Antimutagenic effect of an antioxidant in mammals

To test a possible antimutagenic activity of ethoxyquin (EQ) in bone-marrow cells, 3 cytogenetic tests with distinct genetic end-points were applied. Cyclophosphamide (CPA), serving as test mutagen, and the antioxidant EQ were administered immediately following each other to Chinese hamsters by stomach tube. Whereas the CPA dose was the same in each test, the EQ doses were increased up to a ratio of CPA/EQ = 1:25, in some cases up to 1:50. The formation of SCEs induced by CPA was not influenced by EQ--even at the highest dose. In the micronucleus test, however, EQ drastically reduced the micronucleus rate even at the lowest dose applied (20 mg/kg) and abolished the CPA effects at a dose of 100 mg/kg. This action of EQ against CPA was also found in the rat and mouse in the micronucleus test system. Two inbred strains of mouse showed similar reactions, but the induced micronucleus rate was higher and its decrease in response to increasing doses of EQ was more delayed. In the chromosome aberration test, EQ also showed a distinct anticlastogenic response. At higher EQ doses, all CPA-induced chromosomal damage was reduced down to the level of spontaneous rates. The anticlastogenic effect of EQ was quantitatively similar in the micronucleus and chromosome aberration tests. Only minor qualitative differences were recognizable.     

Comparative analysis of cytotoxic, genotoxic and antioxidant effects of 2,2,4,7-tetramethyl-1,2,3,4-tetrahydroquinoline and ethoxyquin on human lymphocytes

2,2,4,7-Tetramethyl-1,2,3,4-tetrahydroquinoline (THQ) is a new synthetic compound with potential antioxidant activity. In this study, cytotoxic, genotoxic and antioxidant activities of THQ were studied on human lymphocytes with the use of the trypan blue exclusion assay, the TUNEL method, the comet assay and the micronucleus test. The activities of THQ were compared with those of a structurally similar compound-ethoxyquin (1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline, EQ), which is used in animal feeds as a preservative. Cytotoxic effects of THQ were observed after 1-h treatment at the concentration of 500 microM and after 24-h treatments at the concentrations of 250-500 microM. Although the micronucleus test did not reveal a genotoxic effect of THQ, in the comet assay the statistically significant increase in DNA damage was observed as compared with the control. On the other hand, the protection of human lymphocytes against DNA damage induced by hydrogen peroxide suggests an antioxidant activity of THQ. The comparative analysis of THQ and EQ activities performed in these studies revealed that THQ was less cytotoxic and less genotoxic than EQ. Slightly lower antioxidant activity of THQ was also shown in the comet assay when it was used at the lower studied doses (1-5 microM), but for the highest one (10 microM) its efficiency was similar to that of EQ. In the micronucleus assay THQ was more effective than EQ in protecting the cultured lymphocytes from clastogenicity of H2O2. We believe that THQ is worthy of further detailed studies on its antioxidant properties to confirm its usefulness as a preservative.     

Interactions of dietary lead with fish oil and antioxidant in chicks

Two experiments were conducted with day-old broiler chicks reared to 18 or 19 d of age. The objectives were: (1) to examine the effects of the antioxidant ethoxyquin (EQ) on peroxidation in feeds containing fish oil (FO) or lead (Pb), and (2) to determine whether systemic effects of Pb, which are attributed to tissue peroxidation, can be reversed by dietary EQ. Experiment 1 was a 2 x 2 factorial arrangement with the factors being 4% dietary cottonseed oil (CSO) vs FO and dietary Pb as lead acetate trihydrate (0 vs 1000 ppm). Feed was mixed 1 d prior to initiation of the experiment and stored at 4 degrees C until it was placed in the feeders. Experiment 2 was a 2 x 2 x 2 factorial arrangement with the factors being 3.5% dietary oil (CSO vs FO), dietary Pb (0 vs 1000 ppm), and EQ (0 vs 75 ppm). Feed was mixed 1 d prior to initiation of the experiment and held at room temperature thereafter. Growth depression by FO and Pb was less pronounced in Experiment 1 than in Experiment 2. In Experiment 2, FO and Pb increased the concentration of feed peroxide, and the increases were prevented by EQ. The growth depression by FO was completely reversed by EQ. EQ reversal of Pb-induced growth depression, although substantial, was not complete. The FO diet without Pb had a peroxide content (12.4 meq/kg feed) similar to the CSO + Pb diet (12.3 meq/kg feed); however, growth was not similar (407 vs 213 g body weight at 19 d, respectively). The results suggest that the toxic effects of Pb are mediated by peroxidative alterations both in the feed and in tissues. The ability of EQ to reverse significantly Pb effects on growth suggests a systemic action of this antioxidant.     

