Fruit flavonol

Flavonols Fruits of Forsythia suspense Buffer + SDS + organic solvent EC ... 

JUSTESEN u, KNUTHSEN p and LETH T (1998) Quantitative analysis of flavonols, flavones, and flavanones in fruits, vegetables and beverages by high-performance liquid chromatography with photo-diode array and mass specfrometric detection, /C/u matogr A, 799, 101-10. 

Flavanones In some cases, flavanones produced by CHI will accumulate to sizeable amounts instead of being diverted away to form flavonols, anthocyanins, and flavanols (see Fig. 5.4). These flavanone products, hesperetin and naringenin being the most common, are frequently encountered in citrus fruits and juices (USDA Flavonoids Database Release 2.1,2007). In most of these cases, essentially no flavonols or anthocyanins are encountered the flavonoid pathway is essentially blocked at the F3H step. 

Flavonoids are a complex group of polyphenolic compounds with a basic C6-C3-C6 structure that can be divided in different groups flavonols, flavones, flavanols (or flavan-3-ols), flavanones, anthocyanidins, and isoflavones. More than 6,000 flavonoids are known the most widespread are flavonols, such as quercetin flavones, such as lu-teolin and flavanols (flavan-3-ols), such as catechin. Anthocyanidins are also bioactive flavonoids they are water-soluble vegetable pigments found especially in berries and other red-blue fruits and vegetables. 

Sanchez-Morcno (2002) considered that this assay is an easy and accurate method for determining antioxidant capacity in fruit and vegetable samples. The DPPH assay has been used to determine the antioxidant activity of polyphenols (Sanchez-Moreno and others 1998 Bao and others 2004) flavonols (Jimenez and others 1998 1999 Choi and others 2002) anthocyanin-based natural colorants from berries (Espin and others... 

Lako J, Trenerry, VC, Wahlqvist M, Wattanapenpaiboon N, Sotheeswaran S and Premier R. 2007. Phytochemical flavonols, carotenoids and the antioxidant properties of a wide selection of Fijian fruit, vegetables and other readily available foods. Food Chem 101(4) 1727-1741. 

FLAVONE. FLAVONOL AND FLAVANONE CONTENTS IN FRUITS. VEGETABLES AND BEVERAGES PRESENTED AS AVERGAE VALUE STANDARD DEVIATION (MG/G FRESH WEIGHT)... 

Zuo, Y. Chen, H. Deng, Y. Isolation and Identification of Flavonol Glycosides in American Cranberry Fruit using HPLC and GC-MS. Proceedings of the 233rd American Chemical Society National Meeting, Chicago, IL, March 25-29, 2007. 

Among the numerous applications of SPE are separations of phenolic acids and flavonoids from wines and fruit juices. Sep-Pak Cig cartridges have been used for the fractionation of flavonol glycosides and phenolic compounds from cranberry juice into neutral and acidic parts before HPLC analysis. Antimutagenic flavonoids were identified in aqueous extracts of dry spinach after removal of lipophilic compounds by SPE. ... 

The overproduction of an enzyme at a rate-limiting step to increase levels of specific flavonoids is well illustrated by the Forsythia ANS example described earlier, and also by the use of CaMV35S CF[I increase flavonol levels in A. thalicma and L. esculentum. In particular, fruit of L. esculentum plants expressing P. hybrida CHI had up to a 78-fold increase in flavonol content, principally rutin, in fruit peel. 

Quercetin is the most common flavonol in fruits, elderberries (17.0 mg/100 g), lingonber-ries (12.6 mg/100 g), and cranberries (13.0 mg/100 g) being particularly rich sources. Berries and currants are also the fruits containing most kaempferol and myricetin. For example, these two flavonols account for 29 and 18%, respectively, of the total flavonol content of the bilberry. Although kaempferol and myricetin have also been identified in fruits such as peaches and pears, concentrations are generally too low to be readily quantified in the whole fruit. The skin of these fruits contains these flavonols in significant amounts however, their flesh, which constitutes >70% of the fresh weight, does not. Consequently, when analyzed as normally eaten only trace levels are present. 

---