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Tytuł:
Inhibitory effect of resveratrol on free radical generation in blood platelets
Autorzy:
Olas, Beata
Żbikowska, Halina
Wachowicz, Barbara
Krajewski, Tadeusz
Buczyński, Andrzej
Magnuszewska, Arleta
Powiązania:
https://bibliotekanauki.pl/articles/1044455.pdf
Data publikacji:
1999
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
resveratrol
blood platelet
free radicals
Opis:
Resveratrol (3,4',5-trihydroxystilbene), a compound found in many plants, has been shown to prevent coronary heart diseases and to exert a variety of antiinflammatory and anticancerogenic effects. It is effective in lowering the level of serum lipids and in inhibiting platelet aggregation. We evaluated the effect of trans-resveratrol on the production of free radicals in pig blood platelets and showed that resveratrol inhibited the production of different reactive oxygen species (O^·_2H^2O^2, singlet oxygen and organic radicals) measured by the luminol-dependent chemiluminescence in resting platelets (P < 0.05). Resveratrol inhibited also the generation of radicals in platelets activated by thrombin (P < 0.05). Treatment of platelets with resveratrol at concentrations of 6.25 and 12.5 μg/ml caused a statistically insignificant increase in the production of O^·-_2 in these cells, as measured by reduction of cytochrome c; however, at higher doses (25, 50 and 100 μg/ml) resveratrol distinctly reduced the generation of O^·-_2 in platelets (P < 0.05). We suggest that free radicals play an important role in the reduced reactivity of blood platelets induced by resveratrol.
Źródło:
Acta Biochimica Polonica; 1999, 46, 4; 961-966
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interactions of dietary carotenoids with singlet oxygen (1O2) and free radicals: potential effects for human health
Autorzy:
Böhm, Fritz
Edge, Ruth
Truscott, T
Powiązania:
https://bibliotekanauki.pl/articles/1039764.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
dietary carotenoids
singlet oxygen
free radicals
redox potentials
Opis:
The dietary carotenoids provide photoprotection to photosynthetic organisms, the eye and the skin. The protection mechanisms involve both quenching of singlet oxygen and of damaging free radicals. The mechanisms for singlet oxygen quenching and protection against free radicals are quite different - indeed, under some conditions, quenching of free radicals can lead to a switch from a beneficial anti-oxidant process to damaging pro-oxidative situation. Furthermore, while skin protection involves β-carotene or lycopene from a tomato-rich diet, protection of the macula involves the hydroxyl-carotenoids (xanthophylls) zeaxanthin and lutein. Time resolved studies of singlet oxygen and free radicals and their interaction with carotenoids via pulsed laser and fast electron spectroscopy (pulse radiolysis) and the possible involvement of amino acids are discussed and used to (1) speculate on the anti- and pro-oxidative mechanisms, (2) determine the most efficient singlet oxygen quencher and (3) demonstrate the benefits to photoprotection of the eye from the xanthophylls rather than from hydrocarbon carotenoids such as β-carotene.
Źródło:
Acta Biochimica Polonica; 2012, 59, 1; 27-30
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EPR examination of free radicals thermally formed in vaselinum flavum
Autorzy:
Ramos, P.
Pilawa, B.
Powiązania:
https://bibliotekanauki.pl/articles/148032.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
vaselinum flavum
thermal sterilization
free radicals
EPR spectroscopy
Opis:
The popular pharmaceutical base used in pharmacy – vaselinum flavum – was studied by an X-band (9.3 GHz) EPR spectrometer in the range of microwave power of 2.2–70 mW. The samples were sterilized in hot air oven at temperatures: 160°C (120 min), 170°C (60 min), and 180°C (30 min). The aim of this work was to determine properties and free radical concentrations in vaselinum flavum thermally sterilized at different conditions. The changes in free radical system in vaselinum flavum during storage were analyzed. Free radicals were found in all the heated samples. The lowest free radical concentration was obtained for vaselinum flavum heated at 180°C for 30 min; so these parameters are proposed for the thermal sterilization of this pharmaceutical base. Interactions with oxygen decreased free radical concentration in vaselinum flavum during storage. Strong quenching of free radicals in vaselinum flavum was observed after 2 days for the samples sterilized at temperatures 160 and 180°C. Such an effect for vaselinum flavum heated at temperature 170°C was observed later, 13 days after sterilization. Fast spin-lattice relaxation processes exist in thermally sterilized vaselinum flavum. The EPR lines of heated vaselinum flavum were homogeneously broadened. EPR spectroscopy and its use for examining the thermal sterilization process in pharmacy was confirmed.
