Mexico, Sudan, Senegal, Tanzania and Mali.
Jamaica is a small producer of sorrel, producing 841.47 tonnes in 2001. Of this amount 247 .3 tonnes was grown in Clarendon, the main sorrel producer in Jamaica.4 Three varieties of sorrel are grown in Jamaica, a common variety (traditional red) which bears in the first and last quarter of the year, a blood red variety (early bearing red) which bears all year round and was introduced in the last two years and a white/green sorrel, which bears in December. Traditionally, a refreshing beverage flavoured with rum and ginger is prepared using the fleshy calyces at Christmas time. However, in recent times, the use of the sorrel in Jamaica has been extended to include the production of a squash and chutney. Other reported uses of the fleshy calyces in the West Indies and elsewhere in the Tropics includes preparation of jelly, tea, marmalade, ices, ice creams, pies, sauces, tarts and other desserts.
Although the use of the sorrel plant has been limited to its calyces in Jamaica, with leaves, stalks and a considerable number of seeds being discarded' (some seeds are removed for replanting), other cultures make full use of the plant. The leaves and stalks are usually used in salads and as pot-herb and in seasoning curries. The seeds, which are said to be diuretic and tonic in action, have also been used to relieve dysuria, strangury and mild cases of dyspepsia and debility. Other uses of the seeds include that of an aphrodisiac coffee substitute and a substitute for crude castor oil.
CONSTITUENTS AND DOCUMENTED HEALTH BENEFITS
Sorrel seeds contain 7.6% moisture, 24.0% crude protein, 22.3% fat, 15.3% fiber, 23.8% N-free extract, 7.0% ash, 0.3% Ca, 0.6% P, and 0.4% S. Component acids of the seed lipids were identified as 2.1% myristic-, 35.2% palmitic-, 2.0% palmitoleic-, 3.4% stearic-, 34.0% oleic-, 14.4% linoleic-, and three unusual HBr-reacting fatty acids (cis-12, 13-epoxy-cis-9-Qctadecenoic (12,13-epoxoleic) 4.5%; sterculic, 2.9%; and malvalic, 1.3%).6 Salama and Ibrahim reported on the sterols in the seed oil, which were identified as 61.3% j3-sitosterol, 16.5% campasterol, 5.1% cholesterol, and 3.2% ergosterol (said to be rare in vegetable oil but the most common mycosterol in most fungi, including yeast).7 Sorrel (dried-flowers minus-ovary) contains 13% of a mixture of citric and malic acid, two anthocyanins, gossipetin (hydroxyfiavone) and hibiscin, and 0.004-0.005% ascorbic acid. Petals yield the flavonal glucoside hibiscritin, which yields a crystalline aglycone- hibiscetin (C1sH1OO9)' The flowers contain phytosterols. The dried flower contains about 15.3% hibiscic acid (C6H607)' Root contains saponins and tartaric acid. Calyces contain 6.7% proteins by fresh weight and 7.9% by dry weight. Aspartic acid is the most common amino acid. Dried fruits also contain vitamin C and calcium oxalate; dry petals contain flavonol glucoside hibiscitrin, 7
Hibiscus sabdariffa has several documented health benefits. Research conducted locally, revealed that cancerous liver cells, treated with an extract of the sorrel seed, decreased in activity and dramatic) cell death occurred.
Researchers in Britain are also currently testing the plant's effect on essential hypertension. A paper presented recently, reported that there was a convergence between the public's belief and in vitro studies on the effects of sour tea (sorrel) on high blood pressure - two experimental groups of 54 patients provided sufficient information linking a decline in the systolic and diastolic blood pressures to sorrel (Hibiscus sabdariffa). At the Mexican Institute of Social Security, 'sorrel water' was linked to a significant decline in cholesterol and triglyceride levels in the blood and also to protection against heart disease. Abigail Aguilar Contreras, a Mexican scientist, believe that it is a good habit to consume sorrel water daily to decrease the risk of heart disease: It also helps to prevent the clogging of arteries resulting from excessive levels of cholesterol and triglycerides in the blood.
Researchers at the Scientific Research Council (SRC) and University of the West Indies (Mona), who have been studying the plant and creating new exotic sorrel products, report that sorrel contains a wide range of vitamins and minerals including vitamin C, calcium, niacin, riboflavin and a group of compounds known as flavonoids. These antioxidant compounds are found in the calyces (the red sepals that are used in the sorrel drink).
In India, Africa and Mexico, the plant holds significant value in native medicine. The leaves or calyces are infused and used as a diuretic (stimulating the passing of urine); a hypotensive (to lower the blood pressure) and also to stimulate the production of bile by the liver. The leaves are also heated in some parts of the world and applied to boils and ulcers. The seeds are also said to exhibit diuretic properties and is also used as a tonic. In East Africa, the calyx is infused to make a tea - the "Sudan tea"- taken to relieve coughs; Brazilians find medicinal value in the bitter roots.
Reported to be antiseptic, aphrodisiac, astringent, cholagogue, demulcent, digestive, diuretic, emollient, purgative, refrigerant, resolvent, sedative, stomachic, and tonic, sorrel is a folk remedy for abscesses, bilious conditions, cancer, cough, debility, dyspepsia, dysuria, fever, hangover, heart ailments, hypertension, neurosis, scurvy, and strangury. The drink made by placing, the calyx in water, is said to be a folk remedy for cancer. Medicinally, leaves are emollient, and are much used in Guinea as a diuretic, refrigerant, and sedative; fruits are antiscorbutic; leaves, seeds, and ripe calyces are diuretic and antiscorbutic; and the succulent calyx, boiled in water, is used as a drink in bilious :': attacks; flowers contain gossypetin, anthocyanin, and glucoside hibiscin, which may have diuretic and choleretic effects, decreasing the viscosity of the blood, reducing pleod'" pressure and stimulating intestinal peristalsis. In Burma, the seeds are used fot:debility, the leaves as emollient. Taiwanese regard the seed as diuretic, laxative, and tonic. Philippines use the bitter root as an aperitive and tonic Angolans use the mucilaginous leaves as an emollient and as a soothing cough remedy.. Central Africans poultice the leaves on abscesses. Alcoholics might consider one item: .simulated ingestion of the plant extract decreased the rate of absorption of alcohol, lessening the intensity of alcohol effects in chickens.
- Extraction of Sorrel Seed Oil Sorrel seeds (dried) of the early bearing red variety of sorrel were obtained from Clarendon. These were ground to a flour prior to extraction using a laboratory mill. The ground material (ca. 200 g) was weighed into a Soxhlet extraction thimble and was extracted with hexane (500 ml) for 2h, 4h and 8h periods in order to determine if there are any significant differences in the yield /quality of the oil obtained over time. The extract was then concentrated by rotary evaporation at 50°C, to produce a yellowish brown oil. This weight was used to calculate the yield of oil, which was recorded as w/w. All extractions were done in triplicate.