A crude polysaccharide was extracted from Physalis alkekengi L. fruit. HPLC was used for the component analysis of the polysaccharide. The results indicate that Physalis alkekengi L. polysaccharide(PAP) was composed...A crude polysaccharide was extracted from Physalis alkekengi L. fruit. HPLC was used for the component analysis of the polysaccharide. The results indicate that Physalis alkekengi L. polysaccharide(PAP) was composed of rhamnose, xylose, arabinose, galactose, and glucose. Free radicals scavenging activity of PAP was studied through 3 free radicals scavenging tests. PAP exhibited high scavenging effects on OH and DPPH radicals, and both the scavenging rates were about 80%. The scavenging rate of O2^- radical was about 22%.展开更多
The flower of Butea monosperma(Lam.)(Fabaceae)has been used in traditional Indian medicine in the treatment of many ailments including liver disorders.To understand the pharmacological basis of its beneficial effects,...The flower of Butea monosperma(Lam.)(Fabaceae)has been used in traditional Indian medicine in the treatment of many ailments including liver disorders.To understand the pharmacological basis of its beneficial effects,the extracts of dried flowers in water,methanol,butanol,ethyl acetate and acetone were evaluated for free radical scavenging and pro-apoptotic activities in cell cultures(human hepatoma Huh-7 cell line and immortalized AML-12 mouse hepatocytes).Butrin and butein-the active constituents of flower extracts-were used as reference molecules.The levels of cell injury markers like lactate dehydrogenase,glutathione and lipid peroxidation and primary antioxidant enzymes glutathione S-transferase and catalase were also measured.The aqueous and butanolic extracts exhibited better 2,2-diphenyl-1-picrylhydrazyl scavenging and cytotoxic activities in hepatoma cells than in immortalized hepatocytes.Interestingly,butein inhibited 2,2-diphenyl-1-picrylhydrazyl radical better than butrin.The aqueous and butanolic extracts were further investigated for hepatoprotection against carbon tertrachloride-induced biochemical changes and cell death.Both extracts,just as butrin and butein,significantly reversed the cellular glutathione levels and lipid peroxidation,and glutathione–S-transferase activity.Lactate dehydrogenase leakage and cell death were also prevented.However,only butein revived the catalase activity.Thus,the butein content of Butea monosperma flower extracts is important for free radical scavenging activity,apoptotic cell death and protection against oxidative injury in hepatic cells.展开更多
BACKGROUND: The fluidity of cell membrane can be affected by various factors. Many experiments have confirmed that the ischemia/reperfusion of organic tissue can increase the contents of free radicals, which lead to h...BACKGROUND: The fluidity of cell membrane can be affected by various factors. Many experiments have confirmed that the ischemia/reperfusion of organic tissue can increase the contents of free radicals, which lead to high rigidity and low fluidity of cell membrane, and the conditions can be changed by Chuanxiongqin. OBJECTIVE: To observe the effect and mechanism of Chuanxiongqin hydrochloride on the fluidity of brain cell membrane in rat models of ischemia/reperfusion. DESIGN: A completely randomized controlled animal trial. SETTINGS: Institute of Brain Sciences; Department of Physiology, Medical College, Datong University. MATERIALS: Twenty male grade Ⅰ Wistar rats of 170-220 g were randomly divided into model group (n =10) and control group (n =10). Chuanxiongqin hydrochloride (molecular mass was 172.2) was purchased from the National Institute for the Control of Pharmaceutical and Biological Products (batch number: 0817-9803); Spin labelers: 5-doxyl-stearlic acid methylester (5DS), 16-doxyl-stearlic acid methylester (16DS), xanthine, xanthine oxidase (XOD) and 5,5-dimeth-1-pyrroline- N-oxide (DMPO) from Sigma Company; Bruker ESP 300 electron paramagnetic resonance (EPR) spectrometer by Bruker Company (Germany). METHODS: The experiments were carried out in the State Key Laboratory of Natural and Biomimetic Drugs, Peking University from June 2001 to July 2002. In the model group, rats were made into models of cerebral ischemia by 30-minute ligation and 2-hour reperfusion of common carotid arteries; The rats in the control group were not made into models. The order parameter (S) and rotational correlation time (τc) were detected with the ESR spectrometer by means of spin labeling. The greater the S and τc, the smaller the fluidity. Meanwhile, the clearance rate of free radicals was detected with ESR spin trapping. The measurement data were compared using the t test. MAIN OUTCOME MEASURES: The S, τc and clearance rates of O2 · and OH· free radicals were compared between the model group and control group. RESULTS: The S and τc in the model group [0.738 4±0.003 5; (8.472±0.027)×10-10 s/circle] were obviously different from those in the control group [0.683 9±0.008 3; (7.945±0.082)×10-10 s/circle, t =5.731, 5.918, P < 0.05], which suggested that ischemia/reperfusion injury decreased the fluidity of brain cell membrane. After adding Chuanxiongqin hydrochloride, there were no obvious differences between the model group [0.688 5±0.030 5; (7.886±0.341)×10-10 s/circle] and control group (P > 0.05), indicating that Chuanxiongqin hydrochloride could recover the fluidity of brain cell membrane after ischemia/reperfusion injury close to the level in the normal control group. Chuanxiongqin hydrochloride could directly scavenge the O2 · and OH· free radicals, and the maximal clearance rates were 83.92% and 44.99% respectively. CONCLUSION: Chuanxiongqin hydrochloride increases the fluidity of membrane of ischemia-injured brain cell by scavenging both O2 ·and OH· free radicals.展开更多
Four naturally rare 5,6,7-trimethoxy-2,3-cis-dihydroflavonols (3-6) and two 5,6,7-trimethoxy-2,3-trans-dihydroflavonols (7-8) were designed and synthesized. Their antioxidative properties were evaluated by way of ...Four naturally rare 5,6,7-trimethoxy-2,3-cis-dihydroflavonols (3-6) and two 5,6,7-trimethoxy-2,3-trans-dihydroflavonols (7-8) were designed and synthesized. Their antioxidative properties were evaluated by way of examining their scavenging capacities towards DPPH and O2^*- free radicals, as well as by measuring their inhibitory ability against LPO. Both the 2,3-trans and the 2,3- cis conformers exhibited certain quenching abilities to DPPH and O2^*- radicals, while most of the synthetic dihydroflavonols demonstrated remarkable inhibition to LPO.展开更多
The static O-H bond parameters including O-H bond length, O-H charge difference, O-H Mulliken population and O-H bond stretching force constant (k) for 17 phenols were calculated by ab initio method HF/6-31G**. In com...The static O-H bond parameters including O-H bond length, O-H charge difference, O-H Mulliken population and O-H bond stretching force constant (k) for 17 phenols were calculated by ab initio method HF/6-31G**. In combination with the O-H bond dissociation enthalpies (BDE) of the phenols determined by experiment, it was found that there were poor correlationships between the static O-H bond parameters and O-H BDE. Considering the good correlationship bt tween O-H BDE and logarithm of free radical scavenging rate constant for phenolic antioxidant, it is reasonable to believe that the ineffectiveness of static O-H bond parameters in characterizing antioxidant activity arises from the fact that they cannot measure the O-H BDE.展开更多
