Scientific
Name: Gnetum africanum
Common Name/s: English – Eru
Synonym/s: Thoa africana (Welw.) Doweld
Vernacular names : Eru (En). Koko (Fr). Nkoko (Po).
Local
Names:
English (eru); French (koko); Igbo (okazi); Portuguese (nkoko)
Red List Category & Criteria: Near Threatened ver 3.1
Range
Description:
This species is found from west central
tropical Africa to Angola including Central African Republic, Cameroon, Gabon,
Democratic Republic of the Congo and Angola.
Countries: Native:
Angola (Angola); Cameroon; Central African
Republic; Congo; Congo, The Democratic Republic of the; Gabon. Gnetum africanum
occurs naturally in the humid forest zones from Nigeria to the Central African
Republic and to Angola. Origin, Botanical Information and geographic distribution.
Gnetum africanum is one of the most popular green
leafy vegetable in Nigeria and is gaining equal popularity as a delicious food
leaf in other African countries such as Cameroon, Gabon, Congo and Angola (Eyo
and Abel, 1983).
Gnetum africanum (afang) grows as a wild
evergreen climbing plant in the rainforest of Nigeria where it is searched for
and highly priced in the regional markets. It is recently being cultivated in
South Eastern Nigerian Materials and Methods.
Eru has numerous common names and is grown in
various countries across Africa, including: Cameroon (Eru, okok, m’fumbua, or
fumbua), Angola (KoKo), Nigeria (ukase or afang), Gabon (KoKo), Central African
Republic (KoKo), Congo (KoKo), and the Democratic Republic of Congo (m’fumbua
or fumbua). Eru has also been referred to as a form of ‘wild spinach’ in
English.
Gnetum comprises approximately 35 species of
small trees, shrubs or most often lianas, found in tropical South and Central
America (about 7 species), Africa (2 species) and Asia (about 25 species). They
look much like dicotyledonous flowering plants (having opposite leaves with a
net venation and cherry-like seeds), although in fact they are gymnosperms.
commercial crop (Gnetum africanum or G.buchholzianum) male inflorescence.
The leaves of Gnetum africanum and G.
buchholzianum are highly valued as a nutritious green vegetable across Centre
and West Africa. Traditional dishes prepared with these leaves have provided
the cultural identity for some tribal groups in this region. The traditional harvesting
practices posed no threat to the resource base, but of recent, these species
are an article of considerable cross-border trade.
G.africanum
leaves are widely consumed in the South Eastern Nigeria due to its palatability
and taste. It is now eaten as a vegetable salad when mixed with palm oil. The
popularly known afang soup that is often listed in many continental restaurant
menu is prepared from these leaves which sometimes is cooked with water leaves
(Talicum traiangulare) to give the soup a special savour.
Nutritionally,
Gnetum is very rich in proteins and minerals. The leaves contain high
nutritional values as both species contain eight essential amino acids in
significant quantities.
The
leaves of Gnetum africanum and G. buchholzianum are highly valued
as nutritious green vegetables across Central Africa and are the subject of
considerable cross-border trade.
Both
Gnetum species have significant value to many forest-based communities
and have a number of vernacular and trade names. In the Central African
Republic, Gabon, Congo, DR of Congo and Angola, the two species are locally
called koko. In Anglophone Cameroon,
they are known as eru, while in Francophone Cameroon the name okok is applied.
Eru
is one of the commonest vegetables eaten
in Cameroon today. Its protein content is high and can greatly reduce
malnutrition in areas where meat (or other sources of protein) is scarce.
In
Nigeria, the two Gnetum species are called ukasi by the Igbo tribe while
the Efik/Ibibio tribes call them afang.
In
Nigeria, the leaf of G. africanum is used in the treatment of an
enlarged spleen, sore throats and as a cathartic . In Ubangi (DR Congo), it is
used to treat nausea and is considered to be an antidote to some forms of
poison. In Congo-Brazzaville, the leaves
of both species are used as a dressing for warts and boils and a tisane of the
cut-up stem is taken to reduce the pain of childbirth. Gnetum africanum
is also reported to be used for medicinal purposes in Mozambique.
However,
it is for its edible value that Gnetum is most prized.
The
leaves are either eaten raw or are finely shredded and added to soups and stews.
The leaf of G. buchholzianum is also edible, although it is
reported to be less common in commerce. The leaves of both species have very
high nutritional value and constitute an important source of protein, essential
amino acids and mineral elements.
Eru
also has medicinal qualities; it can be used in the treatment of enlarged
spleens, sore throats and nausea. It can also be used as an antidote to poison,
especially arrow poison common with the Pygmy. The leaves, used as dressing can
accelerate the maturation of furuncles and the stem can be taken as a tisane to
ease childbirth.
