Ziziphin

It has been proposed " that the mechanism(s) of action of gymnemic acids and ziziphins is a biphasic, model-membrane penetration-process. The model suggested that the modifier molecules interact first with the receptor-cell plasma-membrane surface. It was postulated that this initial interaction involves a selective effect on taste perception, including the transduction and quality specification of the sweet stimuli, and selective depression of sweetness perception. Following the initial interaction, the modifier molecules interact with the membrane-lipid interior to produce a general disruption of membrane function and a nonselective effect on taste... 

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Several natural products, eg, gymnemic acid [122168-40-5] and ziziphin [73667-51-3], have also shown sweet-inhibiting activities. These are not allowed for foods in the United States, however. 

The sweetness-inhibiting substance ziziphin was isolated from the leaves of the plant Zizyphus jujuba (Rhamnaceae), which is native to China, by Kurihara et al 1 Like gymnemic acids, ziziphin is a glycoside of triterpene that suppresses sweetness in humans. Removal of the acyl group under mild hydrolytic conditions led to complete abolishment of its antisweet activity. 

There are only a few sweetness inhibitors known. This article will focus on three sodium dodecyl sulfate (SDS), the gymnemic acids (GA) and the ziziphins (ZJ). Each of these substances has the ability to diminish or eliminate the ability to recognize sweetness. The intensity and duration of the effect varies with the inhibitor. 

A more detailed investigation of the ziziphins was carried out by Kennedy and Halpern (r7). Included in their work was a phylogenetic analysis of Z. jujuba and Gymnema sylvestre (Figure... 

Sodium dodecyl sulfate, the gymnemic acids and the ziziphins have all been termed "surface active" taste modifiers because they all possess detergent-like properties. These molecules all have a polar and a non-polar end and they are capable of penetrating the phospholipid membranes that are believed to be components of sweetness receptors. Any speculation about the mechanism of action of these substances must take into account the experimental observations concerning miraculin, monellin, and thaumatin, which were presented at the beginning of this article. Those observations suggested that transport of the modifier to the cell s interior was not occurring and the inhibition effect is manifested at the surface of the cell. 

Much of the ziziphin chemistry was carried out by Dr. Frank Koehn, and psychophysical studies were performed by Drs. Claire Murphy and... 

In the late 1980s, ziziphin (145) was isolated from the Chinese jujube tree, Ziziphus jujuba P. Miller as the first recognized antsweet principle of this plant [146]. Ziziphin (145) has the same dammarane-type aglycone structure as in hodulosides III-V (115-117). Yoshikawa et al. isolated... 

Ziziphin Inhibits sweet taste. Triterpene glycoside isolated from the leaves of Ziziphus jujuba. 

A recent review by Kurlhara deals with structures and physiological action of sweetness-masking substances such as gymnemic acids, ziziphin, heat-stable sweet protein, mabinlins and taste converting protein from sourness to sweetness such as miraculins and curculins. 

The bark of Scutia buxifolia (Rhamnaceae) contains scut-ianine A, B (20), C, D, F (21), and G (22). Similar compounds have been isolated from the roots of Melochia tomen-tosa (23 and 24). A number of 14-membered-ring peptide alkaloids have been isolated from members of the genus Zizyphus (Rhamnaceae) (Fig. 37.8). An alkaloid from diis family, ziziphin (25), blocks activity of the sugar (but not the salt) receptors of flies (Stiidler, 1984). 

A special type of deterrent effect was shown by Ma (1977b). A sesquiterpene dialdehyde isolated from the warburgia plant blocks the sugar receptor cell of S. exempta for 10-20 min after two contacts of 3 min. This inhibitory effect on the sensory neuron has been correlated with a suppression of the feeding response to sucrose. Similarly, Kennedy and Halpern (1980) showed that ziziphin, a cyclic peptide alkaloid of Rhamnaceae, also temporarily inhibits the fly sugar (but not the salt) receptor. 

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