1911 Encyclopædia Britannica/Podophyllin

PODOPHYLLIN, a drug obtained from the rhizome of the American mandrake or may apple, Podophyllum peltatum, an herbaceous perennial belonging to the natural order Berberidaceae, indigenous in woods in Canada and the United States. The plant is about 1 ft. high, bearing two peltate, deeply divided leaves, which are about 5 in. in diameter, and bear in the axil a solitary, stalked, white flower, about the size and shape of the garden anemone, with six or more petals and twice as many hypogynous stamens. The fruit is ripe in July, and is an oval, yellowish, fleshy berry, containing twelve or more seeds, each surrounded by a pulpy outer coat or aril. The rhizome, as met with in commerce, occurs in cylindrical pieces 2 or 3 in. long and about 1/4 in. in diameter, of a chocolate or purplish-brown colour, smooth, and slightly enlarged where the juncture of the leafy stem is indicated by a circular scar on the upper and a few broken rootlets on the under side. The odour is heavy and disagreeable, and the taste acrid and bitter.

Podophyllin is a resinous powder obtained by precipitating an alcoholic tincture of the rhizome by means of water acidulated with hydrochloric acid. It varies in colour from greyish to bright yellow or greenish-brown, the first-named being the purest. The powder is soluble in alcohol and strong solutions of alkalis, such as ammonia. Its composition is somewhat complex. There are certainly at least two resins in the powder (which is known officially as Podophylli resina), one of them being soluble and the other insoluble in ether. Each of these contains an active substance, which can be obtained in crystalline form, and is known as podophyllotoxin It is soluble in alcohol, ether, chloroform and boiling water. Alkalis decompose it into picro-podophyllic acid and picro-podophyllin, minute traces of both of which occur in a free state in the rhizome. The acid is inert, but picro-podophyllin is the active principle. It is a crystalline body, soluble only in concentrated alcohol. Hence the inutility of the pharmacopeial tinctura podophylli, which cannot be diluted before administration. The properties of podophyllin resin vary with the reaction of the tissue with which it is in contact; where this is acid the drug is inert, the micro-podophyllin being precipitated.

The resin does not affect the unbroken skin, but may be absorbed from a raw surface, and will then cause purging. When taken internally it is both a secretory and an excretory cholagogue, but so irritant and powerful that its use in cases of jaundice is generally undesirable. Its value, however, in certain cases of constipation of hepatic origin is undeniable. It is largely used in patent medicines, usually as an auxiliary to aloes. The best method of prescribing podophyllin is in pill form. In toxic doses podophyllin causes intense enteritis, with all its characteristic symptoms, and severe depression, which may end in death. The treatment is symptomatic, there being no specific antidote.