Aurantii Dulcis Cortex (U. S. P.)—Sweet Orange Peel.

Fig. 37. Citrus Aurantium. Preparations: Tincture of Sweet Orange Peel - Syrup of Orange
Related entries: Aurantii Amari Cortex (U. S. P.)—Bitter Orange Peel - Aurantii Flores.—Orange Flowers - Limon.—Lemon - Oleum Bergamottae (U. S. P.)—Oil of Bergamot - Oleum Aurantii Corticis (U. S. P.)—Oil of Orange Peel

"The rind of the fresh fruit of Citrus Aurantium, Linné"—(U. S. P.) (Citrus dulcis, Link).
Nat. Ord.—Rutaceae.
COMMON NAMES: Sweet orange, Portugal orange, China orange.
ILLUSTRATION: Bentley and Trimen, Med. Plants, 51.

Botanical Source.—Citrus Aurantium is a middle-sized evergreen tree, with an arborescent stem, covered with bark of a greenish-brown color, having axillary spines on the branches. The leaves are alternate, ovate-oblong, acute, slightly serrulated or entire, shining green, the stalk more or less winged. The flowers are large, white, rendering the atmosphere around very fragrant; the calyx urceolate and 5-cleft: the petals 5, oblong; the stamens 20 or even more; the filaments compressed at the base, more or less united there, and polyadelphous; the anthers oblong and yellow. The ovary is many-celled. The fruit is roundish, golden-yellow or tawny, and several-celled, with a fleshy, juicy pulp; the seeds white and several. The cysts in the rind are convex (L.).

Description, History, and Chemical Composition.—The orange is a native of Asia, and is cultivated in the southern parts of Europe and America and in the West Indies. Its varieties are numerous. The fruit likewise varies in its character, that of the C. Aurantium, the China orange, being sweet, while that of the C. vulgaris, the Seville orange, is acid and slightly bitter. The ordinary commercial oranges are subvarieties of the sweet orange, and usually take their names from the country where grown, or the shipping ports from which they are sent out. Some varieties are seedless, as St. Michael's orange, and generally the Navel orange of Brazil; another variety having a reddish pulp is known as the Blood orange or Maltese orange. The Mandarin orange differs considerably from the common orange, and on account of its delightful fragrance and flavor the name Citrus deliciosa has been proposed for it by those who regard it as a distinct species.

The leaves of the orange are studded with vesicles containing volatile oil, and have a bitter, aromatic taste, and when rubbed between the fingers are very redolent. They, together with the young twigs, yield by distillation an oil termed essence de petit grain. The original oil bearing this name was distilled from orange berries. It does not differ chemically from orange-oil, though it has a different odor. An infusion of the leaves is sometimes employed as a gently stimulant diaphoretic. The flowers have a delicious fragrance, which is imparted to the surrounding atmosphere, but which is lost by drying; those of the bitter orange are considered the most delicate. They owe their aroma to an essential oil, which may be obtained by distillation; it is termed oil of neroli, and is much used in perfumery. An orange flower water is prepared in Italy and France, which is quite pale, has a rich odor of the flowers, and a bitterish, aromatic taste; it is employed for the purposes of perfumery, although reputed to possess antispasmodic virtues. The peculiar fragrance of the flowers may be preserved for a long time by beating them into a pulp with one-fourth their weight of common salt. The juice of the orange consists chiefly of sugar, mucilage, and citric acid. The outer rind of the mature fruit is the official part, the inner being destitute of useful properties, and the two should always be separated from each other when drying the rind for medicinal purposes, as the spongy, inner rind is apt to occasion moldiness from its absorbing moisture from the air. Orange-peel has a deep orange color, a grateful aroma, and a pleasantly bitter taste, the Seville variety being more bitter than any other. It contains a volatile oil in visible vesicles, mostly lost in drying, a saccharine principle, hesperidin, and a ligneous fiber, agreeing in composition with bitter orange peel, though containing a lesser amount of the bitter principle. The fresh rind, grated and expressed, will yield the volatile oil, or it may be obtained by distilling the fresh rind with water. Water or alcohol takes up the sensible properties of the rind. The finest orange oil, which must not be confounded with the oil of neroli, is obtained from Portugal, and is prepared from the rind of the sweet orange. It has a pale straw tint and a rich fragrance of the rind. It is imported in tinned copper cans, and is much used in perfumery and for other purposes. On exposure it spoils rapidly, acquiring a turpentine odor. When about the size of a pea or cherry, the bitter fruit is sold under the name of orangettes, that variety coming from the isle of Curaçao being known as Curaçao oranges; and the small ones are sometimes used to maintain the discharge from issues. The U. S. P. describes the official drug as "closely resembling bitter orange peel, but having an orange-yellow color. It has a sweetish, fragrant odor, and an aromatic, slightly bitter taste." It is used in the preparation of Syrupus Aurantii and Tinctura Aurantii Dulcis of the U. S. Pharmacopoeia.

Test.—A test to distinguish orange peel from lemon peel was recently proposed by E. G. Clayton. It consists in moistening the rind with strong hydrochloric acid. The orange peel is stated to acquire a rich, dark-green tint, while lemon peel assumes at most a dingy, yellowish-brown color (Amer. Jour. Pharm., 1894).

Action, Medical Uses, and Dosage.—Orange peel is aromatic and slightly tonic, but is seldom used except to cover the taste of disagreeable medicines or to lessen their tendency to nausea, and for these purposes it is frequently added to bitter tinctures, infusions, etc., as quassia, Peruvian bark, etc.; though care should be taken not to subject it to long boiling on account of its oil, which will thus be dissipated. As a tonic the rind of the Seville orange is preferred; its dose in substance is from 30 to 60 grains 3 times a day. Large quantities of it have caused violent colic, convulsions, and even death. The juice of the orange is not only a light refrigerant article of diet, but has a direct beneficial medicinal influence in several diseases; as in all fevers and exanthematous diseases, where acids are craved, and the patient's tongue is coated deep-red, brown, black, or any intermediate color; in such cases its free use may be allowed with advantage; it is also useful as an antiscorbutic in scurvy. In administering the juice the membraneous portion should always be carefully rejected (see also Aurantii Flores).

King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.