Ferric Ion Reducing Antioxidant Power Values Research Articles

Characterization and antioxidant activity of peel extracts from three varieties of citrus sinensis

High volume of postharvest materials including peels from citrus fruits is periodically generated, which contributes to environmental pollution. Investigating the chemical composition cum antioxidant property of these ‘wastes’ would be instructive in achieving value addition in the food and pharmaceutical value chain. On this premise, this study carried out phytochemical screening and antioxidant activity of three (3) commonly cultivated citrus varieties namely Citrus sinensis ‘valencia’, Citrus sinensis ‘washinton’ and Citrus sinensis ‘thompson navel’. The peels were extracted using ethanol and hexane in a Soxhlet extractor and thereafter subjected to phytochemical and Gas Chromatography/Mass Spectrometry (GC/MS) analyses, ferric ion reducing antioxidant power (FRAP), hydrogen peroxide scavenging and cupric ion reducing antioxidant capacity (CUPRAC) assays to evaluate their antioxidant potentials. Results show that Citrus sinensis peel extracts contain alkaloids, flavonoids, phenols, phytosterols, diterpenes, tannins and glycosides. GC/MS analysis identified about 48 compounds in each extract; with the predominant bioactive compounds being limonene (16.5%), ascorbic acid (17.7%), stearic acid (26.3%), linalool (4.7%), linoleic acid (16.18%), palmitic acid (15.23%), pentadecyclic acid (1.1%). Ethanol and hexane extracts of Valencia exhibited higher FRAP (9.09 ± 0.13) and CUPRAC (2.04 ± 0.06) values while the ethanol extract of Ibadan sweet demonstrated greater hydrogen peroxide scavenging activity (1.39 ± 0.00). Citrus peels are rich in bioactive compounds with excellent antioxidant activity and may serve as potential sources of natural antioxidants for food products or pharmaceutical formulations.

Protective effects of Quercus salicina blume leaves aqueous extracts against cadmium-induced oxidative stress and cell cytotoxicity in HK-2 cells

Background: Quercus salicina Blume is an evergreen plant growing southern parts of Korea and Japan, and has been used for the treatment of dysentery, dermatitis, and hemorrhage from possible effects such as anti-inflammatory, anti-endemic and litholytic activities. We investigated the underlying mechanisms of Quercus salicina Blume leaf extracts (QS) protection against cadmium treatment utilizing human kidney origin HK-2 cells.Methods: To ascertain the functional constituents of the hot water-extracted QS, we conducted analyses to determine the total phenolic and flavonoid contents. Subsequently, the antioxidant activity was assessed using DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric ion reducing antioxidant power) methods. After treating HK-2 cells with QS and Cd, we confirmed the production of reactive oxygen species (ROS) and the expression of related proteins through western blotting. This investigation aimed to assess the antioxidant and anti-apoptotic effects of QS against cadmium-induced oxidative stress. Results: QS exhibited strong antioxidative potential, since the samples exhibited significantly high DPPH and FRAP values. Upon exposure of HK-2 cells to cadmium, inducing oxidative stress, the application of QS effectively reinstated cellular antioxidative functions, leading to an augmentation in cell viability. Notably, the presence of QS attenuated the heightened expression of oxidative marker enzymes induced by cadmium treatment, including SOD (superoxide dismutase) 1, catalase, Nrf-2, and Heme-oxygenase. The apparent disappearance of the apoptotic bodies indicates a potential apoptosis controlling effect of QS. Furthermore, the considerable increase in sub-G1 phase with the addition of cadmium was diminished under QS treatment indicating the ability of QS to reduce the degree of apoptosis related cell cycle phase. The apoptotic quenching effects of QS were accompanied by the downregulation of pro-apoptotic protein Bax and up-regulation of pro-apoptotic Bcl-2. The examination of cleaved caspase-9 and caspase-3 has provided evidence that the pronounced anti-apoptotic activities observed in cadmium-challenged HK-2 cells significantly diminished in the presence of QS. Conclusions: QS is a highly effective antioxidant and reduces cell cytotoxicity caused by cadmium through antioxidant functions and anti-apoptotic capabilities.Keywords: Quercus salicina Blume leave, cadmium, antioxidant, anti-apoptosis

