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This study aimed to estimate the protective effect of a combination of S-Adenosyl-L-methionine (SAM) as a precursor of glutathione and oseltamivir as a specific inhibitor of virus replication on oxidative damages caused by influenza infection in the liver of infected mice. Albino mice were inoculated with 10×LD50 of influenza virus A/Aichi/2/68(H3N2). Oseltamivir was applied for five days after infection, twice per day, in a dose of 2.5 mg/kg. SAM was applied for ten days in a 100 mg/kg dose, starting five days before inoculation. Markers of oxidative stress, mortality rate, mean survival time, index, and protection coefficient were followed. Influenza infection causes severe oxidative damage to the liver. All combinations of SAM and oseltamivir restored the levels of the biochemical markers to those in healthy animals and improved the virological parameters. A combination of SAM 100 mg/kg and oseltamivir 2.5 mg/kg, which is 1/4 of the optimal therapeutic mice dose, exhibits protection index and affects most effectively all the tested parameters. This study provides an easy-to-apply approach with a good therapeutic potential for co-medicating influenza infection with a specific antiviral agent and an antioxidant precursor.

The difficult-to-heal wounds continue to be a problem for modern medicine. Chitosan and diosgenin possess anti-inflammatory and antioxidant effects making them relevant substances for wound treatment. That is why this work aimed to study the effect of the combined application of chitosan and diosgenin on a mouse skin wound model. For the purpose, wounds (6 mm diameter) were made on mice’s backs and were treated for 9 days with one of the following: 50% ethanol (control), polyethylene glycol (PEG) in 50% ethanol, chitosan and PEG in 50% ethanol (Chs), diosgenin and PEG in 50% ethanol (Dg) and chitosan, diosgenin and PEG in 50% ethanol (ChsDg). Before the first treatment and on the 3rd, 6th and 9th days, the wounds were photographed and their area was determined. On the 9th day, animals were euthanized and wounds’ tissues were excised for histological analysis. In addition, the lipid peroxidation (LPO), protein oxidation (POx) and total glutathione (tGSH) levels were measured. The results showed that ChsDg had the most pronounced overall effect on wound area reduction, followed by Chs and PEG. Moreover, the application of ChsDg maintained high levels of tGSH in wound tissues, compared to other substances. It was shown that all tested substances, except ethanol, reduced POx comparable to intact skin levels. Therefore, the combined application of chitosan and diosgenin is a very promising and effective medication for wound healing.

Background: Inhibitors of acetylcholinesterase (AChE) are used to treat many disorders, among which are neurodegenerative upsets, like Alzheimer’s disease (AD). One of the limited licensed AChE inhibitors (AChEIs) used as drugs is the natural compound galantamine (Gal). Objective: As Gal is a toxic compound, here we expose data about its four derivatives in hybrid peptide-norgalantamine molecules, which have shown 100 times lower toxicity. Methods: Four newly synthesized galantamine derivatives have been involved in docking analysis made by Molegro Virtual Docker. Biological assessments were performed on ICR male mice. The change in short and long-term memory performance was evaluated by passive avoidance test. AChE activity and levels of main oxidative stress parameters: lipid peroxidation, total glutathione (GSH), enzyme activities of catalase (CAT), superoxide dismutase, and glutathione peroxidase were measured in brain homogenates. Results: Our experimental data revealed that the new hybrid molecules did not impair memory performance in healthy mice. Two of the compounds demonstrated better than Gal AChE inhibitory activity in the brain. None of them changed the level of lipid peroxidation products, one of the compounds increased GSH levels, and all of them increased CAT enzyme activity. Conclusion: The new galantamine-peptide hybrids demonstrated a potential for inhibition of AChE and antioxidant activity and deserve further attention.

Alzheimer’s disease (AD) is the most common type of dementia in elderly. Since oxidative stress is an important feature of AD, it could be assumed that conjugation of the available medicines with substances having antioxidant properties may produce beneficial effect. The aim of this study was to investigate the antioxidant capacity of 7 analogs of memantine (MEM) with Gly, Ala, β-Ala, Val, Phe, Phe (4-F), and Gly-Gly. The antioxidant capacity of the MEM conjugates was tested in chemical systems generating superoxide anion (●O2–) and hydroxyl (●OH) radicals, and by applying the DPPH test. The results showed a negligible effect of the substances on DPPH● reduction. Phe-MEM, (4-F)-Phe-MEM and Gly-Gly-MEM demonstrated ●O2– scavenging potential. The Phe-containing derivatives exerted protective effect on ●OH-induced deoxyribose degradation and had abilities for chelating iron ions. In conclusion, the investigated Phe-containing MEM derivatives manifested a good antioxidant activity, and a promising effect in AD treatment could be expected.

