Flavonoids from luteolin

Redo, M.C. et al., Luteolin 7-galactosylglucuronide, a new flavonoid from Andryala regusina, Pharmazie, 48, 228, 1993. 

Spices (rosemary, sage, thyme) contain considerable amounts of flavonols and flavones, mainly in the glycoside form (154). Thus, phenolic analyses in spices were often considered in order to determine the optimum time for plant collection to give maximum flavonoid contents and for health benefits (154,155). Flavonoids (naringin, luteolin, apigenin, and chrysoeriol) were extracted from spices using a percolation process at room temperature with solvents (MeOH and EtOAc), and HPLC analysis was carried out (155). 

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. 

Vasorelaxant effect of three flavonoids from Satujera obovata was studied, these were luteolin (6), eriodictyol (112) and naringenin (182) [130], as well as vasodilatory activity [131]. 

Attempts to produce flavonoids by in vitro cultures of II. perforatum led to variable results. Some Authors obtained flavonoids of the same type of those synthesized in vivo by II. perforatum, while others report on the isolation of flavonoids derived from luteolin, not described in vivo in plants of H. perforatum [69,70]. 

The number and the position of hydroxyl groups attached even in the same class of flavonoids can influence the lipophilicity of the flavonoids. Octanol-water partition coefficient (log P) values were reported for flavonoids from the flavone, flavonol, and flavanone [11], showing that aglycones are more lipophilic than any glycosylated or sulfated conjugates. However, there is not a trend of retention time of the flavonoid with respect to the log P (Table 69.1). Despite having the same number and position of hydroxyl substituents in luteolin (flavone) and eriodictyol (flavanone), they have different log P values but similar retention times. 

In Chart 37 and Table I, structures of the flavonoids from Hepaticae and their distribution are listed. Representative flavonoids of the Hepaticae are apigenin and luteolin glycosides. Flavanones and flavonols are very rare. The most primitive liverworts, Takakia species, contain the same... 

Flavonoid Flavones ° Luteolin From Reseda Weld ... 

Phlomis consists of about 100 species, a dozen of which occur in Mediterranean Europe (Mabberley, 1997, p. 549). The study of interest here involves a study of the flavonoids of R lychnitys L., a small plant native to Mediterranean Spain (Tomas et ah, 1986). Those workers identified the common flavones apigenin, luteolin, and luteolin 3 -methyl ether (chrysoeriol) 7-0-glucosides and their respective /7-coumaroyl derivatives. A brief review of the literature revealed that Mediterranean species of Phlomis are characterized by the presence of the flavone methyl ether, whereas continental species appear to lack 0-methylated flavones. Species from India have been reported to lack flavones but accumulate flavonols. The suggestion was made that accumulation of flavonols represents an ancestral feature of the genus. 

The optimized RPLC UV-Vis ESI MS method for all typical blue colourants (indi-goids, hematein, tannins, anthocyanins and selected flavonoids) was used for the identification of dyes extracted from a thread taken from an Italian tapestry of unknown origin from the collection of the National Museum in Warsaw (Poland). It was found that to obtain the red-blue colour of the fibre a mixture of dyestuffs was probably used. The presence of indigotin, tannic and ellagic acid (at m/z 301, NI), as well as carminic acid, suggested the use of indigo and cochineal. Reseda luteola could also have been used due to the presence of luteolin and apigenin. 

The effects of flavonoids on in vitro and in vivo lipid peroxidation have been thoroughly studied [123]. Torel et al. [124] found that the inhibitory effects of flavonoids on autoxidation of linoleic acid increased in the order fustin < catechin < quercetin < rutin = luteolin < kaempferol < morin. Robak and Gryglewski [109] determined /50 values for the inhibition of ascorbate-stimulated lipid peroxidation of boiled rat liver microsomes. All the flavonoids studied were very effective inhibitors of lipid peroxidation in model system, with I50 values changing from 1.4 pmol l-1 for myricetin to 71.9 pmol I 1 for rutin. However, as seen below, these /50 values differed significantly from those determined in other in vitro systems. Terao et al. [125] described the protective effect of epicatechin, epicatechin gallate, and quercetin on lipid peroxidation of phospholipid bilayers. 

Flavonoids exhibit protective action against LDL oxidation. It has been shown [145] that the pretreatment of macrophages and endothelial cells with tea flavonoids such as theaflavin digallate diminished cell-mediated LDL oxidation probably due to the interaction with superoxide and the chelation of iron ions. Quercetin and epicatechin inhibited LDL oxidation catalyzed by mammalian 15-lipoxygenase, and are much more effective antioxidants than ascorbic acid and a-tocopherol [146], Luteolin, rutin, quercetin, and catechin suppressed copper-stimulated LDL oxidation and protected endogenous urate from oxidative degradation [147]. Quercetin was also able to suppress peroxynitrite-induced oxidative modification of LDL [148],... 

Fig. 2.45. Gradient elution chromatogram of flavonoids investigated. Peak identification 1 = naringin 2 = hesperidin 3 = quercitrin 4 = myricetin 5 = naringenin 6 = hesperetin 7 = luteolin 8 = apigenin 9 = flavone 10 = acacetin. Reprinted with permission from M. A. Hawryt et al. [136].

Fig. 2.55. Gradient reversed-phase HPLC analysis of flavonoids in white onions (a) and celery (b). ODS column of 150 X 3.9mm i.d particle size 5pm. Mobile phase 20min gradient of 15-35 per cent acetonitrile in water adjusted to pH 2.5 with TFA. Fowrate lml/min. Upper and lower traces represent samples before and after hydrolysis, respectively. Detection wavelength 365 nm. IS = internal standard Qc = quercetin Ap = apigenin Lt = luteolin. Reprinted with permission from A. Crozier et al. [159],...

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