The constituents of hops / Frederick B. Power, Frank Tutin and Harold Rogerson.
- Frederick Belding Power
- Date:
- [1913?]
Licence: Public Domain Mark
Credit: The constituents of hops / Frederick B. Power, Frank Tutin and Harold Rogerson. Source: Wellcome Collection.
27/30 page 1291
![with hot alcohol, and the resulting extract distilled in a current of steam in order to remove the essential oil. From the portion of the extract which was soluble in water there were isolated small amounts of choline, C5H1502N, and of Z-asparagine, C4H803N2, both of which had previously been observed to be present, although no evidence of the identity of the last- mentioned substance appears to have hitherto been recorded. The aqueous liquid also contained, besides tannin, a quantity of potassium nitrate and a sugar which yielded <Aphenylglucosazone (m. p. 208°), together with dark-coloured, amorphous material which possessed an intensely bitter taste. A volatile base, having a coniine-like odour, was also obtained, but the amount was so extremely small that it could not be further characterised. The portion of the alcoholic extract which was insoluble in water consisted of a dark green, oily resin, the amount of which was equivalent to about 14T per cent, of the weight of hops employed. From this resin, which still contained some occluded essential oil, the following compounds were isolated: (i) ceryl alcohol, C27H560; (ii) hentriacontane, C31H64; (iii) a phytosterol, C27H460; (iv) a phytosterolin (phytosterol glucoside), C^HggOg; (v) a mixture of volatile fatty acids, consisting of formic, acetic, butyric, and valeric acids, together with a hexenoic acid, C6H10(X (b. p. 204—208°), which was identified as £-?'sopropylacrylic acid, and apparently a little nonoic acid, C9H1802, was also present; (vi) saturated and unsaturated non-volatile acids, comprising: palmitic, stearic, and cerotic acids, and an acid, C20H40O2 (m. p. 62'5—63°), which is apparently an isomeride of arachidic acid; furthermore, cluytinic acid, C21H4202 (m. p. 69°), the methyl ester of which melts at 47°, and linolic acid; (vii) a new, crystalline, phenolic substance, humulol, C17H1804 (m. p. 196°), possessing a pale fawn colour and a bitter taste, which, on hydrolysis with potassium hydroxide, yielded, among other products, an acid, C15H1405 (m. p. 210°), and p-hydroxybenzaldehyde; (viii) a new, crystalline, phenolic substance, xanthohumol, C13H]403 (m. p. 172°), which is tasteless and possesses an orange-yellow colour. The state¬ ments made many years ago that hops contain a yellow colouring matter resembling quercitrin, and also a wax consisting of myricyl palmitate, cannot be confirmed. A consideration of the results of the present investigation leads to the following conclusions. In the first place, the bitterness of hops is not due to any single substance, such as the so-called “ hop- bitter acid” or “lupulic acid,” but is to be attributed to a number of products, most of which are amorphous. Some of these products are soluble in water, whilst others represent constituents of the](https://iiif.wellcomecollection.org/image/b30620387_0027.jp2/full/800%2C/0/default.jpg)