Lipid peroxidation inhibition capacity and antiradical activity were evaluated in HPLC fractions of different polarity obtained from two cranberry juices and three extracts isolated from frozen cranberries and pomace ...Lipid peroxidation inhibition capacity and antiradical activity were evaluated in HPLC fractions of different polarity obtained from two cranberry juices and three extracts isolated from frozen cranberries and pomace containing antho-cyanins, water-soluble and apolar phenolic compounds, respectively. Compounds with close polarities were collected to obtain between three and four fractions from each juice or extract. The cranberry phenols are good free radi-cal-scavengers, but they were less efficient at inhibiting the lipid peroxidation. Of all the samples tested, the intermediate polarity fraction of extract rich in apolar phenolic compounds of fruit presented the highest antiradical activity while the most hydrophobic fractions of the anthocyanin-rich extract from fruit and pomace appeared to be the most efficient at inhibiting the lipid peroxidation. The antioxidant or pro-oxidant activity of fractions increased with the con-centration. The phenol polarity and the technological process to manufacture cranberry juice can influence the antioxidant and antiradical activities of fractions.展开更多
This work aims to determine the phytochemical characterization of the pericarp of Chamaedorea radicalis Mart.fruit as a non-timber product with potential to obtain phytochemicals with potential applications in the ind...This work aims to determine the phytochemical characterization of the pericarp of Chamaedorea radicalis Mart.fruit as a non-timber product with potential to obtain phytochemicals with potential applications in the industry.Fruit from C.radicalis were grouped in four ripening stages named as S1,S2,S3 and S4,according to maturity;S1 the most unripe stage and S4 the completely ripe stage.Determinations of total phenolic compounds,free radical scavenging activities and total flavonoid contents using spectrophotometric methods were done.Also,the tentative identification of phytochemicals during fruit ripening was done using UPLC-MS-MS.Total phenolic compound(TPC)content ranged from 7.24 to 12.53 mg gallic acid equivalents per gram of fresh weight(mg GAE/g FW).Total flavonoids(TF)contents ranged from 0.163 to 0.23 mg of quercetin equivalents per g FW(mg QE/g FW).Free radical scavenging activity against DPPH and ABTS radicals varied from 40.80 to 53.68 and from 22.29 to 37.76 mmol Trolox equivalents g FW(mmol TE/g FW),respectively.Antioxidant assay in vitro by FRAP(ferric reducing antioxidant power)method showed that S3 was the highest level with antioxidant power while S4 was the lowest with Red ripeness stage showed the lowest contents for all determinations.Mass spectrometry allowed detection of 26 compounds,including phenolics,alkaloids and saponins.Afzelin,Kaempferol 3-neohesperidoside and the four saponins identified were present in all ripeness stages.Preliminary phytochemical identification and the spectrophotometric determinations showed that the pericarp of C.radicalis presented antioxidants and compounds related to alkaloids,phenolics and saponins.The presence and abundance of each phytochemical regarding each ripeness stage should be considered.展开更多
In this study,an online HPLC-DAD-MS coupled with 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid)diammonium salt(A BTS)assay was employed for evaluating free radical scavenging activity of Eagle tea and their ...In this study,an online HPLC-DAD-MS coupled with 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid)diammonium salt(A BTS)assay was employed for evaluating free radical scavenging activity of Eagle tea and their active components.Twenty-three chromatographic peaks were detected,and nineteen components had free radical scavenging activity.Among them,eight compounds were identified as flavonoids(hyperin,isoquercitrin,quercitrin,quercetin,kaempferol),catechins,chlorogenic acid and epicatechin based on MS data and standard chromatographic characters.展开更多
Eight novel silybin analogues (7a-h) were synthesized and their antioxidant properties including the capability of scavenging superoxide anion free radicals and the inhibitory effect on DPPH free radicals were dete...Eight novel silybin analogues (7a-h) were synthesized and their antioxidant properties including the capability of scavenging superoxide anion free radicals and the inhibitory effect on DPPH free radicals were determined. Several synthetic compounds showed comparable antioxidative effect to that of quercetin.展开更多
Objective:The activity of enzymes participating in the systems of antioxidant protection was assayed in the peel and pulp of sunflower.The essential roles of proteases in food stimulate research to find other sources ...Objective:The activity of enzymes participating in the systems of antioxidant protection was assayed in the peel and pulp of sunflower.The essential roles of proteases in food stimulate research to find other sources of the enzyme especially from non-conventional sources.In the present work,we study several biochemical parameters in the pulp and peel of sunflower.Methods:Pulp and peel of sunflower was extracted,antioxidant enzymes and nonenzymatic antioxidant were measured.Alkaline protease was measured and purified from pulp in sunflower.Results:High carbohydrate concentration,beta-carotene,catalase and ascorbate peroxidase activities,free radical scavenging capacity and free flavonoid content were observed in the peel of sunflower.Whereas,MDA and ceruloplasmin activities were high in the pulp of sunflower.Conclusions:The present study concluded that peel in sunflower are strong radical scavengers and can be considered as good sources of natural antioxidants for medicinal and commercial uses.Further analysis showed that protease activity was a significantly high in the pulp compared to the peel.展开更多
