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

Antioxidants, Oxidative Damage and Oxygen Deprivation Stress: a Review

Review article: free radicals, antioxidants and human disease: where are we now?

Free radicals, antioxidants, and human disease: where are we now?

(2003). Hepatotoxicity and Mechanism of Action of Haloalkanes: Carbon Tetrachloride as a Toxicological Model. Critical Reviews in Toxicology: Vol. 33, No. 2, pp. 105-136.

Hepatotoxicity and mechanism of action of haloalkanes: carbon tetrachloride as a toxicological model.

Mechanisms of carbon tetrachloride toxicity

Publisher Summary Like many other substances, naturally occurring lipids exhibit simple end absorption in ultraviolet light as the wavelength is lowered toward 200 nm. The spectra of a variety of organic molecules containing conjugated dienes, however, are characterized by intense absorption, the so-called K band, which may range, with respect to peak absorption, from 215 to 250 nm, depending on nearby substituent groups. Ultraviolet spectrophometric detection of conjugated dienes has been used for many years in the food industry for the detection of autoxidized lipids. The method appears to have been applied for the first time to the problem of liver cell lipid peroxidation of toxigenic origin in 1966 and has been widely used since. For a variety of pathological processes, the question has been raised whether peroxidative decomposition of membrane lipids has occurred in vivo. A second principle of the method recognizes that for whole-animal studies involving possible lipid peroxidation, the fraction of endogenous lipids actually peroxidized may not only be low, but the process of lipid peroxidation may be confined to a particular subcellular structure.

Eric A. Glende

Papers

Mechanisms of carbon tetrachloride toxicity

Spectrophotometric detection of lipid conjugated dienes.

Pathological mechanisms in carbon tetrachloride hepatotoxicity.

Critical role of lipid peroxidation in carbon tetrachloride-induced loss of aminopyrine demethylase, cytochrome P-450 and glucose 6-phosphatase.

Carbon tetrachloride-induced protection against carbon tetrachloride toxicity. The role of the liver microsomal drug-metabolizing system.