5494. Limonin

Nomenclature

CAS number: 1180-71-8
Limonoic acid di-δ-lactone; 8-(3-furyl)decahydro-2,2,4a,8a-tetramethyl-11H,13H-oxireno[d]pyrano[4′,3′:3,3a]isobenzofuro[5,4-f][2]benzopyran-4,6,13(2H,5aH)-trione; limonoic acid 3,19:16,17-dilactone.
C26H30O8; mol wt 470.51.
C 66.37%, H 6.43%, O 27.20%.

Description and references

Tetracyclic triterpenoid; bitter principle of citrus fruits. Isoln: Bernays, Ann. 40, 317 (1841). Improved isoln and purification: P. G. Pifferi et al., Ital. J. Food Sci. 5, 269 (1993). Structure: A. Melera et al., Helv. Chim. Acta 40, 1420 (1957). Stereochemistry: D. Arigoni et al., Experientia 16, 41 (1960); S. Arnott et al., ibid. 49. Partial synthesis: C. Lüthy et al., Helv. Chim. Acta 57, 1060 (1974). HPLC determn in citrus juice: W. W. Widmer, J. Agric. Food Chem. 39, 1472 (1991). Review of chemistry: V. P. Maier et al., ACS Symp. Ser. 143, 63-82 (1980); and removal of juice bitterness: R. F. H. Dekker, Aust. J. Biotechnol. 2, 65 (1988).

Chemical structure

Properties

Bitter crystals from methylene chloride + isopropanol or acetic acid, mp 298°. [α]D 128° (c = 1.21 in acetone). uv max: 207, 285 nm (ε 7000, 38). Slightly sol in water, ether; sol in alcohol, glacial acetic acid.