Źródło:
Nukleonika; 2015, 60, No. 3, part 1; 443-447
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Human tissue investigations using PALS technique - free radicals influence
Autorzy:
Jasińska, B.
Zgardzińska, B.
Chołubek, G.
Pietrow, M.
Gorgol, M.
Wiktor, K.
Wysogląd, K.
Białas, P.
Curceanu, C.
Czerwiński, E.
Dulski, K.
Gajos, A.
Głowacz, B.
Hiesmayr, B.
Jodłowska-Jędrych, B.
Kamińska, D.
Korcyl, G.
Kowalski, P.
Kozik, T.
Krawczyk, N.
Krzemień, W.
Kubicz, E.
Mohammed, Muhsin
Pawlik-Niedźwiecka, M.
Niedźwiecki, S.
Pałka, M.
Raczyński, L.
Rudy, Z.
Sharma, N.
Sharma, S.
Shopa, R.
Silarski, M.
Skurzok, M.
Wieczorek, A.
Wiktor, H.
Wiślicki, W.
Zieliński, M.
Moskal, P.
Powiązania:
https://bibliotekanauki.pl/articles/1057941.pdf
Data publikacji:
2017-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
positron annihilation
positronium
free radicals
tissues
uterine leiomyomas
Opis:
The positron annihilation lifetime spectroscopy was applied to the samples of the human uterine leiomyomas and the normal myometrium tissues taken from the selected place of the uterus during a surgery. The method indicated differences in values of the measured positron annihilation lifetime spectroscopy parameters (lifetimes and intensities) between healthy and diseased tissue samples. The additional measurements were performed either in darkness or in presence of visible light which influenced the free radicals present in both kind of tissues and, as a result, made changes in free annihilation and o-Ps decay lifetime and intensity values.
Źródło:
Acta Physica Polonica A; 2017, 132, 5; 1556-1558
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena koncentracji, trwałości i typu wolnych rodników powstających w tramadolu pod wpływem wysokiej temperatury
Evaluation of concentration, stability and types of free radicals generated in tramadole exposed to high temperature
Autorzy:
Pilawa, B.
Wilczyński, S.
Ramos, P.
Tomasik, A.
Powiązania:
https://bibliotekanauki.pl/articles/283751.pdf
Data publikacji:
2008
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
wolne rodniki
tramadol
leki
free radicals
tramadole
drugs
Opis:
Wpływ wysokiej temperatury na substancje biologicznie czynne jest szczególnie istotny w kontekście termicznej sterylizacji leków. Wysoka temperatura, zabójcza dla mikroorganizmów, może powodować zrywanie się wiązań chemicznych a co za tym idzie powstawanie produktów rozpadu. Wśród produktów rozpadu powstających pod wpływem działania wysokiej temperatury w substancjach leczniczych szczególne miejsce zajmują wolne rodniki. Ich wyjątkowa pozycja wynika z faktu, iż nawet niewielkie koncentracje wolnych rodników mogą powodować niebezpieczne następstwa podczas farmakoterapii zanieczyszczonymi substancjami leczniczymi. Ważny jest fakt, że wolne rodniki mogą negatywnie wpływać na pacjenta nawet w bardzo niewielkich stężeniach. Dotyczy to zwłaszcza leków podawanych parenteralnie, między innymi tramadolu. Tramadol jest syntetycznym lekiem przeciwbólowym o opioidowym i nieopioidowym mechanizmie działaniu [1-2]. Metodą, która pozwala na ilościowe oraz jakościowe pomiary wolnych rodników w termicznie sterylizowanych lekach jest spektroskopia elektronowego rezonansu paramagnetycznego EPR. Sterylizację termiczną