Genotoxic and antioxidant activities of ethoxyquin salts evaluated by the comet assay

Four newly synthesized salts of ethoxyquin (EQ: 1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline), an antioxidant used in animal feeds, were evaluated with the use of the comet assay performed on human lymphocytes: ethoxyquin ascorbate, ethoxyquin hexanoate, ethoxyquin salicylate and ethoxyquin salt of Trolox C (6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid). In the study the abilities of these compounds to cause DNA fragmentation and to protect against H2O2-induced DNA damage were analysed. The obtained results were compared with those noted earlier for EQ. After EQ salts treatments (1-25 microM) the genotoxic effects were observed, but the genotoxic potentials of the compounds studied were lower than that of EQ. On the other hand, EQ salts, similarly to EQ, effectively protected the cells from oxidative effect of H2O2. EQ hexanoate was the most effective and its antioxidant activity was even slightly higher than that of EQ. We suggest that it is worth further detailed studies to estimate its usefulness as a preservative.     

Induction of chromosome aberrations in cultured human lymphocytes treated with ethoxyquin

The chromosomal aberration test was employed to investigate the effect in vitro of a known antioxidant and food preservative, ethoxyquin (EQ, 1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline) on human chromosomes. The studies were undertaken because there are no published in vitro data on genotoxicity of EQ in mammalian cells and there are many reports pointing out that it may be harmful to animals and human beings. Lymphocytes obtained from three healthy donors were incubated with EQ (0.01-0.5mM) both with and without metabolic activation. Stability studies performed by HPLC analysis showed that EQ was stable under the conditions of the lymphocyte cultures. The results of the chromosome aberration assay showed that EQ induces chromosome aberrations: gaps and breaks as well as dicentrics and atypical translocation chromosomes.     

Induction of chromosome aberrations in cultured human lymphocytes treated with ethoxyquin

The chromosomal aberration test was employed to investigate the effect in vitro of a known antioxidant and food preservative, ethoxyquin (EQ, 1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline) on human chromosomes. The studies were undertaken because there are no published in vitro data on genotoxicity of EQ in mammalian cells and there are many reports pointing out that it may be harmful to animals and human beings. Lymphocytes obtained from three healthy donors were incubated with EQ (0.01–0.5 mM) both with and without metabolic activation. Stability studies performed by HPLC analysis showed that EQ was stable under the conditions of the lymphocyte cultures. The results of the chromosome aberration assay showed that EQ induces chromosome aberrations: gaps and breaks as well as dicentrics and atypical translocation chromosomes.     

Vitamin A with L-ascorbic acid sodium salt improves the growth performance,immune function and antioxidant capacity of weaned pigs

Vitamin A is easily degraded by environmental factors. Therefore, it is very important to add antioxidants during Vitamin A production. In the past, ethoxyquin (EQ) was widely used, but recent studies have found that it has potential toxicity. Therefore, in this study, we evaluated the antioxidant activities of 4 antioxidants in vitro: EQ, butylated hydroxytoluene, α-tocopherol and L-ascorbic acid sodium salt (Vitamin C sodium). In vitro experiments showed that Vitamin C sodium had better antioxidant capacity. Then, we explored the effects of different antioxidant types of Vitamin A on the growth performance, immune function and antioxidant capacity of weaned pigs. In total, 288 weaned piglets with an initial mean BW of 8.34 ± 0.02 kg at 30 days old were randomly divided into three groups with four replicates and 24 piglets per replicate for 35 days of feeding. The experimental diets were as follows: i) basal diet without external Vitamin A (NC); ii) basal diet supplemented with 12 000 IU/kg EQ Vitamin A and iii) basal diet supplemented with 12 000 IU/kg Vitamin C sodium Vitamin A. On day 36, two pigs from each replicate were selected to collect serum samples. The in vivo results showed that pigs in the EQ Vitamin A and Vitamin C sodium Vitamin A groups had significantly higher final weight and average daily gain (P < 0.05). During the trial, the levels of IgG and glutathione peroxidase in the EQ Vitamin A and Vitamin C sodium Vitamin A groups were significantly higher than those in the NC group (P < 0.05), and the malondialdehyde content was significantly lower (P < 0.05). On the 36th day, the levels of IgA and total antioxidant capacity in the Vitamin C sodium Vitamin A group were significantly higher than those in the EQ Vitamin A and NC (P < 0.05) groups. Thus, Vitamin C sodium Vitamin A can significantly improve the growth performance, antioxidant capacity and immune function of weaned pigs. Meanwhile, Vitamin C sodium may replace EQ as an antioxidant additive for Vitamin A.     

