Source, Etc

Areca nuts are the seeds of Areca Catechu, Linne (N.O. Palmoe), a handsome palm with a tall slender stem crowned by a number of large elegant leaves. The tree is widely cultivated throughout India and the whole of the islands of the Eastern Archipelago for its seeds, which are universally employed by the natives as a masticatory.

The fruits, which are orange yellow in colour when ripe, and of the size and shape of an egg, are borne in large numbers on a branching axis. The pericarp is fibrous and surrounds a single seed, from which it is easily separated. The seeds are usually boiled in water with the addition of a little lime and dried.

Description

The areca nut has the shape of a short, bluntly rounded cone about 2.5 cm. long. It has a brownish colour, and the surface is marked with a network of paler depressed lines. Frequently portions of a hard, brittle, grey, silvery coat are attached more or less firmly to the seed; these are portions of the inner layer of the pericarp, and do not belong to the seed proper. The latter is hard, but can be cut with a knife, and then exhibits a marbled interior (ruminate endosperm), dark brown lines alternating with opal-white portions. Examination with the lens shows these lines to be slightly fissured. They are folds of the seed-coats, corresponding in position to the fibrovascular bundles that pass into them from the funiculus; they follow the branching of the bundles and produce the reticulate markings on the seed. The outer cells of the seed-coat fill with tannin, to which the brown colour is due, and contain alkaloid (Osenbrug, 1894).

The seed has little odour, but an astringent, slightly bitter taste.

The student should observe

(a) The shape of the seed,

(b) The ruminate endosperm.

Constituents

Areca nuts contain several alkaloids together with tannin (15 per cent.) and fat (14 per cent.). The most important of the alkaloids, and the one to which the sialogogue and vermifuge properties of the seed are due, is arecoline (methylarecaidine). Other alkaloids are arecaidine, arecaine, guvacine, and choline.

Arecoline, C8H13N02 (boiling-point 220°), is a colourless oily liquid yielding crystalli-sable salts. Boiling with hydrochloric acid converts it into methyl chloride and crystalline arecaidine, from which arecoline can be regenerated. Arecaidine, C7H11N02, is methyl-tetrahydronicotinic acid and can be synthesised from trigonelline. Arecaine is methyl-guvacine and can be prepared by methylating guvacine.

Use

The powdered seeds are chiefly used in this country as a vermifuge for dogs.

Fig. 102.   Areca nut. a, vertical section of the fruit and seed, showing fibrous pericarp of the former and ruminate albumen of the latter. b, entire seed, natural size. (Bentley and Trimen.)

Fig. 102. - Areca nut. a, vertical section of the fruit and seed, showing fibrous pericarp of the former and ruminate albumen of the latter. b, entire seed, natural size. (Bentley and Trimen).