A rapid and concentration-dependent generation of superoxide anion （·O2^-）, measured with a superoxide-specific Cypridina luciferin-derived chemiluminescent reagent, was observed when two lanthanide salts （LaC...A rapid and concentration-dependent generation of superoxide anion （·O2^-）, measured with a superoxide-specific Cypridina luciferin-derived chemiluminescent reagent, was observed when two lanthanide salts （LaCl3 and CdCl3 ） were added to tobacco （ Nicotiana tabacum） cell suspension culture. Addition of superoxide dismutase （480 U·ml^-1） and Tiron （5 μmol·L^-1） to cell culture suspension decreases the level of lanthanide cation-induced ·O2^- generation, suggesting that ·O2^- generation is extra-cellular. Pretreatment of the cell culture suspension with diphenyleneiodonium （10 and 50 μmol·L^-1 ）, quinacrine （ 1 and 5 mmol· L^-1 ） and imidazol （ 10 mmol· L^-1 ）, inhibitors of NADPH oxidase, notably inhibits the generation of superoxide induced by lanthanide cation, implying the possible involvement of activation of NADPH oxidase. In addition, addition of SHAM （1 and 5 mmol· L^-1）, azide （0.2 and 1 mmol· L^-1 ）, inhibitor of peroxidase, has no influence on ·O2^- generation.展开更多
A series of N-alkyl or N-aryl chitosan quaternary ammonium salt were prepared using 96% deacetylated chitosan. Their scavenging activities against superoxide anion radical were investigated by chemiluminescence. The I...A series of N-alkyl or N-aryl chitosan quaternary ammonium salt were prepared using 96% deacetylated chitosan. Their scavenging activities against superoxide anion radical were investigated by chemiluminescence. The IC50 values of these compounds range from 280 to 880 μg/mL, which should be attributed to their different substitutes.展开更多
AIM: To investigate the ability of ursodeoxycholic acid (UDCA) to scavenge superoxide anion (O2-).METHODS: We assessed the ability of UDCA to scavenge (O2-) generated by xanthine-xanthine oxidase (X-XO) in a cell-free...AIM: To investigate the ability of ursodeoxycholic acid (UDCA) to scavenge superoxide anion (O2-).METHODS: We assessed the ability of UDCA to scavenge (O2-) generated by xanthine-xanthine oxidase (X-XO) in a cell-free system and its effect on the rate of O2--induced ascorbic acid (AA) oxidation in hepatic post-mitochondrial supernatants.RESULTS: UDCA at a concentration as high as 1 mmol/Ldid not impair the ability of the X-XO system to generate O2-, but could scavenge O2- at concentrations of 0.5 and 1 mmol/L, and decrease the rate of AA oxidation at a concentration of 100 μmol/L.CONCLUSION: UDCA can scavenge O2-, an action that may be beneficial to patients with primary biliary cirrhosis.展开更多
This paper, for the first time, reports a method that can be used as a highly sensitive probe for singlet oxygen (1O2) and superoxide anion (O2-) in vitro or in vivo. FCLA(3,7-dihydro-6-{4-[2-(N'-(5-fluoresceinyl)...This paper, for the first time, reports a method that can be used as a highly sensitive probe for singlet oxygen (1O2) and superoxide anion (O2-) in vitro or in vivo. FCLA(3,7-dihydro-6-{4-[2-(N'-(5-fluoresceinyl)thioureido)ethoxy]phenyl}-2-methylimidazo{1,2-a}pyrazin-3-one sodium salt), a chemiluminescence (CL) analysis reagent, has been reported to sensitively react with 1O2 and O2- to emit photons with a spectral peak of 525nm. In this work, when human serum albumin (HSA) was added into FCLA solution to enhance the CL intensity, approximately 20 times, compared to that without HSA. The enhanced CL had the same 525 nm spectral peak, identical to that without HSA. By gradually reducing the molecular oxygen content in the solution, we find that the auto-oxidation of oxygen molecules dissolved in the solution plays an important role in the CL process. Based on these experimental evidences, we propose a novel and highly sensitive detection method of 1O2 and O2-, which may have a great potential in chemical and medical applications.展开更多
The inhibition effect of rare earths on the production of ·O - 2 produced by radiolysis of aqueous sodium formate saturated with O 2 with high energy pulse electron beam was studied. The result indicates ...The inhibition effect of rare earths on the production of ·O - 2 produced by radiolysis of aqueous sodium formate saturated with O 2 with high energy pulse electron beam was studied. The result indicates that rare earth nitrate obviously inhibits the production of ·O - 2 . The inhibition rate is between 28 6% and 92%. The inhibition effect increases with the increase of rare earth nitrates concentration. The distinguish dose effect relationship was observed.展开更多
