II.—Picrotoxin, the Active Principle of the Cocculus indicus (Indian Berry, Levant Nut).
§ 588. The berries of the Menispermum cocculus comprise at least three definite crystalline principles: menispermine,[612] paramenispermine (nitrogen containing bases), and picrotoxin, which possesses some of the characters of an acid.
[612] Menispermine (C18H24N2O2?), discovered in 1834 by Pelletier and Courbe, is associated with a second named paramenispermine. The powdered berries are extracted by alcohol of 36°; the picrotoxin removed by hot water from the alcoholic extract; the menispermine and paramenispermine dissolved out together by acidulated water, and from this solution precipitated by ammonia. The brown precipitate is dissolved by acetic acid, filtered, and again precipitated by ammonia. This precipitate is dried, treated with cold alcohol, to separate a yellow resinous substance, and lastly with ether, which dissolves out the menispermine, but leaves the paramenispermine.
Menispermine forms white semi-transparent, four-sided, truncated prisms, melting at 120°, decomposed at a higher temperature, insoluble in water, but dissolving in warm alcohol and ether. Combined with 8 atoms of water it crystallises in needles and prisms. The crystals are without any taste; in combination with acids, salts may be formed.
Paramenispermine forms four-sided prisms, or radiating crystalline masses, melting at 250°, and subliming undecomposed. The crystals are soluble in absolute ether, insoluble in water, and scarcely soluble in ether.
Paramenispermine dissolves in acids, but apparently without forming definite salts.
§ 589. Picrotoxin (C30H34O13) was discovered in 1820 by Boullay. It is usually prepared by extracting the berries with boiling alcohol, distilling the alcohol off, boiling the alcoholic residue with a large quantity of water, purifying the watery extract with sugar of lead, concentrating the colourless filtrate by evaporation, and crystallising the picrotoxin out of water.