Antioxidants from several nutrients, e.g. vitamin E,
β-carotene, or flavonoids, inhibit the oxidative modification of low-density lipoproteins. This protective effect could possibly retard ...atherogenesis and in consequence avoid coronary heart diseases. Some studies have shown a positive effect of those antioxidants on cardiovascular disease. Another class of naturally occurring antioxidants are terpenoids, which are found in essential oils.
The essential oil of
Pinus mugo and the contained monoterpene terpinolene effectively prevent low-density lipoprotein (LDL)-oxidation. In order to test the mechanism by which terpinolene protects LDL from oxidation, LDL from human blood plasma enriched in terpinolene was isolated. In this preparation not only the lipid part of LDL is protected against copper-induced oxidation — as proven by following the formation of conjugated dienes, but also the oxidation of the protein part is inhibited, since loss of tryptophan fluorescence is strongly delayed. This inhibition is due to a retarded oxidation of intrinsic carotenoids of LDL, and not, as in the case of some flavonoids, attributable to a protection of intrinsic
α-tocopherol. These results are in agreement with our previous results, which showed the same effects for a monoterpene from lemon oil, i.e.
γ
-terpinene.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Most pathological processes include the production of activated oxygen species augmented or attenuated by transition metal ions catalyzing one electron transitions. Inhalation of airborne particles, ...infections, ingestion of toxins or liberation from endogenous stores represent biological pathways for the induction of pathogenic processes by these metal ions. In this short review basic reactions involving transition metal ions operating during oxidative stress in certain diseases will be discussed.
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BFBNIB, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Low-density lipoprotein (LDL) oxidation may play a significant role in atherogenesis. Flavonoids are well-known for their excellent antioxidative capacity in various model systems, therefore we ...examined the behaviour of rutin, a quercetin-3-rutinosid, in the copper-mediated LDL oxidation. Rutin alone has been shown to protect LDL against oxidation.
Furthermore we investigated the combination of rutin with a hydrophilic (ascorbate) and a lipophilic antioxidant (γ-terpinene) in copper-mediated LDL oxidation. In both cases we found a synergistic effect on lag phase prolongation.
To elucidate whether this effect mainly depends on the copper chelating ability of rutin we examined its reaction in more detail. Although inhibiting the oxidation of α-linolenic acid in the “rose bengal system” no direct influence of a copper-rutin-complex was determined. We conclude that a redox active copper-rutin-complex is still able to initiate the LDL oxidation but may prevent copper from a reaction at the binding sites of apoB-100. The synergistic effect in preventing LDL oxidation is due to this trapping of copper in a complex in the case of ascorbate. The synergistic action of rutin and γ-terpinene can be explained by different distribution of rutin and γ-terpinene in, and around the LDL-particle, respectively.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A combination of ethanolic extracts from nine medicinal plants is successfully used in STW 5 (Iberogast
®) for treatment of gastrointestinal disorders. To elucidate possible modes of action, the ...focus of this study is on antioxidant properties of the phytomedicine STW 5. In fact, functional gastrointestinal diseases, such as non-ulcer dyspepsia (NUD) and irritable bowel syndrome, are often initiated by or correlated to inflammatory processes, where oxidants such as reactive oxygen species (ROS) play a crucial role. Prominent in vivo sources of ROS generation are represented by the enzymes xanthine oxidase (XOD) or myeloperoxidase (MPO). Applying these enzymes in models in vitro, we show that STW 5 and its components possess strong antioxidant activities. Depending on the model investigated, even pro-oxidant activites of single components of STW 5 could be observed. Interestingly, these effects were absent in STW 5, indicating cooperation between the components. Moreover, if one of the component extracts of STW 5 is omitted, the antioxidant activity is reduced. Thus we conclude that all the single extracts combined in STW 5 are of importance for the therapeutic effect, working in concert. The component of STW 5 performing best in vitro differed with the model investigated, respectively, with ROS and ROS generators. In the XOD system, the extracts of lemon balm leaf and peppermint leaf showed the best antioxidant result, whereas concerning MPO driven chlorination reactions, bitter candy tuft extract was the most efficient antioxidant. Best protection against peroxynitrite induced oxidation of methionine like sulfur-compounds exhibited the STW 5 components lemon balm leaf, Matricaria flower and peppermint leaf.