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The prevention of biological damage brought about by free radical mediated mechanisms can be achieved by specific chemical scavengers which trap free radicals as well as by protective enzymes that remove hydrogen peroxide or superoxide radicals. The aim of this study was to carry out a comparative analysis of enzymes acting against free-radicals and peroxides in Trichinella spiralis, T. nelsoni and T. pseudospiralis isolates. The activity of superoxide dismutase in T. pseudospiralis was about two times higher than in T. spiralis and about 1.5 times higher than that of T. nelsoni. In all the isolates only one band representing superoxide dismutase was identified on electrophoretic analysis. Catalase and peroxidase activities were very low. Using electrophoretical analysis we found three identical bands of peroxidase activity in the species investigated. Our data suggest that, with regard to the anti-oxidant enzymes, superoxide dismutase plays an important role whereas peroxidase and catalase play lesser roles in the defence of Trichinella spp. larvae against host generated free radicals released during the response to infection.
Biological damage brought about by free radical mediated mechanisms can be prevented either by specific chemical scavengers or by protective enzymes that neutralise the radicals or their precursors. Protection can also occur by repair of damage once it has occurred. This review summarises studies of the major biochemical defence mechanisms against oxidants and free radicals and the mechanisms that repair oxidatively damaged proteins. These mechanisms may be a field in the search for improved ways to inhibit parasite survival.
Inhibition of oxidation of 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) by free radicals generated by decomposition of 2,2'-azobis(2-amidopropane) (ABAP) by antioxidants and biological material was studied. A correlation was found between the ability of various substances to delay the onset of ABTS oxidation and their rapid reduction of the ABTS+* cation radical, and between the ability to reduce the maximal rate of ABTS oxidation and slow reduction of ABTS+*. The length of the lag period of ABTS oxidation was found to be independent of ABTS concentration. Similar decrease of peroxynitrite-induced ABTS+* formation by antioxidants was observed when the antioxidants were added before and after peroxynitrite. All these findings indicate that the main effect of antioxidants in this system is reduction of ABTS+* and not prevention of its formation. Reduction of oxidation products rather than inhibition of their formation may be the predominant mode of action of antioxidants in various assays of antioxidant activity.
Bee pollen is a product of rich and varied chemical composition, and its biological activities are diverse. Many of these activities are related to the antioxidant effect of bee pollen. The aim of this study was to determine the effect of storage conditions on the antioxidant activity of bee pollen extracts. The study was conducted on three types of bee pollen extracts, namely, ethanol and pepsin extracts of bee pollen, as well as on ethanol extracts of pepsin-digested bee pollen. Antioxidant activity was determined by a DPPH method, directly after obtaining the extracts and after storing them for twelve months under various conditions, i.e. at –18°C in the dark, at 4-8°C in the dark, at room temperature in the dark, and at room temperature in the light. It was concluded that the 12-month storage of bee pollen extracts caused a decrease in the antioxidant activity of all extracts examined, and the decrease depended on storage conditions. The highest decrease in antioxidant activity was observed in all types of extracts stored at room temperature in the light. The lowest decrease in antioxidant activity was found in ethanol extracts of pepsin-digested bee pollen.
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The current study was intended to evaluate abortifacient and antioxidant activity of Avicennia marina leaves extracts. Abortifacient activity was evaluated in rats, compared with standard drug (Mifepristone) and antioxidant activity was evaluated by using three free radicals (Superoxide, Hydroxyl and DPPH) compared with Ascorbic acid. The extracts were showed pre implantation loss, post implantation loss of implantations and decreased the survival ration of foetuses. Among all extracts hydroalcoholic extract showed better activity. The selected plant extracts showed concentration dependent percentage inhibition of free radicals. Among three extracts hydroalcoholic extract showed better activity with IC50 values on superoxide, hydroxyl and DPPH radicals were 203μg, 237μg and 143μg. From the results obtained during the study it the hydroalcoholic extract was used for the isolation of pure compounds, and isolated the different compounds (β-sitosterol, Lupeol and Betulinic acid).