Objective:Reactive oxygen species(ROS)are involved in a variety of biological phenomena and serve both deleterious and beneficial roles.ROS quantification and assessment of reaction networks are desirable but difficul...Objective:Reactive oxygen species(ROS)are involved in a variety of biological phenomena and serve both deleterious and beneficial roles.ROS quantification and assessment of reaction networks are desirable but difficult because of their short half-life and high reactivity.Here,we describe a pro-oxidative model in a single human lung carcinoma SPC-A-1 cell that was created by application of extracellular H2O2 stimuli.Methods:Modified microfluidics and imaging techniques were used to determine O2·-levels and construct an O2^·-reaction network.To elucidate the consequences of increased O2^·-input,the mitochondria were given a central role in the oxidative stress mode,by manipulating mitochondria-interrelated cytosolic Ca2+levels,mitochondrial Ca^2+uptake,auto-amplification of intracellular ROS and the intrinsic apoptotic pathway.Results and conclusions:Results from a modified microchip demonstrated that 1 mmol/L H·-2 O2 induced a rapid increase in cellular O2 levels(>27 vs.>406 amol in 20 min),leading to increased cellular oxidizing power(evaluated by ROS levels)and decreased reducing power(evaluated by glutathione(GSH)levels).In addition,we examined the dynamics of cytosolic Ca^2+and mitochondrial Ca^2+by confocal laser scanning microscopy and confirmed that Ca^2+stores in the endoplasmic reticulum were the primary source of H2O2-induced cytosolic Ca^2+bursts.It is clear that mitochondria have pivotal roles in determining how exogenous oxidative stress affects cell fate.The stress response involves the transfer of Ca^2+signals between organelles,ROS auto-amplification,mitochondrial dysfunction,and a caspase-dependent apoptotic pathway.展开更多
Objectives To study the changes of nitric oxide, angiotensin Ⅱ and superoxide anion in renal artery hypertension pathogenesis. Methods Male Wistar rats weighing 256 -285g were divided into 5 groups randomly, 10 rats ...Objectives To study the changes of nitric oxide, angiotensin Ⅱ and superoxide anion in renal artery hypertension pathogenesis. Methods Male Wistar rats weighing 256 -285g were divided into 5 groups randomly, 10 rats of each group. Control group: false operation was made and routine diet was given; Ligature group: left renal artery was ligatured uncompletely and routine diet was given; Ligature + Losartan group: left renal artery was ligatured uneompletely and Losartan 20mg · kg^(-1) · d^(-1) was added in the drinking water; Ligature + L -Arg group: left renal artery was ligatured uncompletely and L -Arg 2g · kg^(-1) · d^(-1) was added in the drinking water; Ligature + L - Arg + Losartan group: left renal artery was ligatured uncompletely and L - Arg 2g· kg^(-1)· d^(-1) and Losartan 20mg · kg^(-1)· d^(-1) was added in the drinking water. Blood pressure and heart rate were measured before and at the end of the experiment. One week after ligature, blood was drawn to determine angiotensin Ⅱ, cGMP, nitric oxide, nitric oxide synthase (NOS), O_2^-, superoxide dismutase (SOD). Results Systolic blood pressure was higher in ligature group than that in control group (p <0.05), systolic blood pressure was much lower in ligature + Losartan group than that in ligature group. Heart rate did not change significantly after experiment (p > 0. 05). AngⅡ was higher in ligature group than that in control group, even much higher in ligature + Losartan group (p < 0. 01 ). There was no difference of cGMP in each group (p >. 05). The concentration of NO was lower in ligature group (p <0.05), NO was higher in ligature + L - Arg + Losartan group than that in ligature group (p <0.05). O_2^- was higher in ligature group and ligature + L - Arg group than that in control group (p < 0. 05), O_2^- was lower in ligature + Losartan group than that in ligature group (p <0. 05). The level of SOD was lower in ligature group than that in control group (p <0.05), higher in ligature + L- Arg group and ligature + L - Arg + Losartan group than that in ligature group (p <0. 05). Conclusions AngⅡ,O_2^- and NO imbalance play an important role in hypertension pathogenesis, LArg and losartan may have protective effect.展开更多
In this study, the superoxide anion radicals were generated by the auto-oxidation of 1,2,3-trihydroxybenzene and determined by UV spectrophotometry, and the reaction was found to be facilitated by anthraquinone-2-sulf...In this study, the superoxide anion radicals were generated by the auto-oxidation of 1,2,3-trihydroxybenzene and determined by UV spectrophotometry, and the reaction was found to be facilitated by anthraquinone-2-sulfonic acid sodium salt. The bamboo kraft pulps were treated by the 1,2,3-trihydroxybenzene auto-oxidation method or the 1,2,3-trihydroxybenzene auto-oxidation combined with anthraquinone-2-sulfonic acid sodium salt to show the ef-fect of the superoxide anion radicals during the oxygen delignification of bamboo kraft pulp and the enhancing af-fect of anthraquinone compounds as an additive on delignification. The results indicated that the superoxide anion radicals could react with lignin and remove it from pulp with negligible damage on cellulose, and the an-thraquinone-2-sulfonic acid sodium salt could facilitate the generation of superoxide anion radical to enhance delig-nification of pulps. The oxygen delignification selectivity could be improved using the 1,2,3-trihydroxybenzene auto-oxidation system combined with anthraquinone-2-sulfonic acid sodium salt.展开更多
