A powder obtained from cavities in the trunk of the Andira araroba, Aguiar.
COMMON NAMES: Goa powder, Bahia powder, Brazil powder, Ringworm powder, Chrysarobine, Chrysarobin (improperly so-called).
Botanical Source, History, and Description.—This drug must not be confused with Arariba rubra, a Brazilian plant, the bark of which was investigated by Rieth, in 1861, and has been used as a red dye for wool in its native country. Dr. Fayrer was the first to call attention to Goa powder in the Med. Times and Gaz., Oct., 1875, but was unable to give its origin, farther than that it reached Bombay through Goa on the Malabar coast, thus acquiring the name Goa powder, by which it is commonly known. Its source was kept secret for some time, and the powder was sold at exorbitant prices. In the same year (1875) E. M. Holmes called attention to the identity of araroba with goa powder, suggesting that it was probably produced by a species of Caesalpinia, and for some time his conclusion was generally accepted although not without reserve. Dr. J. M. de Aguiar, of Bahia (1879), published an article in pamphlet form upon this subject (Pharm. Jour. and Trans., July, 1879; also New Remedies, Sept., 1879) which lightened the mystery that had heretofore surrounded its source. He informs us that araroba is derived from a large intertropical tree, the ordinary height of which is 80 or 100 feet. It belongs to the Leguminoseae, and tribe of Dalbergieae, resembling, in some respects, Dalbergia miscolobium, Bentham, and Andira fraxifolia, Bentham. After having given a careful botanical description, the author concludes that the tree has been heretofore undescribed, and proposes for it, the name Andira araroba, Aguiar, "since the drupaceous fruit, panicled inflorescence, purple flowers, and other characters, clearly point to its being an Andira."
The araroba powder is obtained by cutting down the older trees, as they yield it in the greatest abundance, and then scraping the powder from cavities found by splitting the trunk into longitudinal sections. The tree contains an abundance of resin, by the oxidation of which, Dr. de Aguiar believes, the araroba is produced. When fresh, it is a pale primrose color, but by age, changes to the color of rhubarb, and, eventually, becomes dark-purple. The tree exists abundantly in all the southern part of the province of Bahia, although the powder now chiefly comes from Camamu and Taperoa. As found in commerce, this agent is in the form of a powder of different degrees of fineness, of a color ranging from light-yellow to dark-chocolate. It resembles the partly decayed matter occasionally observed in cavities of old trees and stumps, and is often mixed with irregular woody fragments. It is now fairly established that it is the partly decayed matter of the South American tree above mentioned, and thus, curiously enough, by the way of distant India, where it had been long used, this product of the South American forest was introduced to the medical profession.
Chemical Composition.—Araroba is remarkable for occasionally yielding from 80 to 85 per cent of chrysophanic acid, as shown by Attfield, in 1875, and, according to the same authority, the remainder of the powder examined consists of 7 per cent of a glucoside and bitter matter, 2 of a resinous substance, 5 1/2 of a red woody fiber, and 1/2 per cent of ash. The ashes consist chiefly of silicate of aluminum, and sulphates of potassium and of sodium. Prof J. U. Lloyd examined several specimens upon the market, and, in all cases, obtained a much smaller proportion of chrysophanic acid than stated by Mr. Attfield. Therefore, he concluded that Attfield must have procured an unexceptionally rich specimen of araroba, or that which reached this country was very inferior. Araroba readily yields chrysophanic acid to benzin. When heated in a suitable vessel, a sublimate is obtained, which, doubtless, consists largely of the aforementioned acid, as it is colored red by alkalies in solution. Araroba is chiefly employed for the preparation of chrysophanic acid (which see). Liebermann and Siedler, are authority for the statement that chrysophanic acid does not exist ready-formed in araroba, but is formed by oxidation of a natural constituent, to which they give the formula C30H26O7, and the name Chrysarobin (previously applied to araroba).
Action, Medical Uses, and Dosage.—In the Indies this agent has been employed for the removal of taenia solium, and in the treatment of certain cutaneous maladies. Attfield, Fayrer, Da Silva Lima, Squire, Hebra, Bernier, Blanc, Thin, and many other medical men have successfully employed this powder in the treatment of herpes circinatus, porrigo scutulata, porrigo decalvans, sycosis, favus, psoriasis, eczema, lichen, acne, and other diseases of the skin. The powder is mixed with vinegar or lemon juice to form a thin, pasty mass, or is well incorporated with glycerin or starch paste, and then applied over the eruption once or twice a day, for from 5 to 8 days successively, in which period of time the cure is generally affected. Its application causes, after some length of time, a temporary uneasy sensation in the part to which it is applied, the eruption assumes a whitish appearance, and the surrounding tegument presents the appearance as of a dark stain; as the cure progresses, the skin assumes its normal color. For internal use, it may be taken in the form of pills, made by incorporating it with medicinal soap. For external application, it may be used as above stated, by means of a small brush, or a tincture of the powder may be painted upon the affected parts. It may be also used in the form of an ointment, consisting of from 15 to 60 grains of the powder, from 15 to 30 drops of acetic acid, all thoroughly mixed with an ounce of benzoinated lard. At the present time, however, chrysophanic acid and chiefly chrysarobin (which see) are used in preference to the goa powder.