Citrus fruits, flavanones

Flavonoids are not evenly distributed within citrus fruit. Flavanone glycosides are concentrated primarily in the albedo,... 

Citrus fruit Flavanones Flavones Methylated flavones... 

Of this class of naturally occurring, sweet compounds, the flavanone glycosides found in citrus fruits have achieved considerable interest, owing to the systematic studies of Horowitz and Gentili " (see Fig. 20). 

Flavanones Naringenin, hesperetin, Oranges and other citrus fruits... 

Flavanonols Flavanonols can be considered as flavanones with a hydroxyl group on position 3. They are sometimes referred to as dihydroflavonols. Similar to the situation of flavanones, flavanonols are no longer a minor subgroup of flavonoids, and they are a structurally highly diverse and multisubstituted subgroup (Grayer and Veitch 2006). A well-known flavanonol is taxifolin from citrus fruits (Kawaii and others 1999) (see Table 5.1 and Fig. 5.2). 

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. 

Di Majo D, Giammanco M, La Guardia M, Tripoli E, Giammanco S and Finotti E. 2005. Flavanones in citrus fruit structure-antioxidant activity relationships. Food Res Int 38(10) 1161-1166. 

Flavanones are 2,3-dihydroderivatives of flavones which have a saturated C-ring, and are mainly present in their glycosidic forms. In contrast to other flavonoid classes found in a wide range of foods and plants, flavanones are present mainly in citrus fruit and in some aromatic herbs such as ntint. However, reports on the isolation of antinticrobial flavanones from medicinal plants mainly concerned those belonging to the Leguntinoseae family. 

Normal phases (unmodified silica gel) are rarely employed, except for the occasional separation of weakly polar flavonoid aglycones, polymethoxylated flavones, flavanones, or isoflavones. The polymethoxylated flavones present in citrus fruits can, for example, be separated on silica gel columns. The big drawback is that solvent gradients cannot normally be run with normal phases. 

Miyake, Y. et al., New potent antioxidative hydroxyflavanones produced with Aspergillus saitoi from flavanone glycoside in citrus fruit, Biosci. Biotechnol. Biochem., 67, 1443, 2003. 

A comprehensive and critical review of food flavonoid literature has led to the development of a food composition database for flavonols, flavones, procyanidins, catechins, and flava-nones. This database can now be used and continuously updated to estimate flavonoid intake of populations, to identify dietary sources of flavonoids, and to assess associations between flavonoid intake and disease. However, there is a need for better food composition data for flavones, procyanidins, and flavanones as current literature is sparse particularly for citrus fruits, fruit juices, and herbs. In addition, anthocyanin food composition data are lacking although validated methods of determination are becoming available. 

Albach RF, Redman GH. Composition and inheritance of flavanones in citrus fruit. 1969 8(1) 127. 

Citrus fruits and associated products (fruit juices, peeled fresh fruit) are a major dietary source of flavanones (Table 13) [35]. However, the distribution is quite scattered, and much higher concentrations are found in the solid tissues compared to the juice. For example, an individual drinking orange juice (250 ml) will have a daily flavone intake (as aglycones) in the range of 25-60 mg eating the flesh of a whole orange (200 g) will provide about 125-375 mg. 

Flavanones are predominantly found in citrus fruits such as oranges, grapefruit, and lemons. They are usually present as mono- and diglycosides (Table 3.1). 

Flavanones Hesperidin Naringenin Eriodictyol Taxifolin Fisetin Citrus fruit, orange juice, grapefruitjuice, lemon... 

The flavonoids are a group of secondary metabolites widely distributed in the plant kingdom [63]. In 1984, more than 4000 flavonoids were identified in plants [64]. The major dietary sources of flavones are spices and pot herbs, such as parsley, rosemary, and thyme [65], whereas flavonols are predominantly found in onions, kale, broccoli, apples, berries and cherries, and in tea and red wine [66]. The flavanones are mainly restricted to citrus fruits [67], and flavanols are found in considerable amounts in tea, apricots, apples, and cherries [66]. 

Since the very beginning, citrus flavonoids have awakened the interest of chemists. Thus, hesperidin was reported for the first time by Lebreton in 1928 [10], Nowadays it is widely accepted that hesperidin, neohesperidin, and eriocitrin are the major flavonoids in citrus fruits. Other flavanones that may be found, although in lower percentages, are isonaringin and isosakuranetin. Likewise, other compounds that occur as... 

Citrus fruits are the main food source of flavanones. The main aglycones are naringenin in grapefruit, hesperetin in oranges, and eriodictyol in lemons. Flavanones are generally... 

Flavanones are commonly found in high concentrations in citrus fruits and tomatoes. Flavanones are present as aglycones such as natingenin in... 

---