5612. Lupulon

Nomenclature

CAS number: 468-28-0
3,5-Dihydroxy-2,6,6-tris(3-methyl-2-butenyl)-4-(3-methyl-1-oxobutyl)-2,4-cyclohexadien-1-one; β-bitter acid; β-lupulic acid.
C26H38O4; mol wt 414.58.
C 75.32%, H 9.24%, O 15.44%.

Description and references

Antimicrobial constituent of hops. Isoln from commercial hops: Bungener, Bull. Soc. Chim. Fr. [2] 45, 487 (1886); Barth, Lintner, Ber. 31, 2022 (1898); Wllmer, Ber. 49, 780 (1916); Lewis, et al., J. Clin. Invest. 28, 916 (1949). Structure: Wllmer, Ber. 58, 672 (1925); Wieland, ibid. 102, 2012; Govaert, Verzele, Bull. Soc. Chim. Belg. 58, 432 (1949); Riedl, Ber. 85, 692 (1952). Toxicity study: R. Hnsel, H. H. Wagener, Arzneim.-Forsch. 17, 79 (1967).

Chemical structure

Properties

Prisms from 90% methanol, mp 92-94°. Bitter taste esp in alc soln. Turns yellow and amorphous within a few days with development of an odor. Perfectly stable in vacuo even at 60°. Slightly acid reaction. Monobasic acid. Optically inactive. Soluble in methanol, ethanol, petr ether, hexane, isooctane. Slightly sol in neutral or acidic aq solns. Forms a sodium salt which is readily sol in water. The addition of 0.1% ascorbic acid exerts a marked protective action on the bacteriostatic activity of lupulon steamed or autoclaved at a concentration of 4 ppm in phosphate buffers at pH 6.5 and 8.5. LD50 in mice, rats (mg/kg): 525, 100 orally (Hnsel, Wagener).