In order to enhance the water-solubility and biological utilization rate of chrysin, sodium 5,7-dihydroxylflavone-8-sulfonate (1, [Na(H2O)1/2]X, X = C15H9OSO3, 5,7-dihydroxylfla- vone-8-sulfonate) was synthesized ...In order to enhance the water-solubility and biological utilization rate of chrysin, sodium 5,7-dihydroxylflavone-8-sulfonate (1, [Na(H2O)1/2]X, X = C15H9OSO3, 5,7-dihydroxylfla- vone-8-sulfonate) was synthesized and its structure was identified on the basis of NMR, FT-IR and elemental analysis. The assembly of 5,7-dihydroxylflavone-8-sulfonate with diethylamide cation afforded diethylamide 5,7-dihydroxylflavone-8-sulfonate (2, NH2(CH2CH3)2X) which was characterized by FT-IR and elemental analysis. The crystal structures of 1 and 2 were determined by X-ray single-crystal diffraction analysis. The crystal of 1 is of triclinic system, space group P1, with a = 8.5628(13), b = 12.8916(19), c = 13.562(2) A, α = 82.494(1), β = 78.601(2), γ = 84.033(2)°, C30H20Na2O15S2, Z = 2, Mr = 730.59, V = 1450.3(4) A3, Dc = 1.673 g/cm3, F(000) = 748, p = 0.295 mm^-1, the final R = 0.0641 and wR = 0.1458. The crystal of 2 crystallizes in the triclinic system, space group Pi, with a = 7.689(2), b = 11.184(3), c = 11.734(3) A, α = 74.268(3), βl = 81.751(4), γ= 87.991(3)°, C19H21NO7S, Z = 2, Mr= 407.43, V= 961.2(4) A3, Dc = 1.408 g/cm3, F(000) = 428, p = 0.210 mm^-1, the final R = 0.0484 and wR = 0.1195. In 1, the three-dimensional structure is organized into organic and inorganic regions; the flavone skeletons are stacked into organic regions by π...π staeking interactions; inorganic regions are generated by Na-O coordination bonds among sulfonate groups, coordinated water molecules and NaI. The sulfonate groups play an important role as a bridge of inorganic and organic regions. One-dimensional chain structure of 2 is extended by N-H…O hydrogen bonds and π...π stacking interactions. Furthermore, the antioxidant activity of 1 was evaluated. The scavenging activity of 1 to DPPH free radical is better than that of the parent compound chrysin.展开更多
The purpose of the experiment was to study the efficacy of edaravone in enhancing flap viability after ischemia/reperfusion(IR) and its mechanism. Forty-eight adult male SD rats were randomly divided into 3 groups:...The purpose of the experiment was to study the efficacy of edaravone in enhancing flap viability after ischemia/reperfusion(IR) and its mechanism. Forty-eight adult male SD rats were randomly divided into 3 groups: control group(n=16), IR group(n=16), and edaravone-treated IR group(n=16). An island flap at left lower abdomen(6.0 cm×3.0 cm in size), fed by the superficial epigastric artery and vein, was created in each rat of all the three groups. The arterial blood flow of flaps in IR group and edaravone-treated IR group was blocked for 10 h, and then the blood perfusion was restored. From 15 min before reperfusion, rats in the edaravone-treated IR group were intraperitoneally injected with edaravone(10 mg/kg), once every 12 h, for 3 days. Rats in the IR group and control group were intraperitoneally injected with saline, with the same method and frequency as the rats in the edaravone-treated IR group. In IR group and edaravone-treated IR group, samples of flaps were harvested after reperfusion of the flaps for 24 h. In the control group, samples of flaps were harvested 34 h after creation of the flaps. The content of malondialdehyde(MDA) and activity of superoxide dismutase(SOD) were determined, and changes in organizational structure and infiltration of inflammatory cells were observed by hematoxylin-eosin(HE) staining, apoptotic cells of vascular wall were marked by terminal deoxynucleotidyl transferase-mediated d UTP nick-end labeling(TUNEL) assay, and the apoptotic rate of cells in vascular wall was calculated. The ultrastructural changes of vascular endothelial cells were observed by transmission electron microscopy(TEM). Seven days after the operation, we calculated the flap viability of each group, and marked vessels of flaps by immunohistochemical staining for calculating the average number of subcutaneous vessels. The results showed that the content of MDA, the number of multicore inflammatory cells and apoptotic rate of cells in vascular wall in the edaravone-treated IR group were significantly lower than those in the IR group. The activity of SOD, flap viability and average number of subcutaneous vessels in the edaravone-treated IR group were significantly higher than those in the IR group. All the differences were statistically significant. The ultrastructure injury of vascular endothelial cells in the edaravone-treated IR group was slighter than that in IR group. It was concluded that edaravone can significantly enhance IR flap viability and protect flap vessels, which is related to scavenging oxygen free radicals, reducing the consumption of SOD, reducing the extent of lipid peroxidation and inflammation, and protecting functional structure of vessels in the early stages of reperfusion.展开更多
[ Objective] This paper was to evaluate the methods of breaking stiffness cell wall of Chlorella sp. and extracting and testing functional antioxidant by ethanol and DPPH method separately. [Method] Extractions were p...[ Objective] This paper was to evaluate the methods of breaking stiffness cell wall of Chlorella sp. and extracting and testing functional antioxidant by ethanol and DPPH method separately. [Method] Extractions were performed at different extraction times (60, 120 and 180 min) at 37 ℃. And the radical scavenging activity of Chlorella spo extract was assayed by the DPPH ( 1,1-Diphenyl-2- picrylhydrazy[) method. [ Result ] The optimal conditions for ethanol extraction from Chlorella sp. were ethanol concentration of 90%, substrate consistency of 5% (w/v) and treating time of 180 min, under which, a concentration of 135.5 mg/L was obtained. Antioxidant pigments obtained from alcoholic extraction from Chlorella sp. showed high free radical scavenging ability. The efficiency increased with increasing concentration of solid microalgae powder, which could reach to 88%. [ Conclusion] Ethanol extraction method is simple and feasible. However, the efficiency of extraction is not high enough, which will limit the yield of antioxidant production from economic prospective.展开更多
Glycyrrhiza glabra L.is the most widely used herb in the ancient history of Ayurvedic medicine,as a medicinal value as well as an aromatic herb,and it is commonly known as Mulhatti.Mulhatti roots are useful for medica...Glycyrrhiza glabra L.is the most widely used herb in the ancient history of Ayurvedic medicine,as a medicinal value as well as an aromatic herb,and it is commonly known as Mulhatti.Mulhatti roots are useful for medically and are also a good source of phytoproducts and secondary metabolites present in Mulhatti roots are triterpenoid saponin,glycosides,glycyrrhizin,prenylated biaurone,licoaagrone,7-acetoxy-2-methylisoflavone,4-methylcoumarin,liqcoumarin,glycyrrhetinic acid,quercetin,liquiritigenin,isoliquiritigenin,etc.This study was carried out to study the evaluation of phenolic compounds,2,2-diphenyl-1-picrylhydrazyl(DPPH)free radical activity and general antioxidant capacity of water extracts of Mulhatti roots prepared at different pH values,namely 2,4,7 and 9.Data have shown great differences in terms of results.Most of the phenolic compounds are at pH 7(19.25),followed by pH 9(17.25),pH 2(14.62)and pH 4(8.89 mg GAE/g),respectively.Similarly,the flavonoid data also showed variations,the maximum has been present in pH 2(5.39),then pH 7(3.02),pH 9(1.79)and pH 4(1.40 mg CE/g),respectively.The value for DPPH IC50 free radical scavenging activity was the lowest at pH 7(82.22),followed by pH 2(110.40),pH 4(111.99)and pH 9(146.24μg/mL)and IC50 reference standard(ascorbic acid)was 59.52μg/mL in distilled water.The total capacity of the antioxidant was the highest at pH 2(9.93)followed by pH 4(5.54),pH 7(5.34)and pH 9(4.23 mg AAE/g).According to current research,pH 7 is the best for phytochemicals as well as antioxidants that catch harmful radicals.展开更多
