Agriculture Reference
In-Depth Information
Description —
Acacia senegal
is a small tree or shrub, up to 7 m high, with a short bole, gray-
fissured stem, usually coming off as papery patches to reveal a powdery underlayer. It branches low,
and its dense foliage gives it the appearance of a somewhat large thorn at the base of the branchlets,
with 3 to 6 pairs of pinnae and 6 to 15 pairs of narrow leaflets, about 6-8 mm long. The cream-color,
fragrant flowers are borne in axillary clusters, as densely crowded spikes, usually longer than the
leaves. The fruits occur as membranous flat cloves, about 11 cm long and 2-4 cm wide, hairy and
pale brown in color; containing 7 or 8 flat and circular beige seeds.
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Habitat and Distribution —
It is found in subdesert regions, the Sahelian, and dry tropical
zones. It occurs in Mauritania, Sudan, Niger, Mali, Senegal, Gambia, Nigeria, Burkina Faso, Kenya,
Uganda, Tanzania, and parts of southern Africa.
Ethnomedicinal Uses —
In West Africa, especially in the Senegal-Gambia region, the gum is
used in the preparation of a remedy for dysentery and diarrhea and applied externally for modular
leprosy. In East, Central, and North Africa, the leaves have been used in remedies for ophthalmia,
colds, and hemorrhage,
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and gum was used for the treatment of local inflammations. The root is
used in the mainland of Tanzania as a gonorrhea remedy.
Constituents —
The most important constituent of this plant is gum arabic, a colorless, odorless,
nontoxic solid substance soluble in water (1:2) that forms a sticky solution used in a variety of con-
sumer products.
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The gum exudes from branches and by stripping off a patch of the bark. Gum arabic
consists of a glycosidal acid of high molecular weight that has been termed arabic acid, and it is com-
bined with potassium, magnesium, and calcium. It also contains diastases and oxidase enzyme (African
Pharmacopoeia
436
). Acacia gums consist of galactose, arabinose, rhamnose, and glucuronic acids as the
only sugars found in all types of the gums. The difference between
A. senegal
and
A. seyal
(and the
other
Acacia
exudates) is the level of each sugar. The polysaccharide fraction is composed of a linear
chain of β-1,3-linked galactose. This chain is ramified in position with chains of galactose and arabi-
nose. Rhamnose, glucuronic acid, or methyl-glucuronic acid units are found as chain terminations.
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Pharmacological Studies —
Acacia gum is used in the food industry and pharmacy as a sus-
pending and emulsifying agent, emollient, and adhesive in the manufacture of tablets and other oral
dosage forms. Acacia gum is highly appreciated in technical applications due to its unique proper-
ties; it is used not only as a film former in the printing industry and as an adhesive agent in glues,
but also as a binding agent when used as a natural substitute for chemicals. The gum's technological
properties (texturing and film forming in confectionery, emulsifying, and encapsulating in flavors
and colors) and, for about 20 years, nutritional properties (fiber and prebiotic) in enriched foods and
nutritional complements have made it a preferred edible industry gum.
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Various modifications have
been made to the natural gum for use in specific pharmaceutical formulations.
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The unique properties of
Acacia
gum have also been adapted to provide a protective coating to
natural foods. For example, shiitake mushrooms coated with gum arabic plus natamycin (GANA)
maintained tissue firmness and showed a reduction in microbial counts from yeasts and molds com-
pared with the control. In addition, GANA coating delayed changes in the soluble solids concentra-
tion, total sugar, and ascorbic acid. Sensory evaluation proved the efficacy of GANA coating by
maintaining the overall quality of shiitake mushrooms during the storage period. The efficiency was
better than that of gum arabic or natamycin treatment alone. Our study suggested that GANA has
the potential to improve the quality of shiitake mushrooms and extend their shelf life up to 16 days.
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ACHYRANTHES ASPERA
Botanical Name —
Achyranthes aspera
L.
Synonyms —
A. canescens
R. Br.,
A. argentea
Decne.,
A. grandifolia
Moq.,
A. obovata
Peter,
A. repens
L.
Family —
Amaranthaceae
