Mechanism of lipid peroxidation of liposomes by cold atmospheric pressure plasma jet irradiation.

Liposome lipid peroxidation induced by cold atmospheric pressure plasma jet (CAPPJ) irradiation was investigated. The formation of thiobarbituric acid reactive substances (TBARS), an indicator of lipid peroxidation final products, as a function of irradiation was observed. Lipid radicals, peroxidation reaction intermediates generated by CAPPJ irradiation, were confirmed by increased NBD-pen fluorescence intensity.

Electrolytic-reduction ion water protects keratinocytes from hydrogen peroxide through radical scavenging activity and induction of AQP3 expression.

Skin exposed to ultraviolet light produces hydrogen peroxide (HO) and reactive oxygen species (ROS) that cause protein denaturation and other disorders. We investigated whether electrolytic-reduction ion water (ERI), which has reducing properties and has been reported to protect skin, exhibits antioxidant activity in skin keratinocytes. The antioxidant activity of ERI was first examined using DPPH assay and Electron Spin Resonance to test for radicals, and using the Amplex Red method to test for HO.

Evaluation of cold atmospheric pressure plasma irradiation of water as a method of singlet oxygen generation.

We used cold atmospheric pressure plasma jet to examine in detail O generation in water. ESR with 2,2,5,5-tetramethyl-3-pyrroline-3-carboxamide, a secondary amine probe, was used for the detection of O. Nitroxide radical formation was detected after cold atmospheric pressure plasma jet irradiation of a 2,2,5,5-tetramethyl-3-pyrroline-3-carboxamide solution.

Method to Improve Azo-Compound (AAPH)-Induced Hemolysis of Erythrocytes for Assessing Antioxidant Activity of Lipophilic Compounds.

We examined the method of oxidative hemolysis for assessment of antioxidant activity of various compounds, especially lipophilic compounds. 2,2'-Azobis(amidinopropane) dihydrochloride (AAPH) was used as the source of free radicals for the oxidative hemolysis of horse erythrocytes. We found that absorbance at 540 nm is not appropriate for monitoring AAPH-induced hemolysis.

Basic Investigations of Singlet Oxygen Detection Systems with ESR for the Measurement of Singlet Oxygen Quenching Activities.

Singlet oxygen (O) is highly oxidative and exerts strong cytotoxic effects. We tried to establish the best combination of a singlet oxygen generation system and a detection method with ESR, for measurement of the quenching activities of various substances. The photosensitizing reaction of rose bengal or thermal decomposition of 4-methyl-1,4-etheno-2,3-benzodioxin-1(4H)-propanoic acid (endoperoxide, EP) was used for the generation of O, and a sterically hindered secondary amine, 2,2,6,6-tetramethyl-4-piperidone (TEMPD) or 2,2,6,6-tetramethyl-4-piperidinol (TEMP-OH), was used as the O detection probe.

Formation of reactive oxygen species by irradiation of cold atmospheric pressure plasma jet to water depends on the irradiation distance.

Because application of cold atmospheric pressure plasma jet (CAPPJ) to biological samples have taken large attentions, it is important to examine the effects of various CAPPJ parameters on the generation of reactive species. Here, we investigated the generation of reactive species in water by CAPPJ irradiation by changing the following parameters: irradiation time, sample volume, and irradiation distance between the sample surface and plasma jet tip. We measured 1) change in the ESR signal intensity of 4-hydroxy-2,2,6,6-tetrametylpeperidine-1-oxyl (Tempol), 2) spin-trapping with 5,5-dimethyl-1-pyrroline -oxide (DMPO), 3) Fricke dosimeter reaction, and 4) hydrogen peroxide (HO) formation induced by CAPPJ irradiation.

Toona sinensis inhibits LPS-induced inflammation and migration in vascular smooth muscle cells via suppression of reactive oxygen species and NF-κB signaling pathway.

Toona sinensis is one of the most popular vegetarian cuisines in Taiwan and it has been shown to possess antioxidant, antiangiogenic, and anticancer properties. In this study, we investigated the antiatherosclerotic potential of aqueous leaf extracts from Toona sinensis (TS; 25-100 μg/mL) and its major bioactive compound, gallic acid (GA; 5 μg/mL), in LPS-treated rat aortic smooth muscle (A7r5) cells. We found that pretreatment with noncytotoxic concentrations of TS and GA significantly inhibited inflammatory NO and PGE2 production by downregulating their precursors, iNOS and COX-2, respectively, in LPS-treated A7r5 cells.

