77 research outputs found
The protective role of carotenoids against 7-keto-cholesterol formation in solution.
No full textThe antioxidant activity of beta-carotene and oxygenated carotenoids lutein, canthaxanthin, and astaxanthin was investigated during spontaneous and peroxyl-radical-induced cholesterol oxidation. Cholesterol oxidation, measured as generation of 7-keto-cholesterol (7-KC), was evaluated in a heterogeneous solution with cholesterol, AAPH, and carotenoids solubilized in tetrahydrofuran and in water, and in a homogeneous solution of chlorobenzene, with AIBN as a prooxidant. The formation of 7-KC was dependent on temperature and on cholesterol and prooxidant concentrations. All the carotenoids tested, exhibited significant antioxidant activity by inhibiting spontaneous, AAPH- and AIBN-induced formation of 7-KC, although the overall order of efficacy of these compounds was astaxanthin > canthaxanthin > lutein = beta-carotene. The finding that carotenoids exert protective effects on spontaneous and free radical-induced cholesterol oxidation may have important beneficial effects on human health, by limiting the formation of atheroma and by inhibiting cholesterol oxidation in food processing or storag
Dietary supplementation with eicosapentaenoic and docosahexaenoic acid inhibits growth of Morris hepatocarcinoma 3924A in rats: effects on proliferation and apoptosis.
No full textInt J Cancer. 1998 Mar 2;75(5):699-705.
Dietary supplementation with eicosapentaenoic and docosahexaenoic acid inhibits
growth of Morris hepatocarcinoma 3924A in rats: effects on proliferation and
apoptosis.
Calviello G, Palozza P, Piccioni E, Maggiano N, Frattucci A, Franceschelli P,
Bartoli GM.
Institute of General Pathology, Catholic University, Rome, Italy.
The effect of individual administration of low doses of highly purified
eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (1 g/kg body weight)
on the growth of Morris hepatocarcinoma 3924A transplanted in ACI/T rats was
investigated. Both EPA and DHA inhibited growth of the hepatocarcinoma (50%
reduction of tumor weight or volume at the 19th day after transplantation for
both of the n-3 PUFA groups). EPA treatment reduced the percentage of
proliferating tumor cells labeled with BUdR (10-fold), whereas DHA did not.
Conversely, DHA supplementation induced a doubling of the number of cells
undergoing apoptosis (labeled by TUNEL), whereas EPA treatment was much less
effective. Analysis of changes in phospholipid fatty acids in tumor-cell
membranes after both treatments with EPA and DHA showed a significant reduction
in arachidonic-acid levels. EPA and docosapentaenoic acid (DPA), its elongation
product, were increased in the phospholipids from EPA-treated animals. DHA and
EPA, but not DPA, were increased in the DHA-treated group. It is concluded from
the results of the present study that the anti-tumoral effect of EPA is related
mainly to its inhibition of cell proliferation, whereas that of DHA corresponds
with its induction of apoptosis. The alterations in fatty-acid composition
induced by EPA or DHA appear to be factors underlying their differential actions
on cell proliferation and apoptosis
Low-dose eicosapentaenoic or docosahexaenoic acid administration modifies fatty acid composition and does not affect susceptibility to oxidative stress in rat erithrocytes and tissues.
No full textIn view of the promising future for use of n-3 polyunsaturated fatty acids (PUFA)
in the prevention of cancer and cardiovascular diseases, it is necessary to
ensure that their consumption does not result in detrimental oxidative effects.
The aim of the present work was to test a hypothesis that low doses of
eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) do not induce harmful
modifications of oxidative cell metabolism, as modifications of membrane fatty
acid composition occur. Wistar rats received by gavage oleic acid, EPA, or DHA
(360 mg/kg body weight/day) for a period of 1 or 4 wk. Fatty acid composition and
alpha-tocopherol content were determined for plasma, red blood cell (RBC)
membranes, and liver, kidney, lung, and heart microsomal membranes.
Susceptibility to oxidative stress induced by tert-butylhydroperoxide was
measured in RBC. EPA treatment increased EPA and docosapentaenoic acid (DPA)
content in plasma and in all the membranes studied. DHA treatment mainly
increased DHA content. Both treatments decreased arachidonic acid content and
n-6/n-3 PUFA ratio in the membranes, without modifying the Unsaturation Index. No
changes in tissue alpha-tocopherol content and in RBC susceptibility to oxidative
stress were induced by either EPA or DHA treatment. The data suggest that EPA and
DHA treatments can substantially modify membrane fatty acids, without increasing
susceptibility to oxidative stress, when administered at low doses. This opens
the possibility for use of low doses of n-3 PUFA for chemoprevention without risk
of detrimental secondary effects
Supplementation with canthaxanthin affects plasma and tissue distribution of alpha- and gamma-tocopherols in mice.
