Elena Serbinova - Academia.edu (original) (raw)
Papers by Elena Serbinova
Biochemistry international, 1992
The aim of this study was to determine the tissue distribution of carotenoids in palm oil and to ... more The aim of this study was to determine the tissue distribution of carotenoids in palm oil and to correlate the accumulation of carotenoids with protection against oxidative stress. We found that: (i) After 2 weeks beta-carotene in the liver increased from 7.3 to 30 ng/g wet tissue; alpha-carotene and lycopene after 10 weeks of feeding were 74 and 49 ng/g wet tissue respectively; (ii) Beta-carotene content in heart and hind limb skeletal muscles increased after 10 weeks to 17 and 6 ng/g wet tissue respectively; (iii) No carotenoids were detected in the brain, adipose and skin during the period of feeding; (iv) After in vitro induction of lipid peroxidation in liver homogenates by an azo-initiator of peroxyl radicals an inverse correlation between tissue carotenoid level and accumulation of lipid peroxidation products was observed; alpha-carotene > lycopene > beta-carotene.
Archives of Toxicology, 1985
The effects of subchronic exposure of some heavy metal salts on the activity of the rat liver mon... more The effects of subchronic exposure of some heavy metal salts on the activity of the rat liver monooxygenases and NADPH-dependent lipid peroxidation have been studied. The salts of Co, Cd and Zn (when given repeatedly for one month in subtoxic doses) shortened the duration of hexobarbital sleeping time, increased the activities of Ethylmorphine-N-demethylase (EMD) and Benzphetamine-N-demethylase (BND), and the cytochrome P-450 and heme contents. The same metal salts increased the activity of delta-aminolevulinic acid synthetase (ALAS), decreased that of Heme-oxygenase and decreased NADPH-dependent lipid peroxidation. Whereas the salts of Co, Cd and Zn seem to exert an enzyme-inducing action on the mixed function oxidizing enzyme systems, the salts of Hg and Ni did not show such effects.
Eksperimentalna meditsina i morfologiia, 1986
Acta physiologica et pharmacologica Bulgarica, 1990
In experiments on female albino rats the effect of 30-day treatment with salts of Co, Cd, Ni, Zn ... more In experiments on female albino rats the effect of 30-day treatment with salts of Co, Cd, Ni, Zn and Hg on the liver monooxygenase system was studied. It was found that CdCl2 and HgCl2 significantly decreased the activity of aniline hydroxylase whereas the activity of ethylmorphine-N-demethylase tended to remain almost constant and no significant changes were observed. The cytochrome P-450 level in Zn-treated female rats was decreased while the other metal salts did not change it. The cytochrome b5 levels were relatively stable and there were no significant differences between treated and untreated animals. Co, Cd and Hg decreased the NADPH-dependent lipid peroxidation whereas Ni and Zn did not change it. All metal salts caused no marked alterations in the female rat liver microsomal membrane fluidity.
Bulletin of Experimental Biology and Medicine, 1990
Bulletin of Experimental Biology and Medicine, 1983
Bulletin of Experimental Biology and Medicine, 1986
Doklady Akademii nauk SSSR, 1986
Biulleten' eksperimental'noĭ biologii i meditsiny, 1990
Studies were made of the ability of alpha-tocopherol, incorporated into unilamellar liposomes fro... more Studies were made of the ability of alpha-tocopherol, incorporated into unilamellar liposomes from saturated or unsaturated phospholipids (donor liposomes) to inhibit the accumulation of lipid peroxidation (LPO) products in unilamellar liposomes from rat cerebral cortex lipids (acceptor liposomes) in the presence of LPO inducer (Fe + ascorbate). With the molar alpha-tocopherol: phospholipids rations from 1:1000 to 1:100 in donor liposomes, obtained through sonication of lipid dispersions, alpha-tocopherol was incorporated into both monolayers of liposomes and was distributed in monomeric form without forming clusters. Based on the dependencies of LPO inhibition on the alpha-tocopherol concentrations, we chose the ones that completely prevented the accumulation of LPO products in donor liposomes. Under these conditions LPO inhibition in mixtures of donor and acceptors liposomes was fully determined by the antioxidant effect of alpha-tocopherol in acceptor liposomes due to its interme...