The aim of the present study was to perform a pilot assessment and analysis of the oxidative stress (OS) level in four commercially important fish species (round goby, red mullet, sprat and horse mackerel) from different localities of the Bulgarian Black Sea coast. The fish were sampled during trawl selectivity experiments. The OS level in the fish was assessed by measuring lipid peroxidation (LPO), glutathione concentration (GSH), activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST), as well as acetylcholine esterase (AChE) in gills and liver. Round goby and red mullet caught in the Nessebar Bay showed clear signs of OS with the highest levels of LPO and GST activities, accompanied by the lowest AChE activities in both liver and gills. On the contrary, round goby caught near Maslen Nos (a region with good ecological conditions) were least affected by OS with low LPO and high GSH concentrations and SOD activity. There were no significant differences in the OS bioindicators of horse mackerel from the different localities. Sprat caught in Nessebar Bay, compared to those caught from the other localities, showed presence of OS indicated by lower GSH levels and relatively higher CAT, GPx and GST activities, accompanied by low AChE activity in gills. It can be concluded that round goby and red mullet were more vulnerable to OS induced by marine environmental factors than the horse mackerel and sprat. However, their antioxidant defense system allows them to tolerate and adapt to the environment of their habitats. Further studies are needed for the assessment of OS in important fish species in the Bulgarian part of the Black Sea.

Small-scale photobioreactors (PBRs) in the inoculum stage were designed with internal (red or green) and external white LED light as an initial step of a larger-scale installation aimed at fulfilling the integral biorefinery concept for maximum utilization of microalgal biomass in a multifunctional laboratory. The specific growth rate of Scenedesmus obliquus (Turpin) Kützing biomass for given cultural conditions was analyzed by using MAPLE software. For the determination of total polyphenols, flavonoids, chlorophyll “a” and “b”, carotenoids and lipids, UHPLC-HRMS, ISO-20776/1, ISO-10993-5 and CUPRAC tests were carried out. Under red light growing, a higher content of polyphenols was found, while the green light favoured the flavonoid accumulation in the biomass. Chlorophylls, carotenoids and lipids were in the same order of magnitude in both samples. The dichloromethane extracts obtained from the biomass of each PBR synergistically potentiated at low concentrations (0.01–0.05 mg/mL) the antibacterial activity of penicillin, fluoroquinolones or oregano essential oil against the selected food-borne pathogens (Staphylococcus aureus, Escherichia coli and Salmonella typhimurium) without showing any in vitro cytotoxicity. Both extracts exhibited good cupric ion-reducing antioxidant capacity at concentrations above 0.042–0.08 mg/mL. The UHPLC-HRMS analysis revealed that both extracts contained long chain fatty acids and carotenoids thus explaining their antibacterial and antioxidant potential. The applied engineering approach showed a great potential to modify microalgae metabolism for the synthesis of target compounds by S. obliquus with capacity for the development of health-promoting nutraceuticals for poultry farming.

Alzheimer’s disease (AD), a progressive neurodegenerative disorder characterized by memory loss and cognitive functions decline, is a leading cause for dementia and currently ranked as the sixth foremost cause of death. As of present, treatment of AD is symptomatic without convincing therapeutic benefits and new, effective, therapeutic agents are pursued. Due to massive loss of cholinergic neurons and decreased acetylcholine levels, cholinesterase inhibitors like galantamine, remain the backbone of pharmacological treatment of the disease. In the present study, using behavioral and biochemical methods, four newly synthesized galantamine derivatives, Gal 34, Gal 43, Gal 44, and Gal 46, were evaluated for a beneficial effect in a scopolamine model of dementia in mice. They were designed to have all the advantages of galantamine and additionally to inhibit β-secretase and exert favorable effects on plasma lipids. Behavioral tests included step-through inhibitory avoidance, T-maze, and the hole-board test, whereas biochemical evaluations involved assessment of acetylcholinesterase activity, brain monoamines levels, lipid peroxidation, catalase, glutathione peroxidase, and superoxide dismutase activities along with measurement of total glutathione. Results show that Gal 43, Gal 44, and, in particular, Gal 46 are especially effective in improving both short- and long-term memory and in the case of Gal 46 having a significant effect on exploratory activity as well. Although Gal 34 did not show behavioral effects as convincing as those of the other three galantamine derivatives, it demonstrated persuasive antioxidant and restorative capacities, making all four galantamine derivatives promising AD treatment agents and prompting further research, especially that in many of our studies they performed better than galantamine.

