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1.
Seahorse, Hippocampus kuda (SH) a marine teleost fish, is well known not only for its special medicinal composition and used as one of the most famous and expensive materials of traditional Chinese medicine. It was extracted with water (SHW), methanol (SHM), and ethanol (SHE), respectively and evaluated by various antioxidant assays. The including reducing power, total antioxidant, DPPH radical scavenging, hydroxyl radical scavenging, superoxide anion radical scavenging, alkyl radical scavenging, and protective effect on DNA damage caused by hydroxyl radicals generated. Further, the ROS level was detected using a fluorescence probe, 2′,7′-dichlorofluorescin diacetate (DCFH-DA), which could be converted to highly fluorescent dichlorofluorescein (DCF) with the presence of intracellular ROS on mouse macrophages, RAW264.7 cell and inhibited myeloperoxidase (MPO) activity in human myeloid, HL60 cells, respectively. Those various antioxidant activities were compared to standard antioxidants such as α-tocopherol. Among SHM exhibited the highest antioxidant activity in linoleic acid system, effective reducing power, DPPH radical scavenging, hydroxyl radical scavenging, superoxide radical scavenging, alkyl radical scavenging, inhibitory intracellular ROS, and inhibited MPO activity. Furthermore, MTT assay showed no cytotoxicity on mouse macrophages cell (RAW264.7) and human cell lines (MRC-5, HL60, U937). This antioxidant property depends on concentration and increasing with increased amount of extracts. The results obtained in the present study indicated that the see horse (Hippocampus kuda Bleeker) is a potential source of natural antioxidant.  相似文献   

2.
Flavones exhibit a variety of beneficial effects and are well known for their medicinal importance in several diseases, including cardiovascular, neurodegenerative and cancer. The inclusion of the piperazine ring to the flavone backbone is an important strategy in drug discovery but only a few studies have synthesized piperazinyl flavone compounds to test their biological activity. While there is a major focus on the antioxidant properties of drugs in therapy of several diseases of inflammatory origin, we synthesized a series of the novel piperazinyl flavone analogues bearing the phenyl ring with different substituents. The analogues were evaluated for in vitro antioxidant activity against superoxide anion radical, hydroxyl radical, 2,2‐diphenyl‐1‐picrylhydrazyl radical, and hydrogen peroxide scavenging properties. The total antioxidant status based on the absorbance of the 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid) radical cation (ABTS+?) and total antioxidant capacity using the Fe(III)‐ferrozine complex were also monitored. The results of the above studies showed that the compounds synthesized were found possessed moderate radical scavenging potential, and that their interaction with reactive oxygen species is complex and depends on their structural conformation and the type of substituent R in the piperazine ring being attached. Best antiradical activity were found for the compounds with methoxy groups on the phenyl ring of substituent R, whereas the presence of methoxy or trifluoromethyl groups in substituent R resulted in higher ABTS+? and ion Fe(III) reduction. These compounds are promising molecules to be used for their antioxidant properties and may be regarded, after improvement of the antioxidant potential, to control diseases of free radical etiology.  相似文献   

3.
Free radical scavenging and antioxidant activities of baicalein, baicalin, wogonin and wogonoside, the four major flavonoids in the radix of Scutellaria baicalensis Georgi, were examined in different systems. ESR results showed that baicalein and baicalin scavenged hydroxyl radical, DPPH radical and alkyl radical in a dose-dependent manner, while wogonin and wogonoside showed subtle or no effect on these radicals. Ten micromol/l of baicalein and baicalin effectively inhibited lipid peroxidation of rat brain cortex mitochondria induced by Fe(2+)-ascorbic acid, AAPH or NADPH, while wogonin and wogonoside showed significant effects only on NADPH-induced lipid peroxidation. In a study on cultured human neuroblastoma SH-SY5Y cells system, it was found that 10 micromol/l of baicalein and baicalin significantly protected cells against H(2)O(2)-induced injury. Baicalein was the most effective antioxidant among the four tested compounds in every system due to its o-tri-hydroxyl structure in the A ring. Compared with a well-known flavonoid, quercetin, the antioxidant activity of baicalein was lower in DPPH or AAPH system, but a little higher in those systems which might associate with iron ion. These results suggest that flavonoids in the radix of Scutellaria baicalensis with o-di-hydroxyl group in A the ring, such as baicalein and baicalin, could be good free radical scavengers and might be used to cure head injury associated with free radical assault.  相似文献   

