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Miriama Simunkova Zuzana Barbierikova Klaudia Jomova Lenka Hudecova Peter Lauro Saleh H. Alwasel Ibrahim Alhazza Christopher J. Rhodes Marian Valko 《International journal of molecular sciences》2021,22(4)
Kaempferol is a flavonoid that occurs in tea and in many vegetables and fruits, including broccoli, cabbage, beans, grapes, apples, and strawberries. The efficacy of Kaempferol has been demonstrated in the treatment of breast, esophageal, cervical, ovarian, and liver cancers and leukemia, which very likely arises from its prooxidant properties and the activation of pro-apoptotic pathways. Indeed, this matter has already been the focus of a number of published studies and reviews. The aim of the present study was to elucidate the antioxidant vs. prooxidant properties of flavonoids in the presence of the redox-active metal, copper (II) ion, by means of the Fenton reaction. The specific motivation of this work is that, since an increased level of Cu(II) ions is known to be associated with many disease states such as neurological conditions (Alzheimer’s disease) and cancer, any interaction between these ions and flavonoids might affect the outcome of therapeutic uses of the latter. The structure of the Cu-kaempferol complex in DMSO was investigated by means of low temperature EPR spectroscopy, which confirmed the existence of at least two distinct coordination environments around the copper (II) ion. UV vis-spectra of kaempferol and its Cu(II) complex in DMSO revealed an interaction between the 5-OH (A ring) group and the 4-CO (C ring) group of kaempferol with Cu(II) ions. An ABTS assay confirmed that kaempferol acted as an effective radical scavenger, and that this effect was further enhanced in the form of the Cu(II)-kaempferol complex. Quantitative EPR spin trapping experiments, using DMPO as the spin trap, confirmed suppression of the formation of a mixture of hydroxyl, superoxide, and methyl radicals, in a Fenton reaction system, upon coordination of kaempferol to the redox-active Cu(II) ions, by 80% with respect to the free Cu(II) ions. A viscometric study revealed a better DNA-intercalating ability of the Cu-kaempferol complex than for free kaempferol, essential for conferring anticancer activity of these substances. The results of the viscometric measurements were compared with those from a DNA damage study of Cu-kaempferol complexes in a Fenton reaction system, using gel electrophoresis. At low concentrations of kaempferol (Cu–kaempferol ratios of 1:1 and 1:2), a very weak protective effect on DNA was noted, whereas when kaempferol was present in excess, a significant DNA-protective effect was found. This can be explained if the weakly intercalated kaempferol molecules present at the surface of DNA provide protection against attack by ROS that originate from the Fenton reaction involving intercalated Cu(II)-kaempferol complexes. Following the application of ROS scavengers, L-histidine, DMSO, and SOD, gel electrophoresis confirmed the formation of singlet oxygen, hydroxyl radicals, and superoxide radical anions, respectively. We propose that the prooxidant properties of Cu-kaempferol complexes may provide anticancer activity of these substances. When present in excess, kaempferol displays antioxidant properties under Cu-Fenton conditions. This suggests that kaempferol might prove a suitable candidate for the prevention or treatment of oxidative stress related medical conditions that involve a disturbed metabolism of redox metals such as copper, for example, Menkes disease, and neurological disorders, including Alzheimer’s disease. For the potential use of kaempferol in clinical practice, it will be necessary to optimize the dose size and critical age of the patient so that this flavonoid may be beneficial as a preventive drug against cancer and neurological disorders. 相似文献
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研究了抗氧剂1010和辅助抗氧剂DLTP对高全同聚丁烯-1的防护效果。加工热稳定性测试试验表明:1010的最佳组分是0.3份;DLTP的加入能大幅度提高防护效果。长效热稳定性试验表明:防护效果随1010的加入量的增加而提高,当1010超过0.1份后防护效果趋于稳定;DLTP的加入能够提高热氧稳定性。 相似文献
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Z. Y. Chen P. T. Chan K. Y. Kwan A. Zhang 《Journal of the American Oil Chemists' Society》1997,74(6):749-753
The anticarcinogenic effect of conjugated linoleic acids (CLA) has been attributed to their antioxidant activity. Strong evidence
is lacking, however, to substantiate that CLA is an antioxidant. The objective of this study was, therefore, to test whether
CLA is an antioxidant or a prooxidant in canola oil. The oxidation was conducted at 90°C by monitoring oxygen uptake and changes
