ArarobaBotanical Name: Andira araroba (AGUIAR.)
Family: N.O. Leguminosae
Synonyms: Goa Powder. Crude Chrysarobin. Bahia Powder. Brazil Powder. Ringworm Powder. Chrysatobine. Goa. Araroba Powder. Voucapoua Araroba.
Parts Used: The medullary matter of the stem and branches, dried and powdered.
Description: The powder is named Goa, after the Malabar port, and it was not realized until 1875 that the drug was Brazilian Araroba, and reached the East Indies through Portugal and her colonies. The tree from which it is obtained, Andira Araroba, is large, smooth, and quite commonly found in Bahia, Brazil. The yellowish wood has longitudinal canals and interspaces in which the powder is deposited in increasing quantity as the tree ages. It is probably due to a pathological condition. It is scraped out with an axe, after felling, sawing, and splitting the trunk, and is thus inevitably mixed with splinters and debris, so that it needs sifting, and is sometimes ground, dried, boiled, and filtered.
It irritates the eyes and face of the woodmen.
As it darkens quickly, the crude chrysarobin is changed from primrose yellow to shades of dark brown before it is met with in commerce, when it often contains a large percentage of water, added to prevent the dust from rising.
An amber skin-varnish is made with 20 parts of amber to 1 of chrysarobin in turpentine.
Constituents: The powder is insoluble in water, but yields up to 80 per cent. of its weight to solutions of caustic alkalies and to benzene. It contains 80 to 84 per cent. of chrysarobin (easily convertible into chrysophanic acid), resin, woody fibre, and bitter extractive. Goa Powder is usually regarded as crude chrysarobin, while the purified chrysarobin, or Araroba, is a mixture extracted by hot benzene, which melts when heated, and leaves not more than 1 per cent. of ash when it finally burns.
Chrysarobin is a reduced quinone, and chrysophanic acid (also found in rhubarb yellow lichen, Buckthorn Berries, Rumox Eckolianus, a South African dock, etc., etc.), is a dioxymethylanthraquinone.
Chrysarobin contains at least five substances, and owes its power to one of these, chrysophanol-anthranol.
Lenirobin, a tetracetate,, and eurobin, a triacetate, are recommended as substitutes for chrysarobin, as they do not stain linen indelibly. (Benzin helps to remove the stains of chrysarobin.)
The action of chrysarobin on the skin is not due to germicidal properties, but to its chemical affinity for the keratin elements of the skin. The oxygen for its oxidation is abstracted from the epithelium by the drug.
Oxidized chrysarobin, obtained by boiling chrysarobin in water with sodium peroxide, can be used as an ointment for forms of eczema which chrysarobin would irritate too much.
Medicinal Action and Uses: The internal dose in pill or powder is a gastro-intestinal irritant, producing large, watery stools and vomiting. It is used in eczema, psoriasis, aene, and other skin diseases.
In India and South Ameriea it has been esteemed for many years for ringworm, psoriasis, dhobi's itch, etc., as ointment, or simply moistened with vinegar or saliva. The application causes the eruption to become whitish, while the skin around it is stained dark.
In the crude form it should never be applied to the head, as it may cause erythema and oedema of the face. The 2 per cent. ointment is good in ecezema (after exudation has ceased), fissured nipples, and tylosis of the palms and soles after the skin has been removed by salicylic acid plaster, etc.
A drachm of chrysarobin may be dissolved in a fluid ounce of official flexible collodion, painted over the parts with a camel's-hair brush, and the part coated with plain collodion to avoid staining the clothing; or chrysarobin may be dissolved in chloroform and the solution painted on the skin. For haemorrhoids, an ointment mixed with iodoform, belladonna, and petrolatum is recommended.
It is said to have been used as a taenifuge.
Dosage: One-half grain.
Other Species: A. Inermis, or Cabbage Tree of South America and Senegambia, has a narcotic, anthelmintic bark, known as Bastard Cabbage Bark or Worm Bark. The powder, in doses of 3 to 4 grains, purges like jalap. The decoction is usually preferred.
The symptoms of an overdose are feverish delirium and vomiting, which should be counteracted with lime-juice or castor oil.
It is no longer officially used in England.
See CABBAGE TREE.