Archives of Biochemistry and Biophysics, 1992
ABSTRACT
Archives of Biochemistry and Biophysics, 1991
Free Radical Biology and Medicine, 1990
Ubiquinones (CoQn) are intrinsic lipid components of many membranes Besides their role in electro... more Ubiquinones (CoQn) are intrinsic lipid components of many membranes Besides their role in electrontransfer reactions they may act as free radical scavengers, yet their antlox~dant function has received relatively little study The efficiency of ubiquinols of varying lsoprenold chain length (from Q0 to Q~0) in preventmg (Fe 2÷ + ascorbate)-dependent or (Fe 2÷ + NADPH)-dependent lipid peroxidatlon was investigated in rat liver mlcrosomes and brain synaptosomes and mitochondria Ublqumols, the reduced forms of CoQn, possess much greater antloxldant activity than the oxidized ublqumone forms In homogenous solution the ra&cal scavenging activity of ublqumol homologues does not depend on the length of their isoprenold chain However in membranes ublqulnols with short lsoprenold chains (Q~-Q4) are much more potent mhibitors of lipid peroxldatlon than the longer chain homologues (Q~-Q~0) It is found that i) the inhibitory action, that is, antloxldant efficiency of shortchain ublqulnols decreases m order Q~ > Q2 > Q3 > Q4, n) the antloxldant efficiency of long-chain ublqulnols is only shghtly dependent on their concentrations m the order Q5 > Q6 > Q7 > Q8 > Q9 > Q~0 and m) the antlOxldant efficiency of Q0 is markedly less than that of other homologues Interaction of ublqumols with oxygen radicals was followed by their effects on luminol-activated chemiluminescence Ublqulnols Qt-Q, at 0 l mM completely inhibit the luminol-activated NADPH-dependent chemtlumlnescent response of mlcrorosomes, while homologues Q6-Q~0 exert no effect In contrast to ublquinol Q~0 (ubiqumone Q~0) ubiqumone Q~ synergistically enhances NADPH-dependent regeneration of endogenous vitamin E in microsomes thus providing for higher antioxidant protection against lipid peroxidation The differences in the antloxidant potency of ubiqumols in membranes are suggested to result from differences in partmoning into membranes, lntramembrane moblhty and non-uniform dlstribuuon of ublqulnols resulting in differing efficiency of interaction with oxygen and hpld radicals as well as different efficiency of ublqulnols in regeneration of endogenous vitamin E
Biulleten' eksperimental'noĭ biologii i meditsiny, 1990
According to Bulgarian-Soviet program "Biostab" we studied char... more According to Bulgarian-Soviet program "Biostab" we studied characteristics of different phenol compounds (ionol derivatives). The aim of the present study is to determine antiradical and antioxidant activity of a number of ionol derivatives in pure chemical systems and in different membrane fractions of a natural origin.
Archives of Toxicology, 1986
Natural and synthetic antioxidants (AOs) are widely used as stabilizers of biomembranes against l... more Natural and synthetic antioxidants (AOs) are widely used as stabilizers of biomembranes against lipid peroxidation (LPO). Natural AOs (tocopherols, ubiquinols) containing hydrocarbon "tails" do not disturb the membrane lipid bilayer. Synthetic AOs devoid of hydrocarbon radicals may perturb the lipid bilayer. It was shown that AOs devoid of hydrocarbon tails (butylated hydroxytoluene, 2,2,5,7,8-pentamethyl-6-hydroxychromane) exerted toxic effects on erythrocyte membranes (induced hemolysis), on sarcoplasmic reticulum membranes (inhibited Ca2+-transport) and on platelet membranes (initiated Ca2+-dependent aggregation) in vitro. These AOs are the substrates of cytochrome P-450, and underwent oxidative hydroxylation. This suggests that they have short half-life times in biomembranes and in the organism. Antioxidants with hydrocarbon tails, are hydroxylated at very low rates and are slowly excreted. Antioxidants devoid of hydrocarbon tails, are 10-20 fold more potent LPO inhibitors than the corresponding AOs with hydrocarbon tails. The strategy of AOs application for long and short-term stabilization of biomembranes against LPO in vivo is discussed.
