Willis (1973) classified Garcinia kola (Heckel) taxonomically as follows:-
Kingdom : plant ordor . Guttiferales.
Family: Guttiferales . sub -family clusiudeae
Tribe: Garcinieae: Garcinia
Botanical name: Garcinia Kola (Heckel)
Common name: Bitter Kola
Igbo : Agbi-ilu, Aki-ilu
Hausa: Namijin gor
The seeds of several plants have been used either wholly as a substitute for, or as adulterants of, true kola. All of these, however, lack the characteristic principles of the true kola. Among these plants is Garinia Kola (Heckel). The fruit of this plant is rarely found as an adulterant of kola, as their external features are entirely different. However, it bears the name of false kola, male kola, and bitter kola. It is highly esteemed by the native of Africa, though devoid of marked stimulant properties of true kola. Negroes chewed it as a powerful aphrodisiac and, as masticatory, they employ them in common colds. They contain tannin, colour matter, and a brown and a yellowish- white resin but no alkaloids (Harvey Wickes, 1898).
The flowers of Garcinia kola are greenish white, with reddish hair on both the sepals and petals. The flowers have very short stalk, while its ovaries are hairy and the stigmas are four lobed. The fruits is reddish-yellow, about 6.25cm in diameter, and each fruit contains two to four brown seeds embedded in orange- coloured pulp (Atilad Akanmu 1997 pg 121). Garinia species is a wide forest tree, height varies considerable but can grow up to 30m.
DISTRIBUTION OF GARCINIA KOLA
Garcinia kola is endemic in the humid lowland rainforest vegetation of the west and central African subregions. It is found in coastal areas and lowland plains up to 300m above sea level with an average of 2, 500mm of rainfall per annum. The trees are abundant in densely populated areas of natural and secondary forests where the predominant land use system is tree crop plantation farming (Aiyelagbe and Adeola 1993). Temperature ranges from 32.150C to 21.40C and a minimum relative humidity of 76.343% (Atilad Akanmu 1997 pg 117).
An important and ancient trade product, the nuts of Garcinia kola are available in markets throughout west and central Africa, from Senega town in Sierra Leone to South-West Cameroon (Atilad Akanmu 1997 pg 116). In Nigeria, its trade is as important as that of kolanut in major towns and cities in the Southern parts of the country, where the tree is endemic. It is favoured by the three major ethnic groups in Nigeria, the yorubas, Igbos and Hausas. Its domestic trade thus extends beyond the Southern production areas to the Northern parts of the country.
There is long gestation period before flowering and fruiting. However, many of the germinating difficulties have been overcome by methods developed by (Okafor 1998, Atilad Akanmu 1997 pg 121), and interest is developing to cultivate the tree species in plantations. CULTIVATION
They require temperature range from 32.150C to 21.40C and a minimum relative humidity of 76.34% (Atilad Akanmu 1997 pg 117). The seed is raise in nurseries. Fruiting in the tree commences in July and ends in October. HARVESTING
Fruit harvest continues intermittently as ripe fruit fall and are then collected for the extraction of seeds.
When ripe, the green pericarp turns to a reddish yellow colour, and the fruit falls from the tree. The fruit are collected and kept in an open, cool place till the pericarp and the pulpy musocarp become soft. Once softened, the fruits are threshed to released the nuts, which are thoroughly washed to remove sticky mucilaginous material that sheaths the nut. Nuts that are not sold fresh are then spread out and air- dried in preparation for storage, which is provided by wrapping the nuts in leaves and storing them in a basket lined with jute bag materials. This process is repeated as fruits ripens and is collected throughout the harvesting period.
CHEMICAL HISTORY AND COMPOSITION
The constituents of Garcinia kola include: biflavonoids xanthones and benzophenones. The antimicrobial properties of this
plant are attributed to the benzophenone, flavanones (Iwu, 1993). Dimethylamine, methylamine, ethylamine and Isopentylamine in three varieties of kola nut, cola acuminates, C. nitida and Garcinia cola (Atawodi; 1995) , Lipid composition of the seeds of Garcinia Kola, Chrysophyllum albidum, and Dennettia tripelattia range from 32-69 gm/kg (Akintonwa A, and A.R. Essien, 1995). The biflavanones GB1, GB2 and kolaflavanone were isolated as the active constituents (Iwu 1985).
ACTION, MEDICAL USES AND DOSAGE
Medicinal uses of Garcinia kola, include purgative, antiparasitic, antimicrobal . The seeds are used in the treatment of bronchitis and throat infections. They are also used to prevent and relieve colic, cure head or chest colds and relieve cough. Also the plant is used for the treatment of liver disorders and as a chewing stick (Iwu 1993). Studies show very good antmicrobial and antiviral properties.
In addition, the plant possesses antidiabetic; and antihepatotoxic activities (Iwe 1993).
Garcinia kola seeds are considered a poison antidote in Africa. Kolaviron at 100mg/kg orally reduced thiopental- induced sleep in CCL4- poisoned rats and protected microsomal enzymes against phalloodin (Iwu 1987). Paracetamol- induced hepatotoxicity in rats was reduced by Garcinia kola seed extract. Protection might be due to inhibiting P-450 activation of the toxin (Akintonwa 1990). Blood sugar was lowered from 115mg/dL to 65mg/dL by Kolaviron, a mixture of C-3/C-8 linked biflavonoids obtained from Garcinia kola, at 100mg/kg in rabbits. It also inhibited rate lens aldose reductase IC50 =5.4 x10(-6) (Iwu 1990). Lipid peroxidation of rat liver was inhibited by G.Kola in a dose dependent manner; possibly due to isoflavones (Adegoke, 1998).