Tamarind has been cultivated in India for centuries and was taken by the Spanish conquistadores to the West Indies and Mexico in the 17th century. It is now widely grown in the tropics as an ornamental to provide shade as well as for the fruit. The name tamarindus comes from the Arabic Tamar-Hindi, meaning 'date of India', and refers to the date-like pulp inside the pods. According to folklore the sailors used to eat tamarind fruit as a complement to their otherwise starchy diet, in the belief that eating it would prevent scurvy.
The tree is native to tropical Africa and is now naturalised and widely cultivated throughout India as well as other tropical countries, including the Caribbean, south east Asia and China, where it is found on roadsides and in gardens.
A large tree up to 30 m high, with spreading branches (Plate 60). The bark is brownish?grey, peeling off in flakes. Leaves are even-pinnate, consisting of 10-18 pairs of small leaflets, rather close together. Petioles and rachis up to 12 cm long; leaflets oblong, up to 30 by 10 mm; opposite, pink or reddish when young, membranous, glabrous, with an obtuse apex and unequal base. The inflorescence is a terminal raceme, yellowish orange to pale green, consisting of a narrow turbinate calyx tube with four imbricate segments. There are three unequal petals, the upper cordate about 1 cm long, and two lateral petals, narrowed towards the base. There are three fertile stamens, the base conical; ovary linear, about 7 mm long, pubescent, on a stalk adnate to the calyx tube. Pods are oblong, slightly curved, up to 15 cm long and reddish brown. The seed is glossy, dark brown, embedded in a thick, sticky aromatic and acid brown pulp.
Fruits, fruit pulp, seeds, leaves, flowers and bark.
The fruits are eaten fresh and made into a refreshing drink and the pulp is an important ingredient of Indian cuisine. Fresh and dried fruits are used as a sour flavouring agent in curries, fish, chutneys and sauces. They are sweet and sour, cooling, carminative, digestive, laxative and antiscorbutic. The bark, leaves and seeds are astringent. The tender leaves and flowers are cooling and antibilious and are used in constipation, colic, cough, dyspepsia, fever, flatulence and urinary infection. The fruit pulp or the leaves may be used in the form of a poultice for external application to inflammatory swellings to relieve pain, and a poultice of the flowers is useful in inflammatory affections of the conjunctiva. The ripe pulp of the fruit is considered as an effective laxative in habitual constipation and enters into many Ayurvedic preparations, where it may be given for loss of appetite and nausea and vomiting in pregnancy. An infusion of the leaves is used as a gargle for aphthous ulcers and sore throats and for washing indolent ulcers. In other parts of the world the plant is equally regarded: in Nigeria, leaf extracts are used in guinea worm infection in Fiji, the fruit and leaves are taken orally for piles2 and in Tanzania, a decoction of dried leaves is given for malaria. In Guatemala the dried fruit is taken as a febrifuge, for urinary tract infections and infections of the skin and mucosa, including ringworm and other fungal diseases. The bark is used as a tonic and febrifuge and the ash obtained by heating it with salt in an earthen pot is mixed with water and taken orally for colic and as a gargle or mouth wash. In the Canary Islands the dried fruit is eaten as a choleretic. Tamarind seed xyloglucan (TSX) is used as a thickener, stabiliser, gelling agent and starch modifier for food, textile and toiletry use.
Fruits and leaves are given to ruminants for fever, internal parasites, bloat and as an appetiser, to pigs for coughs and colds, and to both for constipation. The leaves have been used to treat fractures.
U zarigenin -3-0-?- 0- xylopyranosyl-a- L?rhamnopyranoside and scilliphaeosidin 3-0-?- D-glucopyranosyl- L?rhamnopyranoside have been isolated from the seed.
?-Sitosterol, campesterol, stigmasterol and ?-amyrin occur in the seed.
Arabinose, ribose, xylose, mannose, fructose, galactose, glucose, inositol, sucrose, maltose, raffinose, xyloglucan and polyose (a polysaccharide gum) are present in the seed and pectin, glucose, mannose, maltose and arabinose in the fruit.
Apigenin, vitexin, isovitexin, orientin and others occur in the leaf.
Aspartic, glutamic, tartaric, citric, oxalic and succinic acids, serine, methionine, phenylalanine and others are present in the fruit and seeds and glyoxalic, oxaloacetic, oxalosuccinic and o.-oxoglutaric acid in the leaf and seed.
L-ascorbic acid, tocopherol, carotenes in the fruit.
Calcium, phosphorus, magnesium, potassium, sodium, copper, iron, zinc, manganese in the fruit.
Palmitic, oleic acid, linoleic, arachidic, behenic, lignoceric, linolenic, and ecosa?tetraenoic acid are present in the seed.
2-Acetyl furan, benzaldehyde, phenyl acetaldehyde, dibutyl phthalate,"3 furfural/' linalool, linalool oxides, geraniol, a-terpineol, tamarindineal (5- hydroxy- 2-oxo- hexa-3 ,5?dienaW5 and others have been found in the fruit.
Immunomodulatory activity: A polysaccharide isolated from Tamarindus indica showed phagocytic enhancement, leucocyte migration inhibition and inhibition of lymphocyte proliferation. A biologically active xyloglucan oligosaccharide, obtained by treatment of tamarind xyloglucan with a fungal b-glucanase, was found to be useful for the prevention and/or treatment of immunological damage to skin exposed to UV irradiation. This was due to prevention of the suppression of delayed hypersensitivity and a reduction in the amount of interleukin-IO produced by keratinocytes in the skin. Tamarind xyloglucans were immunoprotective at low (picogram) doses and prevented suppression of immune responses to alloantigen in mice exposed to 30 kJlm2 UVB radiation.
