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Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The extent of DNA damage and lipid peroxidation induced by myricetin, a polyphenolic flavonoid, were studied in isolated rat liver nuclei under aerobic conditions. Myricetin induced significant (P < 0.05) concentration-dependent nuclear DNA degradation concurrent with lipid peroxidation; these effects were enhanced by iron (III) or copper (II). Catalase, superoxide dismutase (SOD), mannitol and sodium azide did not inhibit myricetin-induced nuclear DNA damage in the presence of iron (III) or copper (II). However, all of these antioxidants stimulated myricetin-induced DNA damage in the presence of copper (II). Lipid peroxidation induced by myricetin was significantly inhibited only by SOD in the presence of copper (II), whereas it was enhanced by catalase and sodium azide in the presence of iron (III). These results demonstrate the pro-oxidant properties of polyphenolic flavonoids, which are generally considered to be antioxidants and anticarcinogens, and suggest a dual role for these flavonoids in mutagenesis and carcinogenesis.
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PMID:Interactions of flavonoids, trace metals, and oxygen: nuclear DNA damage and lipid peroxidation induced by myricetin. 833 Mar 5

In the present study the effects of three flavonoids on the repair of H2O2-induced DNA strand breaks were investigated in Caco-2, Hep G2, and V79 cells. At the concentrations used, myricetin, quercetin, rutin, and H2O2 did not significantly affect cell viability in all the cell lines. Catalase activity was measured in V79 cells and was found to be considerably lower than activities previously measured in Caco-2 and Hep G2 cells. Cells were exposed to 50 microM H2O2 for 0.5 hour at 37 degrees C. After treatment, DNA strand break repair in H2O2-treated cells was monitored at various time points over a 48-hour period using the alkaline single-cell gel electrophoresis assay. Caco-2 cells repaired faster than Hep G2 cells, which repaired considerably faster than V79 cells. Preincubation with 50 microM quercetin for 24 hours significantly decreased the extent of H2O2-induced DNA single-strand breaks throughout repair time points in Caco-2 cells (p < 0.05), but not in Hep G2 cells. Myricetin (50 microM) and rutin (50 microM) had no effect on repair in Caco-2 and Hep G2 cells. Preincubation for 10 hours with quercetin and rutin, but not myricetin, significantly decreased the initial extent of DNA damage induced by H2O2 in V79 cells (p < 0.05). However, from the results of this study, none of the three flavonoids increased the rate of repair of strand breaks in any of the cell types.
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PMID:Lack of effect of the flavonoids, myricetin, quercetin, and rutin, on repair of H2O2-induced DNA single-strand breaks in Caco-2, Hep G2, and V79 cells. 1134 Oct 35

Colorectal cancer (CRC) is a leading cause of cancer mortality especially in the western world. The incidence of CRC in Asia is now increasing at an alarming rate from the previously negligible levels. The pathogenesis of CRC is a multistep process wherein pre cancer lesions accumulate in the mucosal cells finally resulting in cancer. Diet plays an important role in its aetio-pathogenesis--the high levels of dietary fat correlates to the increased incidence of CRC. This along with hereditary, environmental factors and singular lack of physical exercise provides a potent combination in its pathogenesis. Besides CRC isfrequently associated with persistent oxidative stress which results not only in DNA damage but also in mutation of cancer related genes besides the epigenetic silencing of the tumor suppressor gene. An important approach in the prevention of cancer is chemoprevention. Variety of plant products have been found to be highly effective in retarding the pathogenesis of the colorectal cancer. Myricetin is a well known bioflavonoid that is claimed to have anti cancer action particularly in colorectal cancer. Myricetin not only brought about significant decrease in the incidence of number of tumor bearing rats but also the tumor incidence. Myricetin supplementation significantly reduced liver TBARS. Further the anti oxidant enzymes like Catalase, Glutathione peroxidase and GSH were significantly rejuvenated following myricetin supplementation in a dose dependent manner. The fecal and colonic bacterial enzyme activity was also significantly decreased with the supplementation of myricetin 50 and 100 mg/kg. There was no additional benefit with the supplementation of 200 mg/kg of myricetin.
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PMID:Effect of myricetin on 1,2 dimethylhydrazine induced rat colon carcinogenesis. 2169 17