Season affects three insufficiently studied seaweed species (Bifurcaria bifurcata, Codium sp., Ericaria selaginoides): bioactivity alterations

ABSTRACT The biological activity and nutraceutical potential of two brown seaweed species (Bifurcaria bifurcata, Ericaria selaginoides) and one green seaweed (Codium sp.) were evaluated taking seasonal effects into account. The phenolic content of B. bifurcata was higher than those of the other two species regardless of season, 10.13–11.01 mg Gallic Acid Equivalent (GAE) g–1 dw seaweed. The ethanol extracts of B. bifurcata were more antioxidant as measured by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) technique than the equivalent extracts from E. selaginoides, 0.428–0.442 mg Ascorbic Acid Equivalent (AA Eq) g dw seaweed–1 vs 0.338–0.361 mg AA Eq g dw seaweed–1. Regarding Ferric Ion Reducing Antioxidant Power (FRAP), the highest activity was measured in Codium sp. extracts and no difference was detected between B. bifurcata and E. selaginoides. The 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) results differed from the FRAP values in that the ethanol extracts from Codium sp. were less antioxidant as measured by ABTS than those of the other two species. Summer E. selaginoides extracts were more antioxidant. The most anti-inflammatory extract was obtained from E. selaginoides harvested in Summer, exhibiting 94.2 ± 4.0% inhibition of cyclooxygenase-2 (COX-2). The extracts from Codium sp. had the lowest activity, 13.6–15.5%. For both B. bifurcata and E. selaginoides, Summer extracts were more anti-inflammatory than Winter extracts.

The physicochemical properties and immunomodulatory activities of gardenia yellow pigment from gardenia fruit

• High temperature, acid, alkali, Fe 3+ , and ultraviolet radiation greatly affected the stability of gardenia yellow pigment (GYP). • GYP exhibited good antioxidant properties. • The immunomodulatory activity of GYP in RAW264.7 cells were confirmed. • GYP can be developed as a potential antioxidant and immunomodulator in functional foods. Gardenia yellow pigment (GYP) was isolated from Gardenia jasminoides fruit. GYP possess various beneficial biological activities, but its immunomodulatory activity remains incompletely known. In present study, we evaluated the stability of GYP at different temperature, light, pH, and metal ions firstly. The antioxidant capacity of GYP was then evaluated by 1, 1-Diphenyl-2-picrylhydrazyl radical (DPPH), 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), Ferric ion reducing antioxidant power (FRAP), and Hydroxyl radicals. Finally, the immunomodulatory activities and underlying mechanism of GYP were determined using RAW264.7 cells. The results indicated that the stability of GYP was greatly affected by higher temperature (60–100 ℃), ultraviolet radiation, acid, alkali, and Fe 3+ . Furthermore, GYP exhibited strong antioxidant activity, and the IC 50 values of DPPH, ABTS, and Hydroxyl radicals were 0.44, 0.07, and 0.09 mg/mL, respectively. Meanwhile, FRAP value was 1.65 ± 0.04 mM FeSO 4 at the GYP concentration of 0.11 mg/mL. The cell experiment exhibited that GYP significantly enhanced the proliferation and phagocytosis of macrophages. It also increased the secretion of NO, TNF-α, IL-10, and COX-2, and promoted the activation of transcription factor (NF-κB) in RAW264.7 cells. Furthermore, GYP promoted the phosphorylation of P13K and Akt in RAW264.7 cells, indicating that GYP might exert its immunoregulatory effects through modulation of PI3K/Akt pathway. Overall, the results of this study suggest that GYP can be used as a natural antioxidant and immunomodulator in the fields of functional foods.