in linoleic acid and α-linolenic acid. Free CLA and CLA methyl ester (CLAME) accelerated lipid oxidation in canola oil. The
prooxidant activity of CLA and CLAME was dose-dependent at concentrations ranging from 0.1 to 1.0% in canola oil heated at
90°C. CLA-containing triacylglycerol, however, was neither an antioxidant nor a prooxidant. Under the present experimental
conditions, CLA was not an antioxidant in fats and oil. 相似文献
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Ivan Valent Lucie Bednrov Igor Schreiber Juraj Bujdk Katarína Valachov Ladislav olts 《International journal of molecular sciences》2022,23(11)
We studied the kinetics of the reaction of N-acetyl-l-cysteine (NAC or RSH) with cupric ions at an equimolar ratio of the reactants in aqueous acid solution (pH 1.4–2) using UV/Vis absorption and circular dichroism (CD) spectroscopies. Cu2+ showed a strong catalytic effect on the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) radical (ABTSr) consumption and autoxidation of NAC. Difference spectra revealed the formation of intermediates with absorption maxima at 233 and 302 nm (ε302/Cu > 8 × 103 M−1 cm−1) and two positive Cotton effects centered at 284 and 302 nm. These intermediates accumulate during the first, O2-independent, phase of the NAC autoxidation. The autocatalytic production of another chiral intermediate, characterized by two positive Cotton effects at 280 and 333 nm and an intense negative one at 305 nm, was observed in the second reaction phase. The intermediates are rapidly oxidized by added ABTSr; otherwise, they are stable for hours in the reaction solution, undergoing a slow pH- and O2-dependent photosensitive decay. The kinetic and spectral data are consistent with proposed structures of the intermediates as disulfide-bridged dicopper(I) complexes of types cis-/trans-CuI2(RS)2(RSSR) and CuI2(RSSR)2. The electronic transitions observed in the UV/Vis and CD spectra are tentatively attributed to Cu(I) → disulfide charge transfer with an interaction of the transition dipole moments (exciton coupling). The catalytic activity of the intermediates as potential O2 activators via Cu(II) peroxo-complexes is discussed. A mechanism for autocatalytic oxidation of Cu(I)–thiolates promoted by a growing electronically coupled –[CuI2(RSSR)]n– polymer is suggested. The obtained results are in line with other reported observations regarding copper-catalyzed autoxidation of thiols and provide new insight into these complicated, not yet fully understood systems. The proposed hypotheses point to the importance of the Cu(I)–disulfide interaction, which may have a profound impact on biological systems. 相似文献
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The effects of amino acids and their analogs on milk fat oxidation were examined under various conditions by measuring oxygen
consumption and total unsaturated fatty acids. All the amino acids tested acted as antioxidants, characteristically extending
the induction period (IP). Not only primary amino groups are responsible for the antioxidative activities of amino acids,
but also the side-chain groups contribute, at least partially, to the protective effects of L-cysteine, L-tryptophan and L-tyrosine.
In aqueous and HCL solutions, the antioxidative effects of L-alanine were significantly reduced. The freeze-dried L-lysine-HCL
and L-alanine-HCL accelerated, while the corresponding control amino acids inhibited, milk fat oxidation. 相似文献
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M. Assunta Dessì Monica Deiana Billy W. Day Antonella Rosa Sebastiano Banni Francesco P. Corongiu 《European Journal of Lipid Science and Technology》2002,104(8):506-512
The propensity of polyunsaturated fatty acids (PUFAs) to undergo oxidation plays an important role in the integrity of biological membrane and lipid containing foods. The ability of squalene (SQ), a naturally occurring dehydrotriterpene present in animal and plant tissues, to protect linoleic, linolenic, arachidonic and docosahexaenoic acids against temperature‐dependent autoxidation and UVA (ultraviolet A, 320‐380 nm) mediated oxidation was assessed. The oxidation of PUFAs was protected in varying degrees, with highest protection observed for linolenic, arachidonic and docosahexaenoic acids. Linoleic acid was less protected. At a molar ratio of 7:1 (PUFA:SQ) the inhibition of the oxidation process was 22% in the presence of linoleic acid and about 50% in presence of the other PUFAs tested. The different protection exerted by SQ against PUFAs with different degrees of unsaturation may be accounted for by the higher stability of octadecadienoic acid hydroperoxide isomers compared with respective PUFA hydroperoxides. Observing mild UVA‐mediated oxidation and the temperature‐dependent autoxidation reactions we found similarities in the oxidation pattern and the protection exerted by SQ. These findings suggest that the reaction of autoxidation is predominant and SQ acts mainly as peroxyl radical scavenger. 相似文献