4.
To obtain a natural antioxidant from a marine biomass, this study investigated the antioxidative activity of methanolic extracts from the marine brown alga, Ishige okamurae collected off Jeju Island. A potent free radical scavenging activity was detected in the ethyl acetate fraction containing polyphenolic compounds, and the potent antioxidant elucidated as a kind of phlorotannin, diphlorethohydroxycarmalol, by NMR and mass spectroscopic data. The free radical scavenging activities of the diphlorethohydroxycarmalol were investigated in relation to 1,1-diphenyl-2-picrylhydrazyl (DPPH), alkyl, and hydroxyl radicals using an electron spin resonance (ESR) system. The diphlorethohydroxycarmalol was found to scavenge DPPH (IC50=3.41 microM) and alkyl (IC50=4.92 microM) radicals more effectively than the commercial antioxidant, ascorbic acid. Therefore, these results present diphlorethohydroxycarmalol as a new phlorotannin with a potent antioxidative activity that could be useful in cosmetics, foods, and pharmaceuticals.  相似文献   

5.
A series of 2-arylbenzimidazole derivatives (3a3p and 4a4i) were synthesized and evaluated as potential antioxidant and antimicrobial agents. Their antioxidant properties were evaluated by various in vitro assays including hydroxyl radical (HO) scavenging, superoxide radical anion (O2?) scavenging, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, and ferric reducing antioxidant power. Results demonstrated that compounds with hydroxyl group at the 5-position of benzimidazole ring had a comparable or better antioxidant activity in comparison to standard antioxidant tert-butylhydroquinone (TBHQ). Markedly, compound 4h that showed the highest HO scavenging activity (EC50 = 46 μM) in vitro had a significant reduction of 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced intracellular oxidative stress and H2O2-induced cell death. In addition, these compounds showed moderate to good inhibitory activity against Staphylococcus aureus selectively at noncytotoxic concentrations.  相似文献   

6.
The short-range properties of alkylpiperazine ionic liquids paired with propionate and lactate anions were analyzed and their affinity for CO2 molecules studied using density functional theory. Anion–cation interactions led to the development of strong intermolecular hydrogen bonding through the cation amine position, as confirmed through variations in structural and vibrational properties upon pair formation. Topological analysis via the atoms-in-molecules approach revealed the development of intense bond and ring critical points in the intermolecular regions, which is in agreement with charge transfer from lone pairs in anion oxygen atoms of carboxylate groups through antibonding orbitals in cation amine groups. Such anion–cation interactions are weakly dependent on cation alkyl chain length but are remarkably affected by the presence of an anion hydroxyl group. Interactions with CO2 molecules are stronger for anions than for cations, especially for propionate anions, and are also affected strongly by the anion hydroxyl group.  相似文献   

7.
A novel biopolymer-based antioxidant, chitosan conjugated with gallic acid (chitosan galloylate, chitosan-GA), is proposed. Electron paramagnetic resonance (EPR) demonstrates a wide range of antioxidant activity for chitosan-GA as evidenced from its reactions with oxidizing free radicals, that is, 1,1-diphenyl-2-picryl-hydrazyl (DPPH), horseradish peroxidase (HRP)-H2O2, carbon-centered alkyl radicals, and hydroxyl radicals. The EPR spectrum of the radical formed on chitosan-GA was attributed to the semiquinone radical of the gallate moiety. The stoichiometry and effective concentration (EC50) of the DPPH free radical with chitosan-GA show that the radical scavenging capacity is maintained even after thermal treatment at 100 °C for an hour. Although the degree of substitution of GA on chitosan was about 15%, its antioxidant capacity, that is, the reaction with carbon-centered and hydroxyl radicals, is comparable to that of GA.  相似文献   

