Structure-antioxidant activity relationships of flavonoids and phenolic acids

http://amborella.net/2010PlantSystematics/DATA/3-24-APG%202003%20Bot%20J%20Linn%20Soc%20APGII.pdf

An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II

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

Antimicrobial activity of flavonoids

As far as is known every plant species produces some unique secondary compounds, often in remarkably large quantities. Although some of these alkaloids, terpenes, phenolics, etc. regulate vital biochemical processes at the cellular level, others mediate the interaction of the plant with other organisms and with other elements of the ecosystem. Some of the secondary chemical constituents appear to be relic compounds in that they are produced today in a wide variety of genetically related species by a genome which was present in the ancestral stock; others may be present in only a very few populations which are restricted to a unique ecosystem and appear to be of more recent origin and thus represent one type of ecochemistry.

Tom J. Mabry

Papers

The Role of the Secondary Plant Chemistry in the Evolution of the Mediterranean Scrub Vegetation

Sesquiterpene lactones and species relationships among the shrubby Ambrosia taxa

Marginatin, a new germacranolide from Vernonia species

The C-glycosylflavonoids of flax, Linum usitatissimum

Sulfated and non-sulfated flavonoids from Pluchea dioscoridis