STERCULIACEAE (former classification)
MALVACEAE (new classification)
Kola trees originate from the warm and humid regions of West Africa.
Botanists distinguish at least 5 species that have edible and medicinal nuts (the botanical classification of the genus Cola is not yet well defined).
Cola nitida and Cola acuminata are the main ones, the others C. verticillata, C. ballayi, C. sphaerocarpa are used locally or sometimes their nuts are mixed with the two main species (adulteration).
Kola nuts are very popular in Africa (as stimulating and toning masticatory or for traditional ceremonies).
The spread of these species in African countries where Kola trees did not exist is old and has continued with varying degrees of success in all regions of the world where the climate allowed their development (Asia, Hawaii, tropical America, West Indies).
These are medium to large (up to 20-25m), slow-growing trees that occur naturally in the hot, humid primary forest of the West African littoral.
The two species, nitida and acuminata, are differentiated mainly by the shape of their leaves (flat for nitida, curved or corrugated for acuminata), by the shape of their fruit (or pod) and by the number of "cotyledons" that contains the seed.
Cola nitida with 2 cotyledons per seed, Cola acuminata has 3 to 6 cotyledons per seed.
The seeds of cola or kola nuts are usually deep red, sometimes pink or white, they are the medicinal parts, but leaves and sometimes bark are sometimes used in traditional African medicine.
The kola nut fruit (pod), seeds surrounded by a white aril, and separated into several cotyledons.
Cola nitida has only two cotyledons per seed.
CHEMICAL COMPOSITION AND PROPERTIES
There are slightly different compositions in the scientific literature, on average the commercial kola nuts contain:
- 10 to 15% water,
- 30 to 45% of carbohydrates (simple sugars and starches),
- 7% cellulose,
- 7 to 12% of proteins,
- 1 to 2% of lipids,
- 4% mineral ash,
about 4% of phenolic compounds including tannins, dyes (anthocyanins), flavanols,
alkaloids: about 3% caffeine and less than 1% other xanthines (theobromine, theophylline, kolatin?).
Carbohydrates (or maybe some proteins) add a sweet taste to chewed kola nuts, which are bitter and astringent at first.
The stimulating, slightly euphoric properties of cola are due to alkaloids, especially caffeine, the effect of which is gradually felt.
The "tonic" effect is delayed by the presence of tannins and persists longer than with coffee.
KOLA NUT A STIMULATING FOOD
Chewed (masticatory) or reduced to powder and consumed as a drink:
- it is stimulating,
- cut the hunger,
- gives a feeling of well-being,
- makes you forget fatigue,
- increases the attention,
- The content of polyphenols, anti-oxidants, anti-free radicals, helps to limit inflammatory reactions especially those related to diabetes or blood lipid disorders (arterio-and atherosclerosis, cardiovascular disorders)
Kola nuts extracts were present in the oldest preparations of carbonated drinks of North American origin (COCA-COLA and similar soft drinks).
Currently these drinks no longer contain cola extracts but caffeine extracted from coffee, usually a by-product of decaffeinated coffee (caffeine citrate).
Kola nuts like all caffeine plants (tea, guarana, mate):
- increases the heart rate,
- raises blood pressure,
- may hinder the onset of sleep (insomnia),
- is slightly diuretic,
- is contraindicated in case of gastric disorders (ulcer, gastritis).
The action of kola nut on digestion is complex:
- Increased gastric acidity but also gastric mucus (promoting digestion or appetite),
- but also drying of intestinal digestive mucosa by tannins hence its use in case of diarrhea.
The kola nut in herbal medicine is consumed:
- in powder form,
- or alcoholic tincture (30 to 50 drops two to three times a day).
- In case of CHRONIC FATIGUE with hypotension and bradycardia, ASTHENIA accompanied by mild depression.
- Like all caffeine plants, the kola nut or its extracts may ACCOMPANY A SLIMMING REGIME.
The argument " to burn fat" is use to advise these caffeine plants, but it is inefficient in the absence of a really low calorie diet, if not to stimulate the nervous system and thus bring a feeling of "well being".
KOLA NUTS IN AFRICAN TRADITIONS
Kola nut, as well as betel nut in some countries, is a traditional gift in Africa, presented on the occasion of many ceremonies (eg wedding, burial) or to honor visitors.
The kola nut is a sacred food in the Muslim religion, and is ritually consumed especially in the Ramadan period.
CULTIVATIN OF KOLA NUT TREES
In Africa, KOLA trees are often "wild" or spontaneous trees preserved by villagers or farmers.
Many are also planted in association with other crops: cocoa, banana.
Kola nut trees can grow in the shade of taller trees but they are also used to protect the cocoa trees of the sun (the cocoa tree is a shade plant).
Propagation is done by the seeds of the best trees or better by cuttings of productive clones.
Kola tree can be cut (coppicing) at the base about 1 m above the ground when it becomes unproductive, too old or sick, it quickly rejects shoots that can also be turned into cuttings.
The majority of Kola trees are in West Africa or Equatorial Africa, but there are some plantations in Asia.
Kola fruits (pods) are harvested at different times according to the species nitida or acuminata.
It is best to pick them from the tree before they fall to the ground to avoid contamination by pests.
The pods are open, the nuts surrounded by their white pulp are allowed to ferment a few days or soak in water to facilitate the elimination of the pulp.
The nuts (seeds) are then dried and stored in the shade wrapped in sheets or jute bags.
The wood of species of the genus Cola is of good quality and is used in carpentry, it is also a good firewood.
KOLA NUT, A NATURAL STIMULANT
Kola nut, Cola nitida and Cola acuminata, is a traditional stimulant food in Africa, used as masticatory or energetic drink.
Its important caffeine content explains its properties.
The kola nut is also a ceremonial gift and considered sacred by Muslims.
Copyright 2019 : Dr Jean-Michel Hurtel