The nature and origin of the poison of Lotus Arabicus / by Wyndham R. Dunstan and T.A. Henry.

  • Dunstan, Wyndham R. (Wyndham Rowland), 1861-1949.
Date:
1901
Catalogue details

Licence: In copyright

Credit: The nature and origin of the poison of Lotus Arabicus / by Wyndham R. Dunstan and T.A. Henry. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

    11/24 (page 523)
    Action of Fused Potash on Lotoflavin. In order to gain further knowledge of the constitution of lotoflavin its decom- position by fused alkalis was examined. About 2 grammes of the colouring matter were dissolved in 5 cub. centims. of a 20 per cent, solution of potash, and to this mixture about 2 grammes of solid potash were added and the whole kept just fused for about an hour. The product was then cooled, dissolved in water, and the solution made acid, filtered, and repeatedly shaken with ether. The ethereal liquids were mixed, decolourised with animal charcoal, dried over calcium chloride, and the solvent distilled off. The residue was dissolved in a little water, the solution filtered and concentrated in a vacuous desiccator. After several weeks a small quantity of a crystalline acid substance separated, which after re-crystallisation from hot water, melted at 207° C., exhibited the fluorescein reaction after fusion with phthalic anhydride, gave a pink coloration with aqueous ferric chloride, and possessed the other properties of /3-resorcylic acid. The residual liquid, which left a gummy mass when evaporated, contained jphloroglucinol, as was proved by the power of striking a violet colour with ferric chloride and of staining a magenta colour a pine shaving moistened with hydro- chloric acid. Eventually a small amount of phloroglucinol crystallised out from this viscid residue and was identified by its melting point and general properties. Alkaline Hydrolysis of Lotusin—Lotusinic Acid. When lotusin is warmed with alkaline liquids it passes into solution, ammonia being evolved and the liquid becoming bright yellow.' From aqueous solutions it is not easy to isolate the product of hydrolysis, and it was found more convenient to carry out the hydrolysis in alcoholic solution. If lotusin is added to alcoholic potash (20 per cent.) it gradually passes into solution with evolution of ammonia. On standing, an insoluble potassium salt separates in the form of bright yellow needles. This potassium salt is very soluble in water, almost insoluble in alcohol, ether, and light petroleum. When aqueous silver nitrate is added to an aqueous solution of the potassium salt, a bright yellow silver salt is precipitated. A determination of the amount of silver in this salt was made with the following results :— 306 gramme gave '0430 gramme silver = 14’05 per cent. Ag. C28H31018Ag requires 14‘14 per cent. Ag. Th is salt decomposes easily and has not been obtained crystalline. 3x2