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Land plants have to sustain a wealth of abiotic and biotic impacts such as extreme temperatures or dryness and high light intensities accompanied by oxygen saturation without being able to escape or ...to switch off the light, which under these conditions is the major reason for their problems. They thus developed a strategy for defence composed of avoidance reactions combined with a set of defence-chemicals. Co-evolution of animals took advantage of this enormous synthesizing capacity of plants. The knowledge about these interrelationships between plants and animals in terms of coping with “oxidative stress” is exponentially increasing and has led to novel insights, especially as far as medical, pharmacological and nutritive aspects are concerned. The biochemistry of oxygen-activation and -detoxification analysed in the past and the identification of similarities between plants and animals opened a new field of research. Biochemical model reactions simulating these common situations allow to predict possible functions of certain chemicals in plants’ defence as well to find new fields of application in human health and to exploit up to date unknown resources. In this report we will specially deal with an underestimated and widely ignored group of chemicals: the terpenoids. We could prove that these substances are effective antioxidants in lipid peroxidation processes. They furthermore are able to prevent carotenoids, another class of secondary plant metabolites, from oxidation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The radical scavenging activity and the antioxidant content of fresh and air-dried tomatoes were investigated. Tomato halves were dried in a pilot-scale dryer under the following conditions: air ...temperature, 80 °C; air flow rate, 1.5 m/s; drying time, 400 min; final moisture, 25%. Carotenoid (lycopene, β-carotene, lutein) and ascorbic acid were analyzed by HPLC with a spectrophotometric and an electrochemical detector, respectively. Total phenolics were determined by using the Folin−Ciocalteu reagent. The radical scavenging activity was studied in three model systems: (a) the xanthine oxidase and xanthine system, which generates superoxide radical and hydrogen peroxide; (b) the 3-morpholinosydnonimine system, which releases spontaneously superoxide radical and nitrogen monoxide, forming peroxynitrite; (c) the linoleic acid and CuSO4 system, which promotes lipid peroxidation. These model systems allow the simulation of key reactions involved in the pathogenesis of certain chronic diseases and may be related to the in vivo activity of tomato antioxidants. Hence, these measurements can be used for optimizing tomato processing and storage. The drying process resulted in a decrease of ascorbic acid content, whereas phenol reagent reducing compounds increased. Carotenoid levels were substantially unchanged upon drying. Fresh and air-dried tomato extracts could act as radical scavengers both in the reactive oxygen species-mediated reactions and in lipid peroxidation. Drying affected the antioxidant effectiveness as measured in the xanthine/xanthine oxidase system, which was found to be the most sensitive method for the measurement of tomato antioxidant activity (lower I 50) but retained the antioxidant effectiveness in the other two systems. Keywords: Tomato (Lycopersicon esculentum); air-drying; radical scavenging activity; xanthine oxidase; peroxynitrite; lipid peroxidation
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Tobacco necrosis virus (TNV) susceptibility of a cytokinin overproducing tobacco line (CTKm) transformed with a CaMV 35S
:ipt gene construct was studied. Expression of the
ipt gene was confirmed by ...RT-PCR. As a result of cytokinin excess caused by the transgene, senescence of CTKm plants was greatly delayed. The number of virus-induced necrotic lesions as well as the coat protein content were significantly lower in the transgenic tobacco, as compared with the control. Leaf discs of CTKm tobacco produced less ethylene and ethane upon inoculation with TNV, which indicated higher stress tolerance and lower level of lipid peroxidation. Diminished H