tramadolu wykonano w suszarce z wymuszonym obiegiem powietrza w temperaturze 180°C. Czas sterylizacji wynosił 30 minut. Próbki miały postać sproszkowaną. Pomiary EPR wykonano za pomocą spektrometru elektronowego rezonansu paramagnetycznego na pasmo X (9.3GHz) produkcji RADIOPAN - Poznań. Zastosowano modulację pola magnetycznego wynoszącą 100kHz. Częstotliwość promieniowania mikrofalowego rejestrowano miernikiem MCM 101 produkcji RADIOPAN - Poznań. Widma EPR rejestrowano w postaci pierwszej pochodnej absorpcji przy wysokim tłumieniu 15dB, aby uniknąć nasycenia mikrofalowego linii. Całkowita moc mikrofalowa wytwarzana przez klistron wynosiła około 2.2mW. Wyznaczono następujące parametry widm EPR: amplitudę linii, szerokość linii oraz współczynnik rozszczepienia spektroskopowego g. Określono również koncentrację wolnych rodników oraz ich stabilność. Wzorcem zewnętrznym służącym wyznaczeniu koncentracji wolnych rodników w termicznie sterylizowanym tramadolu była ultramaryna. Natomiast wzorcem pomocniczym na trwale umieszczonym we wnęce rezonansowej był kryształ rubinu. Określono także wpływ mocy mikrofalowej na podstawowe parametry widm EPE - amplitudę i szerokość linii EPR. Dla tramadolu nie poddanego obróbce termicznej, nie obserwowano widm EPR. Oznacza to, że w badanej substancji leczniczej nie występują trwałe centra paramagnetyczne. Widma EPR badanego leku sterylizowanego w temperaturze 180°C stanowią asymetryczne szerokie linie (RYS. 1), co wskazuje na silne oddziaływania magnetyczne spin-spin w sterylizowanym termicznie tramadolu. Oddziaływania te poszerzają linie EPR i są charakterystyczne dla wolnych rodników położonych blisko siebie w strukturze molekularnej leku. Zarejestrowano wpływ mocy mikrofalowej na amplitudę i szerokość linii EPR. Taki charakter zmian (RYS. 2) wskazuje, że wolne rodniki w termicznie sterylizowanym tramadolu są rozmieszczone jednorodnie w całej objętości próbki. Zaobserwowano wpływ czasu przechowywania na koncentracje wolnych wodników (proporcjonalną do wartości amplitudy linii EPR) w termicznie sterylizowanym tramadolu (RYS. 3). Ilość wolnych rodników maleje w kolejnych dniach pomiarowych. Zjawisko to może być związane z procesami rekombinacji pomiędzy blisko siebie położonymi wolnymi rodnikami oraz interakcji z paramagnetycznym tlenem atmosferycznym. Nie zaobserwowano wpływu czasu przechowywania na szerokość linii EPR tramadolu. Wyznaczono współczynnik rozszczepienie spektroskopowego g świadczący o typie wolnych rodników znajdujących się w próbce. Otrzymany wynik g=0,0027 sugeruje, że niesparowane elektrony zlokalizowane są na atomach tlenu. Nie zaobserwowano wpływu czasu przechowywania na średni współczynnik rozszczepienia spektroskopowego g. Wszystkie przedstawione dane wskazują, że wysoka temperatura (180°C) powoduje generowanie się dużej ilości wolnych rodników. Asymetryczne, złożone linie EPR wskazują na istnienie kilku typów wolnych rodników w tramadolu poddanemu obróbce termicznej. Poszerzenie dipolowe linii EPR sugerują niewielkie odległości pomiędzy wolnymi rodnikami. Nasycenie mikrofalowe widm EPR wskazuje na jednorodne rozmieszczenie wolnych rodników w sterylizowanym termicznie tramadolu. Wraz z czasem przechowywania koncentracja wolnych rodników maleje.
