**6.1.2 Carotenoids**

250 Selected Topics in DNA Repair

Fig. 2. Classification of phytochemicals and the main natural compounds in each group.

antigenotoxic effects against oxidative DNA damage in several cell models.

induced DNA damage (Prasad *et al.*, 2009).

consumption led to a decrease of oxidative DNA damage and BPDE-DNA adduct levels by 41% and 11%, respectively, although the results were not statistically significant. Increases in the total antioxidant capacity of plasma and in plasma quercetin content were observed. Others flavonoids, such as luteolin (Cai *et al.*, 1997; Horvathova et al., 2005; Lima et al., 2006; Min and Ebeler, 2008; Ramos *et al.*, 2010b), rutin (Moon et al., 2006; Ramos et al., 2008), genistein (Cai et al., 1997), catechin and epicatechin (Kanupriya et al., 2006), showed

In an ex vivo study, lymphocytes from three healthy subjects were pre-incubated with several dietary antioxidants. Quercetin and caffeic acid ( a phenolic acid) protected against H2O2 induced DNA damage, however in this study no effect was observed when cells were treated with catechin, epicatechin, catechin gallate and epicatechin gallate (Szeto and Benzie, 2002). Besides quercetin and rutin, we reported that ursolic acid (a triterpenoid) protect against DNA damage induced by tert-butyl hydroperoxide (t-BHP) in HepG2 cells (Ramos et al., 2008). Other reports showed that ursolic acid and/or luteolin protect DNA from damage induced by H2O2, t-BHP or AZT (3\_-azido-3\_-dideoxythymidine) in several cell lines, such as leukemic cells, HEI-OC1 auditory cells and PC12 cells (Horvathova et al., 2003; Horvathova *et al.*, 2004; Ovesna *et al.*, 2006; Yu et al., 2009; Noroozi *et al.*, 1998; Silva *et al.*, 2008). Rosmarinic acid (RA), reduced the frequency of micronuclei and the extent of DNA damage induced by doxorubicin in V79 cells (Furtado *et al.*, 2009). Caffeic acid (3,4-dihydroxy cinnamic acid), also a dietary phenolic compound, showed a photoprotective effect (Devipriya *et al.*, 2008; Benkovic et al., 2009). Human blood lymphocytes irradiated with UVB (280-320) after pretreatment with caffeic acid exhibited lower levels of lipid peroxidation markers such as thiobarbituric acid reactive substance (TBARS) and lipid hydroperoxide (LPH) and also a decrease of UVB-

Tomato is one of the main sources of lycopene, a carotenoid with antioxidant properties. Pretreatment of rat hepatocytes with lycopene (1.86, 9.31 and 18.62 µM) in culture, showed a significant decrease in the levels of TBARS and DNA damage induced by gamma-radiation. Antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), as well as, the levels of GSH, vitamins A, E, C, increased significantly when hepatocytes were pretreated with the carotenoid (Srinivasan et al., 2007). At physiological concentrations (0.3-10 µM) lycopene and beta-carotene also protect Chinese hamster lung fibroblasts against DNA damage induced by 3-morpholinosydnonimine (SIN-1) (Muzandu et al., 2006). In a human intervention study, healthy volunteers were submitted to a supplementation with lycopene during 8 weeks. Consumption of lycopene decreased oxidative DNA damage in lymphocytes and urinary 8-hydroxy deoxoguanosine levels when compared with the basal levels (Devaraj et al., 2008). Also, Zhao *et al.*, (2006) evaluated the protective effect of lycopene and others carotenoids against DNA damage in humans. Here, thirty-seven healthy, nonsmoking postmenopausal women consumed for 56 days a daily dose of mixed carotenoids (lycopene, lutein and beta-carotene; 4 mg each), 12 mg of a single carotenoid (lycopene, lutein or beta-carotene), or placebo. At the end the lymphocytes were isolated and DNA damage measured by comet assay. The results showed that all groups that consumed carotenoids had significantly lower endogenous DNA damage than that found on baseline measurements. No differences were found in placebo group. Lutein also decreased DNA damage induced by cisplatin in mice when evaluated by comet assay and increased GSH levels when compared with a negative control group (Serpeloni *et al.*, 2010). Lorenzo *et al.*, (2009) reported that β-cryptoxanthin at low concentrations, close to those found in plasma, protects Caco-2 and HeLa cells from oxidative DNA damage induced by H2O2 or by visible light in the presence of a photosensitizer. Consumption of βcarotene decreased the number of strand breaks induced by H2O2 in lymphocytes (Panayiotidis and Collins, 1997).

Pre-treatment with astaxanthin, a red carotenoid used as a dietary additive, at 12.5, 25 and 50 mg/kg/day for 5 days before cyclophosphamide treatment resulted in the amelioration of antioxidant defenses (glutathione and superoxide dismutase) in the liver and decreased DNA damage evaluated by standard comet assay and using specific-enzymes (FPG and EndoIII) in bone marrow cells and peripheral blood lymphocytes isolated from mice. This

DNA Damage Protection and Induction of Repair

by Dietary Phytochemicals and Cancer Prevention: What Do We Know? 253

increase protection against H2O2-induced DNA damage in lymphocytes. Also a diet rich in fruit and vegetables for 14 days showed a DNA protection from oxidative damage in lymphocytes (Thompson et al., 1999). Broccoli intake also decreases oxidative DNA damage in smokers and nonsmokers (Riso *et al.*, 2009). In a recent study, Sprague-Dawley rats fed with a wild-blueberry diet or a control diet for four or eight weeks were used to assess the effect of the consumption of this fruit on the resistance to H2O2-induced DNA damage. After treatment period, lymphocytes were exposed, ex vivo, to H2O2 and it was observed that wild-blueberry diet did not change antioxidant capacity in lymphocytes after eight weeks of treatment, but increased DNA protection against oxidative damage (Del Bo et al., 2010). Dulebohn et al., (2008) using the same animal model, reported that blueberries consumption for 3 weeks increase GST activity and decrease oxidative DNA damage in the liver. However, contrarily to in vitro studies, blueberries consumption did not significantly

As described above, many isolated compounds and some plants showed genoprotective effects in several experimental models, however it is important to keep in mind that these dietary agents can also induce DNA damage in certain conditions. The balance between the genoprotective and genotoxic effects of dietary agents is dependent on their concentration,

Alkylation of DNA can be an important initial step in cancer formation. High levels of alkylating damage have been found in human colorectal DNA where high incidence of tumours have been observed (Hall *et al.*, 1991; Povey *et al.*, 2000). To assess antigenotoxic effects of diet against alkylating damage, several experimental models have been developed. Among them, colon tumours induction in rodent models, with carcinogenic chemicals such as 1,2-dimethylhydrazine (DMH) or azoxymethane (AOM) are the most used, and they are

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

Many whole foods and plant crude extracts have also been found to protect against alkylating damage. The water extract of *Salvia officinalis* prevent formation of aberrant crypt foci (ACFs, a pre-carcinogenic lesion) induced by AOM in rat colon and also protected DNA

believed to be representative of colon carcinogenesis in humans (Barth et al., 2005).

increase phase II enzyme activities in short-term supplementation times.

incubation period and types of cells (Rusak et al., 2010).

**6.2.1 Phytochemicals** 

**6.2.2 Whole foods** 

in Swiss albino mice (Nigam *et al.*, 2007).

**6.2 Effect of diet on prevention of alkylating DNA damage** 

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 Jena, 2008).
