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Flavonoids characterization

Grayer, R.J. et al.. The application of atmospheric pressure chemical ionization liquid chromatography-mass spectrometry in the chemotaxonomic study of flavonoids characterization of flavonoids from Ocimum gratissimum var., Phytochem. Anal., 11, 257, 2000. [Pg.907]

The farinose exudate of the frond of the fern Pityrogramma calomelanos (Adiantaceae) has been the source of complex flavonoids characterized by a novel Ce-Cs-Ce-Cs-Ce skeleton (Table 15.7). This group includes four flavanones, calomelanols G (238), H (239), I (240), and J (241) (Figure 15.10). In these compounds, a molecule of p-coumaric or cinnamic acid appears to be fused with the A-ring of the flavanone. Biosynthetic pathways for these complex flavanones and related flavones, chalcones, and dihydrochalcones in P. calomelanos and other Pityrogramma species have been proposed by the authors. [Pg.948]

Flavonols and flavones are present in many food products and medicinal plants and show relevant antioxidant activity in vitro. In this chapter, classical analytical methods sueh as thin layer ehromatography and two-dimensional paper chromatography together with modem methodologies such as HPLC-MS-MS are reported. Preparative ehromatography methods are also reviewed as well as spectroseopie methods used for flavonoid characterization and identification, including UV spectrophotometry and MS spectrometry. Chemical and enzymatic methods used in flavonoid identification are also reviewed. [Pg.207]

MS, has been applied extensively to flavonoid characterization in the last few years, and in this chapter we will review the state of the art of this powerful method, that is particularly useful in the analysis of flavonoid glycosides present in complex extracts. [Pg.225]

There are numerous synthetic and natural compounds called antioxidants which regulate or block oxidative reactions by quenching free radicals or by preventing free-radical formation. Vitamins A, C, and E and the mineral selenium are common antioxidants occurring naturally in foods (104,105). A broad range of flavonoid or phenoHc compounds have been found to be functional antioxidants in numerous test systems (106—108). The antioxidant properties of tea flavonoids have been characterized using models of chemical and biological oxidation reactions. [Pg.373]

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. [Pg.61]

This study of Phlox Carolina represents one of the best examples in the flavonoid chemosystematic literature where workers combined thorough sampling, detailed statistical analysis, and an intimate knowledge of the biology of the system under scrutiny to produce a convincing picture of natural variation. As mentioned at the beginning of this discussion, a more casual approach would have undoubtedly overlooked the subtle differences that characterize this system. [Pg.88]

Each plant tissue tends to have an obviously distinctive profile of flavonoids. The flavonoid content can reach about 0.5% in pollen, 10% in propolis, and about 6 mg/kg in honey. Havonoid aglycones appear to be present only in propolis and honey, while pollen contains flavanols in herosidic forms. The flavonoids in honey and propolis have been identified as flavanones and flavanones/flavanols (Campos et ah, 1990). The antimi-crobially active flavanone pinocembrine was foimd to be a major flavonoid in honey (Bogdanov, 1989). Amiot et ah (1989) studied two blossom and two honeydew Swiss honey samples and foimd that pinocembrine was the main flavonoid. Pinocembrine concentration varied between 2 and 3 mg/kg (Bogdanov, 1989). Berahia et ah (1993) analyzed sunflower honey samples and detected six flavone/flavols, four flavanone/ flavols, and pinocembrin, of which pinocembrin is the main flavonoid. The flavonoids in sunflower honey and propolis were characterized and assessed for their effects on hepatic drug-metabolizing enzymes and benzo [fl]pyrene-DNA adduct formation (Sabatier et ah, 1992 Siess et ah, 1996). [Pg.108]

Siess, M. H., Le Bon, A. M., Canivenc-Lavier, M. C., Amiot, M. ]., Sabatier, S., Yaubert, S. Y., and Suschetet, M. (1996). Flavonoids of honey and propolis Characterization and effects on hepatic drug-metabolizing enzymes and benzoja] pyrene-DNA.. Agric. Food Chem. 44, 2297-2301. [Pg.134]

P. Scheidemann and A. Wetzel, Identification and characterization of flavonoids in the root exudate of Rohinia pseudoacacia. Trees 11 3 6 (1997). [Pg.219]

The plant is used by Malays to assuage body pains, and a decoction of roots is drunk as a protective remedy after childbirth. The pharmacological properties of this plant are unknown, but it is very probable that it elaborates aporphines and flavonoids as characterized in Oxymitra velutina (5). [Pg.173]

Ollila, F., Hailing, K., Vuorela, P., Vuorela, H. and Slotte, J. P. (2002). Characterization of flavonoid-biomembrane interactions. Archives of Biochemistry and Biophysics 399 103-108. [Pg.218]

Ferreres F, Llorach R and Gil-Izquierdo A. 2004. Characterization of the interglycosidic linkage in di-, tri-, tetra- and pentaglycosylated flavonoids and differentiation of positional isomers by liquid chromatogra-phy/electrospray ionization tandem mass spectrometry. J Mass Spectrom 39(3) 312—321. [Pg.82]

Colquhoun and Schumacher [98] have shown that y-linolcnic acid and eicosapentaenoic acid, which inhibit Walker tumor growth in vivo, decreased proliferation and apoptotic index in these cells. Development of apoptosis was characterized by the enhancement of the formation of reactive oxygen species and products of lipid peroxidation and was accompanied by a decrease in the activities of mitochondrial complexes I, III, and IV, and the release of cytochrome c and caspase 3-like activation of DNA fragmentation. Earlier, a similar apoptotic mechanism of antitumor activity has been shown for the flavonoid quercetin [99], Kamp et al. [100] suggested that the asbestos-induced apoptosis in alveolar epithelial cells was mediated by iron-derived oxygen species, although authors did not hypothesize about the nature of these species (hydroxyl radicals, hydrogen peroxide, or iron complexes ). [Pg.756]


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See also in sourсe #XX -- [ Pg.473 ]




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