2O
2 accumulation was observed in both uninoculated and TNV-infected CTKm tobacco leaves as compared to the SR
1 control line. The activity of three antioxidant enzymes (ascorbate peroxidase, glutathione S-transferase, catalase) and the amount of the non-enzymatic antioxidant ascorbic acid were markedly higher in healthy CTKm tobacco leaves and accordingly, CTKm tobacco leaves exhibited tolerance to oxidative stress induced by the herbicide paraquat as compared to control tobacco leaves. Therefore, inhibition of senescence resulting from cytokinin gene introduction confers more efficient reactive oxygen species (ROS) scavenging ability, which may attenuate lipid peroxidation and presumably contributes to the resistance against TNV-induced necrosis development.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Abstract
Potato plants (SOLANUM TUBEROSUM L. cv. Indira) were grown at two levels of N supply in the greenhouse. Plants supplied with 0.8 g N per plant (high N variant) showed significantly increased ...biomass as compared to plants without additional N fertilisation (low N variant). C/N ratio was lower and protein content was higher in leaves of the high N variant. The concentration of chlorogenic acids and flavonols was significantly lower in leaves from the high N variant. Whereas resistance to ALTERNARIA SOLANI increased when plants were supplied with additional nitrogen, these plants were more susceptible to PHYTOPHTHORA INFESTANS. After infection with both pathogens, we found a strong induction of p-coumaroylnoradrenaline and p-coumaroyloctopamine, which are identified for the first time in potato leaves and are discussed as resistance factors of other solanaceous plants.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The essential oil from Pinus mugo (PMEO) was tested on its antioxidative capacity. For this purpose, several biochemical test sytems were chosen (e.g., the Fenton Systen, the xanthine oxidase assay, ...or the copper-induced oxidation of low-density lipoprotein (LDL)). The results show that there is moderate or weak antioxidative activity when tested in aqueous environments, like in the Fenton system, xanthine oxidase induced superoxide radical formation, or in the HOCl driven fragmentation of 1-aminocyclopropane-1-carboxylic acid (ACC). In contrast, when tested in more lipophilic environments (e.g., the ACC-cleavage by activated neutrophils in whole blood) the PMEO exhibits good antioxidative activity. PMEO does also show good antioxidative capacity in another lipophilic test system (i.e., the copper induced oxidation of LDL). Some components of PMEO (i.e., Δ3-carene, camphene, α-pinene, (+)-limonene and terpinolene) were also tested. As the PMEO, they showed weak or no antioxidant activity in aqueous environments, but some of them were effective antioxidants regarding ACC-cleavage by activated neutrophils in whole blood or copper-induced LDL-oxidation. Terpinolene, a minor component of PMEO, exhibited remarkable protection against LDL-oxidation. Keywords: Antioxidants; Pinus mugo; essential oil; monoterpenes; LDL; inflammatory processes
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IJS, KILJ, NUK, PNG, UL, UM, UPUK
Abstract
Spring barley (HORDEUM VULGARE L. cv. Scarlett) was grown at two CO
2
levels (400 vs. 700 ppm) combined with two ozone regimes (ambient vs. double ambient) in climate chambers for four ...weeks, beginning at seedling emergence. Elevated CO
2
concentration significantly increased aboveground biomass, root biomass, and tiller number, whereas double ambient ozone significantly decreased these parameters. These ozone-induced reductions in growth parameters were strongly overridden by 700 ppm CO
2
. The elevated CO
2
level increased C : N ratio of the leaf tissue and leaf starch content but decreased leaf protein levels. Exposure to double ambient ozone did not affect protein content and C : N ratio but dramatically increased leaf starch levels at 700 ppm CO
2
. Resistance against DRECHSLERA TERES (Sacc.) Shoemaker was increased in leaves grown at double ambient ozone but was less obvious at 700 ppm than at 400 ppm CO
2
. Constitutive activities of β‐1,3-glucanase and chitinase were significantly higher in leaves grown at double ambient ozone compared to ambient ozone levels. The sum of methanol-soluble and alkali-released cell wall-bound aromatic metabolites (i.e., C-glycosylflavones and several structurally unidentified metabolites) and lignin contents did not show any treatment-dependent differences.
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