The dismutation kinetics of superoxide anion by copper complex of 1,4,7,10-tetranza- cyctotridecane-11,13-dione was studied by pulse radiolysis.The dismutation rate constants at various pH and concentration of complex...The dismutation kinetics of superoxide anion by copper complex of 1,4,7,10-tetranza- cyctotridecane-11,13-dione was studied by pulse radiolysis.The dismutation rate constants at various pH and concentration of complex were obtained.展开更多
Objective To explore the protective effects of N Acetylcysteine (NAC) on exogenous hydrogen peroxide and endogenous superoxide anion induced DNA strand breakage in human spermatozoa by using the single cell gel el...Objective To explore the protective effects of N Acetylcysteine (NAC) on exogenous hydrogen peroxide and endogenous superoxide anion induced DNA strand breakage in human spermatozoa by using the single cell gel electropherosis (SCGE) Methods Sperm cells were exposed to 0.5 mmol/L of H 2O 2 or 5.0 mmol/L of β NADPH with or without 0.1, 0.5, 1.0 mmol/L of NAC. The percentage of sperm comet cells and the comet tail lengths were measured in the treated sperm cells by using SCGE. Results Both percentage of comet sperm nuclei and mean tail length in sperm cells exposed to 0.5 mmol/L hydrogen peroxide with different concentrations of NAC decrease significantly in a dose dependent manner as compared with sperm cells exposed to H 2O 2 without NAC or catalase. Although mean tail length in sperm cells exposed to 5.0 mmol/L of β NADPH with different concentrations of NAC decreases significantly compared with sperm cells exposed to β NADPH without NAC or SOD, there were no significant differences on the percentage of sperm comet cells between sperm cells exposed to 5.0 mmol/L of β NADPH with different concentrations of NAC and sperm cells exposed to 5.0 mmol/L of β NADPH without NAC. Conclusion NAC has a protective effect on exogenous hydrogen peroxide induced DNA damage, while protective effect of NAC against O - 2 induced DNA strand breakage is significant but very weak.展开更多
The development of tetravalent platinum[Pt(IV)]prodrugs with controllable activation properties represents a crucial strategy for the mitigation of the severe side effects associated with bivalent platinum[Pt(Ⅱ)]drug...The development of tetravalent platinum[Pt(IV)]prodrugs with controllable activation properties represents a crucial strategy for the mitigation of the severe side effects associated with bivalent platinum[Pt(Ⅱ)]drugs,which are used in over 50%of all chemotherapeutics worldwide.Ultrasound(US)irradiation is an ideal method for prodrug activation given its noninvasive nature and efficient tissue penetration capabilities.This study shows that US irradiation alone could directly convert Pt(IV)prodrugs to Pt(Ⅱ)drugs in an aqueous solution,with a significant increase in the reduction rate in the presence of the sonosensitizer riboflavin(Rf;also known as vitamin B2).Rf accelerated the reduction rate by facilitating the production of the superoxide anion radical(•O_(2)^(−)).Subsequently,Rf and tetravalent cisplatin[cisPt(IV)]prodrug were covalently co-loaded into poly(L-glutamic acid)to create a US catalysis-activated nano prodrug[P-Rf/cisPt(IV)]for antitumor therapy.Remarkably,even under low-intensity US irradiation(1.5 W/cm^(2)),P-Rf/cisPt(IV)was effectively converted to cisPt(Ⅱ)in mice,resulting in significant antitumor effects.These findings will facilitate the advancement of US irradiation-activated Pt(IV)prodrugs for use in chemotherapeutics.展开更多
The electrochemical behavior of chrysin in pH 2.0-9.0 Britton-Robinson （B-R） buffer solutions was studied by the means of linear sweep voltammetry and cyclic voltammetry at a static mercury drop electrode. In differ...The electrochemical behavior of chrysin in pH 2.0-9.0 Britton-Robinson （B-R） buffer solutions was studied by the means of linear sweep voltammetry and cyclic voltammetry at a static mercury drop electrode. In different pH range of B-R buffer solutions, chrysin could cause four reduction waves. In pH 2.0-5.8 B-R buffer solutions, wave P1 yielded by chrysin is a one-electron reduction wave, and wave P1 caused by further reduction of the products of wave P1 in pH〈3.0 B-R buffer solution is also a one-electron reduction wave. But in 3.0〈pH〈5.8 B-R buffer solution wave P1 was overlapped by the hydrogen wave. Between pH 5.8 and 9.0, chrysin could yield two reduction waves P2 and P3- The former is an irreversible adsorptive wave of ionized chrysin involving one electron and the latter is also an irreversible adsorptive wave of reduction intermediate radical of chrysin involving one electron and one proton. And a linear relationship between ip3 and the concentration of chrysin can be established from 1.0×10^-6 to 4.0×10^-5 mol·L^-1 （r=0.9924） with the detection limit of 5×10^-7 mol·L^-1. In addition, the antioxidant ability of chrysin was investigated by linear sweep voltammetry （LSV）. The determination result of IC50 of chrysin showed that chrysin is a good antioxidant.展开更多
