This section is from the book "A Text Book Of Materia Medica, Being An Account Of The More Important Crude Drugs Of Vegetable And Animal Origin", by Henry G. Greenish. Also available from Amazon: A Text Book of Materia Medica : Being an Account of the More Important Crude Drugs of Vegetable and Animal Origin.
Cola seeds, sometimes called Cola or Kola nuts, Gooroo nuts, or Bissy nuts, are obtained from Cola vera, Schumann (N.O. Sterculiacece), a large and handsome tree resembling in habit the Spanish chestnut. It is a native of tropical Africa, growing wild in Sierra Leone, North Ashanti, near the sources of the Niger River, etc, but is cultivated in other tropical countries, such as the West Indies, Brazil, Java, etc, our supplies being derived either from the west coast of Africa or from the West Indies.
The woody capsular fruit of the tree contains from five to fifteen large white or crimson seeds which are removed and deprived of their seed-coats, the kernels only being used. These are chewed whilst still fresh, either before or after germination, and have been highly valued by the negroes for many centuries for their stimulating properties, in which they resemble tea, coffee, cocoa, etc.
Large quantities of the seeds are collected and consumed by the natives, who also carry on a considerable trade in them. Packed in baskets with the leaves of the cola tree they can be kept fresh, and in this state are brought chiefly from Lagos to Sokoto, Kano, and Timbuctoo, whence they are distributed to other parts of Africa. The fresh seeds are also occasionally exported, but more commonly the kernels are separated into the two large fleshy cotyledons and dried, during which the white or crimson colour changes to a dull reddish brown.
Dried cola seeds, as commonly seen in this country, consist of the kernels only of the seeds, sometimes entire, but more often separated into the two cotyledons. Externally, they have a dull dark brown or reddish brown colour; internally they are usually somewhat paler. They are hard and solid, and exhibit, when cut, a perfectly uniform section, no mucilage glands being observable. They vary in length from about 2 to 5 cm., and are rather less in breadth and in thickness. In shape, too, they exhibit considerable differences, being frequently flat on one side and curved on the other, or wedge-shaped or irregularly six-sided. A shallow furrow encircles the kernel, dividing it into two cotyledons; transverse to this furrow at one end of the seed a distinct cleft may be found, partially separating each cotyledon into two portions. Complete kernels may easily be separated into their constituent cotyledons, and the small radicle will be found towards the bottom of this transverse cleft.
Fresh cola seeds have a bitterish astringent taste, which is scarcely perceptible in the dry seed; the latter are also destitute of any marked odour.
The student should observe
(a) The two large fleshy cotylodons and small radicle,
(b) The absence of seed-coats, the drug consisting of the kernel only.
The most important constituents of kola seeds are caffeine (1 to 2.5 per cent.), kolatin (0.75 per cent, mostly combined with the caffeine), and traces of theobromine. They also contain kolatein, an oxydase enzyme, fat, sugar, and abundance of starch.
Kolatin, C8H804, is crystalline, slightly soluble in water, but readily in alcohol. During the drying of the seeds it is converted by the oxydase into kola-red, a substance allied to the phlobaphenes, which is therefore present in the dried drug to the exclusion of kolatin and imparts to it the characteristic colour. If, however, the seeds are boiled and the oxydase thus destroyed, the dried seeds retain the colour of the fresh and contain the kolatin. The fresh seeds may also be preserved by beating them into a pulp with an equal weight of loaf sugar.
Kolatein is also crystalline, soluble in alcohol and in hot water; it has not yet been completely investigated.
Kolanin, a reputed constituent of the seeds, appears to be a mixture of kola-red and caffeine.
Cola seeds have properties similar to those of tea, coffee, etc., and are used as a nerve stimulant. Kolatin increases the energy of the cardiac contractions, and as this substance is not present in the commercial drug, it having been converted into kola-red, the therapeutical action of the dried seeds is somewhat different from that of the fresh; hence possibly the strong preference in Africa for the fresh seeds. The action of the dried sterilised seeds resembles that of the fresh.
C. acuminata, Schott and Endlicher; Cameroon and Congo States; the seeds have three to five cotyledons; they are eaten like the genuine, and are sometimes imported, but contain less caffeine and are less esteemed.
C. Ballayi, Carnu; Gaboon; the seeds have six cotyledons and contain but little caffeine.
G. astrophora, Warburg, the red cola of the Ashantis, always has red seeds; C. alba, the white cola of the Ngaus, always has whitish seeds. C. vera is said to be a hybrid of these two species; its seeds are sometimes red, sometimes white.
Other seeds have from time to time been substituted for cola seeds, but the genuine are easily distinguished by the characters given.