Phloretin 2 -0-glucoside

Chalcones and dihydrochalcones have been reported in a restricted number of foods (Robards and others 1999 Tomas-Barbcran and Clifford 2000). Chalconaringenin occurs in tomato skin, but the acid extraction conditions of the usual polyphenol analyses convert the chalcone to the corresponding flavanone (naringenin) in the tomato. The most common dihydrochalcones found in foods are phloretin glucoside (phloridzin) and phloretin xylogalactoside, which are characteristic of apples (see Table 2.2) and derived products such as apple juice, cider, and pomace (Robards and others 1999 Tomas-Barbcran and Clifford 2000). 

Phlorizin, the glucoside of the dihydrochalcone phloretin, is a constituent of the tissues of the apple tree. Its distribution and bio-... 

Fig. 2.56. HPLC chromatogram of (a) Golden peel and (b) Golden pulp extracts at 280 nm. Peaks 1 = procyanidin B3 2 = procyanidin Bl 3 = ( + )-catechin 4 = procyanin B2 5 = chlorogenic acid 6 = ( — )-epicatechin 7 = caffeic acid 8 = phloretin derivative 9 = phloridzin 10 = rutin 11, 12 and 13 = flavonol glucosides. Reprinted with permission from A. Escarpa et al. [160].

For example, the mouth is exposed to a substantial, albeit transient and spasmodic, flux of PPT. It has been reported that quercetin-4 -glucoside, quercetin-3-glucoside, phloretin-2 -glucoside, and genistein-7-glucoside can be rapidly hydrolyzed, and quercetin-3-rutinoside... 

Phloroglucinol (42) is a colorless and odorless solid which is only sparingly soluble in cold water (82). It was discovered in 1855 in the hydrolysis products of the glucoside phloretin, which was obtained from the bark of fruit trees. Phloroglucinol occurs in many other natural products in the form of derivatives such as flavones, catechins, coumarin derivatives, anthocyanidins, xanthins, and glucosides. 

Chalcones, such as butein (1.26), are yellow pigments in flowers. An example of a dihydrochalcone is phloridzin (phloretin-2 -0-D-glucoside) (1.27), a compound found in apple leaves, and which has been reported to have anti-tumor activity (Nelson and Falk, 1993). 

Peaks 1. HMF, 2. conjugated coumaric, 3. chlorogenic, 4. chlorogenic isomer, 5. caffeic, 6. p-coumarylquinic, 7. p-coumaric, 8. phloretin xyloglucoside, 9. quercetin galactoside, 10. quercetin glucoside, 11. phloridzin, 12. quercetin xyloside, 13. quercetin arabinoside,... 

Phloroglucin—CgH3(OH)i—126—is obtained by the action of potash upon phloretin, quercitrin, maclurin (see Glucosids), catechin, kino, etc. It crystallizes in rhombic prisms, containing 2 Aq is very sweet very soluble in water, alcohol, and ether. 

The most characteristic compounds of apple are the dihydrochalcones, analysis of which can be applied to apple-derived food characterisation (juices, jams, purges, cider, etc.). Phloretin 2 -glucoside (phloridzin) (Fig. 5) and phloretin 2 -(2"-xylosylglucoside) are the only dihydrochalcones reported in apple so far [20]. 

Chalcones (l,3-diaryl-2-propen-l-ones) are flavonoids lacking a heterocyclic C ring. Also this category of flavonoids displays a broad spectrum of bio activities such as anticancer, antifungal, antibacterial, antiviral, and anti-inflammatory properties (Calliste et al. 2001). Dihydrochalcones, which do not have a P double bond, comprise phloretin [P- (4-hydroxyphenyl) -1 -(2,4,6-trihydroxypropiophenone) and its glucoside, phlo-ridzin (phloretin 2- P-D-glucose). Comparison with structurally related compounds revealed that the antioxidant pharmacophore of phloretin is 2,6-dihydroxyacetophenone (Rezk et al. 2002). The po-... 

Crespy V, Morand C, Besson C, Manach C, Demigne C, Remesy C (2001) Comparison of the intestinal absorption of quercetin, phloretin and their glucosides in rats. J Nutr 131 2109-2114... 

The occurrence of species-specific constituents is also analytically useful. The composition of the plant phenols of individual fruits can be analyzed quickly and very accurately by using HPLC. These data have shown that certain compounds are suitable indicators of adulteration (Table 18.42). These indicators must be fixed with great care. In fact, phloretin-2-glucoside (phloridzine) and isorhamnetinglucoside have been proposed as markers for apples and pears. Improvements in the analyses, however, showed that phloridzine and isorhamnetinglucoside widely occur in low concentrations in fruit, and the last mentioned glucoside also occurs in apples, among other fruit. 

An example of natural dihydrochalcones is phloretin (9-105). The most famous glycoside of phloretin, phloretin-6-O-P-D-glucoside,... 

Phloridzin (XXXII) is a phenolic glucoside of phloretin. When administered to animals orally or subcutaneously, both phloridzin and its aglu-cone, phloretin, give rise to an intense glycosuria without an accompanying hyperglycemia the blood-sugar level is in fact diminished and the renal... 

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