Concentration of supemxide anion in plasma and ecythrocytes in 21 patients with non-Insulin-dependent diabetes mellitus (NIDDM)(14 with complicating microangiopathy) and 34 normal adults was assayed by chemiluinesenc...Concentration of supemxide anion in plasma and ecythrocytes in 21 patients with non-Insulin-dependent diabetes mellitus (NIDDM)(14 with complicating microangiopathy) and 34 normal adults was assayed by chemiluinesence. Both plasma and erythrocyte concentration of .0-2 were ekvated in NIDDM with complicating microangiopathy beyond normal range (P<0.01),whereas in NIDDM without microangiopathy,in plasma was only slightly raised and RBC(.0-2) was within normal range. The authors think that RBC (.0-2) may be used as an indicator for the detection of presence of microangiopathy in NIDDM.展开更多
Given that platinum-based drugs are widely used clinically as chemotherapeutic agents,their severe toxic side effects have attracted significant attention.Consequently,the development of novel nanoprodrugs based on lo...Given that platinum-based drugs are widely used clinically as chemotherapeutic agents,their severe toxic side effects have attracted significant attention.Consequently,the development of novel nanoprodrugs based on low-toxicity tetravalent platinum(Pt(Ⅳ))com plexes holds substantial research value.Herein,we discovered that coumarin derivatives exhibit inherent antitumor efficacy and significantly enhance superoxide anion radicals(·O_(2)^(-))generation in aqueous solutions under ultrasound(US)irradiation.Given that·O_(2)^(-)is known to mediate the reduction of Pt(Ⅳ)to divalent platinum(Pt(Ⅱ)),we engineered an US-responsive dual-drug nanoprodrug(P-cisPt(Ⅳ)@5-MOP).This nanoprodrug was prepared by covalently conjugating Pt(Ⅳ)and methoxy polyethylene glycol hydroxyl(m PEG-OH)to a poly(_(L)-glutamic acid)(PLG)carrier,followed by encapsulating coumarin derivatives.Under low-intensity US irradiation(1.5 W/cm^(2),1 MHz,10 min),P-cisPt(Ⅳ)@5-MOP achieved a Pt(Ⅳ)reduction rate of 91.4%.Furthermore,upon US exposure,its half-maximal inhibitory concentration(IC_(50))against 4T1 breast cancer cells decreased dramatically from 25.7μmol/L to 0.1μmol/L.Remarkably,this system combined with US therapy yielded a tumor inhibition rate of 90.9%,with 40%of tumor-bea ring mice achieving com plete eradication of tumors,while exhibiting low systemic toxicity.Collectively,this work not only identifies a novel sonosensitizer capable of generating·O_(2)^(-)but also develops a new class of ultrasound-activatable Pt(Ⅳ)nanoprodrug.展开更多
AIM To identify and characterize the protective effect that L-carnitine exerted against an oxidative stress in C2C12 cells.METHODS Myoblastic C2C12 cells were treated with menadione, a vitamin K analog that engenders ...AIM To identify and characterize the protective effect that L-carnitine exerted against an oxidative stress in C2C12 cells.METHODS Myoblastic C2C12 cells were treated with menadione, a vitamin K analog that engenders oxidative stress, and the protective effect of L-carnitine(a nutrient involved in fatty acid metabolism and the control of the oxidative process), was assessed by monitoring various parameters related to the oxidative stress, autophagy and cell death. RESULTS Associated with its physiological function, a muscle cell metabolism is highly dependent on oxygen and may produce reactive oxygen species(ROS), especially under pathological conditions. High levels of ROS are known to induce injuries in cell structure as they interact at many levels in cell function. In C2C12 cells, a treatment with menadione induced a loss of transmembrane mitochondrial potential, an increase in mitochondrial production of ROS; it also induces autophagy and was able to provoke cell death. Pre-treatment of the cells with L-carnitine reduced ROS production, diminished autophagy and protected C2C12 cells against menadione-induced deleterious effects. CONCLUSION In conclusion, L-carnitine limits the oxidative stress in these cells and prevents cell death.展开更多
Reactive oxygen species(ROS),including singlet oxygen(^(1)O_(2)),hydroxyl radicals(·OH),and superoxide anions(O_(2)^(·-)),are highly reactive molecules that play central roles in many chemical,biological,and...Reactive oxygen species(ROS),including singlet oxygen(^(1)O_(2)),hydroxyl radicals(·OH),and superoxide anions(O_(2)^(·-)),are highly reactive molecules that play central roles in many chemical,biological,and environmental processes due to their strong oxidative power[1].Generating ROS in a controlled manner under mild conditions is essential for achieving selective oxidation reactions.Light-driven methods are especially appealing for this purpose,as they offer precise control over where and when ROS are produced.展开更多
Currently,it is still a challenge to develop an organic photosensitizer(PS)with outstanding near-infrared absorption,low O2dependence,precise tumor targeting and rapid clearance through the kidney to improve the overa...Currently,it is still a challenge to develop an organic photosensitizer(PS)with outstanding near-infrared absorption,low O2dependence,precise tumor targeting and rapid clearance through the kidney to improve the overall outcome of phototherapy.In this study,we have designed an organic PS(Nc PB)with an excellent near-infrared light absorption through a refined molecular strategy.Meanwhile,Nc PB was assembled into nanoparticles with different sizes(Nano Nc PB-1 and Nano Nc PB-0)by a supramolecular modulation strategy.As the results,the nanoparticle with an ultra-small size(Nano Nc PB-1)generated a large number of superoxide anion(O_(2)^(·-))in a low-O_(2)-dependent manner and release plenty of heat.Furthermore,the results of in vivo experiments demonstrated that Nano Nc PB-1 actively accumulated in tumor tissues and showed a 92%tumor inhibition after photodynamic and photothermal combination therapy.More importantly,Nano Nc PB-1 could be rapidly cleared from the body of mice via the renal pathway,which alleviates potential side effects of prolonged retention of PS in the circulation.展开更多
