Heptamethoxyflavone

Figure 5.7 Separation of tangeretin and heptamethoxyflavon by recycle HPLC R, recycle C, collected 1, tangeretin 2, heptamethoxyflavon. Reprinted from Essenze Derivati Agrumari, 63, L. Mondello et al., Tsolamento di polimetossiflavoni dagli olii essenziali di arancia dolce e di mandarine mediante cromatografia su colonna e HPLC semipreparativa con riciclo , pp. 395-406, 1993, with permission from Essenze Derivati Agmmari.

The non-volatile range of mandarin and tangerine oil is characterised mainly by the methoxyflavones tangeretin, heptamethoxyflavone and nobiletin this compound class comprises up to 3500 ppm in Italian mandarin oils [38, 80[. 

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]. 

The reports indicate the presence of terpenes, a-pinene, camphene, citral and beta-caryophyllene in the essential oil from the leaves and flavonoids such as casticin, orientin, isoorientin, luteolin, luteolin-7-O-glucoside, corymbosin, gardenins A and B, 3-O-desmethylartemetin, 5-0-desmethylnobiletin, 3, 4, 5,5, 6,7,8-heptamethoxyflavone, 3, 5-dihydroxy-4, 7,8-trimethoxyflavanone and 3, 5-dihydroxy-4, 6,7-trimethoxy... 

Grapefruit Naringin, narirutin, hesperidin, neohesperidin tangeretin, heptamethoxyflavone isosinensetin... 

Sweet orange hesperidin, narirutin, eriocitrin, isosakuranetin 7-rutinoside sinensetin, nobiletin, tangeretin, heptamethoxyflavone tetramethoxyflavone isosinensetin... 

Iwase Y, Takemura Y, Ju-ichi M, Yano M, Ito C, Furukawa El, Mukainaka T, Kuchide M, Tokuda El, Nishino H. Cancer chemopreventive activity of 3,5,6,7,8,3, 4 -heptamethoxyflavone from the peel of citrus plants. Cancer Lett 2001 163 7-9. 

Fig. 1 SFC separation of synthetic mixture of polymethoxylated flavones. Column, 250 x 4.6 mm I.D. stationary phase, Zorhax (5 p,m) sihca 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 = heptamethoxyflavone 3 = nobiletin 4 = sinensetin 5 = tetramethyhsoscutellarein 6 = isosinensetin.

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