Influence of high temperature on biologic active substances is particularly important in context of thermally sterilized drugs. High temperature, lethal for microorganisms, can cause cleavage of chemical bonds and consequent degradation products forming. Among degradation products formed under the influence of high temperature, free radicals are particularly important. Its special status result from fact that even very few free radicals concentrations can cause dangerous sequences during contaminated substances pharmacotherapy. It is important that free radicals even in very few concentrations can have negative influence on patients. It concerns especially parenterally administrated drugs, inter alia tramadole. Tramadole is a synthetic drug that acts analgesic with opioid and non-opioid effect [1,2]. EPR spectroscopy brings information about types and amount of free radicals in thermally sterilized drugs. Thermal sterilization of tramadole was performed in hot air oven with air circulating at 180°C. Sterilization was performed during 30 minutes. Powdered samples were analyzed. Measurements of EPR spectra were done by the use of EPR spectrometer produced by RADIOPAN Firm (Poznań). Modulation of magnetic field of 100kHz was applied. Microwave frequency was evaluated using MCM 101 frequency recorder produced by RADIOPAN - Poznań. The first-derivative EPR spectra were recorded with high microwave power attenuation 15dB to avoid the microwave saturation. Total microwave power produced by klystron was about 2.2mW. The following EPR parameters were determined: amplitude, linewidth and g-factor. Free radicals concentration and stability were also evaluated. Ultramarine was used as reference of paramagnetic centers concentration. A ruby crystal, permanently placed in resonance cavity, was the second reference. Influence of microwave power on basic EPR parameters: amplitude and linewidth of EPR lines were tested. For not heated tramadole EPR spectra were not observed. It indicates absence of stabile paramagnetic centers in initial substance. EPR spectra of the studied drug sterilized at 180°C have asymmetric, broad lines what indicates strong spin-spin magnetic interactions in thermally sterilized tramadole. These interactions causing broadening EPR lines and are characteristic for close located free radicals in molecular structure of the drug. Influence of microwave power on EPR line amplitude was observed. This kind of relationship indicates that free radicals in thermally sterilized tramadole are homogenously located in whole sample volume. Influence of sample storage on free radicals concentration (proportionally to amplitude value) was observed. This phenomenon can be related with recombination processes between close located to each other free radicals and interactions with paramagnetic oxygen molecules. Influence of time of storage on EPR linewidths was not observed. g-factor, free radical type determining, was evaluate. Determined result g=2.0027, suggest that unpaired electrons are located on oxygen atoms. Influence of time of storage on average g - factor value was not observed. All presented data point that high temperature (180°C) cause big amount of free radicals creating. Asymmetric, complex EPR lines indicate on few types of free radicals existing in tra- madole expose to high temperature. Dipole boarded EPR lines suggest little distance between free radicals. Microwave saturation of EPR lines indicates homogeneous distribution of free radicals in thermally sterilized tramadole. Free radicals concentration decrease with increasing time of storage.
Źródło:
Engineering of Biomaterials; 2008, 11, no. 81-84; 63-64
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of UV irradiation on free radicals in synthetic melanin and melanin biopolymer from Sepia offi cinalis : EPR examination
Autorzy:
Zdybel, M.
Pilawa, B.