In this study,we successfully developed an unprecedented superoxide radical anion(O_(2)•^(−))triggered degenerate ring transformation(DRT)of N-benzylpyridinium salts.This method utilizes the electrophilicity enhanceme...In this study,we successfully developed an unprecedented superoxide radical anion(O_(2)•^(−))triggered degenerate ring transformation(DRT)of N-benzylpyridinium salts.This method utilizes the electrophilicity enhancement of pyridine over N-benzylation to facilitate the ring opening and subsequent 6π-electrocyclization and aromatization event,resulting in the reconstruction of a pyridine core.This process allows for selective installation of an aryl and formyl group to the C2 and C3 position of pyridine,respectively,leading to the formation of C2-arylated nicotinaldehydes.The generation of superoxide radical anions under Cu(I)/4-dimethylaminopyridine(DMAP)conditions,in combination with PhBpin as the oxygen atom abstraction reagent,is crucial for the high efficiency of this transformation.Density functional theory calculations further elucidate the important role of the Cu(I)/DMAP/PhBpin system in accelerating this DRT process.展开更多
文摘A rapid and concentration-dependent generation of superoxide anion （·O2^-）, measured with a superoxide-specific Cypridina luciferin-derived chemiluminescent reagent, was observed when two lanthanide salts （LaCl3 and CdCl3 ） were added to tobacco （ Nicotiana tabacum） cell suspension culture. Addition of superoxide dismutase （480 U·ml^-1） and Tiron （5 μmol·L^-1） to cell culture suspension decreases the level of lanthanide cation-induced ·O2^- generation, suggesting that ·O2^- generation is extra-cellular. Pretreatment of the cell culture suspension with diphenyleneiodonium （10 and 50 μmol·L^-1 ）, quinacrine （ 1 and 5 mmol· L^-1 ） and imidazol （ 10 mmol· L^-1 ）, inhibitors of NADPH oxidase, notably inhibits the generation of superoxide induced by lanthanide cation, implying the possible involvement of activation of NADPH oxidase. In addition, addition of SHAM （1 and 5 mmol· L^-1）, azide （0.2 and 1 mmol· L^-1 ）, inhibitor of peroxidase, has no influence on ·O2^- generation.
文摘A series of N-alkyl or N-aryl chitosan quaternary ammonium salt were prepared using 96% deacetylated chitosan. Their scavenging activities against superoxide anion radical were investigated by chemiluminescence. The IC50 values of these compounds range from 280 to 880 μg/mL, which should be attributed to their different substitutes.
文摘AIM: To investigate the ability of ursodeoxycholic acid (UDCA) to scavenge superoxide anion (O2-).METHODS: We assessed the ability of UDCA to scavenge (O2-) generated by xanthine-xanthine oxidase (X-XO) in a cell-free system and its effect on the rate of O2--induced ascorbic acid (AA) oxidation in hepatic post-mitochondrial supernatants.RESULTS: UDCA at a concentration as high as 1 mmol/Ldid not impair the ability of the X-XO system to generate O2-, but could scavenge O2- at concentrations of 0.5 and 1 mmol/L, and decrease the rate of AA oxidation at a concentration of 100 μmol/L.CONCLUSION: UDCA can scavenge O2-, an action that may be beneficial to patients with primary biliary cirrhosis.
文摘This paper, for the first time, reports a method that can be used as a highly sensitive probe for singlet oxygen (1O2) and superoxide anion (O2-) in vitro or in vivo. FCLA(3,7-dihydro-6-{4-[2-(N'-(5-fluoresceinyl)thioureido)ethoxy]phenyl}-2-methylimidazo{1,2-a}pyrazin-3-one sodium salt), a chemiluminescence (CL) analysis reagent, has been reported to sensitively react with 1O2 and O2- to emit photons with a spectral peak of 525nm. In this work, when human serum albumin (HSA) was added into FCLA solution to enhance the CL intensity, approximately 20 times, compared to that without HSA. The enhanced CL had the same 525 nm spectral peak, identical to that without HSA. By gradually reducing the molecular oxygen content in the solution, we find that the auto-oxidation of oxygen molecules dissolved in the solution plays an important role in the CL process. Based on these experimental evidences, we propose a novel and highly sensitive detection method of 1O2 and O2-, which may have a great potential in chemical and medical applications.
文摘The inhibition effect of rare earths on the production of ·O - 2 produced by radiolysis of aqueous sodium formate saturated with O 2 with high energy pulse electron beam was studied. The result indicates that rare earth nitrate obviously inhibits the production of ·O - 2 . The inhibition rate is between 28 6% and 92%. The inhibition effect increases with the increase of rare earth nitrates concentration. The distinguish dose effect relationship was observed.