8.
The interest in the extraction of polyphenolic compounds from plant materials is focused on upgrading of the large amount of by-products coming from food or cosmetics industries from which the press residues have particularly high contents of phenolics. In this study, for value-added use of the brown seaweed Ecklonia cava processing by-product (ECPB), which can be obtained after polyphenolic extraction of E. cava, it was fermented by the yeast Candida utilis and its antioxidant activities were evaluated by 1,1-diphenyl-2-picrylhydrazyl, hydroxyl, and alkyl radical scavenging using electron spin resonance spectrometer. ECPB was fermented for 1~4?days prior to being extracted with 80% ethanol, and significant differences were observed in extraction yields, total phenolic contents (TPC), and radical scavenging activities with the fermentation time. Extract from the ECPB fermented for 1?day exhibited the highest TPC and also found to be the strongest antioxidant. The 1-day fermented ECPB strongly enhanced cell viability against H2O2-induced oxidative damage in Vero cell line. This sample also exhibited good protective properties against H2O2-induced cell apoptosis as was demonstrated by a decreased quantity of sub-G1 hypodiploid cells and decreased apoptotic body formation in the flow cytometry analysis. This study demonstrated that the fermentation elevated functionally important polyphenolic contents of ECPB and resultant antioxidant activities were enhanced. Therefore, the fermentation could offer a tool to further increase the bioactive potential of ECPB.  相似文献   

9.
Hydroxyl radical in living systems and its separation methods   总被引:11,自引:0,他引:11  
It has recently been shown that hydroxyl radicals are generated under physiological and pathological conditions and that they seem to be closely linked to various models of pathology putatively implying oxidative stress. It is now recognized that the hydroxyl radical is well-regulated to help maintain homeostasis on the cellular level in normal, healthy tissues. Conversely, it is also known that virtually every disease state involves free radicals, particularly the most reactive hydroxyl radical. However, when hydroxyl radicals are generated in excess or the cellular antioxidant defense is deficient, they can stimulate free radical chain reactions by interacting with proteins, lipids, and nucleic acids causing cellular damage and even diseases. Therefore, a confident analytical approach is needed to ascertain the importance of hydroxyl radicals in biological systems. In this paper, we provide information on hydroxyl radical trapping and detection methods, including liquid chromatography with electrochemical detection and mass spectrometry, gas chromatography with mass spectrometry, capillary electrophoresis, electron spin resonance and chemiluminescence. In addition, the relationships between diseases and the hydroxyl radical in living systems, as well as novel separation methods for the hydroxyl radical are discussed in this paper.  相似文献   

