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

New antioxidants, cassumunarins A, B, and C, were isolated from the rhizomes ofZingiber cassumunar, and the structures were determined by spectroscopic methods to be complex curcuminoids. The antixidant efficiency of cassumunarins was determined by inhibitory activity of autoxidation of linoleic acid in a buffer-ethanol system. The anti-inflammatory effect was measured by inhibition of edema formation on mouse ear induced by 12-O-tetradecanoylphorbol-13-acetate. Both types of activities were stronger for the cassumunarins than for the curcumin.

Isolation and structure determination of cassumunarins A, B, and C: New anti-inflammatory antioxidants from a tropical ginger,Zingiber cassumunar

Sesquiterpene lactones : chemistry, NMR and plant distribution

Sunflower moth, Homoeosoma electellum (Hulst), is a major pest of cultivated sunflower, Helianthus annuus L., in North America. Thirty perennial and 11 annual species of Helianthus and several cultivars of sunflower were evaluated for resistance to H. electellum larvae. Larvae feeding on sunflower inflorescences in laboratory and greenhouse bioassays performed significantly poorer on 14 Helianthus species than on the cultivar hybrid ‘894’. In in vitro bioassays, nonpolar extracts from H. annuus, Helianthus argophyllus Torrey & Gray, Helianthus ciliaris DC, and Helianthus petiolaris ssp. petiolaris Nuttall caused significant lengthening of larval stadia and retarded larval growth. Larvae feeding on purified sesquiterpene lactones and diterpenes from H. argophyllus , H. ciliaris, Helianthus angustifolius L., and Helianthus mollis Lambert in a wheat-germ diet at 0.1–1.0% concentration experienced high mortality, retarded growth, and an extended developmental period. The sesquiterpene lactone 8 β-sarracinoyloxycumambranolide isolated from glandular trichomes on anthers of Helianthus maximiliani Schrader was toxic to young larvae in bioassays. Two mechanisms giving Helianthus resistance to seed injury by larvae of H. electellum are terpenes in the florets and phytomelanin in the pericarp of seeds.

Terpenes of Wild Sunflowers (Helianthus): An Effective Mechanism Against Seed Predation by Larvae of the Sunflower Moth, Homoeosoma electellum (Lepidoptera: Pyralidae)

Tom J. Mabry

Papers

Isolation and structure determination of cassumunarins A, B, and C: New anti-inflammatory antioxidants from a tropical ginger,Zingiber cassumunar

Sesquiterpene lactones : chemistry, NMR and plant distribution

Terpenes of Wild Sunflowers (Helianthus): An Effective Mechanism Against Seed Predation by Larvae of the Sunflower Moth, Homoeosoma electellum (Lepidoptera: Pyralidae)

Daucane esters from Ferula communis subsp. communis

Tetrachyrin, a new rearranged kaurenoid lactone, and diterpene acids from Tetrachyron orizabaensis and Helianthus debilis