基金Project supported by the Zhejiang Provincial Natural Science Foundation of China(No.LY18H300002)the Medical Health Science and Technology Project of Zhejiang Provincial Health Commission(No.2019RC061/2019312897)+1 种基金the Zhejiang Provincial Natural Science Foundation of China(Nos.Y4110212 and LY19H090001)partly by the National Natural Science Foundation of China(Nos.81372301 and 81301113)
文摘Objective:Reactive oxygen species(ROS)are involved in a variety of biological phenomena and serve both deleterious and beneficial roles.ROS quantification and assessment of reaction networks are desirable but difficult because of their short half-life and high reactivity.Here,we describe a pro-oxidative model in a single human lung carcinoma SPC-A-1 cell that was created by application of extracellular H2O2 stimuli.Methods:Modified microfluidics and imaging techniques were used to determine O2·-levels and construct an O2^·-reaction network.To elucidate the consequences of increased O2^·-input,the mitochondria were given a central role in the oxidative stress mode,by manipulating mitochondria-interrelated cytosolic Ca2+levels,mitochondrial Ca^2+uptake,auto-amplification of intracellular ROS and the intrinsic apoptotic pathway.Results and conclusions:Results from a modified microchip demonstrated that 1 mmol/L H·-2 O2 induced a rapid increase in cellular O2 levels(>27 vs.>406 amol in 20 min),leading to increased cellular oxidizing power(evaluated by ROS levels)and decreased reducing power(evaluated by glutathione(GSH)levels).In addition,we examined the dynamics of cytosolic Ca^2+and mitochondrial Ca^2+by confocal laser scanning microscopy and confirmed that Ca^2+stores in the endoplasmic reticulum were the primary source of H2O2-induced cytosolic Ca^2+bursts.It is clear that mitochondria have pivotal roles in determining how exogenous oxidative stress affects cell fate.The stress response involves the transfer of Ca^2+signals between organelles,ROS auto-amplification,mitochondrial dysfunction,and a caspase-dependent apoptotic pathway.
文摘Objectives To study the changes of nitric oxide, angiotensin Ⅱ and superoxide anion in renal artery hypertension pathogenesis. Methods Male Wistar rats weighing 256 -285g were divided into 5 groups randomly, 10 rats of each group. Control group: false operation was made and routine diet was given; Ligature group: left renal artery was ligatured uncompletely and routine diet was given; Ligature + Losartan group: left renal artery was ligatured uneompletely and Losartan 20mg · kg^(-1) · d^(-1) was added in the drinking water; Ligature + L -Arg group: left renal artery was ligatured uncompletely and L -Arg 2g · kg^(-1) · d^(-1) was added in the drinking water; Ligature + L - Arg + Losartan group: left renal artery was ligatured uncompletely and L - Arg 2g· kg^(-1)· d^(-1) and Losartan 20mg · kg^(-1)· d^(-1) was added in the drinking water. Blood pressure and heart rate were measured before and at the end of the experiment. One week after ligature, blood was drawn to determine angiotensin Ⅱ, cGMP, nitric oxide, nitric oxide synthase (NOS), O_2^-, superoxide dismutase (SOD). Results Systolic blood pressure was higher in ligature group than that in control group (p <0.05), systolic blood pressure was much lower in ligature + Losartan group than that in ligature group. Heart rate did not change significantly after experiment (p > 0. 05). AngⅡ was higher in ligature group than that in control group, even much higher in ligature + Losartan group (p < 0. 01 ). There was no difference of cGMP in each group (p >. 05). The concentration of NO was lower in ligature group (p <0.05), NO was higher in ligature + L - Arg + Losartan group than that in ligature group (p <0.05). O_2^- was higher in ligature group and ligature + L - Arg group than that in control group (p < 0. 05), O_2^- was lower in ligature + Losartan group than that in ligature group (p <0. 05). The level of SOD was lower in ligature group than that in control group (p <0.05), higher in ligature + L- Arg group and ligature + L - Arg + Losartan group than that in ligature group (p <0. 05). Conclusions AngⅡ,O_2^- and NO imbalance play an important role in hypertension pathogenesis, LArg and losartan may have protective effect.
基金Supported by the National Natural Science Foundation of China (No.20477046)the Natural Science Foundation of Fujian Prov-ince of China (No.2004HZ03-5)the Young Scientist Innovation Foundation of Fujian Province of China (No.2006F3009).
文摘In this study, the superoxide anion radicals were generated by the auto-oxidation of 1,2,3-trihydroxybenzene and determined by UV spectrophotometry, and the reaction was found to be facilitated by anthraquinone-2-sulfonic acid sodium salt. The bamboo kraft pulps were treated by the 1,2,3-trihydroxybenzene auto-oxidation method or the 1,2,3-trihydroxybenzene auto-oxidation combined with anthraquinone-2-sulfonic acid sodium salt to show the ef-fect of the superoxide anion radicals during the oxygen delignification of bamboo kraft pulp and the enhancing af-fect of anthraquinone compounds as an additive on delignification. The results indicated that the superoxide anion radicals could react with lignin and remove it from pulp with negligible damage on cellulose, and the an-thraquinone-2-sulfonic acid sodium salt could facilitate the generation of superoxide anion radical to enhance delig-nification of pulps. The oxygen delignification selectivity could be improved using the 1,2,3-trihydroxybenzene auto-oxidation system combined with anthraquinone-2-sulfonic acid sodium salt.
文摘The dismutation kinetics of superoxide anion by copper complex of 1,4,7,10-tetranza- cyctotridecane-11,13-dione was studied by pulse radiolysis.The dismutation rate constants at various pH and concentration of complex were obtained.
