CXXXV.—The constituents of hops

Abstract

H. Bungener (BzLZZ. SOC. chim., 1886, [ii], 45, 487) confirmed the observation of Lermer (Zoc. cit.) respecting the occurrence of a crystalline acid, insoluble in water, which rapidly became yellow and resinous on exposure t o the air. H e designated the substance "lupulic acid," stating it to melt a t 92-93*, and to agree in composition with the formula C50H7008. It was furthermore considered that it is the resinous oxidation product of this acid which imparts bitterness t o a decoction of hops, and that this resinous product exists in hops together with the acid from which it is readily formed. Bungener and Fries (Zeitsch. ges. Brauw., 1885, 8, 267) have stated that hops contain asparagine, but although the method of separation was given, no analysis or other evidence of the identity of the substance appears to have been recorded. Issleib (Arch. Pharm., 1880, 13, 345), from the results of a somewhat extended investigation, has concluded that hops contain a peculiar bitter substance, " hop-bitter," of the composition C29H4,0,0. This, when treated with dilute sulphuric acid, is said to be converted into a resinous product, " lupuliretin," C10H1604, and a crystalline, bitter substance, " lupulinic acid,," C,,H8201,, which is insoluble in water, the change being represented by the following equation : 2C29H46010 + 3H20 =C10H1604 f C48H82019* The same author, furthermore, assigns to hop-resin the formula Cl0HI4O3, and assumes that by the simple addition of a molecule of water it is converted into " lupuliretin," C,,H160,. On the other hand, hop-resin, C10H1403, is considered t o be produced by the oxidation of the essential oil of hops, the latter being given the formula CloH180, and the change represented as follows : C1oH180 + 2 0 , = C,,Hl40, + 2H2O. Inasmuch as it is well known, however, that both hop-resin and the essential oil of hops are very complex products, the latter consisting largely of a sesquiterpene, Cl5HZ4, the fallacy of the above conclusions is apparent.

Ion-Exchange Chromatography of Hop Resins and Its Application to the Preparation of Extracts for Bittering Beer

“…The analysis of hop resins using DeacidiU FF is illustrated in Fig. 5 (6) and it will be seen that the elution pattern obtained resembles that given earlier by Dowex 1. Displacement of total acidic hop resin by means of salt solutions.-In general, acids adsorbed on basic ion-exchange resins are removed by the use of appropriate salts and, indeed, aqueous methanolic sodium chloride has proved effective for desorbing hop resins which are thereby obtained as their sodium salts.…”

Effect of blending HA-g-PLLA on xanthohumol-loaded PLGA fiber membrane

“…It was first isolated by Power et al [2] and its molecular structure consists of two aromatic rings (A and B) substituted with hydroxyl and methoxyl groups, one ␣, ␤ unsaturated double bond, and the prenyl unit [3,4] (Scheme 1). XN has received growing attention in recent years due to its wide spectrum of biological activities and the beneficial effect on human health [5].…”

Synthesis of Demethylxanthohumol, a New Potent Apoptosis-Inducing Agent from Hops

“…Their isolation from plant extracts is usually the only source of these molecules due to serious difficulties in their synthesis. Xanthohumol ( 1-[2,4-dihydroxy-6-methoxy-3-(3-methylbut-2-enyl)phenyl]-3-(4-hydroxyphenyl)-prop-2-en-1-one), a prenylchalcone present in hops (Humulus lupulus), was first isolated and named by Power et al [5]. The structure was elucidated by Verzele et al [6] and confirmed only by partial synthesis and chemical degradation studies [7] [8].…”