Relatively low-dose cyclophosphamide is likely to induce apoptotic cell death in rat thymus through Fas/Fas ligand pathway.

Cyclophosphamide (CPA) is widely used as an efficiently antineoplastic drug, but also causes immunosuppression as its adverse-side effect. To understand the effect of low- or relative low-dose CPA on the immune system, apoptotic cell death in rat thymus, either exposed to different doses of CPA (0, 2, 7, 20 and 70 mg/kg) for 12 h or exposed to 70 mg/kg for different times (4-48 h), was investigated by DNA fragmentation (DNA ladder) detection and in situ morphological examination using hematoxylin and eosin (H and E) staining. Immunohistochemical staining for Fas protein expression in the thymus of rats exposed to CPA was performed. Results showed that exposure of rats to CPA 0-70 mg/kg for 12 h did not cause significant decrease in the ratio of thymus weight to body weight. However, the ratio of thymus weight to body weight was decreased significantly at 48 h after exposure to 70 mg/kg CPA. Exposure to 20 and 70 mg/kg CPA for 12 h caused a visible DNA ladder in gel electrophoresis. DNA ladder formation was increased progressively in the groups from 8 h to optimal magnitude at 12-24 h and then disappeared at 48 h after 70 mg/kg CPA. This pattern was confirmed by a quantitative evaluation of the apoptotic cells using H and E staining. Expression of Fas protein was enhanced in the thymus of rats exposed to 70 mg/kg CPA for 4-8 h as compared to control rats. These results are different from previous studies on high dose CPA and the induction of the apoptotic cell death in thymus by low or relative low doses of CPA might be a result of Fas/Fas-ligand interactions.     

Cyclopiazonic acid production by Aspergillus flavus and its effects on broiler chickens

Cyclopiazonic acid (CPA) was purified from cultures of Aspergillus flavus, and ca. 14 g of the toxin was collected for use in feeding studies. Chicken rations were artificially contaminated with purified CPA at concentrations of 10, 50, and 100 ppm (microgram/g) and fed ad libitum to eight groups of chickens for 7 weeks. Chickens receiving feed with 100 ppm of CPA had high mortality, decreased weight gain, and poor feed conversion when compared with birds receiving other doses. Postmortem examination showed that chickens fed the two greatest doses of CPA had proventricular lesions characterized by mucosal erosion and hyperemia (100 ppm) and by thick mucosa and dilated proventricular lumens (50 ppm). Birds given 100 ppm of CPA in feed also had numerous yellow foci in their livers and spleens. Microscopic examination of tissues of birds that received 100 ppm of CPA revealed ulcerative proventriculitis, mucosal necrosis in the gizzard, and hepatic and splenic necrosis and inflammation. Birds given 50 ppm of CPA had hyperplasia of the proventricular mucosal epithelium. Birds given 10 ppm of CPA and control birds had no significant treatment-related lesions.     

Cyclopiazonic acid production by Aspergillus flavus and its effects on broiler chickens.