Antimutagenic and DNA protective effect of an extract VinOserae from Vitis vinifera grapes on oxidative DNA damage was investigated. The extract’s ability to inhibit mutagenicity induced by tert-butyl hydroperoxide (...Antimutagenic and DNA protective effect of an extract VinOserae from Vitis vinifera grapes on oxidative DNA damage was investigated. The extract’s ability to inhibit mutagenicity induced by tert-butyl hydroperoxide (t-BHP) and hydrogen peroxide (H2O2) was determined with Ames test using Salmonella typhimurium His? TA102 strain. Inhibition values of 44.2% and 67.0% were detected for t-BHP and H2O2, respectively. A protective ability of the extract against DNA strand scission induced by hydroxyl radicals was studied with plasmid pBluescript II SK(-). The analysis of DNA strand breaks in plasmid DNA showed a significant inhibition of DNA damage.展开更多
Quantum calculations(mainly DFT)and molecular dynamics are increasingly effective tools to evaluate the physical chemical properties of natural and bio-inspired compounds.Free Radical Scavenging Capacity.Thermodynamic...Quantum calculations(mainly DFT)and molecular dynamics are increasingly effective tools to evaluate the physical chemical properties of natural and bio-inspired compounds.Free Radical Scavenging Capacity.Thermodynamic parameters(mainly bond dissociation enthalpies(BDE)of the O-H phenolic bond)allowed an accurate prediction of the antioxidant capacities of展开更多
Radiation damage can cause a series of gastrointestinal(GI)tract diseases.The development of safe and effective GI tract radioprotectants still remains a great challenge clinically.Here,we firstly report an oral radio...Radiation damage can cause a series of gastrointestinal(GI)tract diseases.The development of safe and effective GI tract radioprotectants still remains a great challenge clinically.Here,we firstly report an oral radioprotectant Gel@GYY that integrates a porous gelatin-based(Gel)hydrogel and a pH-responsive hydrogen sulfide(H2S)donor GYY4137(morpholin-4-ium 4 methoxyphenyl(morpholino)phosphinodithioate).Gel@GYY has a remarkable adhesion ability and long retention time,which not only enables responsive release of low-dose H2S in stomach and subsequently sustained release of H2S in the whole intestinal tract especially in the colon,but also ensures a close contact between H2S and GI tract.The released H2S can effectively scavenge free radicals induced by X-ray radiation,reduce lipid peroxidation level,repair DNA damage and recover vital superoxide dismutase and glutathione peroxidase activities.Meanwhile,the released H2S inhibits radiation-induced activation of nuclear factorκB(NF-κB),thus reducing inflammatory cytokines levels in GI tract.After treatment,Gel@GYY displays efficient excretion from mice body due to its biodegradability.This work provides a new insight for therapeutic application of intelligent H2S-releasing oral delivery system and potential alternative to clinical GI physical damage protectant.展开更多
Although tremendous efforts have been devoted to the structural and functional tailoring of natural polyphenol-functionalized nan oparticles,preparing ultrasmall sized(<6 nm)particles with precisely-defined structu...Although tremendous efforts have been devoted to the structural and functional tailoring of natural polyphenol-functionalized nan oparticles,preparing ultrasmall sized(<6 nm)particles with precisely-defined structures has remained a grand challenge.In this work,we reported the preparation of ultra-small and precisely structured polyhedral oligomeric silsesquioxanes(POSS)-based polyphenol nanopartides(T8^-,T10^-,and T12^-GAPOSS)by accurately functionalizing the POSS surface with plant polyphenol gallic acid units via thiol-Michael"click"reactions.Those polyphenol nanoparticles exhibited strong free radical scavenging capacity,good biocompatibility and ability to resist cell oxidative damage,which dem on strated great potentials in inhibiting oxidative stress in duced pathologies.展开更多
Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a frequent complication in critically ill patients and cause significant mortality.1 Effects of reactive oxygen species (ROS) on alveolar epithel...Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a frequent complication in critically ill patients and cause significant mortality.1 Effects of reactive oxygen species (ROS) on alveolar epithelial cells are involved in the pathophysiology of ALI/ARDS.ROS can provoke DNA damage,lipid peroxidation,and activation of various genes coding for proteins involved in inflammation and cell damage.展开更多
Objective:To explore the effect of Benefit Liver Granule (BLG), a traditional Chinese medical preparation, in antagonizing liver fibrosis and its possible mechanism. Methods:Carbon tetrachloride was used to establish ...Objective:To explore the effect of Benefit Liver Granule (BLG), a traditional Chinese medical preparation, in antagonizing liver fibrosis and its possible mechanism. Methods:Carbon tetrachloride was used to establish the experimental liver fibrosis model of rat. The model rats were randomly divided into 4 groups and BLG, Astragalus (As), Salvia (Sa) and normal saline (for control) respectively were given to them by gastrogavage. Changes of serum alanine transaminase (ALT), aspartate aminotransferase (AST), transforming growth factor α(TGF α), interleukine 6 (IL 6), liver content of hydroxyproline (Hyp), superoxide dismutase (SOD), malonyldialdehyde (MDA) as well as liver pathology after treatment were observed. A normal control group was also established for control.Results: Pathological examination showed that in the saline group, the structure of normal hepatic lobuli was destroyed with swelled liver cells, focal necrosis, extensive fatty degeneration, and focal inflammatory cell infiltration. Small amounts of proliferated fiber tissue were found in the intra lobular area, peri central vein area, portal area and limiting plate area, and formation of pseudolobuli was also seen. In the 3 treated groups, the serum ALT, AST, TGF α and IL 6 as well as liver content of Hyp, and MDA were lower and SOD were higher than those in the control group significantly, P <0.05 or P <0.01.Conclusion: BLG, As and Sa have the action of anti liver fibrosis, while BLG has the best effect. The mechanisms are probably related to their effects in regulating TGF α and IL 6, reducing collagen fiber synthesis, promoting free radical scavenge and anti lipid peroxidation.展开更多
基金Supported by the Science and Technique Foundation of Jilin Province, China(No20020503-2)
文摘A crude polysaccharide was extracted from Physalis alkekengi L. fruit. HPLC was used for the component analysis of the polysaccharide. The results indicate that Physalis alkekengi L. polysaccharide(PAP) was composed of rhamnose, xylose, arabinose, galactose, and glucose. Free radicals scavenging activity of PAP was studied through 3 free radicals scavenging tests. PAP exhibited high scavenging effects on OH and DPPH radicals, and both the scavenging rates were about 80%. The scavenging rate of O2^- radical was about 22%.