This study assessed phytochemical profile and antioxidant capacity of hydrosols, obtained by water-steam distillation of Rosa alba L. and Rosa damascena Mill. plants, grown in experimental ...

Geraniol is a common component of essential oils of various plant species and is widely used in cosmetics, perfumery and household products. In the present study, we investigated the cytotoxic, genotoxic and antioxidant activities of different concentrations of the monoterpenoid geraniol and its anti-cytotoxic and anti-genotoxic potential against the genotoxin N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) in higher plant and human lymphocyte test-systems frequently used in genotoxicity studies. The cytogenetic analysis did not show any inhibition of cell viability for geraniol at concentrations 10–100 μg/ml in barley cells. Only low cytotoxicity was observed in human lymphocytes depending on the concentration. No high clastogenicity for human lymphocytes and low enhancement of the frequencies both of chromosome aberrations and micronuclei were detected in barley. Geraniol showed a good radical-scavenging capacity similar to that of butylated hydroxytoluene (BHT), ascorbic acid and α- tocopherol. Geraniol applied at low nontoxic concentrations possessed a clearly expressed genoprotective potential and could inhibit the cytotoxic/genotoxic effects of MNNG reducing both the frequency of chromosome aberrations and micronuclei induced by the genotoxin. The anti-cytotoxic/anti-genotoxic effects were independent of the experimental schemes of treatment and the test-systems. The obtained results will be useful for further investigations concerning the pharmaceutical and medical application of the monoterpenoid geraniol.