Powiązania:
https://bibliotekanauki.pl/articles/148610.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
EPR spectroscopy
free radicals
melanin
Sepia officinalis
UV irradiation
Opis:
Free radicals in synthetic melanin and melanin from Sepia officinalis were studied by electron paramagnetic resonance (EPR) spectroscopy. The effect of time of ultraviolet (UV) irradiation on free radicals in these melanins was tested. The samples were exposed to UV during 15, 30, and 60 minutes. EPR spectra were measured with microwaves from an X-band (9.3 GHz) in the range of microwave power of 2.2–70 mW. The performed EPR examinations indicate that high concentrations (~1021–1022 spin/g) of o-semiquinone free radicals with g factors of 2.0039–2.0045 exist in all the tested samples. For nonirradiated samples, free radical concentration was higher in natural melanin than in synthetic melanin. UV irradiation caused the increase of free radical concentrations in synthetic melanin samples and this effect depends on the time of irradiation. The largest free radical formation in the both melanins was obtained for 60 min of UV irradiation. Free radical concentrations after the UV irradiation of melanins during 30 min were lower than during irradiation by 15 min, and probably this effect was the result of recombination of the radiatively formed free radicals. EPR lines of the tested samples broadened with increasing microwave power, so these lines were homogeneously broadened. The two types of melanins differed in the time of spin-lattice relaxation processes. Slower spin-lattice relaxation processes exist in melanin from Sepia officinalis than in synthetic melanin. UV irradiation did not change the time of spin-lattice relaxation processes in the tested melanins. The performed studies confirmed the usefulness of EPR spectroscopy in cosmetology and medicine.
Źródło:
Nukleonika; 2015, 60, No. 3, part 1; 483-488
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of microwave power on EPR spectra of thermally sterilized eucerinum anhydricum
Autorzy:
Ramos, P.
Pepliński, P.
Pilawa, B.
Powiązania:
https://bibliotekanauki.pl/articles/148715.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
EPR
microwave saturation
free radicals
eucerinum anhydricum
thermal sterilization
Opis:
Free radicals formed during thermal sterilization of eucerinum anhydricum – the pharmaceutical base were examined by an X-band (9.3 GHz) spectrometer. Eucerinum anhydricum was sterilized at different physical conditions according to the Polish Pharmacopeia norms. The samples were heated at temperatures: 160°C (120 min), 170°C (60 min), and 180°C (30 min). The aim of this study is to compare free radical concentration and effect of microwave power on EPR spectra of eucerinum anhydricum base thermally sterilized at different temperatures and periods of time. The effect of time storage on the free radicals in the heated samples was tested. Free radical concentrations in the sample stored 15 min strongly decreased with the increasing of sterilization temperature, probably as the result of recombination. Storage caused strong decrease of free radical concentrations in the samples, probably as the result of interactions with oxygen. It was observed to be independent of sterilization conditions from 2 days of storage and longer. Because of the lowest free radical concentration, for eucerinum anhydricum thermal sterilization at 180°C for 30 min is recommended. The sterilized samples should be stored at inert atmosphere without oxygen molecules. Fast spin-lattice relaxation processes existed in sterilized eucerinum anhydricum. The character of changes of amplitudes and linewidths of EPR lines with increasing of microwave power was the same for different storage times. The parameters of thermal sterilization and storage time influenced free radical concentration in eucerinum anhydricum, but magnetic spin-lattice interactions were unchanged. The usefulness of EPR spectroscopy in optimization of thermal sterilization process of eucerinum anhydricum was confirmed.
Źródło:
Nukleonika; 2015, 60, No. 3, part 1; 439-442
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Melatonin and its metabolites: new findings regarding their production and their radical scavenging actions
Autorzy:
Reiter, Russel
Tan, Dun-xian
Terron, M
Flores, Luis
Czarnocki, Zbigniew
Powiązania:
https://bibliotekanauki.pl/articles/1041101.pdf
Data publikacji:
2007
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
electron donation
melatonin synthesis
free radicals
antioxidant
oxidative stress
Opis:
This review summarizes some of the recent findings concerning the long-held tenet that the enzyme, N-acetyltransferase, which is involved in the production of N-acetylserotonin, the immediate precursor of melatonin, may in fact not always control the quantity of melatonin generated. New evidence from several different laboratories indicates that hydroxyindole-O-methyltransferase, which O-methylates N-acetylserotonin to melatonin may be rate-limiting in some cases. Also, the review makes the point that melatonin's actions are uncommonly widespread in organs due to the fact that it works via membrane receptors, nuclear receptors/binding sites and receptor-independent mechanisms, i.e., the direct scavenging of free radicals. Finally, the review briefly summarizes the actions of melatonin and its metabolites in the detoxification of oxygen and nitrogen-based free radicals and related non-radical products. Via these multiple processes, melatonin is capable of influencing the metabolism of every cell in the organism.