Doklady Akademii nauk SSSR, 1987
Eksperimentalna meditsina i morfologiia, 1984
Toxicology Letters, 1989
Iron loading was associated with development of oxidative stress, viz. decrease in tocopherol con... more Iron loading was associated with development of oxidative stress, viz. decrease in tocopherol content and an increase in amount of lipid peroxidation products but only slight, if any, decrease in cytochrome P-450 content. Combinations of iron loading with other stress-inducing treatments (exhaustive physical exercise and hyperoxia) caused marked decreases in cytochrome P-450 content. Thus, a combination of factors favoring development of oxidative stress, but insufficient to exert a damaging effect on the cytochrome P-450-dependent detoxification system when acting alone, may become quite potent when acting in concert.
Journal of Investigative Dermatology, 2000
Biochemical and Biophysical Research Communications, 1989
Enzyme-dependent mechanisms which prevent accumulation of chromanoxyl radicals derived from the v... more Enzyme-dependent mechanisms which prevent accumulation of chromanoxyl radicals derived from the vitamin E analogue, 2,2,5,7,8-pentamethyl-6-hydroxycromane (PMC), were characterized in rat liver microsomal and mitochondrial membranes. The free radical oxidation product of PMC (chromanoxyl radical) was generated in membranes using either photochemical (uv light) or enzymatic (lipoxygenase and arachidonic acid) methods and detected by ESR. Substrates (NADH or NADPH) prevented accumulation of chromanoxyl radicals until the substrate was fully consumed. In microsomes, reduced glutathione increased the efficacy of NADPH in preventing the accumulation of the chromanoxyl radical, but was without effect in the absence of NADPH. Ascorbate also prevented accumulation of the chromanoxyl radical. It is concluded that rat liver microsomes and mitochondria have both enzymatic and non-enzymatic mechanisms for reducing chromanoxyl radicals.
Biochemistry international, 1992
The aim of this study was to determine the tissue distribution of carotenoids in palm oil and to ... more The aim of this study was to determine the tissue distribution of carotenoids in palm oil and to correlate the accumulation of carotenoids with protection against oxidative stress. We found that: (i) After 2 weeks beta-carotene in the liver increased from 7.3 to 30 ng/g wet tissue; alpha-carotene and lycopene after 10 weeks of feeding were 74 and 49 ng/g wet tissue respectively; (ii) Beta-carotene content in heart and hind limb skeletal muscles increased after 10 weeks to 17 and 6 ng/g wet tissue respectively; (iii) No carotenoids were detected in the brain, adipose and skin during the period of feeding; (iv) After in vitro induction of lipid peroxidation in liver homogenates by an azo-initiator of peroxyl radicals an inverse correlation between tissue carotenoid level and accumulation of lipid peroxidation products was observed; alpha-carotene > lycopene > beta-carotene.
Archives of Toxicology, 1985
The effects of subchronic exposure of some heavy metal salts on the activity of the rat liver mon... more The effects of subchronic exposure of some heavy metal salts on the activity of the rat liver monooxygenases and NADPH-dependent lipid peroxidation have been studied. The salts of Co, Cd and Zn (when given repeatedly for one month in subtoxic doses) shortened the duration of hexobarbital sleeping time, increased the activities of Ethylmorphine-N-demethylase (EMD) and Benzphetamine-N-demethylase (BND), and the cytochrome P-450 and heme contents. The same metal salts increased the activity of delta-aminolevulinic acid synthetase (ALAS), decreased that of Heme-oxygenase and decreased NADPH-dependent lipid peroxidation. Whereas the salts of Co, Cd and Zn seem to exert an enzyme-inducing action on the mixed function oxidizing enzyme systems, the salts of Hg and Ni did not show such effects.
