The changes of antioxidant defense system caused by quercetin administration do not lead to DNA damage and apoptosis in the spleen and bone marrow cells of rats M.A. Papiez a, * , A. Cierniak b , W. Krzysciak c , M. Bzowska d , H.M. Taha e , A. Jozkowicz e , M. Piskula f a Department of Cytobiology and Histochemistry, Faculty of Pharmacy, Jagiellonian University, Medyczna 9 Street, 30-688 Krakow, Poland b Department of General Biochemistry, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, Krakow, Poland c Radioligand Laboratory, Faculty of Pharmacy, Jagiellonian University, Krakow, Poland d Department of Immunology, Jagiellonian University, Krakow, Poland e Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland f Department of Food Technology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Poland article info Article history: Received 8 March 2008 Accepted 11 June 2008 Keywords: Quercetin Antioxidant status Comet assay DNA damage Apoptosis abstract Quercetin may have the opposite effect, namely anti- as well as pro-oxidant. The aim of this study was to assess the results of quercetin anti- and/or pro-oxidant activity in the bone marrow and spleen cells of rats. The experimental rats were treated daily, with quercetin in a dose of 8 or 80 mg/kg b.w. by gavage for 40 days. The intracellular redox state in cells were assessed by measuring the ferric ion reducing anti- oxidant power (FRAP) level and malonodialdehyde concentration. HO-1 mRNA expression was examined with real-time PCR. The extent of DNA damage was determined by the alkaline-labile comet assay. A potential pro-apoptotic quercetin action was determined using the FITC-Annexin V kit. The quercetin and isorhamnetin concentrations in serum were analyzed by HPLC-ECD. MDA concentration and FRAP values, were significantly decreased in the spleen and bone marrow cells of rats treated with quercetin, in a dose of 80 mg/kg b.w. in comparison with the control rats; no significant changes were observed after quercetin was administered in a dose ten times as low. Treatment with quercetin dose-dependently upregulated the expression of HO-1 mRNA in the bone marrow cells. Quercetin administration to the rats did not induce either DNA damage or apoptosis in the examined cells. The results of our study prove that changes in the antioxidant state, caused by quercetin, do not lead to DNA damage or exert any pro-apop- totic activity in vivo. Ó 2008 Elsevier Ltd. All rights reserved. 1. Introduction Quercetin (3,3 0 ,4 0 ,5,7-pentahydroxyflavone) is a polyphenolic compound belonging to the flavonoid group widely distributed in plants. The richest sources of this bioflavonoid are onions, apples, black tea, blueberries and cranberries (Formica and Regelson, 1995). It is believed, that the quercetin is mainly responsible for the antioxidant activity of edible plants, which may protect against oxidative stress-related diseases such as: coronary heart disease, cancer, diabetes, stroke, and neurodegenerative disorders (Holl- man and Katan, 1999; Skibola and Smith, 2000). This flavonoid ex- erts its antioxidative effects in cells by chelating transition metal ions, catalyzing electron transport and scavenging free radicals (Hu et al., 1995). Quercetin owes its antioxidant properties to the 3- and 5-OH groups in A-ring, a catechol moiety of the B-ring and the 2,3-double bond in conjugation with a 4-oxofunction of a carbonyl group in the C-ring (Bors et al., 1990). In vitro and in vivo studies, have proven that antioxidant properties of querce- tin protect the DNA of normal cells against oxidative damage (Wil- ms et al., 2005; Kapiszewska et al., 2007). Quercetin is regarded as one of the most promising compounds in the class of flavonoids that might be applied in cancer chemotherapy, as a complemen- tary treatment to diminish the side effects of cytostatics. On the other hand, lately, certain controversies have arisen concerning the safety of antioxidant supplementation, because an increase in adult mortality was observed unexpectedly, after indi- viduals were treated with b-carotene, vitamin A and/or vitamin E (Bjelakovic et al., 2007). It is suspected that oxidative metabolites, 0278-6915/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.fct.2008.06.006 Abbreviations: FBS, fetal bovine serum; FITC, fluorescein isothiocyanate; FRAP, ferric ion reducing ability of plasma; GSH, glutathione; HO-1, heme oxygenase-1; TBA, thiobarbituric acid; TCA, trichloroacetic acid; TDC, the percentage of DNA in the tail; Q, quercetin; MDA, malonodialdehyde; PI, propidium iodide; PS, phos- phatidilserine; TBARS, thiobarbituric acid. * Corresponding author. Tel.: +48 12 658 82 21. E-mail address: mfpapiez@cyf-kr.edu.pl (M.A. Papiez). Food and Chemical Toxicology 46 (2008) 3053–3058 Contents lists available at ScienceDirect Food and Chemical Toxicology journal homepage: www.elsevier.com/locate/foodchemtox