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研究了固相萃取(SPE)富集和预分离,快速分离柱高效液相色谱(HPLC)快速测定枸杞样品中类胡萝卜素的新方法;枸杞样品中的类胡萝卜素用W aters Sep-Pak C18固相萃取小柱预分离,然后以ZORBAX Stab leBound(4.6 mm×50 mm,1.8μm)快速分离柱为固定相,甲醇-四氢呋喃为流动相分离,V(甲醇)∶V(四氢呋喃)=80∶20,用二极管矩阵检测器检测,检测波长为450 nm,枸杞样品中的几种类胡萝卜素在5 m in内可达到基线分离,比常规方法节约时间75%左右。方法标准回收率为95%~103%,RSD为1.9%~2.6%。 相似文献
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将经过表面无机包覆改性和表面有机包覆改性的金红石型纳米级TiO2粉体分散于乙二醇(EG)中,再经研磨设备循环研磨数次,配制成一定浓度的均匀浆料。按一定的比例与PTA、EG配料参加原位缩聚反应,从而制得具备永久抗紫外功能的聚酯切片。同时还研究了含纳米TiO2材料的抗紫外聚酯切片的纺丝、后加工工艺,并测试了所制备样的抗紫外性能。 相似文献
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Hyun Jung Kim Tae Shik Hahm David B. Min 《Journal of the American Oil Chemists' Society》2007,84(4):349-355
Fifteen milliliters of soybean oil having peroxide value (PV) of 0, 2, 4, 6, 8, or 10 meq/kg oil in a 35 mL serum bottle was
sealed air-tight with a Teflon rubber septum and aluminum cap and was stored in a forced-air oven at 50 °C. The oxidative
stability of soybean oil was evaluated daily for six days by measuring the headspace oxygen content and volatile compounds
in the headspace of a sample bottle by gas chromatography. As the initial PV of the oil increased from 0 to 2, 4, 6, 8 and
10, the headspace oxygen decreased and the volatile compounds increased at p < 0.05. Hydroperoxide accelerated the oxidation of soybean oil. The correlation coefficient (R
2) between the headspace oxygen and the volatile compounds was 0.95. The increase of tertiary butyl hydroquinone (TBHQ) from
0 to 50 ppm for the oil of PV 4 or 8 had a significant effect on the oxidative stability at p < 0.05. The increase from 50 to 100 ppm for the oil of PV 4 or 8 did not significantly increase the stability at p > 0.05. The oxidative stability of PV 8 meq/kg and 50 ppm TBHQ was better than the control with PV 0 and 0 ppm TBHQ at p < 0.05. TBHQ was an effective antioxidant to improve the oxidative stability of soybean oil. 相似文献
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Kaarina Viljanen Susanna Sundberg Toshiaki Ohshima Marina Heinonen 《European Journal of Lipid Science and Technology》2002,104(6):353-359
Carotenoids act as antioxidants in photooxidation by quenching singlet oxygen or triplet sensitizer. The antioxidant activities of β‐carotene, lutein and lycopene during photooxidation were investigated by following the formation of methyl linoleate isomeric hydroperoxides. The hydroperoxide formation and the isomeric distribution were determined using high‐performance liquid chromatography and post‐column detection with diphenyl‐1‐pyrenyl phosphine (DPPP). DPPP reacts with both the conjugated and nonconjugated hydroperoxides formed in photooxidation to give fluorescing DPPP‐oxides. Photooxidation with or without added β‐carotene, lutein and lycopene (10, 20 and 40 ppm) were carried out at +3 °C under 2000 lx. All the studied carotenoids were potential antioxidants during photooxidation and their antioxidant activities were concentration‐dependent. There were no significant differences in the antioxidant activities of lycopene and β‐carotene at a concentration of 10 ppm. At a concentration of 20 ppm β‐carotene was a better antioxidant than lycopene or lutein, and at a concentration of 40 ppm lycopene exerted a better antioxidant activity than β‐carotene or lutein. There were no significant differences between lycopene and lutein at a concentration of 20 ppm. The results also showed that carotenoids had no effect on the distribution of isomeric hydroperoxides indicating that the antioxidant mechanism of carotenoids during photooxidation does not involve hydrogen donation. All carotenoids were consumed during photooxidation. At a higher concentration (40 ppm) lycopene was more stable than the other tested carotenoids. That contributed most likely to it having a better antioxidant activity than β‐carotene and lutein. 相似文献
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Sylwia Pietrasik Natalia Cichon Michal Bijak Leslaw Gorniak Joanna Saluk-Bijak 《International journal of molecular sciences》2022,23(4)