10.
Vitamin E and its function in membranes   总被引:10,自引:0,他引:10  
Vitamin E is a fat-soluble vitamin. It is comprised of a family of hydrocarbon compounds characterised by a chromanol ring with a phytol side chain referred to as tocopherols and tocotrienols. Tocopherols possess a saturated phytol side chain whereas the side chain of tocotrienols have three unsaturated residues. Isomers of these compounds are distinguished by the number and arrangement of methyl substituents attached to the chromanol ring. The predominant isomer found in the body is alpha-tocopherol, which has three methyl groups in addition to the hydroxyl group attached to the benzene ring. The diet of animals is comprised of different proportions of tocopherol isomers and specific alpha-tocopherol-binding proteins are responsible for retention of this isomer in the cells and tissues of the body. Because of the lipophilic properties of the vitamin it partitions into lipid storage organelles and cell membranes. It is, therefore, widely distributed in throughout the body. Subcellular distribution of alpha-tocopherol is not uniform with lysosomes being particularly enriched in the vitamin compared to other subcellular membranes. Vitamin E is believed to be involved in a variety of physiological and biochemical functions. The molecular mechanism of these functions is believed to be mediated by either the antioxidant action of the vitamin or by its action as a membrane stabiliser. alpha-Tocopherol is an efficient scavenger of lipid peroxyl radicals and, hence, it is able to break peroxyl chain propagation reactions. The unpaired electron of the tocopheroxyl radical thus formed tends to be delocalised rendering the radical more stable. The radical form may be converted back to alpha-tocopherol in redox cycle reactions involving coenzyme Q. The regeneration of alpha-tocopherol from its tocopheroxyloxyl radical greatly enhances the turnover efficiency of alpha-tocopherol in its role as a lipid antioxidant. Vitamin E forms complexes with the lysophospholipids and free fatty acids liberated by the action of membrane lipid hydrolysis. Both these products form 1:1 stoichiometric complexes with vitamin E and as a consequence the overall balance of hydrophobic:hydrophillic affinity within the membrane is restored. In this way, vitamin E is thought to negate the detergent-like properties of the hydrolytic products that would otherwise disrupt membrane stability. The location and arrangement of vitamin E in biological membranes is presently unknown. There is, however, a considerable body of information available from studies of model membrane systems consisting of phospholipids dispersed in aqueous systems. From such studies using a variety of biophysical methods, it has been shown that alpha-tocopherol intercalates into phospholipid bilayers with the long axis of the molecule oriented parallel to the lipid hydrocarbon chains. The molecule is able to rotate about its long axis and diffuse laterally within fluid lipid bilayers. The vitamin does not distribute randomly throughout phospholipid bilayers but forms complexes of defined stoichiometry which coexist with bilayers of pure phospholipid. alpha-Tocopherol preferentially forms complexes with phosphatidylethanolamines rather than phosphatidylcholines, and such complexes more readily form nonlamellar structures. The fact that alpha-tocopherol does not distribute randomly throughout bilayers of phospholipid and tends to form nonbilayer complexes with phosphatidylethanolamines would be expected to reduce the efficiency of the vitamin in its action as a lipid antioxidant and to destabilise rather than stabilise membranes. The apparent disparity between putative functions of vitamin E in biological membranes and the behaviour in model membranes will need to be reconciled.  相似文献   

11.
Antioxidants solubilized in micellar solutions can change micellar properties like the size and shape of micelles, critical micellar concentration (cmc) and viscosity. Interactions arising between antioxidants and the surfactant determine the locations of antioxidants and vice versa. The location and interaction are dependent on the type of both the antioxidant and surfactant. Influences of various antioxidants on the physical and structural properties were tested in micellar systems of cationic CTAB, non-ionic Brij 58 and anionic SDS. The antioxidants used to investigate the effects of gradually increasing lipophilicity were gallic acid (GA) and the gallate esters from methyl to octyl gallate (MG-OG). Hydroxy cinnamic acids (HCAs) like -coumaric acid (pC), caffeic acid (CA), ferulic acid (FA) and sinapic acid (SA) were employed to observe effects of functional groups like hydroxyl and methoxy groups. Micellar size and shape determined by small angle neutron scattering (SANS), viscosity and cmc were chosen to characterize the antioxidant influence. In Brij 58 systems propyl gallate (PG) did not affect the cmc or aggregation number but decreased micellar size slightly due to an intercalation of PG into the region of the polyoxyethylene chain and the first adjacent alkyl chain methylene groups. In SDS systems the micellar size and cmc decreased in the presence of PG. This was attributed to PG residing in the Stern layer. However, in CTAB systems micelles swelled at low PG concentration and in the presence of GA, while higher PG concentrations and more lipophilic antioxidants led to a sphere-to-rod transition with a simultaneous increase in viscosity and decrease in cmc. This revealed the intercalation of antioxidants in the palisade layer of CTAB micelles entering into strong interactions of electrostatic and hydrophobic origin. It could be demonstrated that the interactions became stronger the more lipophil an antioxidant is and the more hydroxyl groups are attached to the aromatic ring. Differences in the location and interaction of antioxidant and micelles are proposed as being responsible for the effectiveness of antioxidants.  相似文献   