基金supported by grant no.90(0039)/04/EMR-II of Council of Scientific and Industrial Research,Government of India,New Delhi.Anuradha Sehrawat has been a Research Associate of Department of Biotechnology,Government of India,during the period of this study。
文摘The flower of Butea monosperma(Lam.)(Fabaceae)has been used in traditional Indian medicine in the treatment of many ailments including liver disorders.To understand the pharmacological basis of its beneficial effects,the extracts of dried flowers in water,methanol,butanol,ethyl acetate and acetone were evaluated for free radical scavenging and pro-apoptotic activities in cell cultures(human hepatoma Huh-7 cell line and immortalized AML-12 mouse hepatocytes).Butrin and butein-the active constituents of flower extracts-were used as reference molecules.The levels of cell injury markers like lactate dehydrogenase,glutathione and lipid peroxidation and primary antioxidant enzymes glutathione S-transferase and catalase were also measured.The aqueous and butanolic extracts exhibited better 2,2-diphenyl-1-picrylhydrazyl scavenging and cytotoxic activities in hepatoma cells than in immortalized hepatocytes.Interestingly,butein inhibited 2,2-diphenyl-1-picrylhydrazyl radical better than butrin.The aqueous and butanolic extracts were further investigated for hepatoprotection against carbon tertrachloride-induced biochemical changes and cell death.Both extracts,just as butrin and butein,significantly reversed the cellular glutathione levels and lipid peroxidation,and glutathione–S-transferase activity.Lactate dehydrogenase leakage and cell death were also prevented.However,only butein revived the catalase activity.Thus,the butein content of Butea monosperma flower extracts is important for free radical scavenging activity,apoptotic cell death and protection against oxidative injury in hepatic cells.
文摘BACKGROUND: The fluidity of cell membrane can be affected by various factors. Many experiments have confirmed that the ischemia/reperfusion of organic tissue can increase the contents of free radicals, which lead to high rigidity and low fluidity of cell membrane, and the conditions can be changed by Chuanxiongqin. OBJECTIVE: To observe the effect and mechanism of Chuanxiongqin hydrochloride on the fluidity of brain cell membrane in rat models of ischemia/reperfusion. DESIGN: A completely randomized controlled animal trial. SETTINGS: Institute of Brain Sciences; Department of Physiology, Medical College, Datong University. MATERIALS: Twenty male grade Ⅰ Wistar rats of 170-220 g were randomly divided into model group (n =10) and control group (n =10). Chuanxiongqin hydrochloride (molecular mass was 172.2) was purchased from the National Institute for the Control of Pharmaceutical and Biological Products (batch number: 0817-9803); Spin labelers: 5-doxyl-stearlic acid methylester (5DS), 16-doxyl-stearlic acid methylester (16DS), xanthine, xanthine oxidase (XOD) and 5,5-dimeth-1-pyrroline- N-oxide (DMPO) from Sigma Company; Bruker ESP 300 electron paramagnetic resonance (EPR) spectrometer by Bruker Company (Germany). METHODS: The experiments were carried out in the State Key Laboratory of Natural and Biomimetic Drugs, Peking University from June 2001 to July 2002. In the model group, rats were made into models of cerebral ischemia by 30-minute ligation and 2-hour reperfusion of common carotid arteries; The rats in the control group were not made into models. The order parameter (S) and rotational correlation time (τc) were detected with the ESR spectrometer by means of spin labeling. The greater the S and τc, the smaller the fluidity. Meanwhile, the clearance rate of free radicals was detected with ESR spin trapping. The measurement data were compared using the t test. MAIN OUTCOME MEASURES: The S, τc and clearance rates of O2 · and OH· free radicals were compared between the model group and control group. RESULTS: The S and τc in the model group [0.738 4±0.003 5; (8.472±0.027)×10-10 s/circle] were obviously different from those in the control group [0.683 9±0.008 3; (7.945±0.082)×10-10 s/circle, t =5.731, 5.918, P < 0.05], which suggested that ischemia/reperfusion injury decreased the fluidity of brain cell membrane. After adding Chuanxiongqin hydrochloride, there were no obvious differences between the model group [0.688 5±0.030 5; (7.886±0.341)×10-10 s/circle] and control group (P > 0.05), indicating that Chuanxiongqin hydrochloride could recover the fluidity of brain cell membrane after ischemia/reperfusion injury close to the level in the normal control group. Chuanxiongqin hydrochloride could directly scavenge the O2 · and OH· free radicals, and the maximal clearance rates were 83.92% and 44.99% respectively. CONCLUSION: Chuanxiongqin hydrochloride increases the fluidity of membrane of ischemia-injured brain cell by scavenging both O2 ·and OH· free radicals.