Effects of postharvest irradiation and superfine grinding wall disruption treatment on the bioactive compounds, endogenous enzyme activities, and antioxidant properties of pine (Pinus yunnanensis) pollen during accelerated storage

Effects of irradiation and superfine grinding wall disruption treatment on quality parameters and antioxidant activity of pine pollen during storage at 55 °C for 8 weeks were investigated. Results showed that irradiation slowed the reduction of taxifolin and ascorbic acid levels and the increase of ferric-ion reducing antioxidant power (FRAP), but accelerated the increase of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity over storage. In addition, superfine grinding wall disruption accelerated the rise of p-coumaric acid and naringenin contents and the decline of taxifolin level in pine pollen during storage. Moreover, superoxide dismutase activity, FRAP value, naringenin, malondialdehyde, total saturated and polyunsaturated fatty acids content were increased both in untreated and treated pine pollen, whereas the total spins, taxifolin, and ascorbic acid contents were decreased. The changes of parameters in endogenous antioxidant system indicated that metabolism in pine pollen was triggered in response to damage induced by processing and storage. These results would help improve the quality and commercial values of pine pollen in the food and pharmaceutical industries.

Hydroxycinnamic Acids and Carotenoids of Dried Loquat Fruit cv. 'Algar' Affected by Freeze-, Convective-, Vacuum-Microwave- and Combined-Drying Methods.

The effect of different drying techniques (freeze, convective, vacuum-microwave and combined drying) on the drying kinetics, the phytochemical compounds and sensory characteristics in loquat cultivar ‘Algar’ was studied. The convective drying resulted in the highest amount of total hydroxycinnamic acids (5077 mg/kg wet weight (ww)), with 3-caffeoyl quinic acid and 5-caffeoyl quinic acid being the greatest carotenoids. The highest values of total carotenoids were obtained by the freeze-drying technique (2601 mg/kg ww), followed by all convective treatments and vacuum-microwave at 360 W. The highest carotenoid was β-carotene. The ABTS+• (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) and FRAP (Ferric Ion Reducing Antioxidant Power) values ranged from 2.04 up to 3.27 mmol Trolox/100 g ww, and from 1.89 up to 2.29 mmol Trolox/100 g ww, respectively. As expected, the color difference of freeze-dried samples was the lowest (7.06), similar to combined drying conditions (9.63), whilst the highest value was found after convective drying (37.0). All treatments were sensory acceptable (no off-flavors). However, still, further research is needed to fully optimize these studied drying treatments because the freeze-dried sample still had higher carotenoid content and better instrumental color parameters. Although recently the impact of microwave drying has been studied, this is the first work comparing phytochemical composition of loquat fruit under the different drying methods mentioned above.

Antioxidant Properties of Fresh and Frozen Peels of Citrus Species

Citrus peel is a functional food. It is rich in antioxidants. This study aims to investigate the antioxidant properties of selected fresh and frozen peels of Citrus species. Frozen and fresh peels of lemon (Citrus limon), key lime (C. aurantifolia) and musk lime (C. microcarpa) were screened for their antioxidant properties such as total phenolic content and total flavonoid content. DPPH radical scavenging activity and ferric ion reducing antioxidant power (FRAP) assays were also determined. Among the three citrus peels, musk lime peel had the significantly highest total phenolic content and total flavonoid content. Frozen citrus peels showed significantly higher antioxidant content than the fresh peels. The frozen peels also showed promising antioxidant activity as indicated by their significantly higher FRAP value compared with fresh citrus peels. Moreover, frozen citrus peel possessed higher antioxidant activity as indicated by its lower EC50 values which ranged between 0.823 ± 0.1 and 3.16 ± 0.92 mg mL-1. A moderately high correlation was determined between FRAP value and total phenolic content (r=0.783), and between FRAP value and total flavonoid content. This study shows that frozen peels of citrus are functional foods and sources of potent antioxidants.

