Spin Trapping

SUMMARYFree radical scavenging activities of water-soluble extracts from some natural sources, health foods, and antioxidant substances were measured using the JES-FR30 JEOL spectrometer. The objective was to develop a standardized method whereby comparison could be made between the radical scavenging activities of complex mixtures.Scavenging of hydroxyl radical was determined using DMPO. Activity was calibrated using a standard material, L-ascorbic acid 2-[3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6yl-hydrogen phosphate] potassium salt (EPC-K1), an analog of vitamin C and vitamin E which is water soluble and stable at room temperature. The order of greatest hydroxyl radical scavenging activity was green tea extract, pine bark extract (Pycnogenol), Ginkgo Biloba extract (EGb 761), a flavonoid blend of several fruit and vegetable extracts (GNLD), and Bio-Normalizer (Sun-O Corp). Activity was determined after treatment of samples with ascorbic acid oxidase. This treatment revealed the presence of ascorbate in some natural extracts and commercial preparations. The pine bark extract was the most heat resistant and had ascorbate-like activity in the preparations.Scavenging of superoxide anion was determined using the spin trap, 5,5-dimethyll-pyrroline-N-oxide (DMPO), and analyzed by comparison with a standard curve made with superoxide dismutase. Comparison of the water solubilized components of natural source antioxidants showed that filtrates fractionated using centrifuge type Millipore filter tubes (M.W.<100,000; M.W.<10,000) also had almost the same SOD-like activity. Samples were also treated with ascorbate oxidase or by heating (100~ for 10rain). The order of activity, from greatest to least, was Ginkgo biloba extract EGb 761, pycnogenol, ~3-catechin, tea and BioNormalizer.

show abstract

“…Methods for spin trapping of hydroxyl and superoxide radicals were based on earlier reports [6][7][8][9].…”

Section: Esr Measurementsmentioning

confidence: 99%

Hydroxyl and superoxide anion radical scavenging activities of natural source antioxidants using the computerized JES‐FR30 ESR spectrometer system

et al. 1997

View full text Add to dashboard Cite

show abstract

Section: Discussionmentioning

confidence: 99%

“…This technique uses compounds that readily react with free radicals to produce a relatively long-lived free-radical product (spin adduct), which can be identified by its ESR spectrum (18,19). We developed an ESR-based technique to detect free-radical reactions induced by ROS in biological systems in vitro and in vivo (18,19). Regarding in vitro ESR applications, the spin-trapping technique is a well known method of using ESR spin adduct to detect ROS by quantifying spin concentration in experimental systems (18,19 We also examined the bactericidal effect of H 2 O 2 with PUI on E. faecalis, a gram-positive anaerobic facultative coccus that has been recovered from several oral sites (23).…”

Section: Discussionmentioning

confidence: 99%

“…We developed an ESR-based technique to detect free-radical reactions induced by ROS in biological systems in vitro and in vivo (18,19). Regarding in vitro ESR applications, the spin-trapping technique is a well known method of using ESR spin adduct to detect ROS by quantifying spin concentration in experimental systems (18,19 We also examined the bactericidal effect of H 2 O 2 with PUI on E. faecalis, a gram-positive anaerobic facultative coccus that has been recovered from several oral sites (23). E. faecalis was used in the present study because it has a high level of resistance to a wide range of medications, such as calcium hydroxide (24), and is commonly found in cases of root canal treatment failure associated with persistent apical periodontitis (25,26).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Passive ultrasonic irrigation in the presence of a low concentration of hydrogen peroxide enhances hydroxyl radical generation and bactericidal effect against Enterococcus faecalis

et al. 2014

View full text Add to dashboard Cite

“…The spin trapping technique is a powerful tool, enabling the detection of short-lived free radicals in a wide variety of chemical or biological systems [1][2][3][4]. In this method, a transient free radical adds to a trapping agent to form a persistent adduct capable of being identified by conventional electron paramagnetic resonance (EPR) spectroscopy [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Preparation of N-aryl-ketonitrone spin traps

2006

View full text Add to dashboard Cite

Abstract:The syntheses of seven N -aryl-C,C-dialkoxycarbonylnitrones 1-7, six of which were original, were achieved from the appropriate aryl-nitroso compounds. These ketonitrones were found to trap efficiently carbon-centred free radicals in aqueous media, yielding stable aminoxyl radicals whose EPR spectra lasted several days. The two penta-deuterated compounds 6 and 7 were also found to be efficient at trapping methoxyl radical. Their various spin adducts showed simple three line signals, very sensitive to the polarity of the environment. This study represents the very first use of linear ketonitrones as spin traps.

show abstract

Spin Trapping

Cited by 16 publications

References 69 publications

Hydroxyl and superoxide anion radical scavenging activities of natural source antioxidants using the computerized JES‐FR30 ESR spectrometer system

Hydroxyl and superoxide anion radical scavenging activities of natural source antioxidants using the computerized JES‐FR30 ESR spectrometer system

Passive ultrasonic irrigation in the presence of a low concentration of hydrogen peroxide enhances hydroxyl radical generation and bactericidal effect against Enterococcus faecalis

Preparation of N-aryl-ketonitrone spin traps

Contact Info

Product

Resources

About