Źródło:
Acta Biochimica Polonica; 2007, 54, 1; 1-9
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Złożony układ wolnych rodników w sterylizowanych termicznie lekach glikokortykosteroidowych
Complex free radicals system in thermally sterilized glucocorticosteroides
Autorzy:
Kościelniak, M.
Pilawa, B.
Powiązania:
https://bibliotekanauki.pl/articles/284226.pdf
Data publikacji:
2012
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
wolne rodniki
sterylizacja leków
leki glikokortykosteroidowe
free radicals
sterilization
glucocorticostereoides
Źródło:
Engineering of Biomaterials; 2012, 15, no. 116-117 spec. iss.; 55-56
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Light Effect in Semiconductor Bridge Plasma Ignition
Autorzy:
Zhang, L.
Li, N.
Wan, Z.
Zhu, S.
Powiązania:
https://bibliotekanauki.pl/articles/358252.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
SCB plasma ignition
non-heat effect
light effect
free radicals
Opis:
Heat is considered to play an important role in Semiconductor Bridge (SCB) plasma ignition. Nevertheless, in this paper a non-heat effect is reported for SCB ignition of primary explosives. An initial comparison showed that there is no reasonable correlation between the ease of plasma ignition and the 5-s explosion temperature. Meanwhile the addition of Pb3O4 was found to make lead styphnate (LS) more active to SCB plasma ignition whereas the heat decomposition of this mixture was not accelerated. In terms of the phenomena mentioned above and the response of primary explosives to SCB plasma, we propose an effect of light in SCB plasma ignition. The free radical concentration change indicates that light enhances the activity of primary explosives in SCB plasma ignition. Regarding the mixture of LS and Pb3O4, the additive itself does not make LS sensitive to the SCB plasma. However, the supplement makes LS active under light exposure. As a result, the effect of light on SCB plasma ignition was confirmed by the experiments conducted in this study. This paper provides a new understanding of SCB plasma ignition from the viewpoint of explosives, which is of importance for the design of SCBs.
Źródło:
Central European Journal of Energetic Materials; 2017, 14, 4; 996-1006
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reaktywne rodniki tlenowe - skuteczność antyoksydantów w terapii
Reactive oxygen radicals – the therapeutic effectiveness of antioxidants
Autorzy:
Skiba, M.
Pedrycz, A.
Cichacz, B.
Powiązania:
https://bibliotekanauki.pl/articles/366175.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Medycyny i Techniki Hiperbarycznej
Tematy:
oxidative stress
free radicals
antioxidants
stres oksydacyjny
wolne rodniki
antyoksydanty
Opis:
Oxidative stress occurring in cells is a consequence of an excessive activity of reactive oxygen forms, resulting from an imbalance between the release of free oxygen radicals and their removal from the cell by antioxidant systems. 90% of reactive oxygen radicals emerge in mitochondrial respiratory chain during an incomplete four-electron oxygen reduction. The remaining 10% originate from different reactions occurring in the cell. The established compounds are characterised by a short half-life and are highly reactive. Sparse quantities of free oxygen radicals have a positive effect on cell functions. Oxidative stress leads to damage in cellular membranes, enzymatic and non-enzymatic proteins, as well as DNA. Therapy with antioxidants as exogenous dietary supplements aims at preventing or reducing the risk of development of diseases involving the presence of the oxygen radicals. Whether the antioxidant therapy will bring positive or negative effects depends on numerous factors that need to be considered before their inclusion in the applied treatment.
