OBJECTIVETo investigate the kinetic rate constants ozone and hydroxyl radicals towards two groups of antimicrobials -sulfadiazine (SD) and sulfamethoxazole (SMX).

METHODSThe solute consumption method was used to detect the rate constants of ozone alone with sulfadiazine and sulfamethoxazole, and tertiary butanol was selected as a scavenging agent and pH was adjusted to 2.5 by adding orthophosphate buffers (OB); and the competition kinetics studying methodwith nitrobenzene as a reference was applied to measure the rate constants of hydroxyl radicals towards sulfadiazine and sulfamethoxazole, and pH was adjusted to 7.0 by adding OB.

RESULTSThe rate constants of SD and SMX with ozone alone were 261 mol(-1) · dm(3) · s(-1) and 303 mol(-1) · dm3 · s(-1) by calculating in low reaction system. The rate constants of hydroxyl radicals with SD and SMX were 2.2×1010 mol(-1) · dm(3) · s(-1) and 2.7×1010 mol(-1) · dm(3) · s(-1), respectively. Moreover, the rate constants of hydroxyl radicals with SMX were found to have increased from 3.6×109 mol(-1) · dm(3) · s(-1) to 2.8×1010 mol(-1) · dm(3) · s(-1) with pH value rising from 5.0 to 7.8.

CONCLUSIONSMX and SD are both refractory to ozone oxidation alone, and are liable to be degraded by hydroxyl radicals, and the rate constants of SMX with the hydroxyl radical slightly increases with pH rise.

Hydroxyl Radical ; chemistry ; Kinetics ; Ozone ; chemistry ; Sulfamethoxazole ; chemistry ; Sulfonamides ; chemistry ; Water ; chemistry

A mathematical model, which represents the radio-chemical reactions in water, was developed to study the effect of the radio-chemical products on cell kiling. The five differential equations were solved using dose rate equation and cell survival as a function of dose was computed. The known chemical rate constants were taken from the literature and unknown constants were determined by curve fitting to an experimental data. Sensitivity studies were performed by varying the rate constants and showed that the yield of H-radical had little effect whereas the change in concentration of OH-radical and direct interaction resulted in significant change on cell survival. The sensitivity studies showed good agreement with the observed effects. In conclusion, we developed a mathematical model that could be used as a means for the estimation of radiation damage.
Cell Survival ; DNA/*chemistry ; Free Radicals/*chemistry ; Hydroxyl Radical/chemistry ; *Models, Molecular

The present paper intends to discuss the antioxidant and tyrosinase inhibition effect of solanesol from three aspects of ultraviolet radiation and free radical scavenging. The paper makes a survey on diurnal variation rule of the minimum ultraviolet transmittance and ultraviolet transmittance of solanesol, hydroxyl (OH) free radical scavenging method of Smirnoff reaction system model, superoxide anion O2- free radical scavenging method of pyrogallol autoxidation, and the inhibitory effect of solanesol on tyrosinase activity by enzyme kinetic method. The experiment results showed that solanesol could effectively scavenge lipid radicals to block lipid peroxidation, and inhibit effects on tyrosinase. Solanesol is a natural extract which could be used to prevent senile atrophy of human skin and senile plaque.
Enzyme Inhibitors ; chemistry ; Free Radical Scavengers ; chemistry ; Humans ; Hydroxyl Radical ; chemistry ; Lipid Peroxidation ; Monophenol Monooxygenase ; antagonists & inhibitors ; Terpenes ; chemistry ; Ultraviolet Rays

OBJECTIVETo identify the free radical scavenging activity of ethanolic extract of Evolvulus alsinoides.

METHODSThe free radical scavenging activity was evaluated by in vitro methods like reducing power assay, total antioxidant activity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) reduction, superoxide radical scavenging activity, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(+)) scavenging activity, hydroxyl radical scavenging assay, and nitric oxide radical scavenging assay, which were studied by using ascorbic acid as standard.

RESULTSThe extract showed significant activities in all antioxidant assays compared with the reference antioxidant ascorbic acid. The total antioxidant activity as well as the reducing power was also found to increase in a dose-dependent manner.

CONCLUSIONEvolvulus alsinoides may act as a chemopreventive agent, providing antioxidant properties and offering effective protection from free radicals.