A. Alexandrova12, a_alexandrova_bas@yahoo.com, ORCID: 0000-0002-7007-3665, L. Petrov1, dr.lubomir.petrov @gmail.com, ORCID: 0000-0003-1209-959X, R. Makaveev1, racho74@abv.bg, ORCID: 0000-0002-7670-9222, E. Tsvetanova2, elina_nesta@abv.bg, ORCID: 0000-0002-5916-5200, A. Georgieva2, almirageorgieva@gmail.com, ORCID: 0000-0003-1323-2348, S. Kolimechkov1, dr.stefan.kolimechkov@gmail.com, ORCID: 0000-0003-0112-2387 1National Sports Academy, Sofia, Bulgaria, 2Bulgarian Academy of Sciences, Sofia, Bulgaria Александрова Альбена, PhD, доцент кафедры физиологии и биохимии, Национальная спортивная академия; лаборатория свободнорадикальных процессов, Институт нейробиологии, Болгарская академия наук. Болгария, г. София, 1113, ул. Академика Бончева, 23. E-mail: a_alexandrova_bas@yahoo.com, ORCID: 0000-0002-7007-3665. Петров Любомир, PhD, доцент кафедры физиологии и биохимии, Национальная спортивная академия. Болгария, г. София, 1700, ул. Академик Стефан Младенов, 21. E-mail: dr.lubomir.petrov @gmail.com, ORCID: 0000-0003-1209-959X. Макавеев Рашо, PhD, доцент кафедры реслинга и дзюдо, тренерский факультет, Национальная спортивная академия. Болгария, г. София, 1700, ул. Академик Стефан Младенов, 21. E-mail: racho74@abv.bg, ORCID: 0000-0002-7670-9222. Цветанова Элина, PhD, лаборант лаборатории свободнорадикальных процессов, Институт нейробиологии, Болгарская академия наук. Болгария, г. София, 1113, ул. Академика Бончева, 23. E-mail: elina_nesta@abv.bg, ORCID: 0000-0002-5916-5200. Георгиева Альмира, лаборант лаборатории свободнорадикальных процессов, Институт нейробиологии, Болгарская академия наук. Болгария, г. София, 1113, ул. Академика Бончева, 23. E-mail: almirageorgieva@gmail.com, ORCID: 0000-0003-1323-2348. Колимечков Стефан, PhD, научный сотрудник кафедры физиологии и биохимии, Национальная спортивная академия. Болгария, г. София, 1700, ул. Академик Стефан Младенов, 21. E-mail: dr.stefan.kolimechkov@gmail.com, ORCID: 0000-0003-0112-2387. Aim. The aim of this study was to determine the changes in the erythrocyte oxidative status of the wrestlers after performing the maximal aerobic test, by registering in erythrocytes the levels of lipid peroxidation (LPO), total glutathione (tGSH) and activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx). Materials and methods. A group of 12 healthy wrestlers conducted a treadmill maximal aerobic test, and venous blood samples were obtained before and immediately after the exercise. Erythrocytes were separated from plasma and used for spectrophotometric determination of LPO, tGSH and enzyme activities. Plasma was used for determination of hemoglobin concentration (Hb) as an index of hemolysis. Results. The performance of the maximal aerobic test resulted in a significant increase of Hb in blood plasma, a decrease of LPO, and no changes of the tGSH level in erythrocytes. In regards to antioxidant enzymes, our results showed an increase in the activity of GPx, while the CAT and SOD activity remain unchanged. Conclusions. It can be concluded that in active athletes, predominate erythrocytes that are more resistant to oxidative stress, because of the accelerated hemolysis induced by physical exercise, lead to the elimination of the old and oxidative modified cells. Цель. Данное исследование проводилось с целью выявления изменений в оксидатив- ном статусе эритроцитов у борцов после выполнения максимального аэробного теста. В рамках исследования проводилась регистрация уровня пероксидации липидов, общего глутатиона, активности каталазы, супероксиддисмутазы и глутатионпероксидазы. Материалы и методы. 12 здоровых борцов приняли участие в максимальном аэробном тесте на беговой дорожке. Перед тестированием и сразу после выполнения упражнения у участников были взяты образцы венозной крови. Из плазмы крови были выделены эритроциты, в которых методом спектрофотометрии были исследованы пероксидация липидов, общий глутатион и активность ферментов. Плазма была также использована для определения концентрации гемоглобина как показателя гемолиза. Результаты. Выполнение максимального аэробного теста спровоцировало значительное повышения уровня гемоглобина в плазме крови и снижение пероксидации липидов, однако никак не повлияло на уровень общего глутатиона в эритроцитах. Что касается антиоксидантных ферментов, то результаты анализа показали увеличение активности глутатионпероксидазы, при этом активность каталазы и супероксиддисмутазы осталась на том же уровне. Заключение. Можно прийти к выводу, что у активных спортсменов преобладают эритроциты, которые более устойчивы к оксидативному стрессу вследствие ускоренного гемолиза, спровоцированного физическими упражнениями, которые приводят к удалению старых и оксидативно модифицированных клеток.

This study aimed to establish the sensitivity of Muscovy duck semen to oxidative stress (OS) and the effect of Desferal, applied as an antioxidant. The effect of three prooxidant systems in presence and absence of Desferal were tested on the motility and kinetic parameters (determined using CASA system), as well as the level of lipid peroxidation (LPO) and glutathione (tGSH) of Muscovy semen. The semen was diluted (1:3 v/v) with four extenders (saline solution, IMV Canadyl, HIA-1, and AU) and stored at 4 °C for 6 h. The cooled semen was divided into aliquots (50 × 10

Plants from the Rosacea family are rich in natural molecules with beneficial biological properties, and they are widely appreciated and used in the food industry, perfumery, and cosmetics. In this review, we are considering Rosa damascena Mill., Rosa alba L., Rosa centifolia L., and Rosa gallica L. as raw materials important for producing commercial products, analyzing and comparing the main biological activities of their essential oils, hydrolates, and extracts. A literature search was performed to find materials describing (i) botanical characteristics; (ii) the phytochemical profile; and (iii) biological properties of the essential oil sand extracts of these so called “old roses” that are cultivated in Bulgaria, Turkey, India, and the Middle East. The information used is from databases PubMed, Science Direct, and Google Scholar. Roses have beneficial healing properties due to their richness of beneficial components, the secondary metabolites as flavonoids (e.g., flavones, flavonols, anthocyanins), fragrant components (essential oils, e.g., monoterpenes, sesquiterpenes), and hydrolysable and condensed tannins. Rose essential oils and extracts with their therapeutic properties—as respiratory antiseptics, anti-inflammatories, mucolytics, expectorants, decongestants, and antioxidants—are able to act as symptomatic prophylactics and drugs, and in this way alleviate dramatic sufferings during severe diseases.