No full textThe effects of oral doses of canthaxanthin on tissue distribution of alpha- and gamma-tocopherols were investigated in three experiments in male and female Balb/c mice. Mice were assigned to receive canthaxanthin [7 or 14 microg/(g body weight.d)] or placebo (olive oil) by gavage for different periods of time (0, 1, 2, 4 and 6 wk). A 2 wk-treatment with canthaxanthin resulted in incorporation of the carotenoid in all tissues analyzed, including liver, spleen, kidney, lung and heart. In liver, the maximum accumulation of the carotenoid was reached after 2 wk of dosing in female mice and after 6 wk in male mice. Canthaxanthin incorporation was accompanied by changes in alpha- and gamma-tocopherol concentrations in plasma and tissues. These included the following: 1) a significant increase (P < 0.001) in alpha-tocopherol concentration in spleen (21 and 27% in male and female mice, respectively) after 2 wk and in liver ( approximately 50% in both male and female mice) after 6 wk; 2) a significant decrease in gamma-tocopherol concentration in plasma (P < 0.05) and tissues (P < 0.001) after 2 wk of treatment. In female mice, this decrease was 55% in plasma, 43% in liver, 44% in kidney, 71% in lung and 70% in heart. In male mice, the decrease was observed only in plasma (30%), kidney (54%) and heart (46%). In liver, the decrease in gamma-tocopherol concentration was both dose- and time-dependent and significantly (P < 0.001) greater in female than in male mice. We conclude that dietary administration of canthaxanthin modifies tocopherol status in murine tissues
Antioxidant effect of FeAOX-6 on free radical species produced during iron catalyzed breakdown of tert-butyl hydroperoxide.
No full textThere is a body of evidences demonstrating, in biological systems, a cooperative interaction between tocopherols and carotenoids. FeAOX-6 is a novel antioxidant that combines the chroman head of alpha-tocopherol and a fragment of the isoprenyl chain of lycopene. We have tested its antioxidant effect on different radical species generated in a chemical system, where peroxyl, alkoxyl and methyl radicals are generated by the ferrous ion-mediated decomposition of tert-butyl hydroperoxide. We found that FeAOX-6 has the same effectiveness of alpha-tocopherol in quenching peroxyl radical with no contribution by lycopene. The antioxidant activity of FeAOX-6 on alkoxyl and methyl radicals is comparable to that of the equimolar mixture of the parent compounds. Lycopene is able to quench alkoxyl radical, while it has no effect on peroxyl radical, showing a different antioxidant activity compared to other carotenoids, such as beta-carotene and lutein
Antioxidant and prooxidant role of beta-carotene in murine normal and tumor thymocytes: effects of oxygen partial pressure
No full textThe effects of the partial pressure of oxygen (pO2) on antioxidant efficiency of beta-carotene in inhibiting radical-initiated lipid peroxidation were studied in murine normal and tumor thymocytes. At 150 mm Hg pO2 (the pressure of oxygen in normal air), beta-carotene acted as an antioxidant, inhibiting radical-induced lipid peroxidation in both normal and tumor thymocytes. At 760 mm Hg p02, beta-carotene lost its antioxidant activity in normal thymocytes and exhibited a dose-dependent prooxidant effect in tumor thymocytes. In these cells, the prooxidant effect of beta-carotene was also accompanied by an increase of endogenous alpha-tocopherol loss. beta-Carotene radical-trapping and autooxidation reactions were faster at 760 mm Hg pO2 than at 150 mm Hg pO2 in both normal and tumor thymocytes and the carotenoid was more rapidly consumed in tumor cells. These data point out a key role of the oxygen tension on the antioxidant effectiveness of beta-carotene. They also show a selective prooxidant effect of beta-carotene under 100% oxygen in tumor cells
d-alpha-Tocopherol inhibits low density lipoprotein induced proliferation and protein kinase C activity in vascular smooth muscle cells.
No full textNative and malondialdehyde modified low density lipoproteins have been shown to stimulate smooth muscle cell proliferation (A7r5) in vitro. The stimulation is associated with an increase of protein kinase C activity. d-alpha-Tocopherol, at physiological concentrations, has been found to inhibit both protein kinase C activity and cell proliferation
Modificazioni molecolari di vitamine antiossidanti come mezzo per ottenere anti-aging
No full textModificazioni molecolari di vitamine antiossidanti come mezzo per ottenere anti-aging
Novel antioxidant agents deriving from molecular combinations of vitamins C and E analogues: 3,4-dihydroxy-5(R).
No full textMolecular combinations of two antioxidants (i.e., ascorbic acid and the pharmacophore of alpha-tocopherol), namely the 2,3-dihydroxy-2,3-enono-1,4-lactone and the chromane residues, have been designed and tested for their radical scavenging activities. When evaluated for their capability to inhibit malondialdehyde (MDA) production in rat liver microsomal membranes, the 3,4-dihydroxy-5R-2(R,S)-(6-hydroxy-2,5,7,8-tetramethylchroman-2(R,S)yl-methyl)-1,3]dioxolan-4S-yl]-5H-furan-2-one (11a-d), exhibited an interesting activity. In particular the 5R,2R,2R,4S and 5R,2R,2S,4S isomers (11c,d) displayed a potent antioxidant effect compared to the respective synthetic alpha-tocopherol analogue (5) and natural alpha-tocopherol or ascorbic acid, used alone or in combination. Moreover, the mixture of stereoisomers 11a-d also proved to be effective in preventing damage induced by reperfusion on isolated rabbit heart, in particular at the higher concentration of 300 microM. In view of these results our study represents a new approach to potential therapeutic agents for applications in pathological events in which a free radical damage is involved. Design, synthesis and preliminary biological activity are discussed
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