Stres oksydacyjny w komórkach organizmu jest wynikiem nadmiernej aktywności reaktywnych form tlenu, wynikającym z zachwiania równowagi pomiędzy wydzielaniem wolnych rodników tlenowych, a ich usuwaniem z komórki przez systemy antyoksydacyjne. 90% reaktywnych rodników tlenowych powstaje w łańcuchu oddechowym mitochondrium, podczas niepełnej czteroelektronowej redukcji tlenu. Pozostałe 10% pochodzi z innych reakcje zachodzących w komórce. Związki które powstają mają krótki okres półtrwania i są wysoce reaktywne. Niewielkie ilości wolnych rodników tlenowych wpływają pozytywnie na funkcjonowanie komórek. Podczas stresu oksydacyjnego dochodzi do uszkodzenia błon komórkowych, białek enzymatycznych, nieenzymatycznych oraz DNA. Przyjmowanie antyoksydantów jako egzogennych suplementów diety ma na celu zapobieganie lub zmniejszenie ryzyka rozwoju chorób, w których patogenezie biorą udział rodniki tlenowe. To czy terapia z zastosowaniem antyoksydantów przynosi pozytywne czy negatywne efekty zależy od wielu czynników, które należy wziąć pod uwagę podczas włączania antyoksydantów do leczenia.
Źródło:
Polish Hyperbaric Research; 2016, 1(54); 41-48
1734-7009
2084-0535
Pojawia się w:
Polish Hyperbaric Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EPR study of free radicals formed in fusidic acid and neomycin under UV irradiation
Autorzy:
Pierzchała, Ewa
Ramos, Paweł
Pilawa, Barbara
Powiązania:
https://bibliotekanauki.pl/articles/895647.pdf
Data publikacji:
2019-04-30
Wydawca:
Polskie Towarzystwo Farmaceutyczne
Tematy:
free radicals
EPR spectroscopy
Dermatology
UV irradiation
fusidic acid
neomycin
Opis:
Free radicals in UV irradiated antibiotics used in dermatology were examined. Concentrations of free radicals in fusidic acid and neomycin, were determined. EPR spectra of the tested antibiotics were measured by electron paramagnetic resonance spectrometer with magnetic modulation of 100 kHz and numerical acquisition system the Rapid Scan Unit. The influence of microwave powers in the range of 2.2-70 mW on the spectra was obtained. Amplitudes (A) and linewidths (ΔBpp) of the EPR spectra, were analysed. The EPR spectra were homogeneously broadened. Fast spin-lattice relaxation processes existed in UV irradiated fusidic acid and neomycin, which EPR spectra were not saturated up to 70 mW. The influence of the time of UV irradiation on free radicals in the samples was observed. The samples were irradiated by UVA (315-400 nm) in the 30, 60, and 90 minute period. Free radical concentrations in the tested antibiotics exposed to UV were proportional to the amplitudes (A) of the EPR spectra. The highest amplitudes (A) were observed for the UV irradiated antibiotics during 60 minutes. The higher amplitudes (A) characterized fusidic acid than neomycin. Fusidic acid and neomycin used to treat bacterial infection of skin under UV irradiation may produce free radical toxic effects. The stronger photosensitivity characterized fusidic acid relatively to neomycin. EPR spectroscopy is the useful method to examine free radicals formed in antibiotics during photolysis.
Źródło:
Acta Poloniae Pharmaceutica - Drug Research; 2019, 76, 2; 215-223
0001-6837
2353-5288
Pojawia się w:
Acta Poloniae Pharmaceutica - Drug Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of microwave power on EPR spectra of DOPA-melanin-netilmicin complexes with different drug concentrations : a study at temperatures in the range of 125-275 K
Autorzy:
Zdybel, M.
Pilawa, B.
Buszman, E.
Wrześniok, D.
Krzyminiewski, R.
Kruczyński, Z.