Allium siculum Ucria is a perennial bulbous plant that occurs in Bulgaria as A. siculum subsp. dioscoridis (Sm.) K. Richt. The plant is locally known as “samardala”. Its herbage is used traditionally by local communities in Bulgaria as edible green and for preparation of salty spice mixtures. The study was focused on the documentation of traditional knowledge about samardala, covering local collection and cultivation practices, processing methods and consumption preferences. The respondents (aged 30–86 years, 50% over 65) were local producers and small-scale salesmen of the herbage and samardala-containing spices. To assess the health features of samardala spices the total phenol and flavonoid content was measured in home-consumed or marketed flavoured salts. Overall appreciation of the plant and related food products was found to be very high; presenting a considerable engagement of the locals in plant cultivation and gathering, laborious processing and consumption. Traditional ecological knowledge about the biology, phenology and ecology of the samardala plant and methods for its processing is still preserved by elderly people who rely mostly on their own cultivated plants. Although the introduction of modern appliances has altered the method of production, its main stages and the recipes are preserved. Modernization of the processing method has not affected the quality of the products and faster processing could be a contributing factor for the higher content of biologically active substances. Phenolic content was about twice as low as the flavonoid content, following the same pattern for all tested flavoured salts. Measures for better management of natural populations and promotion of cultivation practices of A. siculum subsp. dioscoridis would ensure the sustainable quality of traditional products as well as conservation of the natural plant resources.

Rosa alba L., also known as the white oil-bearing rose, has been cultivated in relatively small areas of Europe – predominantly in the Rose Valley of Bulgaria. An increasing number of studies in vitro and in vivo, including clinical studies, have demonstrated the therapeutic efficacy of rose oils in recent years. However, little is known about the cytotoxic and genotoxic potential of the phytocomplex oil extract derived from Rosa alba L. The aim of the present work was to investigate the cytotoxicity and clastogenic effects of Rosa alba L. essential oil and its main constituent – geraniol, as well as citral A, associated with allergies and contact dermatitis. We used classical cytogenetic methods and comet assay. 1-Methyl-3-nitro-1-nitrosoguanidine was used as a standard mutagen. The data showed that R. alba L. essential oil (in concentrations up to 1000 μg/mL) did not exhibit a statistically significant cytotoxic effect. The essential oil did not significantly increase the level of mitotic disturbances (micronuclei and aneuploidy effects) and had no significant effect on the induction of chromatid aberrations, compared to the untreated control sample. Only geraniol and citral A (in the concentrations used) increased significantly the percentage of migrated DNA in the comet tail, compared to the whole oil extract. This study gives a reason to believe that R. alba L. oil has potential as a supplementary component in some therapeutic strategies. It would be harmless to normal cells and tissues, but with potential for additive or synergistic cytotoxicity against cancer cells.

The pathogenesis of many diseases and different pathological conditions, including inflammation, is associated with excess production of reactive oxygen species (ROS). The present study aimed to investigate the effects of the antidepressant desipramine (DES) on carrageenan (CG)-induced inflammation, as well as on the endogenous levels of cell enzyme and non-enzyme antioxidants in rat liver and spleen, 4 and 24 h after CG injection. The intra-plantar CG injection into the right hind paw resulted in a time-dependent increase in the paw volume; the maximum of CG-induced edema peak was in 2–4 h. A single DES dose of 20 mg·kg−1, administered 30 min before CG, had no effect on paw edema, whereas the higher drug dose used (50 mg·kg−1) suppressed the edematous response to CG. The latter drug dose protected CG-induced decrease of glutathione (non-enzyme antioxidant) in the liver; it did not affect CG-unchanged activities of superoxide dismutase, glutathione peroxidase (enzyme antioxidants) and glucose-6-phosphate dehydrogenase (enzyme, important for the activity of glutathione-conjugated antioxidant enzymes) in both liver and spleen. The drug showed an efficient antioxidant capacity in ROS-generating chemical systems; it was higher than that of fluoxetine (another type of antidepressant). The present results suggest that the good antioxidant activity of DES might contribute to its beneficial effects in liver injuries. Copyright © 2011 John Wiley & Sons, Ltd.