An increasing number of people experience disorders related to the central nervous system (CNS). Thus, new forms of therapy, which may be helpful in repairing processes’ enhancement and restoring declined brain functions, are constantly being sought. One of the most relevant physiological processes occurring in the brain for its entire life is neuroplasticity. It has tremendous significance concerning CNS disorders since neurological recovery mainly depends on restoring its structural and functional organization. The main factors contributing to nerve tissue damage are oxidative stress and inflammation. Hence, marine carotenoids, abundantly occurring in the aquatic environment, being potent antioxidant compounds, may play a pivotal role in nerve cell protection. Furthermore, recent results revealed another valuable characteristic of these compounds in CNS therapy. By inhibiting oxidative stress and neuroinflammation, carotenoids promote synaptogenesis and neurogenesis, consequently presenting neuroprotective activity. Therefore, this paper focuses on the carotenoids obtained from marine sources and their impact on neuroplasticity enhancement. 相似文献
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The effects of dipalmitoylphosphatidylethanolamine (DPE) and dipalmitoylphosphatidylcholine (DPC) on milk fat oxidation was
examined at 50°C and 95°C under various conditions by monitoring oxygen uptake and fatty acid composition. DPE strongly inhibited
milk fat oxidation both at 50°C and 95°C in the absence of water. DPC was less effective than DPE. In aqueous systems, the
reverse was observed. DPE accelerated milk fat oxidation at both 50°C and 95°C. DPC accelerated the oxidation at 50°C, but
inhibited it at 95°C. The free amino group in DPE may be responsible for its inhibiting effect in the dry system. The accelerating
activity of DPE in the aqueous system is probably due to the formation of a more dispersed structure with better oxygen accessibility. 相似文献
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Jaslyn Jie Lin Lee Aaron Li Xiaomei Lyu Jae Jung Kim Wei Ning Chen 《European Journal of Lipid Science and Technology》2021,123(8):2000354
Waste cooking oil (WCO) is a problematic waste product that contains free fatty acids (FFAs), preventing it from being valorized easily as biodiesel and poses an environmental hazard if incorrectly disposed. The use of WCO as a carbon source for Rhodosporidium toruloides (R. toruloides) using a two-phase culture system is developed. The normal growth of R. toruloides when cultured in WCO (OD600 52) reveals its ability to use a hydrophobic substrate as the carbon source compared to glucose (OD600 51.9). Interestingly, the extracellular lipase activity when R. toruloides is grown on WCO is 14.4 U mL−1 compared to when grown on glucose (2.4 U mL−1). Additionally, FFA levels in WCO are reduced from 2% to 0.2% at end of fermentation, suggesting that R. toruloides can consume FFA. Furthermore, higher yield of beneficial products: β-carotene (4.57 µg mL−1), torularhodin (4.2 µg mL−1), fatty acids (1 mg mL−1), and phenylalanine ammonia-lyase (PAL) enzyme (0.12 µmol mg−1) are produced when WCO is the carbon source, compared to glucose (4.1 µg mL−1 β-carotene, 3.0 µg mL−1 torularhodin, 1 mg mL−1 of fatty acids, and 0.096 µmol mg−1 PAL enzyme). This is a first study that shows R. toruloides can grow on hydrophobic carbon source. 相似文献
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Ruijie Liu Mengyao Lu Tao Zhang Zhiyan Zhang Qingzhe Jin Ming Chang Xingguo Wang 《European Journal of Lipid Science and Technology》2020,122(2)
Micronutrients (tocols, sterols, and total phenolic) and antioxidant activities of 15 varieties of common vegetable oil samples obtained from different countries are investigated. All methanol extracts are assayed for total antioxidant ability and cellular antioxidant activity (CAA) using oxygen radical absorbance capacity (ORAC) method and CAA assay. CAA has been widely used in the evaluation of food antioxidants recently. It quantifies antioxidant capacity utilizing a HepG2 cell model, which is more biologically representative. Linseed and sesame oils show much higher CAA values than the others tested; however, levels of walnut, sunflower, and coconut oils are extremely low, which are hard to be quantified. A significant correlation between the ORAC and CAA values and total phenolic content (p < 0.05) is observed. High‐phenolic olive oil has the highest level of phenolics and the highest ORAC, while linseed oil has the highest CAA value. Based on this, choosing proper edible oil consumption may reduce oxidative damage of human body and promote the precision processing of edible oil such as retaining beneficial ingredients moderately. Practical Application: This study demonstrates the evaluation of the universality of vegetable oils by the cellular antioxidant model and provides a data reference for the selection of edible oils with excellent antioxidant properties. 相似文献