Nitric oxide converts fatty acid alkoxyl radicals into fatty acid allyl radicals.

Nitric oxide (()NO) is thought to react with fatty acid alkoxyl radical, which is generated from fatty acid hydroperoxide via one-electron reduction. However, detail in the reaction remains obscure. In the present study, we examined the reaction of nitric oxide with fatty acid alkoxyl radical generated in the lipoxygenase/linoleate/13-hydroperoxyoctadecadienoate (13-HpODE) system under anaerobic conditions via HPLC equipped with mass spectrometry and photodiode array detections.

Trapping of fatty acid allyl radicals generated in lipoxygenase reactions in biological fluids by nitroxyl radical.

Nitroxyl radicals can trap fatty acid allyl radicals on ferric-lipoxygenases at lower oxygen content, which are an intermediate in the lipoxygenase reaction. In the present study, we examined whether nitroxyl radical-trapping of fatty acid allyl radicals on the enzyme proceeds in biological fluids with abundant antioxidants. The fatty acid allyl radical-nitroxyl radical adducts were quantified by HPLC with electrochemical detection (HPLC-ECD); the adducts in eluate degraded into nitroxyl radical by passing through heating coil at 100 degrees C, and then nitroxyl radical was detected by electrochemical detector.

Feedback activation of ferrous 5-lipoxygenase during leukotriene synthesis by coexisting linoleic acid.

Ferrous lipoxygenases seem to be activated through a feedback control mechanism via FA hydroperoxides generated from PUFAs by partially existing ferric lipoxygenases. However, during leukotriene synthesis, feedback activation of ferrous 5-lipoxygenase in the presence of arachidonic acid (AA) was not observed. In the present study, we examined the feedback activation of ferrous 5-lipoxygenase in the 5-lipoxygenase/AA system in the presence of linoleic aicd (LA), which is a predominant component of membrane phospholipids.

Regulation of S-thiolation and S-nitrosylation in the thiol/nitric oxide system by radical scavengers.

Nitric oxide (NO) is a possible agent, which induces crosslinking among molecules containing sulfhydryl groups. However, the S-thiolation is essentially accompanied by S-nitrosylation. In the present study, we evaluated radical scavengers as a regulator for S-thiolation and S-nitrosylation by NO released from NO-generator, 1-hydroxy-2-oxo-3-(N-methyl-3-aminopropyl)-3-methyl-1-triazene (P-NONOate).

Intramolecular rearrangement of linolenate peroxyl radicals in lipoxygenase reactions at lower oxygen content.

Variation of tissue oxygen content is thought to be a possible factor in determining the structural diversity of hydroperoxy fatty acids. In the present study, we evaluated the structural diversity of intermediate carbon-centered radicals at lower oxygen content. When the buffered solution (pH 7.

Radical scavenger can scavenge lipid allyl radicals complexed with lipoxygenase at lower oxygen content.

Lipoxygenases have been proposed to be a possible factor that is responsible for the pathology of certain diseases, including ischaemic injury. In the peroxidation process of linoleic acid by lipoxygenase, the E,Z-linoleate allyl radical-lipoxygenase complex seems to be generated as an intermediate. In the present study, we evaluated whether E,Z-linoleate allyl radicals on the enzyme are scavenged by radical scavengers.

Quantification of lipid alkyl radicals trapped with nitroxyl radical via HPLC with postcolumn thermal decomposition.

Lipid alkyl radicals generated from polyunsaturated fatty acids via chemical or enzymatic H-abstraction have been a pathologically important target to quantify. In the present study, we established a novel method for the quantification of lipid alkyl radicals via nitroxyl radical spin-trapping. These labile lipid alkyl radicals were converted into nitroxyl radical-lipid alkyl radical adducts using 3-carbamoyl-2,2,5,5-tetramethyl-3-pyrroline-N-oxyl (CmdeltaP) (a partition coefficient between octanol and water is approximately 3) as a spin-trapping agent.

In vivo oxygen radical generation in the skin of the protoporphyria model mouse with visible light exposure: an L-band ESR study.

Although oxygen radicals are thought to play a key role in the skin injury that is caused by protoporphyria, there is no direct evidence of generation of these radicals in vivo. This study measured the generation of oxygen radicals caused by visible light non-invasively in the skin of griseofulvin-induced protoporphyria model mice, using an in vivo electron spin resonance spectrometer equipped with a surface-coil-type resonator that could detect radicals within about 0.5 mm of the skin surface.