Impact of heat treatment and acid gelation on polyphenol enriched milk samples

The effects of heat treatment and the stage of polyphenol addition to milk before or after heat treatment on the total phenolic content (TPC), ferric-ion reducing antioxidant power (FRAP), pH, casein micelle size (CMS) and whey protein denaturation content of milk-polyphenol mixtures were investigated. Four sources of phenolic compounds (green tea, white grape, tannic acid, gallic acid) were incorporated into pasteurized-skim milk. A heat treatment (85 °C for 30 min) was applied to pasteurized-skim milk either before (MhP) or after polyphenols addition (MhPh). Acid milk gels were produced using MhPh samples, and their TPC and FRAP were determined. Heat treatment decreased the TPC and FRAP values of the samples, except for tannic acid, probably due to increased polyphenol-protein interactions. However, MhPh tannic acid sample resulted in significantly higher FRAP value than MhP. The addition of gallic acid before heat treatment (MhPh) significantly increased CMS due to the lower pH of this sample during heating. Acid gelation decreased the extractable polyphenols, however there was no significant different on FRAP between acid gel and MhPh milk samples. This study showed that the properties of phenolic source, particularly pH, and the stage of polyphenol addition to milk had an impact on selected properties.

Effect of cold-pressed and normal centrifugal juicing on quality attributes of fresh juices: do cold-pressed juices harbor a superior nutritional quality and antioxidant capacity?

Cold-pressed juices are claimed to contain higher levels of antioxidants and bioactive compounds compared to normally centrifuged ones. Herein, we evaluated the antioxidant capacity and the bioactive compound contents of some freshly prepared fruit juices, extracted by a cold-pressed juicer and compared them to those prepared by a normal centrifugal juicer. We observed no significant differences between cold-pressed and normal centrifugal juices in terms of the contents of bioactive compounds (ascorbic acid, total phenolic, and total carotenoid) and antioxidant capacity (ferric ion reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity). Storage at room temperature (∼28 °C) adversely affected the ascorbic acid, total phenolics, total carotenoids, FRAP and DPPH values of the cold-pressed juices within 48 h. However, under simulated home-refrigerated storage conditions, the antioxidant capacity, contents of bioactive compounds and physicochemical properties of the cold-pressed juices remained unchanged till day 5 post-storage. However, at day 6, most of the parameters exhibited a decreasing trend and reached their lowest values at day 7. Principal component analysis confirmed significant changes in the quality of juices at day 7 of storage related to the first two principal components (ascorbic acid and FRAP). Our results strongly question the claim regarding the superior quality of cold-pressed juices. Moreover, our findings provided compelling evidence regarding the possible adverse effects of long storage under home-refrigerated conditions on the quality of cold-pressed juices.

Trypsin Inhibitors from Cajanus cajan and Phaseolus limensis Possess Antioxidant, Anti-Inflammatory, and Antibacterial Activity

ABSTRACTProtease inhibitors are one of the most promising and investigated subjects for their role in pharmacognostic and pharmacological studies. This study aimed to investigate antioxidant, anti-inflammatory, and antimicrobial activities of trypsin inhibitors (TIs) from two plant sources (Cajanus cajan and Phaseolus limensis). TI was purified from C. cajan (PUSA-992) by ammonium sulfate precipitation followed by ion exchange chromatography. TI from Phaseolus limensis (lima bean trypsin inhibitor; LBTI) was procured from Sigma-Aldrich, St. Louis, Missouri, United States. The antioxidant activity was analyzed by ferric ion reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH). The anti-inflammatory property of TIs was determined by inhibition of albumin denaturation assay. Ascorbic acid and aspirin were used as standards for antioxidant and anti-inflammatory assays, respectively. These TIs were tested against various bacterial and fungal strains. The TIs showed DPPH radical–scavenging activity in a concentration-dependent manner with IC50 values comparable to ascorbic acid. The FRAP values were also observed comparable to ascorbic acid and followed the trend of dose-dependent manner. The half maximal inhibitory concentration (IC50) values of CCTI and LBTI in anti-inflammatory test showed that LBTI is more potent than CCTI. The TIs showed potent antibacterial activity, but apparently no action against fungi. This study has reported the biological properties of CCTI and LBTI for the first time. The results show that TIs possess the ability to inhibit diseases caused by oxidative stress, inflammation, and bacterial infestation.

