The organic constituents of plants and vegetable substances and their chemical analysis / by G.C. Wittstein ; authorised translation from the German original, enlarged with numerous additions, by Baron Ferd. von Mueller.

  • Georg Christian Wittstein
Date:
1878
Catalogue details

Licence: Public Domain Mark

Credit: The organic constituents of plants and vegetable substances and their chemical analysis / by G.C. Wittstein ; authorised translation from the German original, enlarged with numerous additions, by Baron Ferd. von Mueller. Source: Wellcome Collection.

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    LClliratill = C52 H48 O30. Bitter substance, found by Hoelm in all parts of Ophelia Cliirata. Contained in the extract, pre- pared with alcohol of 60%. It forms a light-yellow, very hygro- scopic powder of a strong and lasting bitter taste, dissolves sparingly in cold, better in hot water, easily in alcohol and in ether, has a neutral reaction, does not act on alkaline copper solu- tion, forms a copious, white, flaky precipitate with tannic acid. With acids the Ch. separates into Ophelic acid and Chiratogenin - C26 H24 O 6-] Clllorog-eilic Acid (Payen)=CArFEic Acid. CIllor01>*eilill. A substance contained in the root of Rubia tinctorum^ and distinguished by the green colour it assumes when boiled with acids, but as yet not obtained in the pure state. According to Kraus it appears to be identic with Rochleder's Kubichloric acid and with Runge's Kubiaceic acid. Remains, be- sides sugar and mineral substances, in the liquid obtained for the preparation of Rubian, after the precipitate produced by acids has been filtered off. Precipitate the aqueous decoction of madder with oxalic acid, filter and neutralise the liquid with chalk, filter again and evaporate the liquid on the water-bath until a dark-brown thick syrup is obtained. The latter dissolves in water and leaves behind brown products of decomposition originated in the course of the evaporation (while the solution has an acid re- action on account of phosphoric acid, and assumes a green colour when boiled with acids). Precipitate the solution with subacetate of lead, remove the excess of lead in the filtered liquid by sul- phuret of hydrogen, filter again and evaporate over sulphuric acid; a brownish-yellow, honey-like substance is obtained, which does not dry up again. This is Chlorogenin, mixed with a little sugar, Avhich exists readily formed in the madder, and with the acetates of potash, lime and magnesia. It has a nauseous, sweetish and bitter taste, throws down a brown powder when evaporated in the aqueous solution, dissolves in alcohol, not in ether; emits an offensive smell when boiled with diluted hydro- chloric or sulphuric acid, becomes dark-green and throws down a dark-green powder. Chlorophyll is according to Fremy a mixture of a yellow and a blue pigment. By shaking an alcoholic tincture of chlorophyll with a mixture of two parts of ether and one part of moderately diluted hydrochloric acid, the ether dissolves the yellow matter, while the acid beneath assumes a beautiful blue colour. By mixing the two liquids by means of alcohol the green colour is restored. The yellow pigment, isolated in the above manner, is called by Fremy Phylloxanthin, the blue Phyllocyanin. Closer investigations of these two compounds are Avanting.
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