基金supported by Intramural Foundation from Wenzhou Medical College
文摘Four naturally rare 5,6,7-trimethoxy-2,3-cis-dihydroflavonols (3-6) and two 5,6,7-trimethoxy-2,3-trans-dihydroflavonols (7-8) were designed and synthesized. Their antioxidative properties were evaluated by way of examining their scavenging capacities towards DPPH and O2^*- free radicals, as well as by measuring their inhibitory ability against LPO. Both the 2,3-trans and the 2,3- cis conformers exhibited certain quenching abilities to DPPH and O2^*- radicals, while most of the synthetic dihydroflavonols demonstrated remarkable inhibition to LPO.
文摘The static O-H bond parameters including O-H bond length, O-H charge difference, O-H Mulliken population and O-H bond stretching force constant (k) for 17 phenols were calculated by ab initio method HF/6-31G**. In combination with the O-H bond dissociation enthalpies (BDE) of the phenols determined by experiment, it was found that there were poor correlationships between the static O-H bond parameters and O-H BDE. Considering the good correlationship bt tween O-H BDE and logarithm of free radical scavenging rate constant for phenolic antioxidant, it is reasonable to believe that the ineffectiveness of static O-H bond parameters in characterizing antioxidant activity arises from the fact that they cannot measure the O-H BDE.
基金This research was supported by the Natural Sciences and Engineering Research Council of Canada(NSERC) by Atoka Cranberries Inc.(Manseau,QC,Canada).
文摘Lipid peroxidation inhibition capacity and antiradical activity were evaluated in HPLC fractions of different polarity obtained from two cranberry juices and three extracts isolated from frozen cranberries and pomace containing antho-cyanins, water-soluble and apolar phenolic compounds, respectively. Compounds with close polarities were collected to obtain between three and four fractions from each juice or extract. The cranberry phenols are good free radi-cal-scavengers, but they were less efficient at inhibiting the lipid peroxidation. Of all the samples tested, the intermediate polarity fraction of extract rich in apolar phenolic compounds of fruit presented the highest antiradical activity while the most hydrophobic fractions of the anthocyanin-rich extract from fruit and pomace appeared to be the most efficient at inhibiting the lipid peroxidation. The antioxidant or pro-oxidant activity of fractions increased with the con-centration. The phenol polarity and the technological process to manufacture cranberry juice can influence the antioxidant and antiradical activities of fractions.
基金Authors thank to Universidad Autónoma de Tamaulipas for financial support to the project UAT-PFI2017-ACP02 for J.A.Torres-Castillo.
文摘This work aims to determine the phytochemical characterization of the pericarp of Chamaedorea radicalis Mart.fruit as a non-timber product with potential to obtain phytochemicals with potential applications in the industry.Fruit from C.radicalis were grouped in four ripening stages named as S1,S2,S3 and S4,according to maturity;S1 the most unripe stage and S4 the completely ripe stage.Determinations of total phenolic compounds,free radical scavenging activities and total flavonoid contents using spectrophotometric methods were done.Also,the tentative identification of phytochemicals during fruit ripening was done using UPLC-MS-MS.Total phenolic compound(TPC)content ranged from 7.24 to 12.53 mg gallic acid equivalents per gram of fresh weight(mg GAE/g FW).Total flavonoids(TF)contents ranged from 0.163 to 0.23 mg of quercetin equivalents per g FW(mg QE/g FW).Free radical scavenging activity against DPPH and ABTS radicals varied from 40.80 to 53.68 and from 22.29 to 37.76 mmol Trolox equivalents g FW(mmol TE/g FW),respectively.Antioxidant assay in vitro by FRAP(ferric reducing antioxidant power)method showed that S3 was the highest level with antioxidant power while S4 was the lowest with Red ripeness stage showed the lowest contents for all determinations.Mass spectrometry allowed detection of 26 compounds,including phenolics,alkaloids and saponins.Afzelin,Kaempferol 3-neohesperidoside and the four saponins identified were present in all ripeness stages.Preliminary phytochemical identification and the spectrophotometric determinations showed that the pericarp of C.radicalis presented antioxidants and compounds related to alkaloids,phenolics and saponins.The presence and abundance of each phytochemical regarding each ripeness stage should be considered.
基金The research was supported by a grant from University of Macao(UL015/09-Y3 to Shaoping Li).
文摘In this study,an online HPLC-DAD-MS coupled with 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid)diammonium salt(A BTS)assay was employed for evaluating free radical scavenging activity of Eagle tea and their active components.Twenty-three chromatographic peaks were detected,and nineteen components had free radical scavenging activity.Among them,eight compounds were identified as flavonoids(hyperin,isoquercitrin,quercitrin,quercetin,kaempferol),catechins,chlorogenic acid and epicatechin based on MS data and standard chromatographic characters.
文摘Eight novel silybin analogues (7a-h) were synthesized and their antioxidant properties including the capability of scavenging superoxide anion free radicals and the inhibitory effect on DPPH free radicals were determined. Several synthetic compounds showed comparable antioxidative effect to that of quercetin.
文摘Objective:The activity of enzymes participating in the systems of antioxidant protection was assayed in the peel and pulp of sunflower.The essential roles of proteases in food stimulate research to find other sources of the enzyme especially from non-conventional sources.In the present work,we study several biochemical parameters in the pulp and peel of sunflower.Methods:Pulp and peel of sunflower was extracted,antioxidant enzymes and nonenzymatic antioxidant were measured.Alkaline protease was measured and purified from pulp in sunflower.Results:High carbohydrate concentration,beta-carotene,catalase and ascorbate peroxidase activities,free radical scavenging capacity and free flavonoid content were observed in the peel of sunflower.Whereas,MDA and ceruloplasmin activities were high in the pulp of sunflower.Conclusions:The present study concluded that peel in sunflower are strong radical scavengers and can be considered as good sources of natural antioxidants for medicinal and commercial uses.Further analysis showed that protease activity was a significantly high in the pulp compared to the peel.
