Structure-Taste Correlations in Sweet Dihydrochalcone, Sweet Dihydroisocoumarin, and Bitter Flavone Compounds

Abstract

The dihydrochalcone derivatives of the bitter flavonoids naringin and neohesperedin are intensely sweet. Phyllodulcin is as sweet as the dihydrochalcones with similar taste properties although its structure apparently resembles that of bitter flavanone or flavone. Multifaceted approaches, including X-ray crystal structure analysis, energy calculation, and structure comparison, have been employed to clarify the structure-taste correlations in these classes of compounds. In the crystal, naringin dihydrochalcone assumes a 'J'-shaped conformation with a fully-extended dihydrochalcone moiety while neohesperidin dihydrochalcone assumes the same overall conformation but with a partially-extended moiety. A 2D conformational energy map of dihydrochalcone obtained using molecular mechanics revealed nine local minima. The pseudoequatorial and pseudoaxial forms of phyllodulcin have the same AM1 energies with a low energy barrier between them. The partially-extended form of dihydrochalcone and the pseudoequatorial form of phyllodulcin which are the maximally superposable conformers are proposed to be the active conformers. The major difference between the structures of flavone and phyllodulcin is not in the overall planarity but in the relative orientation of the pyrone and phenyl ring systems.

A second monoclinic polymorph of 1-(2,4-dihydroxy-6-methoxyphenyl)-3-(4-methoxyphenyl)propan-1-one

“…1). The corresponding bond lengths and angles of these two molecules agree with each other and show normal values (Allen et al, 1987), and are comparable to those observed in the other monoclinic polymorph (De Matheus et al, 1991) and a closely related structure (Shin et al, 1998(Shin et al, or 1995.…”

“…The title compound, (I), was isolated from the leaves of R. siamensis, which were collected from Songkhla province in the southern part of Thailand. The naringin dihydrochalcone, which is a derivative of compound (I), was known as a sweetener (Shin et al, 1998(Shin et al, or 1995. As part of our systematic studies on chemical constituents of Thai medicinal plants (Chantrapromma et al, 2003(Chantrapromma et al, , 2004(Chantrapromma et al, , 2005Boonnak et al, 2005;Thongdeeying et al, 2005;Fun et al, 2005), we have undertaken the X-ray crystal structure analysis of (I) in order to establish its molecular structure and relative stereochemistry.…”

Sensory quality of turnip greens and turnip tops grown in northwestern Spain

“…Total flavonoids only showed a significant and moderate relationship with acid taste. Most of the literature related flavonoids with bitter, acid or astringent tastes [25] but minor alterations in the flavonol structure can change their taste from bitter to sweet or the other way around [26].…”

Der Süßstoff Neohesperidin Dihydrochalkon

“…Die Süßempfindung wird durch eine bestimmte räumliche Anordnung des Moleküls ausgelöst, für die es passende Geschmacksrezeptoren auf der Zunge gibt. Neohesperidin DC hat die Form eines »J«, wobei der Dihydrochalkon-Teil des Moleküls nur zum Teil ausgestreckt vorliegt (25).…”