Evaluation of chemical composition, antioxidant and anti-acetylcholinesterase activities of Hypericum neurocalycinum and Hypericum malatyanum

This study was conducted to evaluate the chemical composition, antioxidant and anti-acetylcholinesterase (anti-AChE) activities of methanolic extracts of H. neurocalycinum and H. malatyanum, two endemic species of the Turkish flora. HPLC-DAD analysis indicated that two naphthodianthrones (pseudohypericin and hypericin) together with chlorogenic acid, rutin, hyperoside, isoquercitrin, kaempferol, quercitrin, quercetin, amentoflavone and hyperforin are the main compounds present in the methanol extracts. The extracts were tested in vitro for their antioxidant activities including, inhibition of lipid peroxidation in liposomes, induced by Fe3+/ascorbate system, scavenging effect on DPPH and superoxide anion radicals, and ferric ion reducing antioxidant power (FRAP). H. neurocalycinum demonstrated stronger antioxidant properties than H. malatyanum due to higher activity on scavenging DPPH (EC50=2.49±0.09mg/mL) and superoxide anion radicals (EC50=0.613±0.05mg mg/mL), and inhibition of lipid peroxidation (EC50=2.49±0.09mg/mL). This difference in activity seems to be due to the presence of higher amounts of the antioxidant compounds (flavonoids) such as rutin, quercetin and kaempferol in H. neurocalycinum extract. The antioxidant activities of the extract may be attributed to their reducing capabilities. At 5mg/mL H. neurocalycinum (FRAP value=2.39±0.039mM Fe2+) and H. malatyanum (FRAP value=2.23±0.013mM Fe2+) showed high ability to reduce Fe3+ to Fe2+. The extracts were tested also for their in vitro AChE inhibitory activities. H. neurocalycinum inhibited 72.24±0.39% of AChE activity at a concentration of 5mg/mL. It was concluded that H. neurocalycinum is more effective AChE inhibitor and antioxidant than H. malatyanum.

Comparative study of functional properties of eight walnut (Juglans regia L.) genotypes

Abstract Eight walnut ( Juglans regia L.) genotypes were assessed for the glutathione (GSH) and total phenolic contents (TPC), as well as their antioxidant capacities. The GSH contents were between 1.1 and 7.2 mg 100 g -1 . The TPC contents ranged from 33 to 50.3 mg GAE g -1 , while the ferric ion reducing antioxidant power (FRAP) values ranged from 156 to 302 mg FeSD 4 g -1 . A strong correlation ( r 2 =0.8258) was determined between the FRAP values and the TPC. Cupric ion reducing antioxidant capacity (CUPRAC) values ranged from 13 to 35 mg trolox g -1 . The correlation between the CUPRAC values and the GSH contents was weak ( r 2 =0.2069). The walnut extracts (0.2 mg mL -1 concentration) showed 16.2-40% DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging activity. A strong correlation between DPPH-TPC was determined ( r 2 =0.8538), and it was concluded that the TPC makes the most important contribution to the antioxidant capacity of the walnut. Additionally, the walnut may be appraised, in view of its nutritional value and health benefits, by considering the GSH content revealed in the current study.

Antioxidant content and activity in different parts of pomelo [Citrus grandis (L.) Osbeck] by-products

This study aimed to investigate the total antioxidant content and activity in different parts of pomelo by-products, namely flavedo, albedo and segment membrane. Total phenolic content (TPC) was determined using Folin-Ciocalteu method while total flavonoid content (TFC) was determined using aluminium chloride colorimetric method. The total antioxidant activity was determined by performing DPPH free radical scavenging assay and ferric ion reducing antioxidant power (FRAP) assay. Albedo possessed the highest TPC and TFC while flavedo demonstrated the highest antioxidant activity in both assays as compared to other tissues. Pearson correlation tests revealed that there were no correlations between TPC and EC50 as well as FRAP value. There was also a lack of relationship between TFC and antioxidant activity as determined in DPPH and FRAP assays. The pomelo by-products of 'Ledang' possessed higher antioxidant properties than previous studies and therefore can be considered as a new source of natural antioxidants.

