Agriculture Reference
In-Depth Information
The vast occurrence of primitive types and wild relatives in Africa (especially Ethiopia, Nigeria,
Cameroon, and Ghana) indicates that okra is certainly African. It is, however, widespread in tropi-
cal, subtropical, and warm temperate regions but is particularly popular in West Africa, India, the
Philippines, Thailand, and Brazil. The common okra, Abelmoschus esculentus, grows in the whole
of tropical Africa, whereas West African okra, Abelmoschus manihot (L.) Medik [synonyms: A.
caillei (A.Chev.) Stevels; A. pseudomanihot DC. Endl; A. platidactylus (Bakh.) Nakai; and Hibiscus
manihot ] is a cultigen occurring mainly in West and Central Africa. It has been reported from
Guinea to Nigeria in West Africa; in Cameroon, Gabon, and the Democratic Republic (DR) of the
Congo in Central Africa; and in Uganda in East Africa. Its distribution is restricted to humid and
perhumid climates in Africa, between 12° N and 12° S, most commonly between 5° N and 10° N,
whereas the common okra, Abelmoschus esculentus (L.) Moench, can be found worldwide through-
out the tropics, subtropics, and warm temperate regions.
Ethnomedicinal Uses — The immature fruits and the leaves are eaten in various ways. Fruits,
fresh or sliced and dried, are used for soups (West African draw-soup), also fried in oil. Leaves
are used as a potherb. Young shoots are also eaten. The mucilage is used medicinally and techni-
cally as an industrial raw material. A decoction of the immature okra fruits is demulcent, diuretic,
and emollient. It is also used in the treatment of catarrhal infections, ardor urinae , dysuria, and
gonorrhea. It has been used as a plasma replacement or blood volume expander. The seeds usually
obtained from mature and hard capsules are antispasmodic, cordial, and stimulant. An infusion of
the roasted seeds has sudorific properties. Leaves are sometimes used as a basis for poultices; as an
emollient, sudorific or antiscorbutic; and to treat dysuria.
Constituents — All the aerial parts of the plant are useful, although the ends of the fruits are
usually trimmed, leaving about 80% of the product as the edible portion. The composition of okra
fruits per 100 g edible portion is water 88.6 g (85.7-90.2), energy 144 kJ (36 kcal), protein 2.1 g
(1.1-3.0), fat 0.2 g, carbohydrate 8.2 g, fiber 1.7 g, Ca 84 mg (55-142), P 90 mg, Fe 1.2 mg (1.1-1.5),
ß-carotene 185 µg (180-190), thiamin 0.04 mg, riboflavin 0.08 mg, niacin 0.6 mg, ascorbic acid 47
mg (20-126). The composition of okra leaves per 100 g edible portion is water 81.5 g (75.3-92.4),
energy 235 kJ (56 kcal), protein 4.4 g (2.8-5.6), fat 0.6 g, carbohydrate 11.3 g, fiber 2.1 g, Ca 532 mg
(258-635), P 70 mg, Fe 0.7 mg, ß-carotene 385 µg, thiamin 0.25 mg, riboflavin 2.8 mg, niacin 0.2
mg, ascorbic acid 59 mg (9-75). Compared to other fleshy fruit-vegetables (tomato, eggplant), okra
is particularly rich in Ca and ascorbic acid. Okra seed meal contains more than 20% of good-quality
protein on a fat-free, dry-weight basis, whereas most of the suitable amino acids in okra seed protein
are present in amounts that are equal to or exceed the amounts in eggs and casein, and the U.N. Food
and Agriculture Organization (FAO) references okra as a protein source. The seed protein is similar
in amino acid composition to soya bean protein. It contains 20% oil (similar in fatty acid composition
to cottonseed oil). The seeds are rich in phenolic compounds, mainly composed of oligomeric cate-
chins (2.5 mg/g of seeds) and flavonol derivatives (3.4 mg/g of seeds). The skin's polyphenolic profile
is composed principally of hydroxycinnamic and quercetin derivatives (0.2 and 0.3 mg/g of skins). 1
Pharmacological Studies — Because of its high nutrient value, okra is considered a good
source for food fortification strategies. Okra has also been used in the management of duodenal
ulcers and diabetes. The glycosylated molecules found in the okra mucilage have been related to the
inhibition of adhesion of Helicobacter pylori to human gastric mucosa. 2 Such molecules could also
contribute to glucose entrapment and alpha-glucosidase inhibition, which might be advantageous
in the management of diabetes. 3 The fruit and the leaves have antioxidant properties. It has been
observed that the distribution of phenolics in methanolic extracts of okra correlates with distribution
of antioxidant activity. Studies have also shown that roasting of okra seed flour at 160°C for up to
40 min caused an increase in antioxidant activity, as determined by free-radical scavenging using
the DDPH (2,2-Diphenyl-1-picrylhydrazyl) assay. 4 A methanolic extract of okra seeds was shown to
have antioxidant activity, as evidenced by several criteria, and to exert antihypoxic activity in two
mouse models. 5
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