Structure-antioxidant activity relationships of flavonoids and phenolic acids

Reactive oxygen species and antioxidant machinery in abiotic stress tolerance in crop plants

Flavonoids are nearly ubiquitous in plants and are recognized as the pigments responsible for the colors of leaves, especially in autumn. They are rich in seeds, citrus fruits, olive oil, tea, and red wine. They are low molecular weight compounds composed of a three-ring structure with various substitutions. This basic structure is shared by tocopherols (vitamin E). Flavonoids can be subdivided according to the presence of an oxy group at position 4, a double bond between carbon atoms 2 and 3, or a hydroxyl group in position 3 of the C (middle) ring. These characteristics appear to also be required for best activity, especially antioxidant and antiproliferative, in the systems studied. The particular hydroxylation pattern of the B ring of the flavonoles increases their activities, especially in inhibition of mast cell secretion. Certain plants and spices containing flavonoids have been used for thousands of years in traditional Eastern medicine. In spite of the voluminous literature available, however, Western medicine has not yet used flavonoids therapeutically, even though their safety record is exceptional. Suggestions are made where such possibilities may be worth pursuing.

The Effects of Plant Flavonoids on Mammalian Cells:Implications for Inflammation, Heart Disease, and Cancer

Estimation of total flavonoid content in propolis by two complementary colorimetric methods

Advances in flavonoid research since 1992.

The Systematic Identification of Flavonoids

As a follow-up to Dr Markham's highly successful publication, The Systematic Identification of Flavonoids (1970) co-authored with T.J. Mabry and M.B. Thomas, this book presents a more extensive, up-to-date and thorough guide to techniques used in flavonoid research. The techniques are discussed in the approximate order in which they are normally needed by the researcher and extensive cross-referencing is used throughout to guide the reader to the next recommended technique. Techniques covered include: chromatography, recrystallization, UV-visible spectroscopy, hydrolysis and product analysis, derivation degradation, H-NMR, C-NMR, and mass spectroscopy. The book, as a self-contained laboratory manual, contains extensive tabulations of reference data, discusses examples of a wide range of spectra, and features diagrams of flavonoid structures, reaction schemes and apparatus. Of special interest and importance to the beginner are the tables of trivial names, the list of sources of flavonoid standards and a discussion of the means for proving a new flavonoid identical to a known standard.

Techniques of flavonoid identification.

Separation and Quantification of Flavonoids A. Marston and K. Hostettmann Spectroscopic Techniques Applied to Flavonoids T. Fossen and O.M. Andersen Molecular Biology and Biotechnology of Flavonoid Biosynthesis K.M. Davies and K.E. Schwinn Flavonoids in Foods J.A.M. Kyle and G.G. Duthie Flavonoids in Wine V. Cheynier Dietary Flavonoids and Health - Broadening the Perspective M. Clifford and J.E. Brown Isoflavonoids and Human Health H. Wiseman Flavonoid Functions in Plants K.S. Gould and C. Lister Flavonoid-Protein Interactions O. Dangles and C. Dufour The Anthocyanins O.M. Andersen and M.Jordheim Flavans and Proanthocyanidins D. Ferreira, D. Slade, and J.P.J. Marais Flavones and Flavonols K.M. Valant-Vetschera and E. Wollenweber Flavone and Flavonol O-Glycosides C.A. Williams C-Glycosylflavonoids M. Jay, M.R. Viricel, and J.F. Gonnet Flavanones and Dihydroflavonols R.J. Grayer and N.C. Veitch Chalcones, Dihydrochalcones, and Aurones N.C. Veitch and R.J. Grayer Bi-, Tri-, Tetra-, Penta-, and Hexaflavonoids D. Ferreira, D. Slade, and J.P.J. Marais Appendix - Checklist for Isoflavonoids O.M. Andersen Index

FLAVONOIDS: Chemistry, Biochemistry and Applications

Purified anthocyanin extracts show strong antioxidant properties in vitro, but it is not known whether they can scavenge reactive oxygen in living cells. The oxidative responses in red and green portions of Pseudowintera colorata leaf laminae were compared by the real-time imaging of H2O2 in cells after mechanical injury. An oxidative burst was elicited almost immediately from chloroplasts in the palisade mesophyll, as evidenced using the fluorochromes dichlorofluorescein and scopoletin. H2O2 accumulated in green lamina regions for 10  min, and then decreased slowly. By contrast, red regions recovered rapidly, and maintained consistently low levels of H2O2. Infusion of cells with N-acetyl-l-cysteine accelerated the depletion of H2O2 from green regions. Wounded leaves ultimately developed a localized necrotic lesion and an intense anthocyanic band. The red regions were enriched in anthocyanins, flavonols, dihydroflavonols, and hydroxycinnamic acids. Only the anthocyanins were suitably located to account for the enhanced rates of H2O2 scavenging. The data support the hypothesis that red cells have elevated antioxidant capabilities in vivo.

https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-3040.2002.00905.x

Kenneth R. Markham

Papers

The Systematic Identification of Flavonoids

Techniques of flavonoid identification.

FLAVONOIDS: Chemistry, Biochemistry and Applications

The Systematic Identification of Flavonoids

Do anthocyanins function as antioxidants in leaves? Imaging of H2O2 in red and green leaves after mechanical injury