The in vivo effects of nociceptin (N/OFQ(1-13)NH(2) ) and its structural analogues ([Dab(9) ]N/OFQ(1-13)NH(2) , [Dap(9) ]N/OFQ(1-13)NH(2) and [Cav(9) ]N/OFQ(1-13)NH(2) ) on the levels of lipid peroxidation and cell antioxidants (enzyme and non-enzyme) in brain of control and kainic acid (KA)-treated rats were studied. In control animals, [Dab(9) ]N/OFQ(1-13)NH(2) and [Dap(9) ]N/OFQ(1-13)NH(2) , unlike N/OFQ(1-13)NH(2) and [Cav(9) ]N/OFQ(1-13)NH(2) , slightly increased the brain lipid peroxidation; the rest of the parameters were unchanged by all neuropeptides tested. KA (0.25 µg in 0.5 µl, i.c.v) increased the lipid peroxidation (4 and 24 h after KA-injection) and decreased the glutathione level (1 h after KA-administration). One hour after KA-administration, the neuropeptides (2 µg in 0.5 µl, injected 30 min before KA) showed the following effects: a slight decrease in the KA-induced lipid peroxidation by all nociceptin analogues and an enhancement of the KA-decreased GSH level, but by [Cav(9) ]N/OFQ(1-13)NH(2) only. The brain antioxidant enzyme activities were unchanged in all used experimental groups. In addition, the nociceptin analogues, especially [Can(9) ]N/OFQ(1-13)NH(2) , showed a good antioxidant capacity in chemical systems, generating reactive oxygen species. In conclusion, the substitution of lysin (Lys) in N/OFQ(1-13)NH(2) molecule with other amino acids might contribute to changes in its antioxidant properties. Copyright © 2011 John Wiley & Sons, Ltd.

Aim: Previous studies have shown that proteasome inhibitors exerted protective effects against ischemia/reperfusion injury (IRI) of brain, heart, kidney and intestine. The aim of the present study was to investigate: (i) whether the proteasome inhibitor MG132 protects rat liver against IRI; and (ii) whether MG132 modulates prooxidant/antioxidant status of rat liver subjected to warm IRI. Methods: The left lateral and medial lobes (approximately 70% of the total liver volume) of livers of male Wistar rats were subjected to 30-min ischemia followed by 60-min reperfusion. Lactate dehydrogenase (LDH), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) levels were measured in the plasma. Proteasome chymotryptic-like (ChT-L) activity, levels of thiobarbituric acid-reactive substances (TBARS), protein carbonyls (PC) and glutathione (GSH), as well as superoxidase dismutase (SOD), catalase (CAT), glutathionine peroxidase and glutathionine reductase activities were measured in liver fractions. Results: Thirty-min ischemia followed by 60-min reperfusion increased liver TBARS and PC, CAT and SOD activities, but decreased GSH level. Ischemia/reperfusion-induced oxidative stress was exacerbated in mitochondria, indicating that these organelles are the preferential target of IRI. Plasma LDH and AST levels were decreased by MG132 during both ischemia and reperfusion, while ALT values were decreased only after 30 min of reperfusion. MG132 did not significantly affect liver TBARS and GSH levels, but it increased PC and decreased ChT-L activity; the activities of CAT and SOD were also decreased. Conclusions: MG132 exerts a protective effect during the early phase of reperfusion and it modulates prooxidant/antioxidant status of rat liver subjected to warm IRI.

