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

Lepechinia urbaniana was investigated with respect to abietane diterpenes. In addition to four widespread diterpenes, two rare compounds were isolated and characterized.

Abietane diterpenes from Lepechinia urbaniana.

C24H30O4, Mr = 382.5, orthorhombic, P212121, a = 13.091 (2), b = 19.711 (1), c = 8.242 (1) A, V = 2126.7 (5) A3, Z = 4, Dx = 1.195 Mg m-3, lamba (Cu K alpha) = 1.54184 A, mu(Cu K alpha) = 0.56 mm-1, F(000) = 824, T = 295 K. Final R = 0.045 for 2446 unique reflections. The planar A ring is bent relative to the rest of the steroid skeleton. The B ring has a typical chair conformation and the C and D rings assume 13 beta,14 alpha-half-chair and 13 beta-envelope conformations, respectively. The conformation of the progesterone side chain is similar to the conformation observed in other 17 alpha-ester pregnanes: C16-C17-C20-O20 torsion angle -27.4(3) degrees.

Structure of (±)‐encecanescin

Flavonoids of Asanthus, a Segregate Genus of Brickellia

Dihydroglaucolide‐C, C21H28O8

Two flavones, hypolaetin 8-O-β-glucuronopyranoside 3″-O-sulfate and isoscutellarein 8-O-β-glucuronopyranoside 3″-O-sulfate, together with hypolaetin 8-O-β-glucuronopyranoside, kaempferol 3-O-α-rham...

https://journals.sagepub.com/doi/pdf/10.1177/1934578X0700201007

Tom J. Mabry

Papers

Abietane diterpenes from Lepechinia urbaniana.

Structure of (±)‐encecanescin

Flavonoids of Asanthus, a Segregate Genus of Brickellia

Dihydroglaucolide‐C, C21H28O8

Bioactive Flavone Sulfates of Abutilon indicum Leaves