Cyclopiazonic acid (CPA) was purified from cultures of Aspergillus flavus, and ca. 14 g of the toxin was collected for use in feeding studies. Chicken rations were artificially contaminated with purified CPA at concentrations of 10, 50, and 100 ppm (microgram/g) and fed ad libitum to eight groups of chickens for 7 weeks. Chickens receiving feed with 100 ppm of CPA had high mortality, decreased weight gain, and poor feed conversion when compared with birds receiving other doses. Postmortem examination showed that chickens fed the two greatest doses of CPA had proventricular lesions characterized by mucosal erosion and hyperemia (100 ppm) and by thick mucosa and dilated proventricular lumens (50 ppm). Birds given 100 ppm of CPA in feed also had numerous yellow foci in their livers and spleens. Microscopic examination of tissues of birds that received 100 ppm of CPA revealed ulcerative proventriculitis, mucosal necrosis in the gizzard, and hepatic and splenic necrosis and inflammation. Birds given 50 ppm of CPA had hyperplasia of the proventricular mucosal epithelium. Birds given 10 ppm of CPA and control birds had no significant treatment-related lesions.     

In vitro inhibition of the cytopathic action of herpes simplex virus, type 1, with a natural cytokine complex

The antiviral action of a natural cytokine complex (NCC)--the preparation Superlymph and its peptide antimicrobial fraction (AMF)--in the culture of Vero cells infected with type 1 herpes simplex virus (HSV-1), strain VR-3, was studied. The NCC preparation did not alter the morphology of the cells for 6 days and was not toxic for the culture of Vero cells. The NCC and AMF produced a protective antiviral effect, which was manifested by the inhibition of the cytopathic action (CPA) of the virus. In the presence of the preparation, the CPA of HSV-1 was equal to 10(-4.67) ICPD50, while in the control CPA was equal to 10(-5.60). The fraction containing antimicrobial peptides (protegrins) and isolated from NCC, characterized by the method of mass spectrometry, produced the maximum antiviral effect on the cell strain Vero (10(-4.58) ICPD50). Thus Superlymph, an immunomodulator with antiviral activity, could be regarded as an effective preparation for the treatment of HSV infection. The action of such preparation was aimed at the inhibition of the CPA of the virus and the stimulation of the antiviral protective mechanisms of the cell.     

Differential Expression of Cerebellar Metabotropic Glutamate Receptors mGLUR2/3 and mGLUR4a after the Administration of a Convulsant Drug and the Adenosine Analogue Cyclopentyladenosine

Metabotropic glutamate receptors (mGluR) play a role in synaptic transmission, neuronal modulation and plasticity but their action in epileptic activity is still controversial. On the other hand adenosine acts as a neuromodulator with endogenous anticonvulsive properties. Since cerebellum from epileptic patients has shown neuronal damage, sometimes associated with Purkinje cells loss, we have explored the effect of repetitive seizures on two types of mGluR in the cerebellum. Seizures were induced by the convulsant drug 3-mercaptopropionic acid (MP) and the effect of the adenosine analogue cyclopentyladenosine (CPA) alone or before MP administration (CPA+MP) were also evaluated. The expression of the receptors subtypes 2/3 (mGluR2/3) and 4a (mGluR4a) was assessed by immunocitochemistry. Granular cell layer was labeled with mGluR2/3 antibody and increased immunoreactivity was observed after MP (60%), CPA (53%) and CPA + MP (85%) treatments. Control cerebellum slices showed mGluR4a reactivity around Purkinje cells, while MP, CPA and CPA+MP treatment decreased this immunostaining. Repetitive administration of MP and CPA induces an increased cerebellar mGluR2/3 and a decreased mGluR4a immunostaining, suggesting a distinct participation of both receptors that may be related to the type of cell involved. A protective action and /or an apoptotic effect may not be discarded. CPA repetitive administration although increase seizure latency, cannot prevent seizure activity.     

The acceptor availability at photosystem I and ABA control nuclear expression of 2-Cys peroxiredoxin-A in Arabidopsis thaliana

The redox-regulated 2-Cys peroxiredoxin-A (2CPA) promoter, which drives expression of a dominant chloroplast antioxidant enzyme, responds to signals originating from the photosynthetic electron transport downstream of PSI. Modulation of CO(2)- and NO(3)(-) -reduction rates in reporter gene plants expressing glucuronidase under control of the Arabidopsis thaliana 2CPA promoter revealed that promoter activity correlates with the availability of electron acceptors at PSI. The photosynthetic redox-regulation can be simulated by oxidant and antioxidant treatments. Inhibitor studies with PD98059 and staurosporine showed that a mitogen-activated protein kinase kinase transmits the oxidative response, while the antioxidant signal is transmitted by a serine/threonine kinase. Analysis of 2CPA promoter regulation in the abscisic acid (ABA)-biosynthetic mutants aba2 and aba3 and the ABA-insensitive mutants abi1 and abi2 support a regulatory circuitry in which the redox signal cross-talks with the ABA-signaling cascade downstream of ABI1 and ABI2.     

