The constituents of Rumex ecklonianus / by Frank Tutin and Hubert W.B. Clewer.

  • Tutin, Frank.
Date:
[1910]
Catalogue details

Licence: Attribution 4.0 International (CC BY 4.0)

Credit: The constituents of Rumex ecklonianus / by Frank Tutin and Hubert W.B. Clewer. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    marshy places. It had, however, been incorrectly designated b7 Mr. Oliver as Polygonum tomentosum, var. glahrum, but its identity as the first-mentioned plant was ascertained by Mr. E. M. Holmes, F.L.S., who had kindly compared it with specimens in the herbarium at Kew. A portion (50 grams) of the finely-powdered, dried herb was successively extracted in a Soxhlet apparatus with various solvents, when the following amounts of extract, dried at 110°, were obtained: Petroleum (b. p. 35—50°) e.'ctracted 077 gram = 1'54 per cent. Ether ,, 0-51 ,, = 1-02 Chloroform ,, 0-69 ,, = 1-38 Ethyl acetate ,, 0-69 „ = 1'38 Alcohol „ 4-07 „ = 8-14 „ Total = 673 grains or 13 46 per cent. After having ascertained by a preliminary experiment that no> alkaloid was present, a quantity (11'733 kilograms) of the dried and ground herb was completely extracted by percolation with cold alcohol. The greater part of the alcohol was removed from the resulting extract, when 1'8 kilograms of a thin extract, con- taining a quantity of black, tarry matter, were obtained. The entire amount of the above-mentioned extract was mixed with water and distilled with steam until volatile products ceased to be removed. The distillate, which contained a small amount of oil, and also some solid, was extracted with ether, the resulting ethereal liquid being shaken with a solution of sodium carbonate. This treatment removed from the ether a small amount of a sub- stance, which, after being twice crystallised from ethyl acetate, formed yellowish-brown, slender prisms, melting at 159°. This substance dissolved in concentrated sulphuric acid, yielding a golden-yellow liquid, and its alcoholic solution gave with ferric chloride a green colour, which gradually changed to reddish-brown, but the amount obtained was not sufficient for its further examina- tion. The ethereal liquid which had been treated with sodium carbonate yielded, on evaporation, a small amount of an essential oil, which possessed a dark green colour and an odour closely resembling that of the rhubarb of the Pharmacopoeias. The contents of the distillation flask then consisted of a quantity of a dark green resin (A), together with a dark-coloured aqueous liquid. These products were separated while still hot, when, on allowing the liquid to cool, a quantity of a brown resin (B) was deposited. The latter was likewise separated from the aqueous liquid (C).