8- Hydroxy luteolin

Petroselinin (Graveolbioside A) luteolin 3, 4, 5,7-tetra- hydroxy- flavone Petroselinum crispum (parsley)25 and Apium graveolens (celery)27- 5... 

Luteolin 7-3-neohesperldoslde (5,7,3, 4 -tetrahydroxyflavone) Natsudaldain (3-hydroxy-5,6,7,8,3, 4 -hexamethoxyflavone) Neodlosmln (5,7,3 -trlhydroxy-4 -methoxyflavone 7-3-neohesperldoslde)... 

Unlike the phytoestrogens mentioned earlier, flavones do not possess estrogenic activity. However, the flavones apigenin and luteolin act as potent inhibitors of aromatase and 17P-hydroxy-steroid oxidoreductase, enzymes involved in estrogen metabolism. Studies have also demonstrated these flavones and several glycosylflavones are potent goitrogens, particularly in association with millet consumption. 

Total syntheses of chrysin (93) and luteolin (94), which are non-toxic potent inhibitors of reverse transcriptases from Rauscher murine leukemia (RLV) and the human immunodeficiency virus (HIV), were accomplished by Antus and coworkers via cyclodehydrogenation of the appropriately substituted 2 -hydroxy-chalcone (179) in the presence of PIDA/KOH in MeOH [136] (Scheme 45). 

This enzyme was first reported in the microsomal fractions of Haplopappus gracilis cell cultures,33 studied in more detail in parsley,34 and later shown to occur in the flowers of several species.7 F3 H catalyzes the hydroxylation of naringenin and dihydrokaempferol (DHK), as well as of apigenin or kaempferol to their respective 3 -hydroxy derivatives, eriodictyol, dihydroquercetin (DHQ), luteolin, and quercetin, but does not accept the flavan 3,4-diols or anthocyanidins as substrates,34 indicating that B-ring hydroxylation of the latter is determined at the dihydroflavonol level. It was more than two decades later that the first cDNA clone encoding F3 H was isolated and characterized from the flowers of Petunia hybridal Arabidopsis thaliana,36 and Perilla frutescens.37 Their recombinant proteins were shown to... 

Pisutthanan et al. (27) isolated six flavonoids out of which three were reported in this plant for the first time. They include 3,5,4 -trihydroxy-7-methoxyflavanone 5,7,3 -trihydroxy-5 -methoxyflavanone and 3,5,7-trihydroxy-4 -methoxyflavanone. Ling et al. (28) also isolated a total of eleven flavonoids from the leaf extract and identified them as eriodictyol 7,4 -dimethyl ether, quercetin 7,4 -dimethyl ether, naringenin 4 -methyl ether, kaempferol 4 -methyl ether, kaempferol 3-0-mtinoside, taxifolin 4 -methyl ether, taxifolin 7-methyl ether and quercetin 4 -methyl ether. Suksamram et al. (23) isolated the flavanones, isosakuranetin (5,7-dihydroxy-4 -methoxyflavanone), persicogenin (5,3 -dihydroxy-7,4 -dimethoxyflavanone), 5,6,7,4 -tetramethoxyflavanone and 4 -hydroxy-5,6,7-trimethoxyflavanone, the chalcones, 2 -hydroxy-4,4, 5, 6 -tetramethoxychalcone and 4,2 -dihydroxy-4, 5, 6 -trimethoxychalcone, and the flavones, acacetin (5,7-dihydroxy-4 -methoxyflavone) and luteolin (5,7,3, 4 -tetrahydroxyflavone) from the flowers. 

In our first study with Salvia species, S. triloba L.f. [8] we have isolated a new flavone salvigenin (1) (6,7,4 -trimethylapigenin), later the same compound was obtained from other Salvia species. From S. tomentosa [9] cirsimaritin (2), jaceosidin (3), 5-hydroxy-6,7,3 ,4 -tetramethoxyflavone (4), 6-methoxyluteolin (5), luteolin (6), luteolin 7-glucoside (7) were isolated, in an other study with the same plant [10] further compounds eupatilin (8), cirsilineol (9), diosmetin (10), 6-hydroxyluteolin 7- and 5-glucosides (11 and 12) were obtained. 

T. satureioides exhibited spasmolitic activity on smooth muscles. The compounds obtained were cirsilineol (9), 8-methoxycirsilineol (153), and thymonin (162) [82]. From T. membranaceus Boiss. subsp. membranaceus luteolin (6), 5-hydroxy-6,7,3 4 -tetramethoxyflavone (4), 5-desmethyl-nobiletin (147), eupatorin (49), sideritoflavone (154), chrysoeriol (17), 7-methoxyluteolin (179), genkwanin (16), xanthomicrol (132) and naringenin (175) [83]. 

LLE Hexane 60% aqueous MeOH MeOH/H O (1 1 v/v) Tyrosol, 2.3-dihydroxyphenylethanol, oleuropein glycoside, hydroxytyrosol, dihydrocaffeic acid, cinnamic acid, 4-hydroxy-phenylacetic acid, gentisic acid, taxifolin, syringic acid, ferulic acid, luteolin, o-coumaric acid, p-coumaric acid, quercetin, vanillic acid, 4-hydroxy-benzoic acid, caffeic acid, 3,4-dihydroxyphenylacetic acid, gallic acid, and protocatechuic acid UV-vis (200 nm) ESI-MSD CZE-DAD HPLC... 

Desmoxyphyllin B 5-Hydroxy, l-0-(i-D-glucopyranoside, in D-20031 Luteolin 7-(9- -D-Glucuronoside, Me ester, in T-10052... 

In order to avoid the oxidation of the compounds, several antioxidants can be added as diethyldithiocarbamate [52,79,82], tert-butyl-hydroquinone (TBHQ), [80,83,84] or butylated-hydroxy-toluene (BHT) [81]. Furthermore, internal standards are usually used, such as morin [52,80], luteolin [80], isorhanmetin, [79,82] or kaempferol [79] depending on the phenolic compounds analyzed to monitor losses during sample preparation. 

---