Protective effects of Borago officinalis extract on amyloid β-peptide(25-35)-induced memory impairment in male rats: a behavioral study.

Alzheimer's disease (AD) is a neurodegenerative disorder and most common form of dementia that leads to memory impairment. In the present study we have examined the protective effects of Borago officinalis (borage) extract on Amyloid β (Aβ)-Induced memory impairment. Wistar male rats received intrahippocampal (IHP) injection of the Aβ(25–35) and borage extract throughout gestation (100 mg/kg). Learning and memory functions in the rats were examined by the passive avoidance and the Morris water maze (MWM) tasks. Finally, the antioxidant capacity of hippocampus was measured using ferric ion reducing antioxidant power (FRAP) assay. The results showed that Aβ(25–35) impaired step-through latency and time in dark compartment in passive avoidance task. In the MWM, Aβ(25–35) significantly increased escape latency and traveled distance. Borage administration attenuated the Aβ-induced memory impairment in both the passive avoidance and the MWM tasks. Aβ induced a remarkable decrease in antioxidant power (FRAP value) of hippocampus and borage prevented the decrease of the hippocampal antioxidant status. This data suggests that borage could improve the learning impairment and oxidative damage in the hippocampal tissue following Aβ treatment and that borage consumption may lead to an improvement of AD-induced cognitive dysfunction.

Antioxidant perspective of selected medicinal herbs in India: A probable source for natural antioxidants

ObjectiveTo analyze the phytochemical and radical scavenging activities of leaf fractions of commonly used 6 medicinal plants in India. MethodsThe plant leaves were extracted with 80% methanol. The methanolic extracts were subjected to total flavonoids and phenolics estimation. Antioxidant activities of the extracts were determined by DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (Ferric ion reducing antioxidant power) assay. ResultsOur results showed that Phyllanthus amarus had higher levels of flavonoids (57.18 mg/100 g) and phenolics (46.92 mg/g). All the extracts showed significant antioxidant activity. The highest DPPH radical scavenging activity was found in Leucas aspera (75.06%) followed by Coleus aromaticus (72.26%). The highest FRAP value was observed in the P. amarus (12.68 mM/g) whereas L. aspera (2.11 mM/g) showed the lowest. The results suggest that the secondary metabolites like polyphenolics and other compounds present in these plants may contribute to the medicinal properties of that plant. ConclusionsThe results concluded that P. amarus have relatively more phytochemical content and showed significant antioxidant activity. Our finding is a prologue for characterization and isolation of antioxidant components from the medicinal plants and invitro and invivo studies are essential to use it as a potential source of natural antioxidants.

Application of response surface methodology to optimize pressurized liquid extraction of antioxidant compounds from sage (Salvia officinalis L.), basil (Ocimum basilicum L.) and thyme (Thymus vulgaris L.)

The present study optimized pressurized liquid extraction (PLE) conditions using Dionex ASE® 200, USA to maximize the antioxidant activity [Ferric ion Reducing Antioxidant Power (FRAP)] and total polyphenol content (TP) of the extracts from three spices of Lamiaceae family (sage, basil and thyme). Optimal conditions with regard to extraction temperature (66-129 °C) and solvent concentration (32-88% methanol) were identified using response surface methodology (RSM). For all three spices, results showed that 129 °C was the optimum temperature with regard to antioxidant activity. Optimal methanol concentrations with respect to the antioxidant activity of sage and basil extracts were 58% and 60% respectively. Thyme showed a different trend with regard to methanol concentration and was optimally extracted at 33%. Antioxidant activity yields of the optimal PLE were significantly (p < 0.05) higher than solid/liquid extracts. Predicted models were highly significant (p < 0.05) for both total phenol (TP) and FRAP values in all the spices with high regression coefficients (R(2)) ranging from 0.651 to 0.999.

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

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 antioxidant 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-apoptotic activity in vivo.