基金Supported by the National Basic Research Program of China (973 Program,2009CB219906)NNSFC(20776117)+1 种基金Specialized Research Fund for the Doctoral Program of Higher Education of China(20070698037)Natural Science Foundation of Shaanxi Province (No.2005B01)
文摘In order to enhance the water-solubility and biological utilization rate of chrysin, sodium 5,7-dihydroxylflavone-8-sulfonate (1, [Na(H2O)1/2]X, X = C15H9OSO3, 5,7-dihydroxylfla- vone-8-sulfonate) was synthesized and its structure was identified on the basis of NMR, FT-IR and elemental analysis. The assembly of 5,7-dihydroxylflavone-8-sulfonate with diethylamide cation afforded diethylamide 5,7-dihydroxylflavone-8-sulfonate (2, NH2(CH2CH3)2X) which was characterized by FT-IR and elemental analysis. The crystal structures of 1 and 2 were determined by X-ray single-crystal diffraction analysis. The crystal of 1 is of triclinic system, space group P1, with a = 8.5628(13), b = 12.8916(19), c = 13.562(2) A, α = 82.494(1), β = 78.601(2), γ = 84.033(2)°, C30H20Na2O15S2, Z = 2, Mr = 730.59, V = 1450.3(4) A3, Dc = 1.673 g/cm3, F(000) = 748, p = 0.295 mm^-1, the final R = 0.0641 and wR = 0.1458. The crystal of 2 crystallizes in the triclinic system, space group Pi, with a = 7.689(2), b = 11.184(3), c = 11.734(3) A, α = 74.268(3), βl = 81.751(4), γ= 87.991(3)°, C19H21NO7S, Z = 2, Mr= 407.43, V= 961.2(4) A3, Dc = 1.408 g/cm3, F(000) = 428, p = 0.210 mm^-1, the final R = 0.0484 and wR = 0.1195. In 1, the three-dimensional structure is organized into organic and inorganic regions; the flavone skeletons are stacked into organic regions by π...π staeking interactions; inorganic regions are generated by Na-O coordination bonds among sulfonate groups, coordinated water molecules and NaI. The sulfonate groups play an important role as a bridge of inorganic and organic regions. One-dimensional chain structure of 2 is extended by N-H…O hydrogen bonds and π...π stacking interactions. Furthermore, the antioxidant activity of 1 was evaluated. The scavenging activity of 1 to DPPH free radical is better than that of the parent compound chrysin.
基金supported by Henan Provincial Key Scientific and Technological Project of China(No.132102310088)
文摘The purpose of the experiment was to study the efficacy of edaravone in enhancing flap viability after ischemia/reperfusion(IR) and its mechanism. Forty-eight adult male SD rats were randomly divided into 3 groups: control group(n=16), IR group(n=16), and edaravone-treated IR group(n=16). An island flap at left lower abdomen(6.0 cm×3.0 cm in size), fed by the superficial epigastric artery and vein, was created in each rat of all the three groups. The arterial blood flow of flaps in IR group and edaravone-treated IR group was blocked for 10 h, and then the blood perfusion was restored. From 15 min before reperfusion, rats in the edaravone-treated IR group were intraperitoneally injected with edaravone(10 mg/kg), once every 12 h, for 3 days. Rats in the IR group and control group were intraperitoneally injected with saline, with the same method and frequency as the rats in the edaravone-treated IR group. In IR group and edaravone-treated IR group, samples of flaps were harvested after reperfusion of the flaps for 24 h. In the control group, samples of flaps were harvested 34 h after creation of the flaps. The content of malondialdehyde(MDA) and activity of superoxide dismutase(SOD) were determined, and changes in organizational structure and infiltration of inflammatory cells were observed by hematoxylin-eosin(HE) staining, apoptotic cells of vascular wall were marked by terminal deoxynucleotidyl transferase-mediated d UTP nick-end labeling(TUNEL) assay, and the apoptotic rate of cells in vascular wall was calculated. The ultrastructural changes of vascular endothelial cells were observed by transmission electron microscopy(TEM). Seven days after the operation, we calculated the flap viability of each group, and marked vessels of flaps by immunohistochemical staining for calculating the average number of subcutaneous vessels. The results showed that the content of MDA, the number of multicore inflammatory cells and apoptotic rate of cells in vascular wall in the edaravone-treated IR group were significantly lower than those in the IR group. The activity of SOD, flap viability and average number of subcutaneous vessels in the edaravone-treated IR group were significantly higher than those in the IR group. All the differences were statistically significant. The ultrastructure injury of vascular endothelial cells in the edaravone-treated IR group was slighter than that in IR group. It was concluded that edaravone can significantly enhance IR flap viability and protect flap vessels, which is related to scavenging oxygen free radicals, reducing the consumption of SOD, reducing the extent of lipid peroxidation and inflammation, and protecting functional structure of vessels in the early stages of reperfusion.
文摘[ Objective] This paper was to evaluate the methods of breaking stiffness cell wall of Chlorella sp. and extracting and testing functional antioxidant by ethanol and DPPH method separately. [Method] Extractions were performed at different extraction times (60, 120 and 180 min) at 37 ℃. And the radical scavenging activity of Chlorella spo extract was assayed by the DPPH ( 1,1-Diphenyl-2- picrylhydrazy[) method. [ Result ] The optimal conditions for ethanol extraction from Chlorella sp. were ethanol concentration of 90%, substrate consistency of 5% (w/v) and treating time of 180 min, under which, a concentration of 135.5 mg/L was obtained. Antioxidant pigments obtained from alcoholic extraction from Chlorella sp. showed high free radical scavenging ability. The efficiency increased with increasing concentration of solid microalgae powder, which could reach to 88%. [ Conclusion] Ethanol extraction method is simple and feasible. However, the efficiency of extraction is not high enough, which will limit the yield of antioxidant production from economic prospective.