基金China Medical Board ( 980 0 1 ) and Natural Science Foundation ofAnhui Province( 99j1 0 0 95)
文摘Objective To explore the protective effects of N Acetylcysteine (NAC) on exogenous hydrogen peroxide and endogenous superoxide anion induced DNA strand breakage in human spermatozoa by using the single cell gel electropherosis (SCGE) Methods Sperm cells were exposed to 0.5 mmol/L of H 2O 2 or 5.0 mmol/L of β NADPH with or without 0.1, 0.5, 1.0 mmol/L of NAC. The percentage of sperm comet cells and the comet tail lengths were measured in the treated sperm cells by using SCGE. Results Both percentage of comet sperm nuclei and mean tail length in sperm cells exposed to 0.5 mmol/L hydrogen peroxide with different concentrations of NAC decrease significantly in a dose dependent manner as compared with sperm cells exposed to H 2O 2 without NAC or catalase. Although mean tail length in sperm cells exposed to 5.0 mmol/L of β NADPH with different concentrations of NAC decreases significantly compared with sperm cells exposed to β NADPH without NAC or SOD, there were no significant differences on the percentage of sperm comet cells between sperm cells exposed to 5.0 mmol/L of β NADPH with different concentrations of NAC and sperm cells exposed to 5.0 mmol/L of β NADPH without NAC. Conclusion NAC has a protective effect on exogenous hydrogen peroxide induced DNA damage, while protective effect of NAC against O - 2 induced DNA strand breakage is significant but very weak.
基金This research was made possible as a result of a generous grant from the National Key R&D Program of China(grant no.2022YFE0110200)the National Natural Science Foundation of China(grant nos.52273157,52073279,and 52025035)+1 种基金Jilin Province,China(grant no.20230508102RC)the Youth Innovation Promotion Association of Chinese Academy of Sciences(grant no.2022224).
文摘The development of tetravalent platinum[Pt(IV)]prodrugs with controllable activation properties represents a crucial strategy for the mitigation of the severe side effects associated with bivalent platinum[Pt(Ⅱ)]drugs,which are used in over 50%of all chemotherapeutics worldwide.Ultrasound(US)irradiation is an ideal method for prodrug activation given its noninvasive nature and efficient tissue penetration capabilities.This study shows that US irradiation alone could directly convert Pt(IV)prodrugs to Pt(Ⅱ)drugs in an aqueous solution,with a significant increase in the reduction rate in the presence of the sonosensitizer riboflavin(Rf;also known as vitamin B2).Rf accelerated the reduction rate by facilitating the production of the superoxide anion radical(•O_(2)^(−)).Subsequently,Rf and tetravalent cisplatin[cisPt(IV)]prodrug were covalently co-loaded into poly(L-glutamic acid)to create a US catalysis-activated nano prodrug[P-Rf/cisPt(IV)]for antitumor therapy.Remarkably,even under low-intensity US irradiation(1.5 W/cm^(2)),P-Rf/cisPt(IV)was effectively converted to cisPt(Ⅱ)in mice,resulting in significant antitumor effects.These findings will facilitate the advancement of US irradiation-activated Pt(IV)prodrugs for use in chemotherapeutics.
基金Project supported by the National Natural Science Foundation of-China （No. 20275030） and the Natural Science Foundation of Shaanxi Province（No.2004B20）.
文摘The electrochemical behavior of chrysin in pH 2.0-9.0 Britton-Robinson （B-R） buffer solutions was studied by the means of linear sweep voltammetry and cyclic voltammetry at a static mercury drop electrode. In different pH range of B-R buffer solutions, chrysin could cause four reduction waves. In pH 2.0-5.8 B-R buffer solutions, wave P1 yielded by chrysin is a one-electron reduction wave, and wave P1 caused by further reduction of the products of wave P1 in pH〈3.0 B-R buffer solution is also a one-electron reduction wave. But in 3.0〈pH〈5.8 B-R buffer solution wave P1 was overlapped by the hydrogen wave. Between pH 5.8 and 9.0, chrysin could yield two reduction waves P2 and P3- The former is an irreversible adsorptive wave of ionized chrysin involving one electron and the latter is also an irreversible adsorptive wave of reduction intermediate radical of chrysin involving one electron and one proton. And a linear relationship between ip3 and the concentration of chrysin can be established from 1.0×10^-6 to 4.0×10^-5 mol·L^-1 （r=0.9924） with the detection limit of 5×10^-7 mol·L^-1. In addition, the antioxidant ability of chrysin was investigated by linear sweep voltammetry （LSV）. The determination result of IC50 of chrysin showed that chrysin is a good antioxidant.
文摘Concentration of supemxide anion in plasma and ecythrocytes in 21 patients with non-Insulin-dependent diabetes mellitus (NIDDM)(14 with complicating microangiopathy) and 34 normal adults was assayed by chemiluinesence. Both plasma and erythrocyte concentration of .0-2 were ekvated in NIDDM with complicating microangiopathy beyond normal range (P<0.01),whereas in NIDDM without microangiopathy,in plasma was only slightly raised and RBC(.0-2) was within normal range. The authors think that RBC (.0-2) may be used as an indicator for the detection of presence of microangiopathy in NIDDM.
