Mohammad Athar

Bio: Mohammad Athar is an academic researcher from University of Alabama at Birmingham. The author has contributed to research in topics: Oxidative stress & Glutathione. The author has an hindex of 63, co-authored 329 publications receiving 14384 citations. Previous affiliations of Mohammad Athar include Case Western Reserve University & Columbia University.

Induction of oxyradicals by arsenic: Implication for mechanism of genotoxicity

Abstract: Although arsenic is a well-established human carcinogen, the mechanisms by which it induces cancer remain poorly understood We previously showed arsenite to be a potent mutagen in human–hamster hybrid (AL) cells, and that it induces predominantly multilocus deletions We show here by confocal scanning microscopy with the fluorescent probe 5′,6′-chloromethyl-2′,7′-dichlorodihydrofluorescein diacetate that arsenite induces, within 5 min after treatment, a dose-dependent increase of up to 3-fold in intracellular oxyradical production Concurrent treatment of cells with arsenite and the radical scavenger DMSO reduced the fluorescent intensity to control levels ESR spectroscopy with 4-hydroxy-2,2,6,6-tetramethyl-1-hydroxypiperidine (TEMPOL-H) as a probe in conjunction with superoxide dismutase and catalase to quench superoxide anions and hydrogen peroxide, respectively, indicates that arsenite increases the levels of superoxide-driven hydroxyl radicals in these cells Furthermore, reducing the intracellular levels of nonprotein sulfhydryls (mainly glutathione) in AL cells with buthionine S-R-sulfoximine increases the mutagenic potential of arsenite by more than 5-fold The data are consistent with our previous results with the radical scavenger DMSO, which reduced the mutagenicity of arsenic in these cells, and provide convincing evidence that reactive oxygen species, particularly hydroxyl radicals, play an important causal role in the genotoxicity of arsenical compounds in mammalian cells

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

Abstract: 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.