Areca Nut. Semen Arecae. Betel Nut. Noix d'Arec, Fr. Arekanuss, Betelnuss, G.—The Areca Catechu, L., is an East India palm. The fruit, which is ovoid and from 2 to 3 cm. in diameter, and of an orange-yellow color, contains the nut embedded in a fibrous, fleshy envelope, and invested with a brittle shell which adheres to the exterior flesh. The kernel, the betel nut of commerce, is of a roundish-conical shape, rather larger than a chestnut, externally of a deep brown, diversified with a fawn color, so as to present a reticulate appearance, internally brownish-red with whitish veins, very hard, of a feeble odor when broken, and of an astringent, somewhat acrid taste. It abounds in tannin, and contains also gallic acid, a fixed oil, gum, a little volatile oil, lignin and various saline substances. It yields its astringency to water, and in some parts of Hindustan an extract is prepared from it having the appearance and properties of catechu. A red coloring matter known as Areca red is extracted, probably resulting from the decomposition of a tannin. It is insoluble in cold water and ether, soluble in boiling water and alkaline liquids, out of which it is precipitated by acids. E. Jahns (Ber. d. Chem. Ges., 1888, 3404) has found three alkaloids in areca nut:
1. Arecoline, C8H13NO2, identical with the arekane of Bombalon.
2. Arecaine, C7H11NO2 + H2O, which occurs in permanent, colorless crystals, soluble in water, insoluble in absolute alcohol, ether, chloroform, and benzene.
3. An alkaloid which exists in such small quantities that sufficient was not obtainable for close examination. On heating arecoline with strong hydrochloric acid to 150° C. (302° F.) it is decomposed into methyl chloride, CH3CI, and arecaidine, C7H11NO2. This latter base forms colorless plates, stable in the air, fusing at from 223° to 224° C. (433.4°-435.2° F.), easily soluble in water, difficultly soluble in strong alcohol, and insoluble in ether and chloroform. Arecaidine has been shown to be methyltetrahydronicotinic acid, and has been made synthetically from nicotinic acid. The third alkaloid of Jahns is probably guvacine, C6H9NO2, of which the methyl derivative is the base arecaidine before mentioned.
Immense quantities of areca nut are consumed in the East, mixed with the leaves of the Betel pepper (Piper Betle, L., Chavica Betle (L.) Miq.) and with lime, forming the masticatory so well known by the name of Betel. The red color which this mixture imparts to the saliva and the excrements is owing to the areca nut, which is also powerfully astringent, and, by its internal use, tends to counteract the relaxation of bowels to which the heat of the climate so strongly predisposes. (See N. R., 1876, 71.) Arecoline resembles pilocarpine in its effects on the system. (Patz, Z. E. P. T., 1910, vii.) According to Jahns (B. G. T., 1889) arecaine is the active principle of the areca nut, and a powerful taenicide, and is an active poison with an action of the type of muscarine and pilocarpine. Locally applied, or when given internally, it contracts the pupils.
In India the areca nut has long been used as a vermifuge, the dose being a teaspoonful of the freshly grated nut, and its value against the tape worm has been confirmed by various European and American practitioners. The usual dose is from one to two drachms (3.9-7.7 Gm.). In this country the nut has also been used for the making of a hard charcoal, employed as a basis of tooth-powder.