基金financially supported by the National Natural Science Foundation of China(Nos.52533015,52495013,52403211,52573183,52273157,52073279 and 52025035)Jilin Province,China(Nos.20250601009RC and 20230508102RC)Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2022224)。
文摘Given that platinum-based drugs are widely used clinically as chemotherapeutic agents,their severe toxic side effects have attracted significant attention.Consequently,the development of novel nanoprodrugs based on low-toxicity tetravalent platinum(Pt(Ⅳ))com plexes holds substantial research value.Herein,we discovered that coumarin derivatives exhibit inherent antitumor efficacy and significantly enhance superoxide anion radicals(·O_(2)^(-))generation in aqueous solutions under ultrasound(US)irradiation.Given that·O_(2)^(-)is known to mediate the reduction of Pt(Ⅳ)to divalent platinum(Pt(Ⅱ)),we engineered an US-responsive dual-drug nanoprodrug(P-cisPt(Ⅳ)@5-MOP).This nanoprodrug was prepared by covalently conjugating Pt(Ⅳ)and methoxy polyethylene glycol hydroxyl(m PEG-OH)to a poly(_(L)-glutamic acid)(PLG)carrier,followed by encapsulating coumarin derivatives.Under low-intensity US irradiation(1.5 W/cm^(2),1 MHz,10 min),P-cisPt(Ⅳ)@5-MOP achieved a Pt(Ⅳ)reduction rate of 91.4%.Furthermore,upon US exposure,its half-maximal inhibitory concentration(IC_(50))against 4T1 breast cancer cells decreased dramatically from 25.7μmol/L to 0.1μmol/L.Remarkably,this system combined with US therapy yielded a tumor inhibition rate of 90.9%,with 40%of tumor-bea ring mice achieving com plete eradication of tumors,while exhibiting low systemic toxicity.Collectively,this work not only identifies a novel sonosensitizer capable of generating·O_(2)^(-)but also develops a new class of ultrasound-activatable Pt(Ⅳ)nanoprodrug.
基金the Association Francaise contre les Myopathies for financial support
文摘AIM To identify and characterize the protective effect that L-carnitine exerted against an oxidative stress in C2C12 cells.METHODS Myoblastic C2C12 cells were treated with menadione, a vitamin K analog that engenders oxidative stress, and the protective effect of L-carnitine(a nutrient involved in fatty acid metabolism and the control of the oxidative process), was assessed by monitoring various parameters related to the oxidative stress, autophagy and cell death. RESULTS Associated with its physiological function, a muscle cell metabolism is highly dependent on oxygen and may produce reactive oxygen species(ROS), especially under pathological conditions. High levels of ROS are known to induce injuries in cell structure as they interact at many levels in cell function. In C2C12 cells, a treatment with menadione induced a loss of transmembrane mitochondrial potential, an increase in mitochondrial production of ROS; it also induces autophagy and was able to provoke cell death. Pre-treatment of the cells with L-carnitine reduced ROS production, diminished autophagy and protected C2C12 cells against menadione-induced deleterious effects. CONCLUSION In conclusion, L-carnitine limits the oxidative stress in these cells and prevents cell death.
文摘Reactive oxygen species(ROS),including singlet oxygen(^(1)O_(2)),hydroxyl radicals(·OH),and superoxide anions(O_(2)^(·-)),are highly reactive molecules that play central roles in many chemical,biological,and environmental processes due to their strong oxidative power[1].Generating ROS in a controlled manner under mild conditions is essential for achieving selective oxidation reactions.Light-driven methods are especially appealing for this purpose,as they offer precise control over where and when ROS are produced.
基金the National Natural Science Foundation of China(Nos.T2322004 and 22078066)。
文摘Currently,it is still a challenge to develop an organic photosensitizer(PS)with outstanding near-infrared absorption,low O2dependence,precise tumor targeting and rapid clearance through the kidney to improve the overall outcome of phototherapy.In this study,we have designed an organic PS(Nc PB)with an excellent near-infrared light absorption through a refined molecular strategy.Meanwhile,Nc PB was assembled into nanoparticles with different sizes(Nano Nc PB-1 and Nano Nc PB-0)by a supramolecular modulation strategy.As the results,the nanoparticle with an ultra-small size(Nano Nc PB-1)generated a large number of superoxide anion(O_(2)^(·-))in a low-O_(2)-dependent manner and release plenty of heat.Furthermore,the results of in vivo experiments demonstrated that Nano Nc PB-1 actively accumulated in tumor tissues and showed a 92%tumor inhibition after photodynamic and photothermal combination therapy.More importantly,Nano Nc PB-1 could be rapidly cleared from the body of mice via the renal pathway,which alleviates potential side effects of prolonged retention of PS in the circulation.
基金the National Natural Science Foundation of China(grant nos.22072099 and 21871187)Sichuan Provincial Natural Science Foundation Project(grant no.2024YFFK0016)+2 种基金the Fundamental Research Funds for the Central Universities(grant no.1082204112I96)Central Guidance for Local Science and Technology Development Fund Project(grant no.2024ZYD0099)Postgraduate Education and Teaching Reform Programme of Sichuan University(grant no.GSSCU2024058).
文摘In this study,we successfully developed an unprecedented superoxide radical anion(O_(2)•^(−))triggered degenerate ring transformation(DRT)of N-benzylpyridinium salts.This method utilizes the electrophilicity enhancement of pyridine over N-benzylation to facilitate the ring opening and subsequent 6π-electrocyclization and aromatization event,resulting in the reconstruction of a pyridine core.This process allows for selective installation of an aryl and formyl group to the C2 and C3 position of pyridine,respectively,leading to the formation of C2-arylated nicotinaldehydes.The generation of superoxide radical anions under Cu(I)/4-dimethylaminopyridine(DMAP)conditions,in combination with PhBpin as the oxygen atom abstraction reagent,is crucial for the high efficiency of this transformation.Density functional theory calculations further elucidate the important role of the Cu(I)/DMAP/PhBpin system in accelerating this DRT process.