Eksperimentalna meditsina i morfologiia, 1986
Acta physiologica et pharmacologica Bulgarica, 1990
In experiments on female albino rats the effect of 30-day treatment with salts of Co, Cd, Ni, Zn ... more In experiments on female albino rats the effect of 30-day treatment with salts of Co, Cd, Ni, Zn and Hg on the liver monooxygenase system was studied. It was found that CdCl2 and HgCl2 significantly decreased the activity of aniline hydroxylase whereas the activity of ethylmorphine-N-demethylase tended to remain almost constant and no significant changes were observed. The cytochrome P-450 level in Zn-treated female rats was decreased while the other metal salts did not change it. The cytochrome b5 levels were relatively stable and there were no significant differences between treated and untreated animals. Co, Cd and Hg decreased the NADPH-dependent lipid peroxidation whereas Ni and Zn did not change it. All metal salts caused no marked alterations in the female rat liver microsomal membrane fluidity.
Bulletin of Experimental Biology and Medicine, 1990
Bulletin of Experimental Biology and Medicine, 1983
Bulletin of Experimental Biology and Medicine, 1986
Doklady Akademii nauk SSSR, 1986
Biulleten' eksperimental'noĭ biologii i meditsiny, 1990
Studies were made of the ability of alpha-tocopherol, incorporated into unilamellar liposomes fro... more Studies were made of the ability of alpha-tocopherol, incorporated into unilamellar liposomes from saturated or unsaturated phospholipids (donor liposomes) to inhibit the accumulation of lipid peroxidation (LPO) products in unilamellar liposomes from rat cerebral cortex lipids (acceptor liposomes) in the presence of LPO inducer (Fe + ascorbate). With the molar alpha-tocopherol: phospholipids rations from 1:1000 to 1:100 in donor liposomes, obtained through sonication of lipid dispersions, alpha-tocopherol was incorporated into both monolayers of liposomes and was distributed in monomeric form without forming clusters. Based on the dependencies of LPO inhibition on the alpha-tocopherol concentrations, we chose the ones that completely prevented the accumulation of LPO products in donor liposomes. Under these conditions LPO inhibition in mixtures of donor and acceptors liposomes was fully determined by the antioxidant effect of alpha-tocopherol in acceptor liposomes due to its interme...
Archives of Biochemistry and Biophysics, 1992
ABSTRACT
Archives of Biochemistry and Biophysics, 1991
Free Radical Biology and Medicine, 1990
Ubiquinones (CoQn) are intrinsic lipid components of many membranes Besides their role in electro... more Ubiquinones (CoQn) are intrinsic lipid components of many membranes Besides their role in electrontransfer reactions they may act as free radical scavengers, yet their antlox~dant function has received relatively little study The efficiency of ubiquinols of varying lsoprenold chain length (from Q0 to Q~0) in preventmg (Fe 2÷ + ascorbate)-dependent or (Fe 2÷ + NADPH)-dependent lipid peroxidatlon was investigated in rat liver mlcrosomes and brain synaptosomes and mitochondria Ublqumols, the reduced forms of CoQn, possess much greater antloxldant activity than the oxidized ublqumone forms In homogenous solution the ra&cal scavenging activity of ublqumol homologues does not depend on the length of their isoprenold chain However in membranes ublqulnols with short lsoprenold chains (Q~-Q4) are much more potent mhibitors of lipid peroxldatlon than the longer chain homologues (Q~-Q~0) It is found that i) the inhibitory action, that is, antloxldant efficiency of shortchain ublqulnols decreases m order Q~ > Q2 > Q3 > Q4, n) the antloxldant efficiency of long-chain ublqulnols is only shghtly dependent on their concentrations m the order Q5 > Q6 > Q7 > Q8 > Q9 > Q~0 and m) the antlOxldant efficiency of Q0 is markedly less than that of other homologues Interaction of ublqumols with oxygen radicals was followed by their effects on luminol-activated chemiluminescence Ublqulnols Qt-Q, at 0 l mM completely inhibit the luminol-activated NADPH-dependent chemtlumlnescent response of mlcrorosomes, while homologues Q6-Q~0 exert no effect In contrast to ublquinol Q~0 (ubiqumone Q~0) ubiqumone Q~ synergistically enhances NADPH-dependent regeneration of endogenous vitamin E in microsomes thus providing for higher antioxidant protection against lipid peroxidation The differences in the antloxidant potency of ubiqumols in membranes are suggested to result from differences in partmoning into membranes, lntramembrane moblhty and non-uniform dlstribuuon of ublqulnols resulting in differing efficiency of interaction with oxygen and hpld radicals as well as different efficiency of ublqulnols in regeneration of endogenous vitamin E
Biulleten' eksperimental'noĭ biologii i meditsiny, 1990
According to Bulgarian-Soviet program "Biostab" we studied char... more According to Bulgarian-Soviet program "Biostab" we studied characteristics of different phenol compounds (ionol derivatives). The aim of the present study is to determine antiradical and antioxidant activity of a number of ionol derivatives in pure chemical systems and in different membrane fractions of a natural origin.
