Chrysarobin

CHRYSAROBIN, Chrysarobinum, Araroba depurata, Pulvis Goa, Goa powder; the main constituent of araroba powder, which accumulates in hollows and internal cavities of the tree Andira Araroba (Leguminosae), growing in Brazil and India. Chrysarobin is obtained by extracting araroba with boiling benzene. Chrysarobin is a mixture of emodin, chrysophanic acid, emodin monomethyl ether, and their reduction products. The main constituent of chrysarobin consists of reduction products of emodin and chrysophanic acid—anthranols and the ketone anthrone corresponding to anthranol (up to 60%).

on oh oh

Na

O anthranol

anthrone

chrysophanic acid Chrysarobin is a golden-yellow powder, tasteless and odorless, soluble in chloroform and benzene, sparingly soluble in ether, partially soluble in 200 parts of boiling water with a neutral reaction. The melting point is not sharp, according to various authors ranging from 147° to 204°. In its physiological action, chrysarobin resembles pyrogallol, adjoining in this respect other reducing agents of the phenol series used in the treatment of certain skin diseases, mainly psoriasis. Chrysarobin has an irritating effect on the skin and mucous membranes, causing erythema and sometimes even a pustular rash. When it gets into the eye, it causes acute conjunctivitis, sometimes leading to persistent opacities of the cornea. When taken internally (for therapeutic purposes, chrysarobin is used only externally!), even a few centigrams of chrysarobin cause vomiting and enteritis. Chrysarobin finds therapeutic application in dermatological practice in the form of a 5-25% ointment for psoriasis, herpes tonsurans, eczema marginatum, and the like. The disadvantages of chrysarobin include brownish-purple staining of the skin and linen, caustic action on the eyes, and frequent complications (see Dermatitis). When applied to large areas of the skin, chrysarobin, being absorbed, produces a picture of general poisoning: nephritis, albuminuria. Chrysarobin preparations such as Eurobin (triacetyl-chrysarobin) and lenirobin (tetraacetyl-chrysarobin), proposed to replace chrysarobin, are of little reliability. Of greater importance is anthrarobin (1,2-dioxyanthranol), obtained synthetically by the reduction of alizarin, a yellowish-brownish powder, odorless and tasteless, very difficultly soluble in water, more easily in alcohol. Possessing somewhat less sharply expressed therapeutic properties than chrysarobin, anthrarobin irritates the skin and mucous membranes significantly less, etc. Form of application: a 10-20% alcoholic solution. Cignolin, Cignolin, isomer of the previous preparation: 1,8-dioxyanthranol. Properties and action are similar to the previous one.

S. Shubin. CHRYSOGIDIN, chrysoidine, a basic azo dye with the formula C₆H₅N=NC₆H₃(NH₂)₂HCl (diamidoazobenzene hydrochloride), is a brownish-red powder or glossy crystals; easily soluble in water with an orange-red color; the solution gives a red precipitate with hydrochloric acid, a yellowish precipitate with caustic soda, and reducing agents decolorize the solution. In microscopic technique, chrysoidine finds limited application due to the low selectivity of staining and was recommended only by Martinotti for staining and fixation of fat. Sections on a freezing microtome from formalin-fixed objects are treated with a 1% aqueous solution of chrysoidine, quickly washed with water and transferred to a 2% aqueous solution of potassium dichromate for 2 minutes or to a 10% solution of chromic acid in 95% alcohol for 1 minute; rapid washing with water, alcohol, xylene, balsam. Fat is stained an intensely brown color. A mixture of 1% chrysoidine and safranin T in equal parts followed by treatment with 10% chromic acid reveals red inclusions in the brown fat.