Testicular phosphatase activity in rats treated with cyproterone acetate & flutamide

Cyproterone acetate (CPA) and flutamide (F), 2 antiandrogens were tested in the rat, to determine their effect on acid (ACP) and alkaline (ALP) phosphatase activity. 70 fertile male rats were injected with either CPA, F, or testosterone propionate (TP) at either 2.5 or 10 mg. TP was injected either alone or in combination with the others. Histological examinations of the testes were performed. Spermatogenesis was arrested and Leydig cells atrophied in animals treated with CPA or F. Histochemical examination revealed that CPA enhanced ALP and ACP in the testes while F decreased ALP and ACP. TP treatment in combination with either antiandrogens was unable to overcome their effect. The changes in the 2 phosphatases depending on which antiandrogen was injected suggests different modes of action.     

Chemotactic selection of Tetrahymena pyriformis GL induced with histamine, di-iodotyrosine or insulin

Ethoxyquin (6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline (EQ) is a synthetic antioxidant used for preventing rancidity in animal foodstuffs. Three groups of ten fish were given a diet containing respectively 75 (control group with the commercial food), 200 and 400 ppm EQ for 16 days. The control group had a plasma osmolality and chloride concentration within the normal range of marine teleosts, but sodium concentrations of only about 110 mM, indicating the presence in the plasma of substantial amounts of another cation. Fish given food with 400 ppm EQ displayed a 70 mM increase in the plasma concentration of sodium. This indicates that EQ has disturbed the iono-regulatory mechanisms, probably by reducing the ATP production or inhibiting directly the Na/K-ATPase in the gills. The large increase in plasma sodium concentration was not accompanied by any significant increase in plasma osmolality, indicating that at least a part of the sodium added to the plasma is made osmotically inactive. In spite of the elevated plasma sodium concentration, the sodium content of erythrocytes of the 400-ppm EQ fish was reduced to half, while the content of calcium was unaffected. The transmembrane energy gradient of sodium in the EQ exposed turbot obviously increased, allowing them to use a sodium coupled antiport system to keep the cellular calcium content low when the Ca-ATPases is blocked. A mechanism of this kind is also likely to be important to turbot that experience hypoxia under natural conditions. The 400-ppm group also displayed a substantial increase in liver weight, but the physiological significance of this effect is not clear. The leucocyte counts indicated the absence of obvious immunological effects.     

Homeostatic action of adenosine A3 and A1 receptor agonists on proliferation of hematopoietic precursor cells

Two adenosine receptor agonists, N6-(3-iodobenzyl)adenosine-5'-N-methyluronamide (IB-MECA) and N6-cyclopentyladenosine (CPA), which selectively activate adenosine A3 and A1 receptors, respectively, were tested for their ability to influence proliferation of granulocytic and erythroid cells in femoral bone marrow of mice using morphological criteria. Agonists were given intraperitoneally to mice in repeated isomolar doses of 200 nmol/kg. Three variants of experiments were performed to investigate the action of the agonists under normal resting state of mice and in phases of cell depletion and subsequent regeneration after treatment with the cytotoxic drug 5-fluorouracil. In the case of granulopoiesis, IB-MECA 1) increased by a moderate but significant level proliferation of cells under normal resting state; 2) strongly increased proliferation of cells in the cell depletion phase; but 3) did not influence cell proliferation in the regeneration phase. CPA did not influence cell proliferation under normal resting state and in the cell depletion phase, but strongly suppressed the overshooting cell proliferation in the regeneration phase. The stimulatory effect of IB-MECA on cell proliferation of erythroid cells was observed only when this agonist was administered during the cell depletion phase. CPA did not modulate erythroid proliferation in any of the functional states investigated, probably due to the lower demand for cell production as compared with granulopoiesis. The results indicate opposite effects of the two adenosine receptor agonists on proliferation of hematopoietic cells and suggest the plasticity and homeostatic role of the adenosine receptor expression.     