Powiązania:
https://bibliotekanauki.pl/articles/146482.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
DOPA-melanin
electron paramagnetic resonance (EPR) spectroscopy
free radicals
netilmicin
Opis:
Electron paramagnetic resonance (EPR) spectra of the model eumelanin – DOPA-melanin complexes with netilmicin measured with a microwave power in the range 0.3–200 mW were examined. The influence of microwave power on amplitudes (A) and linewidths (ΔBpp) of the spectra was determined. The EPR spectra were recorded by a BRUKER spectrometer at temperatures 125, 175, 225 and 275 K. Continuous microwave saturation of EPR lines was used to compare the acceleration of spin-lattice relaxation processes in melanin samples. Changes of the parameters of the EPR spectra of DOPA-melanin-netilmicin complexes, with the microwave power for the samples differing in netilmicin concentrations, were observed. The effect of temperature on the changes of the EPR spectra of the analyzed melanin complexes with the microwave power was determined. The spin-lattice relaxation is faster at higher temperatures for all the tested melanin complexes.
Źródło:
Nukleonika; 2013, 58, 3; 407-411
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EPR studies of free radicals in thermally sterilized famotidine
Autorzy:
Ramos, P.
Pilawa, B.
Stroka, E.
Powiązania:
https://bibliotekanauki.pl/articles/148414.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
free radicals
thermal sterilization
famotidine
electron paramagnetic resonance (EPR) spectroscopy
Opis:
Free radicals formation in thermally sterilized famotidine was studied by the use of an X-band (9.3 GHz) electron paramagnetic resonance (EPR) spectroscopy. The influence of temperature and time of sterilization on free radicals generated in famotidine was determined. The best sterilization conditions for the tested drug were found. Sterilization was done according to the pharmaceutical norms at temperatures 160°C (120 min), 170°C (60 min), and 180°C (30 min). It was pointed out that the optimal temperature of thermal sterilization for famotidine was 170°C and time of heating 60 min in this conditions the lowest free radicals concentration was found. The highest free radicals concentration was measured in famotidine heated at 160°C during 120 min, the long time of sterilization is responsible for this effect. Free radicals concentration changes during storage of famotidine after thermal sterilization. Its value increased with storage time for the drug sterilized at both temperatures of 170°C and 180°C. Free radicals concentration decreases from 7 days after sterilization. Complex system of free radicals with the shape of EPR lines, dependent on microwave power exist in thermally sterilized famotidine. Slow spin-lattice relaxation processes, strong dipolar interactions characterize thermally sterilized famotidine. Microwave saturation indicates that EPR lines of famotidine are homogeneously broadened. The usefulness of EPR spectroscopy to examine of the sterilized drugs was evaluated.
Źródło:
Nukleonika; 2013, 58, 3; 413-418
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Melatonin as an antioxidant: biochemical mechanisms and pathophysiological implications in humans.
Autorzy:
Reiter, Russel
Tan, Dun-xian
Mayo, Juan
Sainz, Rosa
Leon, Josefa
Czarnocki, Zbigniew
Powiązania:
https://bibliotekanauki.pl/articles/1043401.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
neurodegeneration
respiratory distress
melatonin
sepsis
free radicals
antioxidant enzymes
antioxidant
Opis:
This brief resume enumerates the multiple actions of melatonin as an antioxidant. This indoleamine is produced in the vertebrate pineal gland, the retina and possibly some other organs. Additionally, however, it is found in invertebrates, bacteria, unicellular organisms as well as in plants, all of which do not have a pineal gland. Melatonin's functions as an antioxidant include: a), direct free radical scavenging, b), stimulation of antioxidative enzymes, c), increasing the efficiency of mitochondrial oxidative phosphorylation and reducing electron leakage (thereby lowering free radical generation), and 3), augmenting the efficiency of other antioxidants. There may be other functions of melatonin, yet undiscovered, which enhance its ability to protect against molecular damage by oxygen and nitrogen-based toxic reactants. Numerous in vitro and in vivo studies have documented the ability of both physiological and pharmacological concentrations to melatonin to protect against free radical destruction. Furthermore, clinical tests utilizing melatonin have proven highly successful; because of the positive outcomes of these studies, melatonin's use in disease states and processes where free radical damage is involved should be increased.
Źródło:
Acta Biochimica Polonica; 2003, 50, 4; 1129-1146
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
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