Tangeretin flavones

Methoxyhydnocarpin-D (flavonolignan) 5,6,7,8,4 -Pentamethoxy-flavone (= Tangeretin) (flavone)... 

Chaumontet et al. conducted an extensive study into the tumor-promoting potentials of four flavonoids (quercetin, tangeretin, flavone, and flavanone) to induce rat liver... 

Different extracts of Citrus were subjected to SPE on Cig cartridges to remove polar components. The retained flavonoids (mainly flavanones) were eluted with methanol-dimethyl sulfoxide, which enhanced solubility of hesperidin, diosmin, and diosmetin. Recoveries of eriocitrin, naringin, hesperidin, and tangeretin from spiked samples of mesocarp tissue exceeded 96%. Flavones were relatively abundant in the leaves. ... 

Flavones contribute to plant tissue color provided that they occur in high concentrations or are complexed with metal ions. Some flavones participate in taste for example, the highly methoxylated aglycones nobiletin, sinensetin and tangeretin are responsible for the bitter taste of citrus peel. On the other hand, some glycosylated flavones (for instance neodiosmin and rhoifolin) reduce the bitterness of some substances (limonin, naringin, caffeine, quinine) [2]. 

Flavones (Figure II. 3.7) are less commonly found in plants, but often occur in citrus. Poly-methoxylated flavones, which include no-biletin, sinensetin, and tangeretin, are the characteristic features in citrus plants. Flavones are generally detected at 360 or 370 nm. The elution order, when analyzed as described in the Basic Protocol, is rhoifolin, luteolin, and apigenin (Table 11.3.1). 

Substantial quantities of luteolin-7-O-glucuronide, luteolin-7-O-glucoside, and luteolin-7-O-rutinoside occur in Red Oak Leaf and Lollo Rosso, two red-leaved varieties of lettuce (Lactuca sativa) [Llorach et al., 2008], Polymethoxylated flavones such as nobiletin, scutellarein, sinensetin, and tangeretin (Fig. 1.8) are found exclusively in citrus species [Crozier et al., 2006c], while diosmetin-7-O-glucuronide has been isolated from the fruits of a Chinese herb, Luffa cylindrical. 

Chemical structures of flavonoids. These flavonoids consisted of three groups flavone (apigenin and lutolin), flavonols (flavonol, kaempferol, quercetin, myricetin, tangeretin, and nobiletin) and isoflavones (daizein, genistein, biochanin A, and equol). 

Fig. 1 SFC separation of synthetic mixture of polymethoxy-lated flavones. Column, 250 mm x 4.6 mm I.D. stationary phase, Zorbax (5 pm) silica mobile phase, carbon dioxide modified with 10% methanol inlet pressure, 220 atm outlet pressure, 200 atm column temperature, 40°C carbon dioxide flow-rate, 3 mL/min methanol flow-rate, 0.3 mL/min UV detection at 313 nm. Peaks 1 =tangeretin 2=heptamethoxy-flavone 3 = nobiletin 4 = sinensetin 5 = tetramethylisoscutellar-ein 6=isosinensetin.

Hadj-Mahammed et al. analyzed a mixture of flavone, 5-methoxyflavone, and tangeretin by supercritical CO2 SFC on capillary columns with two types of detectors flame ionization (FID) and FT-IR. Peafe identification was achieved with the help of the FT-IR fingerprint of each compound. However, the separation was satisfactory only by the use of supercritical C02g density programs, without the use of a phase modifier. The separations were accomplished using a Carlo Erbaa SFC system equipped with a Model SFC 300 pump and Model SFC 3000 oven. The fused silica capillary column were BPl (12 mxO.l mm I.D. 0.1-pm film of di- methylpolysiloxane) and DB5 (15 mxO.l mm TD. 0.4-pm film of 94% dimethyl-, 5% diphenyl-, and 1% vinylpolysiloxane). The two supercritical CO2 density programs used in this work were PI [from 0.127 g/mIi->... 

A characteristic pattern of various flavones can be detected in the non-volatile part of orange oil heptamethoxyfla-vone, nobiletin, tetra-O-methylscutellarein, tangeretin, hexamethoxyflavone and sinensitin. 

While methoxyflavones constitute the non-volatile part of Citrus sinensis oils, bitter orange oil possesses a completely different pattern of coumarins and flavones. Characteristic for this range of bitter orange oil are meranzin, isomeranzin, bergapten, epoxybergamottin, tangeretin, os-thol, nobiletin and heptamethoxyflavone [38, 89]. 

Tangeretin is a citrus flavone that inhibits the release of both ROS by human neutrophils and histamine by human basophils. In addition, it inhibits the proliferation of malignant tumor cells in vitro. Hirano et al. [144] demonstrated that the compound s anticancer activity is mediated in part through induction of apoptosis, but that this occurs without affecting the immune cells. 

Nielsen SE, Breinholt V, Cornett C, Dragsted LO. Biotransformation of the citrus flavone tangeretin in rats. Identification of metabolites with intact flavane nucleus. Food Chem Toxicol 2000 38 739-746. 

---