Evaluation of five additives to mitigate toxicity of cryoprotective agents on porcine chondrocytes

Cryoprotective agents (CPAs) are used in cryopreservation protocols to achieve vitrification. However, the high CPA concentrations required to vitrify a tissue such as articular cartilage are a major drawback due to their cellular toxicity. Oxidation is one factor related to CPA toxicity to cells and tissues. Addition of antioxidants has proven to be beneficial to cell survival and cellular functions after cryopreservation. Investigation of additives for mitigating cellular CPA toxicity will aid in developing successful cryopreservation protocols. The current work shows that antioxidant additives can reduce the toxic effect of CPAs on porcine chondrocytes. Our findings showed that chondroitin sulphate, glucosamine, 2,3,5,6-tetramethylpyrazine and ascorbic acid improved chondrocyte cell survival after exposure to high concentrations of CPAs according to a live-dead cell viability assay. In addition, similar results were seen when additives were added during CPA removal and articular cartilage sample incubation post CPA exposure. Furthermore, we found that incubation of articular cartilage in the presence of additives for 2 days improved chondrocyte recovery compared with those incubated for 4 days. The current results indicated that the inclusion of antioxidant additives during exposure to high concentrations of CPAs is beneficial to chondrocyte survival and recovery in porcine articular cartilage and provided knowledge to improve vitrification protocols for tissue banking of articular cartilage.     

Cyclopiazonic acid decreases spontaneous transient depolarizations in guinea pig mesenteric lymphatic vessels in endothelium-dependent and -independent manners

Guinea pig mesenteric lymphatic vessels exhibit vasomotion through a pacemaker mechanism that involves intracellular Ca(2+) release and resultant spontaneous transient depolarizations (STDs) of the smooth muscle membrane potential. This study presents a detailed characterization of the effects of cyclopiazonic acid (CPA) on this pacemaker activity. Microelectrode recordings from smooth muscle in vessel segments revealed that application of CPA (1-10 microM) caused a hyperpolarization accompanied by a decrease in the frequency and amplitude of STDs. The CPA-induced hyperpolarization was abolished after destruction of the endothelium and in the presence of N(G)-nitro-L-arginine (100 microM) or 1H-[1,2,4]oxadiazolol-[4,3-a]quinoxaline-1-one (10 microM), which suggests a contribution of endothelium-derived nitric oxide (EDNO) in this response. In the absence of EDNO-induced effects, CPA decreased the frequency and amplitude of STDs recorded before and in the presence of the thromboxane A(2) mimetic U-46619, norepinephrine, or thimerosal. CPA abolished U-46619-induced vasomotion as determined by measurement of constriction-associated intracellular Ca2+ concentration using the ratiometric Ca2+ indicator fura-2. The endothelial actions of CPA were compared with those of ACh, which is known to cause EDNO release in this preparation. Although CPA and ACh both increased endothelial intracellular Ca2+ concentration and depolarized the membrane potential, the kinetics of action for both parameters were markedly slower for CPA than ACh. These results suggest that CPA first hyperpolarizes the lymphatic smooth muscle and decreases STD frequency and amplitude through endothelial release of EDNO, and second, consistent with the action of CPA to inhibit sarcoplasmic reticulum Ca2+-ATPase and deplete Ca2+ stores, it further reduces STD activity. Inhibition of the lymphatic smooth muscle pacemaker mechanism is thought to abolish agonist-induced vasomotion.     

The antioxidant and antiaggregant effects of the covalent bienzyme superoxide dismutase — Chondroitin sulfate — Catalase conjugate on platelets

A covalent bienzyme superoxide dismutase-chondroitin sulfate-catalase conjugate (SOD-CHS-CAT) demonstrated the dose-dependent inhibitory action on induced platelet aggregation both in the presence and the absence of hydrogen peroxide. The antioxidant activity of SOD-CHS-CAT was noted at much lower doses than that of other CAT derivatives. The conjugate SOD-CHS-CAT inhibited platelet aggregation regardless of the nature of inducers; it also prevented platelet spreading on the glass surface. The latter suggests conjugate influence on adhesive properties of platelets. Novel properties of the SOD-CHS-CAT conjugate underlie prospects of its biopharmaceutical applicability as a tool for antioxidant therapy.