Glucosides chemical structure

Research into the copigmentation of anthocyanins started as early as 1913 when Willstatter and Everest determined the chemical structure of cyanidin 3-glucoside isolated from blue cornflowers and red roses, and attributed the color changes to different pH levels in cell saps. This theory, however, was questioned and in 1916, Willstatter and Zollinger,revising the previous work, proposed a new theory according to which the colors of the anthocyanins varied significantly by the effects... 

Another problem is that the anthocyanin mixtures may be very complicated and not all absorptivity coefficients may be known. Even when they are known, it is necessary to first evaluate whether the objective is the estimation of total anthocyanin content or the determination of individual pigments, and then to decide which absorption coefficient(s) to use. The absorptivity is dependent on both the chemical structure of the pigment and also on the solvent used, and preferably the coefficient used should be one obtained in the same solvent system as the one used in the experiment. If the identity of the pigment is unknown, it has been suggested that it could be expressed as cyanidin-3-glucoside since that is the most abundant anthocyanin in nature. 

FIGURE 7.2 Chemical structures of the main soy (genistein and daidzein) and red clover (biochanin A and formononetin) isoflavonoids (aglycones and glucosides). 

The QSAR data show that glucuronidation can be either a detoxification or bioactivation mechanism, depending chemical structure. For N SAIDs, it appears to be mostly a detoxification mechanism. Nonetheless, the toxicity of acyl glucuronide and glucoside adducts (espedally as it relates to isomerization and protein adduct formation) must be considered when designing carboxylic acids [38]... 

Two new phenylpropanoid glucosides and an alkyl glucoside from the fruits of I. vemm were isolated and their chemical structures were elucidated on the basis of spectroscopic studies (Lee et al., (2003a,b). The two racemic mixtures of phenylpropanoids 1-(4 -molhoxyphonyl)-(1 / , 2S and IS, 27 )-propanediol and l-(4 -methoxyphenyl)-(17 , 27 and IS, 2S)-propanediol] were isolated, along with two known phenylpropanoids. 

One of the most relevant and extensively studied stilbene is trani-resveratrol (3,5,4 -trihydroxystilbene), a phytoalexin produced by grapevines in response to fungal infection, particularly Botrytis cinerea. Synthesis of resveratrol in grape berries is mainly located in the skin cells and is absent or low in the fruit flesh. In nature, resveratrol exists in two isomeric forms (cis- and frani -conflgured) in the free as well as in 6-glucoconjugated form. The 3-0-6-D-glucosides of cis- and trans-resveratrol cis-and trans-conflgured are called piceids. The chemical structures of resveratrol and further stilbenes are depicted in Fig. 9C.6. 

Figure 4.3 Chemical structures of Isoflavone glycosides. In soy foods, Isoflavones form 7-0-P-glucosIde conjugates. A Is the simple glucoside commonly found In soy milk, B Is the 6"-0-malonyl-7-0-p-glucoslde from the soybean, and C Is the 6"-0-acetyl-7-O-p-glucoside, a product of toasting of soy flour. D is the 7-0-P-glucuronide that is the principal conjugate in the blood.

The difference in the chemical structure of fraws-resveratrol and cis-piceid is that the latter has a glucose at the Rj position while the former has a hydroxyl group. This implies that the presence of the hydroxyl substituent is necessary for antitumor activity of the stilbene. The difference in activity may also be due to geometric stereochemical differences between the cis and trans double bonds and/or the poor solubility of the glucoside derivative in water which inhibits the interaction of this compound with cellular components. 

The metabolism of jasmonic acid itself was investigated using suspension cultures of Eschscholtia California [46]. From cells incubated with racemic jasmonic acid, the major metabolite was isolated and the chemical structure was determined as 11-hydroxyjas-monic acid 11-O-P-D-glucoside. The configuration at C-11 was determined as R by the Horeau-Brooks method. 

Starch is another widely available natural polymeric biomaterial, which is generally isolated from corn, wheat, potato, tapioca, rice, etc. The major carbohydrate reserve in the plants is in the form of starch. It mainly consists of two glucosidic macromolecules 20%-30% of linear molecule amylase and 70%-80% of branched molecule amylopectin. The chemical structure of starch is given in Figure 53.2. 

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