Antioxidant activity: 2-Hydroxy-3'A'?dihydroxyacetophenone, methyl 3A-dihydroxybenzoate and 3A?dihydroxyphenyl acetate were isolated from the ethyl acetate extract of the seed coat and demonstrated strong antioxidative activity in the linoleic acid autoxidation system as measured by the thiocyanate and thiobarbituric acid methods.
Antiinflammatory activity: Aqueous, ethanol and chloroform extracts demonstrated antiinflammatory activity in mice (ear oedema induced by arachidonic acid) and rats (subplantar oedema induced by carrageenan) after topical or intraperitoneal administration, respectively.
Hypolipidaemic activity: Tamarind xyloglucan has a p-l A-glucan backbone, so is not digested by human digestive enzymes and acts as a dietary fibre. Both intact and hydrolysed xyloglucan reduced plasma and liver lipids in rats fed a high-cholesterol diet and significantly reduced adipose tissue weight. In another study, high-fat diets containing 5% w/w ofxyloglucan or cellulose were given to the test or control groups of rats for 4 weeks. Blood total cholesterol, plasma triglyceride and lipoprotein levels of the test groups were reduced, indicating the beneficial effect of xyloglucan supplementation. Blood GOT and GPT levels of the test groups were also lower than those ofthe control group.
Hypoglycaemic activity: The effect of oligosaccharides obtained from tamarind xyloglucan on absorption of3-O-methyl-D?glucose was studied using everted sacs from rat small intestine. Among the oligosaccharides tested, octasaccharide and nonasaccharide, which contain O-galactose residues at their non-reducing terminals, inhibited absorption of 3-0-methyl- 0?glucose and inhibition was concentration dependent. The results indicate that the octasaccharide and nonasaccharide may not only serve as a soluble dietary fibre of low molecular weight but also lower the blood sugar level.
Antibacterial activity: An acetone extract of the fruit showed antibacterial activity against Salmonella typhimurium on agar plates. The 70% alcoholic extract was active on Bacillus cereus, B. megatherium, Escherichia coli, Psew1omonas aeruginosa, Salmonella typhimurium, Staphylococcus alba and Staph. aureus. The methanol extract of the dried stem bark was active on Sarcina lutea.
Antifungal activity: The ethanol (95 %) extract of the fruit was active against Trichophyton mentagrophytes and T rubrnm. An aqueous alcoholic extract was also active against Aspergillus fumigatus, A. niger, Penicillium digitatum and Rhizophus nigricans.
Molluscicidal activity: Water and methanol extracts of the fruit pulp were found to have molluscicidal activity against Bulinus trnncatus. The LCsos were 400 ppm and 300 ppm respectively.
Antiviral activity: Tamarind gum (glyloid) and three sulphate derivatives (GP4311, GP4327 and GP4324) were evaluated for their inhibitory effect on Rubella virus (RV) infection ofVero cells. Glyloid sulphate 4324 had the highest inhibitory effect on RV antigen synthesis. The results indicated that the polysaccharides blocked a step in virus replication subsequent to virus attachment, such as internalisation and/or uncoating. Glyloid sulphate 4323 and glyloid sulphate 4327 were also found to inhibit rabies virus infection in chicken embryo-related cells by interfering with the virus adsorption process, in a dose-dependent manner. The effective concentration was far below the cytotoxicity threshold.
Effect on fluoride toxicity: The effect of tamarind ingestion on fluoride retention was studied in dogs. The urinary excretion of fluoride was significantly higher in dogs supplemented with fluoride and tamarind in comparison with the fluoride-only supplemented group and the control group, indicating the beneficial effect of tamarind ingestion on fluoride retention and toxicity.
Ophthalmic delivery system: Tamarind seed polysaccharide (TS- P) has been used as an ophthalmic delivery system for ocular administration of hydrophilic and hydrophobic antibiotics. TS-P has high viscosity and mucoadhesive properties, which make it suitable for addition to ophthalmic solutions to prolong the residence time on the cornea. The effect of a preparation containing TS- P on intraocular pressure (lOP) was evaluated in rabbits. Administration into the conjunctival sac of 0.5% timolol, or 0.5% timolol with 1 % and 2% TS-P, had no effect on normal lOP but significantly reduced betamethasone?induced ocular hypertension over 20 days. Timolol in conjunction with TS-P had a longer duration of action.
Bioavailability enhancement: The influence of tamarind fruit extract, incorporated into a traditional meal, on the bioavailability of aspirin tablets 600 mg dose was studied. There was an increase in plasma levels of aspirin and salicylic acid when the meal containing the extract was administered with the aspirin, compared to when it was taken in the fasting state or with the meal but without the fruit extract.
No health hazards or side effects are known in conjunction with therapeutic dosages. A 90-day repeated dose toxicity study of flavonoid tamarind pigments cocoa brown (TRSP(B)) and roasted seed pigments was conducted in Sprague-Dawley SPF rats. During the entire period of administration, there were changes in clinical signs, body weight, food consumption, ophthalmological, urinalysis, haematological, blood chemistry or pathological parameters. An ethanoVwater (1 :1) extract ofthe flowers, when administered orally to mice, gave a maximum tolerated dose of 1.0 g/kg.