Archives of Toxicology, 1986
Natural and synthetic antioxidants (AOs) are widely used as stabilizers of biomembranes against l... more Natural and synthetic antioxidants (AOs) are widely used as stabilizers of biomembranes against lipid peroxidation (LPO). Natural AOs (tocopherols, ubiquinols) containing hydrocarbon "tails" do not disturb the membrane lipid bilayer. Synthetic AOs devoid of hydrocarbon radicals may perturb the lipid bilayer. It was shown that AOs devoid of hydrocarbon tails (butylated hydroxytoluene, 2,2,5,7,8-pentamethyl-6-hydroxychromane) exerted toxic effects on erythrocyte membranes (induced hemolysis), on sarcoplasmic reticulum membranes (inhibited Ca2+-transport) and on platelet membranes (initiated Ca2+-dependent aggregation) in vitro. These AOs are the substrates of cytochrome P-450, and underwent oxidative hydroxylation. This suggests that they have short half-life times in biomembranes and in the organism. Antioxidants with hydrocarbon tails, are hydroxylated at very low rates and are slowly excreted. Antioxidants devoid of hydrocarbon tails, are 10-20 fold more potent LPO inhibitors than the corresponding AOs with hydrocarbon tails. The strategy of AOs application for long and short-term stabilization of biomembranes against LPO in vivo is discussed.
Doklady Akademii nauk SSSR, 1987
Eksperimentalna meditsina i morfologiia, 1984
Toxicology Letters, 1989
Iron loading was associated with development of oxidative stress, viz. decrease in tocopherol con... more Iron loading was associated with development of oxidative stress, viz. decrease in tocopherol content and an increase in amount of lipid peroxidation products but only slight, if any, decrease in cytochrome P-450 content. Combinations of iron loading with other stress-inducing treatments (exhaustive physical exercise and hyperoxia) caused marked decreases in cytochrome P-450 content. Thus, a combination of factors favoring development of oxidative stress, but insufficient to exert a damaging effect on the cytochrome P-450-dependent detoxification system when acting alone, may become quite potent when acting in concert.
Journal of Investigative Dermatology, 2000
Biochemical and Biophysical Research Communications, 1989
Enzyme-dependent mechanisms which prevent accumulation of chromanoxyl radicals derived from the v... more Enzyme-dependent mechanisms which prevent accumulation of chromanoxyl radicals derived from the vitamin E analogue, 2,2,5,7,8-pentamethyl-6-hydroxycromane (PMC), were characterized in rat liver microsomal and mitochondrial membranes. The free radical oxidation product of PMC (chromanoxyl radical) was generated in membranes using either photochemical (uv light) or enzymatic (lipoxygenase and arachidonic acid) methods and detected by ESR. Substrates (NADH or NADPH) prevented accumulation of chromanoxyl radicals until the substrate was fully consumed. In microsomes, reduced glutathione increased the efficacy of NADPH in preventing the accumulation of the chromanoxyl radical, but was without effect in the absence of NADPH. Ascorbate also prevented accumulation of the chromanoxyl radical. It is concluded that rat liver microsomes and mitochondria have both enzymatic and non-enzymatic mechanisms for reducing chromanoxyl radicals.