Some observations regarding "oleuropein" from olive leaves by Frederick B. Power and Frank Tutin.

  • Power, Frederick B. (Frederick Belding), 1853-1927
Date:
[1908?]
Catalogue details

Licence: In copyright

Credit: Some observations regarding "oleuropein" from olive leaves by Frederick B. Power and Frank Tutin. Source: Wellcome Collection.

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    that, contrary to the assumption of Bourquelot and Vinfci- lesco, we had not only afforded proof of the existence of material of a glucosidic nature in olive bark, but had also demonstrated that at least two such substances were present. Substances of a similar nature were likewise observed in the course of our investigation of olive leaves, although not specially noted in the account of that work. In any case we should not have considered it desirable to assign a distinctive name to amorphous, resin-like pro¬ ducts, possessing none of the attributes of homogeneity. The characters ascribed by Bourquelot and Yintilesco to the “ oleuropein ” obtained by them from fresh olive fruit are briefly as follows:—A yellowish, hygroscopic powder, quite readily soluble in cold water and in hot alcohol, insoluble in ether, and possessing a strongly bitter taste. [a]D = —127’9° (3026 grammes dissolved to 150 C.c.). The aqueous solution is coloured yellow by alkalis, blood-red by concentrated sulphuric acid, and green by ferric chloride. It is incompletely precipitated by basic lead acetate. The substance reduces Fehling’s solution, and more strongly after heating with dilute sulphuric acid. Although our previous investigation of the constituents of olive leaves and bark (loc. cit.) enabled us to feel con¬ vinced that the product designated as “ oleuropein ” could not be, in the chemical sense, an even approximately pure substance, some experiments have been undertaken which not only confirm this conviction but afford definite proof of its heterogeneous character. Experimental. For the purpose of obtaining a product corresponding to the “ oleuropein ” of Bourquelot and Yintilesco, a portion of the same alcoholic extract of olive leaves was employed as that which had previously served for our investigation of the constituents of these leaves (Journ. Cliem. Soc., 1908, 93, 891). In the preparation of the product the method described by the above-mentioned authors (loc. cit.) was followed as closely as possible in all essential details. A quantity (2000 grammes) of an alcoholic extract, repre¬ senting 4360 grammes of air-dried olive leaves, was mixed with a considerable volume of water, 150 grammes of