Antioxidants ; chemistry ; Benzothiazoles ; chemistry ; Biphenyl Compounds ; chemistry ; Convolvulaceae ; chemistry ; Ethanol ; chemistry ; Free Radical Scavengers ; chemistry ; Hydroxyl Radical ; chemistry ; Nitric Oxide ; chemistry ; Oxidation-Reduction ; drug effects ; Picrates ; chemistry ; Plant Extracts ; chemistry ; Sulfonic Acids ; chemistry ; Superoxides ; chemistry

OBJECTIVETo study the scavenging effects of Lu-Duo-Wei, thiourea, superoxide dismutase, and sodium azide on carbon disulfide-induced generation of hydroxyl radicals.

METHODSPhenanthroline-CuSO(4)-Vit C-H(2)O(2) chemiluminescence system (PHEN system) containing alcohol was established to probe the influence of various concentrations of carbon disulfide on hydroxyl radicals emission intensity and the scavenging effects of Lu-Duo-Wei and other antioxidants on carbon disulfide-induced hydroxyl radicals were observed.

RESULTSThe average emission intensity of PHEN system containing alcohol appeared lower luminescence [91.03 x 10(3) (cp6s)] and longer time (75 s) to get the peak than the system without alcohol [96.11 x 10(3) (cp6s), 55 s]. The specific scavenger of hydroxyl radical, thiourea, showed clear inhibitory effect on the system. Carbon disulfide in the range of 40 - 160 mmol/L promoted the generation of hydroxyl radical, however, this effect could be efficiently inhibited by thiourea. 160 mmol/L carbon disulfide in PHEN system without copper seemed as an activator to promote the luminescence, while in PHEN system withdrawing phenanthroline appeared some weak action of luminescence agent at low concentration. Meanwhile, Lu-Duo-Wei may efficiently scavenge hydroxyl radicals induced by carbon disulfide in PHEN system but superoxide dismutase and sodium azide had little effects on the system.

CONCLUSIONCarbon disulfide may induce PHEN system to generate hydroxyl radicals and Lu-Duo-Wei may efficiently scavenge these free radicals and play an important role in protection against oxidative injury induced by carbon disulfide.

Carbon Disulfide ; pharmacology ; Drugs, Chinese Herbal ; pharmacology ; Free Radical Scavengers ; pharmacology ; Hydroxyl Radical ; antagonists & inhibitors ; chemistry ; metabolism ; Luminescent Measurements ; Phenanthrolines ; chemistry ; Superoxide Dismutase ; pharmacology ; Thiourea ; pharmacology

OBJECTIVESupercritical CO2 fluid extraction process of antioxidation active components from Rosmarinus officinalis was studied.

METHODA new extraction process of components extracted from R. officinalis by supercritical CO2 fluid extraction (SFE-CO2 ) was studied in detail. The capability of that the extract eliminate *OH radical was tested by electron paramagnetic resonance (EPR) technique and spin catch technique.

RESULT AND CONCLUSIONWith free radical clearance as index, by range and variance analysis, the optimum extraction process conditions were: keeping pressure at 30 MPa and temperature at 75 degrees C for 1 h, in the same time adding alcohol 0.30 mL x g(-1).

Carbon Dioxide ; chemistry ; Chromatography, Supercritical Fluid ; methods ; Drugs, Chinese Herbal ; chemistry ; Electron Spin Resonance Spectroscopy ; Hydroxyl Radical ; chemistry ; Plant Extracts ; chemistry ; Rosmarinus ; chemistry

In this review, we provide information on hydroxyl radical generation, trapping and detection methods, including electron spin resonance (ESR), electrochemistry detection (ECD), fluorescence detection, UV detection, chemoluminescence and mass spectrometry (MS). In addition, the advantages and disadvantages of the above methods were discussed.
Chromatography, Liquid ; methods ; Electron Spin Resonance Spectroscopy ; methods ; Electrophoresis, Capillary ; methods ; Hydroxyl Radical ; analysis ; chemistry ; Luminescent Measurements ; methods ; Mass Spectrometry ; methods ; Spectrophotometry, Ultraviolet ; methods ; Spin Trapping ; methods

OBJECTIVETo investigate the effect and mechanism of prepared Radix Polygoni Multiflori (RPM) on the elevation of extracellular hydroxyl radical in striatum of rats induced by intracerebral perfusion of 6-hydroxy dopamine (6-OHDA).