12.
Antioxidant properties of gingerol related compounds from ginger   总被引:5,自引:0,他引:5  
Ginger (Zingiber officinale Roscoe) shows an antioxidant activity, and we have been engaging to determine the structures of more than 50 antioxidants isolated from the rhizomes of ginger. The isolated antioxidants are divided into two groups; gingerol related compounds and diarylheptanoids. In this study, structure-activity relationship of gingerol related compounds was evaluated. Gingerol related compounds substituted with an alkyl group bearing 10-, 12- or 14-carbon chain length were isolated from the dichloromethane extract of rhizomes using repeated chromatographic techniques. The antioxidant activities of these compounds were evaluated by the following measurements; 1) 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, 2) inhibitory effect on oxidation of methyl linoleate under aeration and heating by the Oil Stability Index (OSI) method, and 3) inhibitory effect on oxidation of liposome induced by 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH). These results suggested that the substituents on the alkyl chain might contribute to both radical scavenging effect and inhibitory effect of autoxidation of oils, while inhibitory effects against the AAPH-induced peroxidation of liposome was somewhat influenced by the alkyl chain length; the antioxidant activity might be due to not only radical scavenging activity of antioxidants but also their affinity of the antioxidants to the substrates.  相似文献   

13.
Several novel antioxidant-iron chelators bearing 8-hydroxyoxyquinoline moiety were synthesized, and various properties related to their iron chelation, and neuroprotective action were investigated. All the chelators exhibited strong iron(III) chelating and high antioxidant properties. Chelator 9 (HLA20), having good permeability into K562 cells and moderate selective MAO-B inhibitory activity (IC50 110 microM), displayed the hightest protective effects against differentiated P19 cell death induced by 6-hydroxydopamine. EPR studies suggested that Chelator 9 also act as radical scavenger to directly scavenge hydroxyl radical.  相似文献   

14.
The "photo-Fenton" reagent, 2-mercaptopyridine N-oxide (MPO), which releases a hydroxyl radical on ultraviolet irradiation, has been found to act as an antioxidant. In the peroxidation of linoleate initiated by a water-soluble azo-initiator, MPO has about one-third the activity of the water-soluble vitamin E analogue Trolox C. In contrast, the oxygen-containing analogue, 2-hydroxypyridine N-oxide (HPO), does not have measurable antioxidant activity in this system. Both reagents react with hydroxyl radical with second order rate constants very close to the diffusion-controlled limit. With the less oxidising dithiocyanate radical anion, MPO reacts approximately 50 times more rapidly than HPO at pH>7. The more reducing properties of MPO result in its activity as an antioxidant and make it less suitable than HPO as a source of hydroxyl radicals for investigation of oxidative stress in biological systems.  相似文献   

15.
Potential biological properties of newly synthesized single and double alkyl chain N-oxides of tertiary amines (NTA) were studied. Individual compounds in each of the series had alkyl chains of different length. Various experiments were performed to determine a mechanism of the interaction between NTA and model and biological membranes. These were measurements of hemolytic efficiencies of NTA (pig erythrocytes), their influence on the transition temperatures (DPPC liposomes), on potassium leakage from cucumber, its growth and chlorophyll content (Cucumis sativus cv. Krak F1), and on the resting membrane potential in alga cells (Nitellopsis obtusa). Also, prevention of erythrocyte membrane lipid oxidation induced by UV irradiation was studied. Potential antioxidative properties of NTA were additionally tested in radical chromogen (ABTS) experiments in which antioxidative efficiencies of NTA were compared to that of the standard antioxidant Trolox. It was found that NTA readily interacted with erythrocyte membranes. Their hemolyzing efficiency increased with the alkyl chain length. Slightly more intensive interaction was found for double alkyl chain compounds. Similar results were obtained in DSC experiments, where incorporation of NTA into liposomal membranes shifted the main transition temperatures and caused a broadening of the main transition peaks depending on the alkyl chain length. Double alkyl chain compounds were also found more efficiently influencing the growth of cucumber. Influence of NTA on the resting membrane potential of algae cells was not quite following the alkyl chain length rule found in erythrocyte and liposome experiments. Also potassium leakage and chlorophyll content determined in physiological experiments were not following the increase of lipophilicity of compounds. Most efficiently influencing those parameters were NTA having shorter alkyl chains, and efficiencies of single alkyl chain compounds were evidently stronger. Both methods used to test the antioxidative properties of NTA showed that they depended on the alkyl chain lengths of compounds within each series, but double alkyl chain ones exhibited markedly greater efficiency.  相似文献   

