Sweeteners, oximes

The binding specificity of d-[ C]glucose by the taste-papillae membranes, compared to that of control membranes isolated from epithelial tissue, has been confirmed in two studies. One inherent problem in the approach is that the stimuli, primarily carbohydrate sweeteners, are not ideal model compounds to use, as they are not active at low concentrations and do not show sufficiently high binding-constants. The use of other stimulus compounds that are at least several hundred times sweeter than sucrose, such as saccharin, dihydrochalcone sweeteners, dipeptide sweeteners, stevioside, perillartine and other sweet oximes, the 2-substituted 5-nitroanilines, and... 

Perillartine, a-syn-oxime of perillaldehyde, is reported to be 2000 times sweeter than sucrose.48 49 Perillaldehyde is a principal volatile oil of Perilla frutescens (L.) Britton (Labiatae) and is reported to be only slightly sweet. Perillartine is used as a replacement for maple syrup and licorice for the sweetening of tobacco in Japan. However, due to its low solubility in water as well as a menthol-licorice off-taste, there is some limitation to its use. 

Two natural product derived semisynthetic compounds are utilized as a limited basis, namely, perillartine [28] and neohesperidin dihydrochalcone [45]. Perillartine is an a-jy -oxime and synthesized from perillaldehyde, a constituent of the volatile oil of Perilla frutescens (L.) Britton (Labiatae), and used in Japan as a sweetener for tobacco [28]. Neohesperidin dihydrochalcone is a dihydrochalcone glycoside prepared from a flavanone constituent of Citrus aurantium L. (Rutaceae), which is permitted for use in chewing gum and certain beverages in Belgium and elsewhere [45]. 

From analysis of third sites for different sweeteners, inter-class relationships have been developed by a Dutch group for the sweet classes oximes, nitroanilines, sulphamates, dipeptides and isocoumarins104. 

Monoterpenoids. It was mentioned earlier in this chapter that the semi-synthetic oxime, perillartine (1), is sweet and has some commercial use in Japan. In experiments designed to optimize the sensory attributes of the oxime sweeteners, it was found that the introduction of ether groups was advantageous, while hydroxyl groups and ring oxygen atoms tended to lower sweetness intensity and to destroy the sweet taste, respectively (16). Despite the discovery of cyclic derivatives of perillartine that are sweeter than this lead compound (20), the further development of this class of sweet substances is limited by poor water solubility and inappropriate hedonic qualities (20,21). 

C10H14O, Mr 150.22, oil. Monocyclic monoterpene aldehyde occurring in both enantiomeric forms (/ )-(- )- and(S)-(-)-P.,bp. 104°C(900 Pa), [o]d 150.7°. LD50 (rat p. 0.) 2500 mg/kg. (-)-P. constitutes ca. 50% of Perilla oil from Perilla arguta and P. frutescens var. crispa (Lamiaceae), (+)-P. constitutes ca. 60% of the Philippine Sulpicia oil from Sulpicia orsuami and also occurs in Siler trilobum, Siam latifolium. Citrus reticulata, and other plants. The ( )-oxime of (5)-(-)-P. is used in Japan as a sweetener Perilla sugar and has a 2000-fold higher sweetness than saccharose. 

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