METHODSCerebral microdialysis was used to establish the model. Hydroxyl radical was captured by salicylic acid, and 2,3-dihydroxy benzyl acid (2,3-DHBA) and 2,5-dihydroxy benzyl acid (2,5-DHBA) formed by hydroxyl radical in vital brain were measured by high performance liquid chromatography-electrochemical detector (HPLC-ED).

RESULTSAfter perfusion of 6-OHDA in brain of rats, the levels of 2,3-DHBA and 2,5-DHBA in the model group increased rapidly. The former was higher during the whole course of observation (P<0.01), while the latter was higher at most time points than that in the control group (P<0.05 or P<0.01). The level of 2,3-DHBA in the RPM group was lower than that in the model group at 5 time points (P < 0.05, P < 0. 01).

CONCLUSIONRPM could inhibit the elevating of extracellular hydroxyl radical in striatum of rats induced by intracerebral perfusion of 6-OHDA, indicating one of the brain protective mechanisms of RPM may be related to its anti-oxidation effect.

Animals ; Corpus Striatum ; drug effects ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Hydroxyl Radical ; metabolism ; Male ; Microdialysis ; Neuroprotective Agents ; pharmacology ; Oxidopamine ; Polygonum ; chemistry ; Random Allocation ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study the chemical components of essential oils from Meconopsis oliverana and their antioxidant activity.

METHODThe essential oil was extracted by steam distillation, and GC-MS analysis was used to identify its constituents. The OH free radical scavenging activity of the essential oils was evaluated with an enzyme mark instrument by assay of the ability of DPPH free radical scavenging. BHT was used as positive control.

RESULTForty-seven compounds, account for 91.866% of the essential oils, were identified. The ability of scavenging OH and DPPH radicals of the essential oils is stronger than that of BHT.

CONCLUSIONThe main chemical constituents of the essential oils from M. oliverana are n-hexadecanoic acid (27.653%) and 6,10,14-trimethyl-2-pentadecanone (16.330%). And the essential oils showed strong antioxidant activity.

Antioxidants ; chemistry ; metabolism ; Biphenyl Compounds ; metabolism ; Butylated Hydroxytoluene ; metabolism ; China ; Fatty Alcohols ; chemistry ; isolation & purification ; Free Radical Scavengers ; chemistry ; metabolism ; Gas Chromatography-Mass Spectrometry ; Hydroxyl Radical ; metabolism ; Oils, Volatile ; chemistry ; isolation & purification ; Oxidation-Reduction ; Palmitic Acid ; chemistry ; isolation & purification ; Papaveraceae ; chemistry ; Picrates ; metabolism ; Plant Oils ; chemistry ; isolation & purification

OBJECTIVETo observe the antioxidative effect of Safflor Yellow (SY).

METHODHydroxyl radical scavenge effect of SY was tested with 1,10-phenanthroline-Fe2+ oxidative assay. Lipid peroxidation of mouse liver suspension was measured with thiobarbituric acid colorimetry technique. Hemocytocatheresis was determined with colorimetry.

RESULTHydroxyl radical could be scavenged by 1.39 to 3.42 g x L(-1) SY dose dependently. Mouse liver suspension peroxidation was inhibited by 77.8 to 776.1 mg x L(-1) SY dosage dependently. Hemocytocatheresis was attenuated by 37.1 to 297.1 mg x L(-1) SY dose dependently.

CONCLUSIONSY is an antioxidative part of Carthamus tinctorius.

Animals ; Antioxidants ; isolation & purification ; pharmacology ; Carthamus tinctorius ; chemistry ; Chalcone ; administration & dosage ; analogs & derivatives ; isolation & purification ; pharmacology ; Dose-Response Relationship, Drug ; Flowers ; chemistry ; Free Radical Scavengers ; pharmacology ; Hydroxyl Radical ; metabolism ; Lipid Peroxidation ; drug effects ; Liver ; metabolism ; Male ; Mice ; Plants, Medicinal ; chemistry ; Rabbits