16.
Embelin (from Embelia ribes) is a component of herbal drugs and possess wide range of medicinal properties. These properties may be, in part, due to scavenging of oxidizing free radicals. In this context, free radical scavenging reactions and antioxidant activity of embelin (2,5-dihydroxy-3-undecyl-1,4-benzoquinone) have been studied. It has been found to scavenge DPPH radical and inhibit hydroxyl radical induced deoxyribose degradation. It has been also found to inhibit lipid peroxidation and restore impaired Mn-superoxide dismutase in rat liver mitochondria. Further, kinetics and mechanism of the reactions of embelin with hydroxyl, one-electron oxidizing, organo-haloperoxyl and thiyl radicals have been studied using nanosecond pulse radiolysis technique. Its redox potential has been also evaluated with cyclic voltammetry. These studies suggest that embelin can act as a competitive antioxidant in physiological conditions.  相似文献   

17.
Microcrystals of monosodium urate monohydrate(MSUM)induce cytolysis and hemolysis inerythrocytes.In this report,we studied the effect of vitamin E on MSUM-mediated hemolysis in humanerythrocytes.Vitamin E significantly inhibited hemolysis induced by MSUM.The hydroxyl group in thechromanol ring of vitamin E is dispensable for protecting erythrocytes against hemolysis induced by MSUM,indicating that the inhibitory effect of vitamin E is not due to its antioxidant properties.However,both thechromanol ring and the isoprenoid side chain are important for vitamin E to suppress MSUM-induced hemolysis.Our current study suggests that vitamin E inhibits hemolysis induced by MSUM as a membrane stabilizer.  相似文献   

18.
We purified a novel antioxidant peptide from Ruditapes philippinarum (R. philippinarum) and investigated its free radical scavenging activities. To prepare the peptide, eight proteases were tested for enzymatic hydrolysis. α-chymotrypsin hydrolysate, which showed clearly superior hydroxyl radical scavenging activity (p < 0.05), were further purified using a flow filtration system and consecutive chromatographic methods. Finally, a novel antioxidant peptide was obtained, and the sequence was identified as Ser-Val-Glu-Ile-Gln-Ala-Leu-Cys-Asp-Met. The peptide from R. philippinarum effectively scavenged hydroxyl, DPPH, alkyl and superoxide radicals, with observed IC50 values of 0.042, 0.091, 0.107 and 0.372 mg/ml, respectively. This is the first report of an antioxidant peptide derived from the hydrolysates of R. philippinarum which, further, possesses competitive free radical quenching potential.  相似文献   

19.
This study evaluated the antioxidant potential of extracts from Cornus walteri W. (CW) using various assays for natural antioxidants. We determined the polyphenol and flavonoid contents, as well as the antioxidant properties of water and ethanol extracts from the CW compared with those of other natural and synthetic antioxidants. CW extracts had high total phenolic and flavonoid contents in both the water and ethanol extracts. Various radical (DPPH, hydroxyl, and alkyl) scavenging activities of extracts from CW were higher than that of vitamin C. In addition, the antioxidant capacity measured as ferric reducing antioxidant power (FRAP), and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) as diammonium salt (ABTS) radical scavenging were higher than that of 2,6-di-tert-butyl-4-methylphenol (BHT), used as a positive control. The cytoprotective effect of CW extracts was also observed in tert-butyl hydroperoxide (t-BHP)-induced oxidative damage in Chang cells. These results showed that CW extracts have antioxidant properties through their ability to enhance cell viability, prevent reactive oxygen species (ROS) generation, and inhibit mitochondrial membrane depolarization. The antioxidant potency of the CW extracts could be exploited for their health promoting potential.  相似文献   

20.
目的从鄂尔多斯婴儿粪便中分离出动物双歧杆菌,并对其进行抗氧化性的研究。方法结合细菌形态学和16SrDNA序列同源性分析进行鉴定,并对其还原性和·OH自南基清除能力进行了抗氧化研究。结果该分离出的菌株为动物双歧杆菌,其还原能力与·OH自由基清除能力随着浓度的增加而增大。结论动物双歧杆菌具有抗氧化性且与菌液的浓度呈现效量关系。  相似文献   

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