Nobiletin flavones

Citrus aurantium (Christen.) Swingle var. amara Suan Cheng (Bitter orange) (unripe fruit) Synephrine, N-methyltyramine, flavones including tangeratin and nobiletin.33 Treat indigestion, relieve abdominal distension, ptosis of the anus or uterus. 

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]. 

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. 

Certain bioflavonoids may play a preventive role against cardiovascular diseases. Some citrus and other bioflavonoids have been demonstrated to reduce serum cholesterol levels and to affect fatty acid metabolism (70,71,72). The strong antiadhesive action on red cells and platelets of highly methoxylated flavones such as nobiletin, which also demonstrates antithrombogenic activity (73), indicates an important role in blood rheology and tissue perfusion. The antiadhesive action may indicate a preventive role in atherosclerosis since there is evidence that reduced perfusion of the vascular wall may interact with serum lipids to promote atherogenesis (74). 

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.

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]. 

Besides sinensetin (Rf 0.35/T2), A. pericarpium (3) shows eight to ten blue to violet-blue zones of hydroxylated flavans (e.g. nobiletin, tangeritin), coumarins and methylanthranilate in the R, range 0.05-0.8 (see also Chap. 6, Fig. 17,18). Orthosiphonis folium (4) sinensetin (Tl) is the major compound with scutellarein tetramethyl ether directly above and eupatorin and 3 -hydroxy-5,6,7,4 -tetramelhoxy-flavone below (R, 0.3-0.4). 

Flavones Apigenin Luteolin Tangeretin Nobiletin Citrus fruits and pear [11,13]... 

Flavones consist chiefly of glycosides of luteolin, chrysin, and apigenin. They are less common in fruits [8]. Polymethoxylated flavones, the most hydrophobic flavonoids, present in citrus fruits (mainly in the peel, the nonedible part of the fruit) are tangeretin and nobiletin. Apigenin and chrysin possess anti-inflammatory and free-radical scavenging properties in several cancer cell lines and inhibit tumor cell invasion, metastasis, and mitogen-activated protein kinases (MAPK) and their downstream oncogenes [26]. 

Six polymethoxylate flavones (tangeretin, nobiletin, sinensetin, tetra-O-methy-scutellarein, 3,3, 4, 5,6,7,8-hepta- and 3,3, 4, 5,6,7-hexamethoxyfiavone) were isolated from mandarin oils and analyzed on a silica column (2 = 315 nm) using a 95/5 hexane/ethanol mobile phase [680]. Quantitation was made against a coumarin IS. Concentration levels ranged from 0.01-0.40 g analyte/100 g oil. Peaks were well resolved and elution was complete in 24 min. 

Flavone Nobiletin (citrus fruit) Oxidative stress... 

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