In vivo effects of N-benzyloxycarbonyl (Cbz)-Leu–Leu-leucinal (MG132) on chymotryptic-like (ChT-L), tryptic-like, and post-glutamyl peptide hydrolytic-like proteasome activities, protein oxidation, lipid peroxidation (LP), glutathione (GSH) level, as well as on the activity of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione-reductase) in the rat liver were studied. The possibility of MG132 provoking the formation of free oxygen radicals was also assayed in primary hepatocytes. The following results were obtained: (1) In vivo, MG132 did not change the spontaneous LP, but increased Fe-induced LP and the amount of oxidized proteins; it decreased the GSH level in liver. From the proteasome activities studied in liver cytosol only ChT-L activity was significantly decreased after MG132 administration. Furthermore, MG132 increased antioxidant enzyme activities of SOD, CAT, and GSH-Px. (2) In vitro, MG132 increased free radical oxygen species in hepatocytes; this effect disappeared in the presence of CAT or mannitol. In conclusion, since nowadays proteasome inhibitors are entering into the swing of laboratory and clinical practice, the present data could provide useful information for MG132 action. Consequently, future in vivo experiments with MG132 could highlight the possibility of its use at different pathological conditions. Copyright © 2008 John Wiley & Sons, Ltd.

Summary 1 In vitro studies of the potential antioxidant activity of the selective cyclo-oxygenase-2 inhibitor celecoxib and the non-steroid anti-inflammatory drug amtolmetin guacyl (AMG) were carried out. The study included experiments on the ability of these drugs to affect some indices of the oxidative stress [lipid peroxidation (LP), activity of antioxidant enzymes, glutathione (GSH) level] in rat stomach and colon mucosa and in liver. 2 Celecoxib and AMG did not change the activity of the enzymes GSH-peroxidase, oxidased glutathione (GSSG)-reductase and glucose-6-phosphate-dehydrogenase, as well as the GSH level in all tissue preparations. An increased superoxide dismutase (SOD) activity and a tendency to a decreased Fe/ascorbic acid-induced LP in stomach and colon mucosa were found, but only in the presence of AMG. 3 In the liver, both celecoxib and AMG decreased spontaneous and Fe/ascorbic acid-induced LP. SOD activity was enhanced only in the presence of AMG. 4 Experiments aimed at studying celecoxib and AMG in free oxygen radical-generating systems were also carried out. AMG and tolmetin (the main metabolite of AMG) inhibited OH•-provoked deoxyribose degradation in a Fenton system. Celecoxib had no effect on free radicals when tested in the same system. 5 In conclusion, the results of the present in vitro studies suggest that AMG and celecoxib possess antioxidant and metal-chelating abilities, which might contribute to their beneficial effects.

The in-vivo effects of alloxan on protein oxidation and lipid peroxidation, as well as on proteasome and antioxidant enzyme activities in liver and kidney of copper-loaded and iron-loaded rats, were studied. In control animals, a single alloxan dose (120 mg/kg, i.p.) increased blood-glucose concentration at the 24th hr and 48th hr and, especially, on the 5th day. For these periods of alloxan action, no changes in lipid peroxidation and antioxidant enzyme activities were found; only a slight increase of carbonyl content and strong increase of trypsin-like proteasome activity in rat liver on the 5th day was observed. Five days after alloxan injection, the blood-glucose concentration in iron-pretreated rats was similar to that of the controls. However, it was significantly lower in copper-pretreated animals; hence, insulin-mimetic action of copper might be suggested. The lower proteasome activity, measured in liver of copper-pretreated diabetic rats is probably due to a potential copper-chelating ability of alloxan. The present results showed that the action of alloxan was different in copper-and iron-pretreated rats. Analogous studies, using pretreatment with other metals, would contribute to a further elucidation of the role of different metals in diabetes development, especially in regions with environmental metal contamination.

The present study aimed to investigate the effects of pentoxifylline (PTX) on the carrageenan (CG)-induced paw oedema and on the endogenous levels of cell enzyme and non-enzyme antioxidants in rat liver, 4 and 24 h after CG injection. PTX (50 mg kg(-1) , i.p.), administered 30 min before CG, decreased the paw oedema, 2-4 h after CG administration. The drug protected CG-induced decrease of glutathione (non-enzyme antioxidant) and had no effect on CG-unchanged activities of superoxide dismutase, glutathione peroxidase (enzyme antioxidants) and glucose-6-phosphate dehydrogenase (enzyme, important for the activity of GSH-conjugated antioxidant enzymes). The drug showed a good antioxidant capacity in chemical systems, generating reactive oxygen species. The present results suggest that the antioxidant activity of PTX might contribute to its beneficial effects in liver injuries.