Properties
The dry matter content of fresh leaves is
much higher than for other dark or medium green leaf vegetables. This gives a
feeling of firmness during preparation, hence certain consumers consider eru as
a substitute for meat. The leaves of Gnetum africanum are somewhat thinner and
paler than the dark green leaves of Gnetum buchholzianum. Consequently, the
content of micronutrients in the latter might be somewhat higher.
Eru leaves
contain C-glycosylflavones, including 2"- xylosylisoswertisin and
2"-glucosylisoswertisin, compounds that are only known from these two
species; characteristic of Gnetum africanum is the presence of
2"-Orhamnoylisoswertisin and apigenin-7-hesperidoside and the absence of
vitexin and 2"-O-glycosylvitexin.
Adulterations and substitutes
The leaves of Gnetum africanum can be
replaced by those of the other eru species, Gnetum buchholzianum, or leaves of
the shrub Lasianthera africana P.Beauv., which impart a similar taste to the
dish.
This research finding revealed G.africanum (afang)
seeds as containing high percentage carbohydrate of 87.62 which is quite unique
when compared with other vegetable seeds. The seed therefore promises a good
nutritive supplementary source for rodents (rabbit) husbandry. Its mineral composition
is relatively low and needs to be supplemented when utilized in isolation. The
results of this investigation also show that G.africanum seed contains
substantial amounts of antinutrients.
The preponderance of these toxic substances is
presumed to be the main reason why the seeds of this popular vegetable is not
consumed as is done to fluted pumpkin seeds except for medicinal purposes. Pretreatment
and proper process of G.africanum seed is advocated before its incorporation
into food formulation for animal and man. This work has provided research data
which hitherto was very scanty about
afang seed. Its high food caloric value of 448.83kcal/100g
makes more research into its amino acids profile and characterization of its
lipid content quite compelling.
Importance
of Gnetum
The leaves of
Gnetum africanum and G. buchholzianum are highly valued as a nutritious green
vegetable across Centre and West Africa (Shiembo 1998). Traditional dishes
prepared with these leaves have provided the cultural identity for some tribal
groups in this region. The traditional harvesting practices posed no threat to
the resource base, but of recent, these species are an article of considerable
cross-border trade. This multimillion trade with Gnetum leaves has
significantly increased their exportation to European countries and America
where Africans resident in those countries consume it. The upsurge in demand
has mounted enormous pressure on the wild population thereby threatening its
continuous existence. The species has completely disappeared in some areas
where it used to be commonly found.Gnetum leaves are values as a tasty vegetable when finely shredded and incorporated into soup or stew, or made into condiments, or even taken raw. Nutritionally, Gnetum is very rich in proteins and minerals. The leaves contain high nutritional values as both species contain eight essential amino acids in significant quantities (Mialoundama 1993). This suggests the potential role of these species in the fight against malnutrition in poor rural areas with limited sources of meat. In areas where local population depends on a dwindling wildlife population as a source for protein intake, Gnetum provides an affordable alternative to maintain the nutritional values of their meals. Today, dishes based on Gnetum leaves are prominent on the menu list in many restaurants in Centre and West Africa, and in special eating places offering African dishes in Europe and USA.
The socio-economic value can not be over-emphasised. Dishes prepared of Gnetum leaves gives the cultural identity of some tribes in this region. For example the Bayangi in Cameroon that consider their traditional meals prepared with Gnetum leaves as very unique to them.
Economically, Gnetum leaves sustain an active cross-border multimillion trade stretching from West and Centre Africa to Europe and America. This provides employment to a wide range of persons, most of who are women. Most of the middlemen are young adults whose major source of income is from Gnetum trade (Nkefor 2000; unpublished report). In a single local market in Limbe, Cameroon, Gnetum trade has an annual turnover of over one hundred thousand US dollars. While at a border market - Idenau, the turnover is in the tone of one million US dollars. Fundamentally, thousands of people depend on the harvesting and marketing of Gnetum leaves for their living - women constitute more than 80 percent (Nkefor, 2000).
Gnetum as an economic crop has an important role to play in the fight against rural poverty. If compared with other highly valued forest products as timber, Gnetum trade touches the life of more people in the rural areas. It generates income for a wide range of people in the villages who otherwise are left out from benefiting from exploitation of the forest. It provides jobs for the youths that are involved at all stages of the process - harvesting, loading, transportation etc. Women dominate the marketing of Gnetum leaves in both internal and cross-border markets. For the rural woman it provides an opportunity for her to earn money that contributes in the well being of her household. The marketing of this product in local markets has so far not attracted government interest hence, is not taxed.
Medicinally, Gnetum africanum is used in the treatment of a variety of illnesses. In Nigeria the leaves are used for the treatment of enlarged spleen, for sore throat and as a cathartic (Ndam et al 2000). In Ubangi (DR Congo), it is used to treat nausea and is considered to be an antidote to some form of poison (Burkill 1994). In Congo - Brazzavile, the leaves of both species are used as a dressing for warts and boils, a tisane of the cut-up stem is taken to reduce pains at childbirth (Bouguet 1969).
References:
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