Tomato chalcones

Chalcones Chalconaringenin White grapes Cherry tomatoes... 

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). 

Schijlen EWGM, de Vos CHR, Martens S, Jonker HH, Rosin FM, Molthoff JW, Tikunov YM, Angenent GC, van Tunen AJ, Bovy AG (2007) RNA interference silencing of chalcone synthase, the first step in the flavonoid biosynthesis pathway, leads to parthenocarpic tomato fruits. Plant Physiol 144 1520-1530... 

Muir, S.R. et al.. Overexpression of petunia chalcone isomerase in tomato results in fruit containing increased levels of fiavonols. Nat. BiotechnoL, 19, 470, 2001. 

Chalcones are comparatively rare in foods. Naringenin chalcone is present in tomato skin and may be present in juice, paste and ketchup. Acid hydrolysis, commonly applied prior to HPLC, converts the chalcone to the corresponding flavanone (naringenin), which is naturally present only in trace amounts (2-15 mg/kg) in the tomato [23],... 

Krause M, Galensa G. 1992. Determination of naringenin and naringenin-chalcone in tomato skins by reversed phase HPLC after solid phase extraction. Z Lebensmittel... 

MUIR S. R, COLLINS, G. J., ROBINSON, S HUGHES, S., BOVY, A., DE VOS, C. H. R, VAN TUNEN, A., VERHOEYEN, M. E., Overexpression of petunia chalcone isomerase in tomato results in fruit containing increased levels of flavonols, Nature Biotech., 2001,19,470-474. 

MUIR S.R., COLLINS G.J., ROBINSON S., HUGHES S., BOVY A., RIC DE VOS C.H., VAN TUNEN A.J. and VERHOEYEN ME. (2001) Ovcrexpression of petunia chalcone isomerase in tomato results in frait containing increased levels of flavonols. Nature Biotechnol. 19 470-474. 

Fig. 12 shows a characteristic chromatogram of the phenolic compounds of tomato peel. Especially interesting is the relatively large naringenin chalcone peak. Other peaks are observed in the chromatogram, corresponding to unidentified hydroxycinnamic and benzoic acid derivatives. 

Fig. (12). HPLC chromatogram of tomato peel phenolics (1) chlorogenic acid, (2) quercetin 3-rutinoside, and (3) naringenin chalcone. HPLC conditions RP Cjg column (12 x 0.4 cm particle size S pm). Mobile phase acidified water (5% formic acid) and methanol. Gradient 0 min- 10% B, 30 min- 40% B, 40 min- 80% B. Flow rate 1 mL/min.

Chalcones Cinnamic acids Flavonols Flavonones Isoflavones Phenolic acids 10 Tomato, pepper, eggplant SEE CO2 + methanol 20 NS [28]... 

Although tomato was the matrix most studied with this technique, other matrices such as pepper, eggplant, apple, pear, beans, mango, orange, citrus fruit, onion, garlic, potato, chillies, and strawberries were also studied by UAE. The extracted phenolic compounds included phenolic acids, isoflavones, flavonols, flavonones, fla-vones, flavonones, cinnamic acids, dihydrochalcones, chalcones, flavanols, and pro-cyanidins (Table 16.3). 

Tomato Tomato/RNAi CaMVd35S/ CHS Chalcone synthase Chalcones Lower total flavonoid and parthenocarpic fmit [62]... 

Tomato (Petunia) (alfalfa)/ oveiexpiession CaMV35S/ CHSl + CHR Chalcone synthase + chalcone reductase Chalcones -I- deoxychalcones Higher butein, isoliquiritigenin, naringenin, chalcone, and rutin [63]... 

Tomato Grape/ overexpression CaMVd35S/ STS Stilbene synthase Resveratrol High stilbenes (resveratrol and piceid), naringenin chalcone, rutin [63]... 

Tomato Petunia/ CaMVd35S/ chi- Chalcone isomerase Flavanones Higher flavonols mainly rutin in [71] 3 rD... 

Tomato Petunia CaMV35S/ CHI Chalcone isomerase + Flavanones -i- flavones Higher rutin (16-fold), luteolin- [63] 2... 

Tomato Tomato/RNAi CaMV35S/ MYB12 MYB12 R2R3-MYB TF mediates the accumulation of flavonoids in tomato peel Lower flavonoid pigment naringenin chalcone Exhibited a y-like phenotype [78]... 

Tomato Tomato/ overexpression CaMV35S/ TAGLl TOMATO AGAMOUS-LIKE 1 MADS-box TF Higher lycopene and naringenin chalcone [81]... 

Parthenocarpic tomatoes with suppressed chalcone synthase obtained by using RNA interference [55] showed abolished production of flavonoids. Several smdies [55, 57] have clearly demonstrated the importance of flavonols for normal pollen tube development and male fertility. Flavonols have been detected in the pollen of all plant species tested so far and clearly play an important role in pollen tube development. In tomato plants overexpressing STS, the analysis of flavonols showed that pollen ablation was independent of the production of detectable amounts of flavonols in flowers [38]. 

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