The aim of the study was to examine the toxic effect of different doses of zearalenone on liver cells by estimating mycotoxin influence on antioxidant systems and on formation of free radicals in the liver. The research was carried out on male Wistar rats. The rats were divided into nine groups of 10 animals each. Group A was orally given 8% ethyl alcohol once a day for 10 d. Groups B, C, D, and E were given, orally once a day 50, 100, 200, and 500 µg/kg b.w. of zearalenone in alcohol solution for 10 days. The animals from groups X, Y. and Z received a single dose of 1, 2, and 3 mg/kg b.w of zearalenone, respectively, and group W (control) - a single dose of 8% ethyl alcohol. The liver was removed and homogenised. Glutathione peroxidase and superoxide dismutase activities, and concentration of L-ascorbic acid in the homogenate were determined. Received outcome and statistical analysis showed the essential fall of superoxide dismutase activity after 10 d of administering 200 and 500 µg/kg b.w of ZEA in comparison with the control group, and drop of glutathione peroxidase activity after 500 µg/kg b.w. dose. The results of the experiment showed that oxidative stress is one of the main toxic effects of zearalenone activity. Low doses of zearalenone applied for a long time do not have an influence on free radical reaction. Short-lasting zearalenone influence does not cause changes in the activity of antioxidant enzymes.
Stimulation of neutrophils by different factors increases their oxidative activity and the free radicals produced can report on the degree of activation. Poly(adenosine 5’-diphosphate ribose)polymerase-1 (PARP-1), a nuclear enzyme activated by strand breaks in DNA, plays an important role in the tissue injury associated with ischaemia-reperfusion injury and inflammation. 5-Aminoisoquinolin-1-one (5-AIQ) is a potent inhibitor of PARP-1 activity in vitro and in vivo in rats. Acute (80 min) and prolonged (24h) focal cerebral ischaemia was induced in rats by obstruction of the median cerebral artery, with or without reperfusion, with or without administration of 5-AIQ. The oxidative activity of neutrophils was measured by chemiluminescence. Administration of 5-AIQ.HCl (3.0 mg kg-1 b.w. - i.v.) caused a significant decrease in the oxidative activity of neutrophils in the group which had experienced chronic ischaemia for 24h but had no significant effect in the group which had received 80 min ischaemia, when compared to the control group. Increase of the oxidative activity of neutrophils was confirmed in rats with prolonged cerebral ischaemia, followed by reperfusion. 5-AIQ probably may decrease this activity through inhibition of PARP-1 in focus of local ischaemia as well as hence lowering the expression of inflammatory mediators by activated neutrophils.
Background. Free radicals play a key role in the development of several pathological conditions. Therefore, antioxidants (AOs) are the first line of defense against free radical damage and are critical for maintaining optimum health and wellbeing. Objectives: To assess the perception of dental practitioners regarding use of antioxidants in oral health. Method. A cross-sectional questionnaire study was conducted among 296 dental practitioners in Tricity (Chandigarh, Mohali, Panchkula, India). A self-structured close-ended questionnaire was used to assess the perception of dentists regarding the use of antioxidants in their patients. It consisted of 12 questions with dichotomous response and five point likert scale ranging from strongly agree to strongly disagree. Descriptive statistics were used to summarize the data, followed by the Chi-square test to check significant differences between the responses. Correlation between responses were analysed through the Spearman’s rank correlation. Statistical analysis was done using Statistical Package for Social Sciences version 20 (Illinois, Chicago, USA). Results. A statistically significant difference was observed between genders, with females 181 (61%) having more knowledge than males 115 (39%) regarding the use of antioxidants in their clinical practice. It has been found that dental professionals in academics prescribes more antioxidants to their patients than the private practitioners. Postgraduates 76 (77.6%) had a higher level of knowledge than graduates 86 (43%). Conclusions. Knowledge about antioxidants should be highlighted in the health sciences curriculum. It is recommended to expand the use of antioxidants in oral health to bring down the burden of chronic diseases like periodontitis and catastrophic diseases like precancerous lesions and oral cancer.
This study was planned to assess the antioxidant and free radical scavenging effect of D-carvone against L-NAME (Nω-nitro-L-arginine methyl ester hydrochloride) induced hypertension. Hypertension was encouraged in adult male albino rats of the Wistar strain, considering 180–230 g, by oral administration of the L-NAME (40 mg/kg/ body weight/day) in drinking water for 4 weeks. Rats were cured with D-carvone (5, 10 and 20 mg/kg body weight) for four weeks. A significant reduction in the levels of non-enzymatic antioxidants such as vitamin C, vitamin E and reduced glutathione (GSH), in plasma were perceived in L- NAME induced hypertensive rats. Moreover, in vitro free radical scavenging activity of ABTS+ and DPPH• radical scavenging possible of D-carvone was also quantified. Treatment with D-carvone (5, 10 and 20 mg/kg bw) carries back all the above parameters to near usual level, in which 20 mg/kg displayed the highest effect than that of other two doses. Further, D-carvone displays concentration dependent antioxidant potential. These results suggest that D-carvone acts as an antioxidant and free radical scavenging agent against L-NAME induced hypertension.
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