Oxidative damage is involved in the formation of free radicals, which can cause various diseases. Oxidation was effected by the flash-quench technique In our experiment, samples containing Ru(phen)2dppz2+ (phen = 1,10-phenanthroline, dppz = dipyridophenazine), Co(NH3)5Cl 2+ histone protein, calf thymus DNA and either water or green tea were irradiated for 0-4 minutes with 442 nm light from a HeCd laser to effect guanine damage. The extent of crosslinking was determined by the chloroform extraction assay, whereby protein and DNA-protein crosslink is extracted away from unreacted DNA. Our results showed as the irradiation time increased, the absorption of free DNA decreased less in the presence of green tea, consistent with inhibition of DNA oxidation. In addition, agarose gel electrophoresis experiments of samples containing pUC19 DNA with tea that was stored at cold temperatures showed that the free DNA band persisted at dilutions of green tea up to 1:10000. While green tea was proven effective in vitro, the extent of antioxidative effects of green tea is studied in vivo studied in human melanoma cells (A375). A line of melanoma cells was cultured and propagated. By inducing oxidative damage with treatment and incubation for 0.5 hours with 200 μM H202, and preincubation for 4 hours with serial dilutions of green tea, the effectiveness of green tea in preventing oxidative damage was assessed using the Comet Assay.

Inhibition of DNA oxidative damage by green tea in vitro and in human melanoma cells

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.