文摘Glycyrrhiza glabra L.is the most widely used herb in the ancient history of Ayurvedic medicine,as a medicinal value as well as an aromatic herb,and it is commonly known as Mulhatti.Mulhatti roots are useful for medically and are also a good source of phytoproducts and secondary metabolites present in Mulhatti roots are triterpenoid saponin,glycosides,glycyrrhizin,prenylated biaurone,licoaagrone,7-acetoxy-2-methylisoflavone,4-methylcoumarin,liqcoumarin,glycyrrhetinic acid,quercetin,liquiritigenin,isoliquiritigenin,etc.This study was carried out to study the evaluation of phenolic compounds,2,2-diphenyl-1-picrylhydrazyl(DPPH)free radical activity and general antioxidant capacity of water extracts of Mulhatti roots prepared at different pH values,namely 2,4,7 and 9.Data have shown great differences in terms of results.Most of the phenolic compounds are at pH 7(19.25),followed by pH 9(17.25),pH 2(14.62)and pH 4(8.89 mg GAE/g),respectively.Similarly,the flavonoid data also showed variations,the maximum has been present in pH 2(5.39),then pH 7(3.02),pH 9(1.79)and pH 4(1.40 mg CE/g),respectively.The value for DPPH IC50 free radical scavenging activity was the lowest at pH 7(82.22),followed by pH 2(110.40),pH 4(111.99)and pH 9(146.24μg/mL)and IC50 reference standard(ascorbic acid)was 59.52μg/mL in distilled water.The total capacity of the antioxidant was the highest at pH 2(9.93)followed by pH 4(5.54),pH 7(5.34)and pH 9(4.23 mg AAE/g).According to current research,pH 7 is the best for phytochemicals as well as antioxidants that catch harmful radicals.
文摘Antimutagenic and DNA protective effect of an extract VinOserae from Vitis vinifera grapes on oxidative DNA damage was investigated. The extract’s ability to inhibit mutagenicity induced by tert-butyl hydroperoxide (t-BHP) and hydrogen peroxide (H2O2) was determined with Ames test using Salmonella typhimurium His? TA102 strain. Inhibition values of 44.2% and 67.0% were detected for t-BHP and H2O2, respectively. A protective ability of the extract against DNA strand scission induced by hydroxyl radicals was studied with plasmid pBluescript II SK(-). The analysis of DNA strand breaks in plasmid DNA showed a significant inhibition of DNA damage.
文摘Quantum calculations(mainly DFT)and molecular dynamics are increasingly effective tools to evaluate the physical chemical properties of natural and bio-inspired compounds.Free Radical Scavenging Capacity.Thermodynamic parameters(mainly bond dissociation enthalpies(BDE)of the O-H phenolic bond)allowed an accurate prediction of the antioxidant capacities of
基金the National Natural Science Foundation of China(Nos.22175182,21471103)Sheng Yuan Cooperation(No.2021SYHZ0048)+1 种基金Beijing Natural Science Foundation(No.2202064)the directional institutionalized scientific research platform relies on Beijing Synchrotron Radiation Facility of Chinese Academy of Sciences.
文摘Radiation damage can cause a series of gastrointestinal(GI)tract diseases.The development of safe and effective GI tract radioprotectants still remains a great challenge clinically.Here,we firstly report an oral radioprotectant Gel@GYY that integrates a porous gelatin-based(Gel)hydrogel and a pH-responsive hydrogen sulfide(H2S)donor GYY4137(morpholin-4-ium 4 methoxyphenyl(morpholino)phosphinodithioate).Gel@GYY has a remarkable adhesion ability and long retention time,which not only enables responsive release of low-dose H2S in stomach and subsequently sustained release of H2S in the whole intestinal tract especially in the colon,but also ensures a close contact between H2S and GI tract.The released H2S can effectively scavenge free radicals induced by X-ray radiation,reduce lipid peroxidation level,repair DNA damage and recover vital superoxide dismutase and glutathione peroxidase activities.Meanwhile,the released H2S inhibits radiation-induced activation of nuclear factorκB(NF-κB),thus reducing inflammatory cytokines levels in GI tract.After treatment,Gel@GYY displays efficient excretion from mice body due to its biodegradability.This work provides a new insight for therapeutic application of intelligent H2S-releasing oral delivery system and potential alternative to clinical GI physical damage protectant.
基金the National Natural Science Foundation of China(Nos.51603133 and 21774079)National Key R&D Program of China(No.2019YFA0904500)+1 种基金the Program of the Science,Technology Department of Guangzhou,China(No.201803020039)the Fundamental Research Funds for Central Universities.
文摘Although tremendous efforts have been devoted to the structural and functional tailoring of natural polyphenol-functionalized nan oparticles,preparing ultrasmall sized(<6 nm)particles with precisely-defined structures has remained a grand challenge.In this work,we reported the preparation of ultra-small and precisely structured polyhedral oligomeric silsesquioxanes(POSS)-based polyphenol nanopartides(T8^-,T10^-,and T12^-GAPOSS)by accurately functionalizing the POSS surface with plant polyphenol gallic acid units via thiol-Michael"click"reactions.Those polyphenol nanoparticles exhibited strong free radical scavenging capacity,good biocompatibility and ability to resist cell oxidative damage,which dem on strated great potentials in inhibiting oxidative stress in duced pathologies.
文摘Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a frequent complication in critically ill patients and cause significant mortality.1 Effects of reactive oxygen species (ROS) on alveolar epithelial cells are involved in the pathophysiology of ALI/ARDS.ROS can provoke DNA damage,lipid peroxidation,and activation of various genes coding for proteins involved in inflammation and cell damage.
文摘Objective:To explore the effect of Benefit Liver Granule (BLG), a traditional Chinese medical preparation, in antagonizing liver fibrosis and its possible mechanism. Methods:Carbon tetrachloride was used to establish the experimental liver fibrosis model of rat. The model rats were randomly divided into 4 groups and BLG, Astragalus (As), Salvia (Sa) and normal saline (for control) respectively were given to them by gastrogavage. Changes of serum alanine transaminase (ALT), aspartate aminotransferase (AST), transforming growth factor α(TGF α), interleukine 6 (IL 6), liver content of hydroxyproline (Hyp), superoxide dismutase (SOD), malonyldialdehyde (MDA) as well as liver pathology after treatment were observed. A normal control group was also established for control.Results: Pathological examination showed that in the saline group, the structure of normal hepatic lobuli was destroyed with swelled liver cells, focal necrosis, extensive fatty degeneration, and focal inflammatory cell infiltration. Small amounts of proliferated fiber tissue were found in the intra lobular area, peri central vein area, portal area and limiting plate area, and formation of pseudolobuli was also seen. In the 3 treated groups, the serum ALT, AST, TGF α and IL 6 as well as liver content of Hyp, and MDA were lower and SOD were higher than those in the control group significantly, P <0.05 or P <0.01.Conclusion: BLG, As and Sa have the action of anti liver fibrosis, while BLG has the best effect. The mechanisms are probably related to their effects in regulating TGF α and IL 6, reducing collagen fiber synthesis, promoting free radical scavenge and anti lipid peroxidation.