Lupulinum, B.P., Lupulin.
Related entry: Hops
Lupulin consists of the glandular trichomes separated from the strobiles of Humulus Lupulus, Linn. (N.O. Urticaceae). It is also official in the U.S.P. The glands, which are distributed over the bases of the bracts, over the fruits, and, to a less degree, over the stipules, may be separated by shaking and beating the hops. The drug occurs in a granular, brownish-yellow powder, with the strong odour and bitter, aromatic taste characteristic of hops. Examined under the microscope, the glands are seen to be more or less rounded or broadly ovoid, and to measure from 140μ to 200μ in diameter; the upper portion is bounded by a thin cuticle, the lower by a single hemispherical layer of cells. They readily burst on the application of slight pressure, and discharge their granular oleoresinous contents. Lupulin should contain not more than 40 per cent. of matter insoluble in ether, and should yield not more than 12 per cent. of ash on incineration. Commercial lupulin is often of very inferior quality, and may consist of the sifted sweepings from the floors of hop kilns. A dark colour and disagreeable odour indicate an old drug, the latter character being attributed to the presence of valerianic acid, which is produced gradually from the resin; the ash may rise to .25 per cent., or even more, while the percentage insoluble in ether may be more than 40.
Constituents.—The chief constituent of lupulin is about 3 per cent. of volatile oil, which consists chiefly of the sesquiterpene humulene, together with various oxygenated bodies, to which the oil owes its peculiar odour. Other constituents are α- and β-lupamaric acids, choline, resin, and wax (see Lupulus).
Action and Uses.—Lupulin is an aromatic bitter, and is reputed to be mildly sedative. It is occasionally administered as a hypnotic, either in pills, with alcohol as an excipient, or enclosed in a cachet. Preparations of lupulin are not much used in this country.
Dose.—1 to 3 decigrams (2 to 5 grains), or more.
- Fluidextractum Lupulini, U.S.P.—FLUIDEXTRACT OF LUPULIN.
- Lupulin, 100; alcohol (95 per cent.), sufficient to produce 100. Average dose.—5 decimils (0.5 milliliters) (8 minims).
- Oleoresina Lupulini, U.S.P. and B.P.C.—OLEORESIN OF LUPULIN.
- A thick liquid which will barely pour. It should be preserved in a well-stoppered bottle. It has the properties of lupulin. Dose.—1 to 3 decigrams (2 to 5 grains).