Humulus lupulus
Humulus lupulus
Origin - Netherlands, North American, Europe
Part of the plant used - Female strobiles (fruit)
Edible Parts Hops is a hedgerow climber with a tendency to twine around trees. Hops have been used since Roman times in brewing and as a traditional nervine and sedative herb. Hop tea has been recommended for insomnia, restlessness, and diarrhea. In addition, a hop pillow was frequently used in the past for the sedative effects of the volatile oils released while sleeping. The Hop cones - or strobiles - are fit to gather when a brown-amber colour and of a firm consistence. The stalks are then cut at the base and removed with the poles and laid horizontally on frames of wood, to each of which is attached a large sack into which the Hops fall as they are picked. When picked, the Hops are at once taken to the kiln or oast-house, and dried, as they are liable to become spoiled in a few hours, especially when picked moist. During the process of drying which is carried out in a similar manner to the drying of malt, great care is required to prevent overheating, by which the essential oil would become volatilized. The Hops are spread 8 to 12 inches deep, on hair-cloth, also being sometimes exposed to fumes of burning sulphur. When the ends of the stalks shrivel, they are removed from the kiln and laid on a woodenfloor till quite cool, when they are packed in bales, known as 'pockets.'
Pharmacology - Extensive modern research indicates that hops can relax smooth muscles as well as act as a sedative. The bitter acids, lupulone and humulone, are some of the identified active ingredients with sedative properties. The flavonglucosides have diuretic and spasmolytic properties. In addition, estrogenic substances have been identified in hops and account for the traditional use of hops as an anaphrodisiac. Hops has been used to treat digestive tract disorders involving spasms of the smooth muscle, especially irritable bowel syndrome and Crohn’s disease. The aromatic odour of the Hop strobiles is due to a volatile oil, of which they yield about 0.3 to 1.0 per cent. It appears to consist chiefly of the sesquiterpene Humulene. Petroleum spirit extracts 7 to 14 per cent of a powerfully antiseptic soft resin, and ether extracts a hard resin. The petroleum spirit extract contains the two crystalline bitter principles (a) Lupamaric acid (Humulone), (b) Lupamaric acid (Lupulinic acid). These bodies are chiefly contained in the glands at the base of the bracts. The leafy organs contain about 5 per cent of tannin which is not a constituent of the glands. Hops yield about 7 per cent Ash.
The oil and the bitter principle combine to make Hops more useful than Chamomile, Gentian or any other bitter in the manufacture of beer: hence the medicinal value of extra-hopped or bitter beer. The tannic acid contained in the strobiles adds to the value of Hops by causing precipitation of vegetable mucilage and consequently the cleansing of beer.
Fresh Hops possess a bitter aromatic taste and a strong characteristic odour. The latter, however, changes and becomes distinctly unpleasant as the Hops are kept. This change is ascribed to oxidation of the soft resin with production of Valerianic acid. On account of the rapid change in the odour of Hops, the recently dried fruits should alone be used: these may be recognized by the characteristic odour and distinctly green colour. Those which have been subjected to the treatment of sulphuring are not to be used in pharmacy. This process is conducted with a view of improving the colour and odour of the Hops, since sulphuric acid is found to retard the production of the Valerianic odour and to both preserve and improve the colour of the Hops.
Lupulin, which consists of the glandular powder present on the seeds and surface of the scales, may be separated by shaking the strobiles. The drug occurs in a granular, brownish-yellow powder, with the strong odour and bitter aromatic taste characteristic of Hops. The glands readily burst on the application of slight pressure and discharge their granular oleo-resinous contents. Commercial Lupulin is often of a very inferior quality, and consists of the sifted sweepings from the floors of hop-kilns. It should contain not more than 40 per cent of matter insoluble in ether and not yield more than 12 per cent of ash on incineration. A dark colour and disagreeable odour indicates an old drug.
The chief constituent of Lupulin is about 3 per cent of volatile oil, which consists chiefly of Humulene, together with various oxygenated bodies to which the oil owes its peculiar odour. Other constituents are the two Lupamaric acids, cholene and resin. Lupulin is official both in the British Pharmacopoeia and the United States Pharmacopoeia.
Historical Uses -
Processing - Ethanol extraction, type repercolation at room temperature at reduced pressure. Spray drying with maltodextrine as carrier substance.
Toxicity, Cautions & Contra-indications - No known toxicity. Large quantities can have an anaphrodisiac effect. Female hop pickers have suffered from loss of menstruation from absorbing the oil through their hands. Hops are not recommended for persons suffering from depressive illness.