The in vivo effects of nociceptin (N/OFQ(1-13)NH(2) ) and its structural analogues ([Dab(9) ]N/OFQ(1-13)NH(2) , [Dap(9) ]N/OFQ(1-13)NH(2) and [Cav(9) ]N/OFQ(1-13)NH(2) ) on the levels of lipid peroxidation and cell antioxidants (enzyme and non-enzyme) in brain of control and kainic acid (KA)-treated rats were studied. In control animals, [Dab(9) ]N/OFQ(1-13)NH(2) and [Dap(9) ]N/OFQ(1-13)NH(2) , unlike N/OFQ(1-13)NH(2) and [Cav(9) ]N/OFQ(1-13)NH(2) , slightly increased the brain lipid peroxidation; the rest of the parameters were unchanged by all neuropeptides tested. KA (0.25 µg in 0.5 µl, i.c.v) increased the lipid peroxidation (4 and 24 h after KA-injection) and decreased the glutathione level (1 h after KA-administration). One hour after KA-administration, the neuropeptides (2 µg in 0.5 µl, injected 30 min before KA) showed the following effects: a slight decrease in the KA-induced lipid peroxidation by all nociceptin analogues and an enhancement of the KA-decreased GSH level, but by [Cav(9) ]N/OFQ(1-13)NH(2) only. The brain antioxidant enzyme activities were unchanged in all used experimental groups. In addition, the nociceptin analogues, especially [Can(9) ]N/OFQ(1-13)NH(2) , showed a good antioxidant capacity in chemical systems, generating reactive oxygen species. In conclusion, the substitution of lysin (Lys) in N/OFQ(1-13)NH(2) molecule with other amino acids might contribute to changes in its antioxidant properties. Copyright © 2011 John WileySons, Ltd.

Copper toxicity is associated with formation of reactive oxygen species, which are capable to oxidize proteins. The selective removal of the latter by the 20S proteasome is considered an essential part of the cell antioxidant defense system. The aim of the present study was to investigate whether peptidase activities of rat liver proteasomes were affected by chronic (40 mg CuSO(4)/rat/daily with the drinking water for 2 weeks) and acute (20 mg/kg CuSO(4), s.c.) copper treatment. To evaluate the role of proteasome, its inhibitor MG132 was also used. The degree of copper-induced oxidative stress (OS), established by measuring lipid peroxidation, protein oxidation, and cellular glutathione level, as well as activities of antioxidant enzymes--catalase, superoxide dismutase, and gultathionine peroxidase, depended on the mode of copper administration. Chronic copper administration (mild oxidative stress) did not affect proteasome activities, whereas acute copper treatment (severe oxidative stress) caused a decline in chymotryptic- and tryptic-like activities. The treatment of copper-loaded animals with MG132 did not change copper-induced alterations in the tested indices, except an additional increase in protein oxidation and inhibition of glutathionine peroxidase activity. The results suggested that the in vivo copper-induced oxidative stress was associated with changes in the catalytic activity of proteasome.

The in vitro effects of arachidonyl-2-chloroethylamide (ACEA; a selective CB(1)-receptor agonist) and N-piperidin-l-yl)-5-(4-chlorophenyl)-1-(2,4-cochlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (SR141716A; a selective CB(1)-receptor antagonist) on lipid peroxidation (spontaneous and Fe (2+)-induced), total glutathione (GSH)-level and activity of antioxidant enzymes (superoxide dismutase, glutathione peroxidase and glutathione reductase) in the rat brain were studied. The effects of these CB(1)-induced), total glutathione (GSH)-level and activity of antioxidant enzymes (superoxide dismutase, glutathione peroxidase and glutathione reductase) in the rat brain were studied. The effects of these CB(1)-ligands in Fenton system (generating *OH radicals) were also examined. The cannabinoids did not change the total GSH-level and were without effects on the activity of antioxidant enzymes in the rat brain. These results proved a lack of in vitro pro-oxidant activity of the CB(1)-receptor ligands, as well as a lack of direct effects on GSH and enzyme molecules. ACEAand SR141716A were without effect on spontaneous lipid peroxidation, but decreased the Fe(2+)-induced brain lipid peroxidation and OH-provoked deoxyribose degradation in Fenton system. It can be suggested that the tested cannabinoids possess a metal-chelating activity, which might contribute to an antioxidant activity. The data, obtained in this study offer a background for investigation of the in vivo effects of these CB(1)-receptor ligands on antioxidant defense systems in the brain of healthy animals and animals, previously subjected to oxidative stress.