Ellagic acid, a natural polyphenol protects rat peripheral blood lymphocytes against nicotine-induced cellular and DNA damage in vitro: with the comparison of N-acetylcysteine.
ABSTRACT The present work is aimed at evaluating the protective effect of ellagic acid (EA), a natural polyphenolic compound that is widely distributed in fruits and nuts against nicotine-induced toxicity in rat peripheral blood lymphocytes. The effect of EA against nicotine toxicity was compared with N-acetylcysteine (NAC), a well-known antioxidant. Lymphocytes were exposed to nicotine at the doses of 0.125, 0.25, 0.5, 1, 2, 3 and 4 mM for 1h in culture media. Thiobarbituric acid reactive substances (TBARS), a lipid peroxidative marker and reduced glutathione (GSH), as indicative of endogenous antioxidant status were analyzed to fix the optimum dose. The lowest concentration eliciting significant damage was 1 mM nicotine and maximum damage was observed with 3 mM concentration, as evidenced by increased levels of TBARS and decreased levels of GSH. Hence, the test concentration was fixed at 3 mM nicotine. To establish most effective protective support we used five different concentrations of EA (10, 50, 100, 150 and 300 microM) against 3 mM nicotine. A dose-dependent inhibitory effect was observed with all doses of EA. Maximum protection was observed at the dose of 100 microM EA. So, 100 microM dose was used for further studies. We have tested five different concentrations of NAC-0.25, 0.5, 1, 2 and 4 mM to elucidate the optimum protective dose against nicotine toxicity. One millimolar NAC showed a significant protection against nicotine toxicity. Protective effect of EA against nicotine toxicity was elucidated by analyzing the lipid peroxidative index, viz., TBARS, hydroperoxides (HP) and endogenous antioxidant status, viz., superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), Vitamins A, E and C. DNA damage and repair were assessed by using alkaline single-cell microgel electrophoresis (Comet assay) and micronucleus assay. There was a significant increase in the levels of lipid peroxidative index, severity in DNA damage and micronuclei number in nicotine-treated group, which was positively modulated by EA treatment. Antioxidant status was significantly depleted in nicotine-treated group, which was effectively restored by EA treatment. The protection of EA against nicotine toxicity was equally effective to that of NAC. EA and NAC treatment alone did not produce any damage to the normal lymphocytes at their effective doses. These findings suggest the potential use and benefit of EA as a modifier of nicotine-induced genotoxicity.
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ABSTRACT: Phenolics are broadly distributed in the plant kingdom and are the most abundant secondary metabolites of plants. Plant polyphenols have drawn increasing attention due to their potent antioxidant properties and their marked effects in the prevention of various oxidative stress associated diseases such as cancer. In the last few years, the identification and development of phenolic compounds or extracts from different plants has become a major area of health- and medical-related research. This review provides an updated and comprehensive overview on phenolic extraction, purification, analysis and quantification as well as their antioxidant properties. Furthermore, the anticancer effects of phenolics in-vitro and in-vivo animal models are viewed, including recent human intervention studies. Finally, possible mechanisms of action involving antioxidant and pro-oxidant activity as well as interference with cellular functions are discussed.Molecules 01/2010; 15(10):7313-52. · 2.43 Impact Factor
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ABSTRACT: Human papillomavirus (HPV) is the causative factor in the development and progression of cervical cancers in >97% of the cases, although insufficient. Epidemiological studies suggest an elevated risk of cervical cancer for cigarette smokers; therefore, we examined cigarette smoke-induced DNA damage and repair in HPV16-transformed human ectocervical cells (ECT1/E6 E7). Cells were treated with cigarette smoke condensate (CSC) for 72 h to assess the formation of single- and double-strand DNA breaks, measured by alkaline and neutral single cell gel electrophoresis assays, respectively. The mean tail length of cells with single-strand breaks was increased by 1.8-, 2.7- and 3.7-fold (p<0.001) after treatment with 4, 8 and 12 microg/ml CSC, respectively. The tail length with double-strand breaks was also increased dose-dependently. These results were further supported by measurement of the mean tail moment: the increase in both single- and double-strand breaks were much more pronounced with increasing concentration of CSC, by up to 23.5-fold (p<0.0001 for both assays). To examine the DNA repair, cells were treated with CSC for 72 h, followed by CSC withdrawal and re-incubation of the cells with fresh medium for 24, 48, or 72 h. Both single- and double-strand DNA breaks were removed during the initial 24 h but no further removal of the damage was observed. Up to 80% of residual single- and double-strand DNA breaks (p<0.05) were found to persist at all CSC concentrations examined. Ellagic acid, a known antioxidant and free-radical scavenger, was found to significantly inhibit DNA breaks induced by CSC. Thus, free radicals may be a plausible source of CSC-induced DNA damage. These data show that CSC-mediated DNA strand breaks are highly persistent, and suggest that persistence of cigarette smoke-associated DNA damage in the presence of HPV infection may lead to increased mutations in cervical cells and ultimately higher cancer risk.International Journal of Oncology 12/2009; 35(6):1297-304. · 2.66 Impact Factor
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ABSTRACT: The present study is designed to investigate the neuroprotective effect of a kind of phlorotannins, diphlorethohydroxycarmalol (DPHC) isolated from Ishige okamurae against hydrogen peroxide (H(2)O(2))-induced oxidative stress in murine hippocampal neuronal cells, HT22. H(2)O(2) treatment induced neurotoxicity, whereas DPHC prevented cells from H(2)O(2)-induced damage then restoring cell viability was significantly increased. DPHC slightly reduced the expression of Bax induced by H(2)O(2) but recovered the expression of Bcl-xL as well as caspase-9 and -3 mediated PARP cleavage by H(2)O(2). Intracellular reactive oxygen species (ROS) and lipid peroxidation was overproduced as the result of the addition of H(2)O(2); however, these ROS generations and lipid peroxidation were effectively inhibited by addition of DPHC in a dose-dependent manner. Moreover, DPHC suppressed the elevation of H(2)O(2)-induced Ca(2+) release. These findings indicate that DPHC has neuroprotective effects against H(2)O(2)-induced damage in neuronal cells, and that an inhibitory effect on ROS production may contribute to the underlying mechanisms.Applied biochemistry and biotechnology 03/2012; 166(6):1520-32. · 1.94 Impact Factor