**6.2.1 Phytochemicals**

252 Selected Topics in DNA Repair

carotenoid also reduced the frequency of chromosomal breakage and micronucleus formation in the mouse bone marrow cells and peripheral blood. Astaxanthin, also showed antigenotoxic effects against cyclophosphamide in germ cell from male mice (Tripathi and

Several studies, including our own with colon cancer cells, have found that polyphenol rich plant extracts inhibit formation of SBs and 8-oxoGua induced by oxidantive agents (Ramos *et al.*, 2010a). Some plants, such as *Salvia officinalis L.* (sage), *Rosmarinus officinalis L.* (rosemary) and *Origanum vulgare L.* (oregano) have antioxidant properties that confer protection against oxidative DNA damage in colon cells as demonstrated by Aherne et al.,

Green tea is rich in polyphenolic antioxidants and their effects on health are the subject of several studies. Green tea decreased DNA oxidation in lymphocytes, colonocytes and hepatocytes when rats ingested 6.5 mg/kg bw per day, 5 days of tea extract (Kager et al., 2010). Evidences of genoprotective effects of green tea appear not only from in vitro and in vivo studies, but also from human supplementation trials. Human lymphocytes isolated from healthy volunteers that took 2 x 150 ml/d of 1% (w/v) green tea showed a decrease of basal oxidation-induced DNA damage with and without FPG enzyme (Han *et al.*, 2011). One of the main constituents of green tea is (-)-epigallocatechin-3-gallate (EGCG) that could be responsible for their beneficial effects. In human peripheral leucocytes treatement with low EGCG concentrations (2-100µM) decreased both bleomycin-induced breaks and

Apple is one of the most consumed fruit, therefore is an important source of polyphenols in humans. Their chemoprotective effects have been shown in vitro and in vivo studies (Koch et al., 2009; Veeriah et al., 2008). Apple juice has been found to possess antioxidant and antiproliferative activities as well as the ability to increase the expression of phase II gene glutathione S-transferase T2 (GSTT2) in human colon cells (Petermann et al., 2009). Apple extract can also protect against oxidative-induced DNA damage in human colon cells, such as LT97 (Miene (Miene *et al.*, 2009), HT29, HCT115 and CaCo-2 cells (McCann et al., 2007; Schaefer et al., 2006). Also, grape juices exhibit antigenotoxic activity (Dani et al., 2009). The anticarcinogenic properties of olive oil have been attributed to the presence of phenolic compounds. Fabiani et al., (2008) reported that some of its isolated compounds (e.g. hydroxytyrosol, [3,4-dyhydroxyphenyl-ethanol (3,4-DHPEA)] and a complex mixture of phenols extracted from virgin olive oil) protected against H2O2 in human peripheral blood mononuclear cells and promyelocytic leukemia cells (HL60). These results have a great impact not only because of the high level of protection observed (between 80 and 90%) but also because, according to the authors, the concentrations tested could easily be reached

Annatto is a native shrub from Tropical America, whose seeds are a rich source of carotenoids, such as bixin, norbixin and phytoene and have antigenotoxic effects against

Results from human intervention trials have demonstrated the protective effect of isolated compounds as well as fruits and vegetables in peripheral lymphocytes. Pool-Zobel *et al.*, (1997) showed a decrease in pyrimidine oxidation during supplementation with carrot juice. Porrini and Riso, (2000) reported that supplementation with tomato that is rich in lycopene,

endonuclease III sensitive sites (Glei and Pool-Zobel, 2006).

with normal intake of olive oil.

oxidative DNA damage (Kovary et al., 2001).

Jena, 2008).

(2007).

**6.1.3 Whole foods** 

Dolara et al., (2005) reported that red wine polyphenols (50 mg/kg) administered to F344 rats for 16 weeks inhibited colon carcinogenesis induced by AOM or DMH. Wine polyphenols also decreased basal level of DNA oxidative damage of the colon mucosa. Supplementation of Wistar male rats with resveratrol showed to significantly decrease DMH-induced leukocyte DNA damage. In this study, an increase of levels of enzymic and non-enzymic antioxidant defense and a decrease in the extent of lipid peroxidation markers were also observed (Sengottuvelan *et al.*, 2009). Other chemopreventive agents, such as quercetin, rutin, curcumin, silymarin, lycopene and farnesol, with antioxidant properties, have been found to inhibit DMH- and AOM-induced colon carcinogenesis and DNA damage in animal models (Kim et al., 1998; Volate *et al.*, 2005). Lupeol, a pentacyclic triterpene present in mango, also protected against DMBA induced DNA alkylation damage in Swiss albino mice (Nigam *et al.*, 2007).
