Free-radical trapping in the precipitation polymerization of acrylamide

2003 ◽  
Vol 41 (11) ◽  
pp. 1192-1197 ◽  
Author(s):  
Suparna Guha ◽  
T. R. Gundu Rao ◽  
Broja M. Mandal
Keyword(s):  
Free Radical ◽  
Precipitation Polymerization ◽  
Radical Trapping

scholarly journals Visualization of the protective ability of a free radical trapping compound against rat C6 and F98 gliomas with diffusion tensor fiber tractography

2008 ◽  
Vol 28 (3) ◽  
pp. 574-587 ◽  
Author(s):  
Taketoshi Asanuma ◽  
Sabrina Doblas ◽  
Yasvir A. Tesiram ◽  
Debra Saunders ◽  
Rebecca Cranford ◽  
...  
Keyword(s):  
Free Radical ◽  
Diffusion Tensor ◽  
Fiber Tractography ◽  
Protective Ability ◽  
Radical Trapping

scholarly journals Pengaruh Penambahan Rempah dan Bentuk Minuman terhadap Aktivitas Antioksidan Berbagai Minuman Tradisional Indonesia

2017 ◽  
Vol 37 (1) ◽  
pp. 7 ◽  
Author(s):  
Aisyah Tri Septiana ◽  
Mohammad Samsi ◽  
Mustaufik Mustaufik
Keyword(s):  
Antioxidant Activity ◽  
Linoleic Acid ◽  
Free Radical ◽  
Total Phenolic Content ◽  
Phenolic Content ◽  
Total Phenolic ◽  
Phenolic Contents ◽  
Beverage Type ◽  
Radical Trapping ◽  
Palm Sugar

Indonesia traditional beverages such as minuman jahe, kunyit asam, beras kencur, and minuman temulawak are usually made with the addition of spices. They can be served in the form of  liquid or powder. This research was aimed to study the effect of  the beverage type, addition of spices, and the form of product on their antioxidant activity. The type of sugar used in this study was palm sugar juice. Total phenolic contents were measured to  indicate the level of antioxidants. Measurement of antioxidant  activity was conducted by analyzing malonaldehyde from linoleic  acid and capturing capacity of DPPH radical. The results showed  that Indonesian traditional beverage could inhibit the oxidation of linoleic acid and capture free radicals. Free radical capturing  capacity of curcuma beverage greater than other beverages, but  the malonaldehyde (MDA) inhibitor effect was not different. Total phenolic content of curcuma tended to be higher than the other traditional beverages. The addition of spices could raise the level  of total phenolic content in beverages and increase free radical  trapping capacity. Drying the beverages into powder could reduce the levels of total phenolic content and but did not reduce the  antioxidant activity. ABSTRAKMinuman tradisional Indonesia seperti minuman jahe, kunyit  asam, beras kencur, dan minuman temulawak biasanya dibuat  dengan tambahan berbagai rempah. Minuman tersebut dapat  disajikan dalam bentuk cair maupun serbuk. Penelitian ini  bertujuan untuk mengetahui pengaruh jenis minuman,  penambahan rempah tambahan, dan bentuk minuman terhadap aktivitas antioksidan minuman. Jenis gula yang ditambahkan  adalah gula nira. Jenis antioksidan yang diuji adalah total fenolik. Pengukuran aktivitas antioksidan dilakukan dengan uji  penghambatan malonaldehid dan kapasitas penangkapan radikal  DPPH. Hasil penelitian menunjukkan bahwa minuman  tradisional Indonesia dapat menghambat oksidasi asam linoleat dan menangkap radikal bebas. Kapasitas penangkapan radikal  bebas oleh minuman temulawak lebih besar dibandingkan  minuman yang lain tetapi kemampuan penghambatan  malonaldehid (MDA) oleh minumaan tradisional tidak berbeda.  Total fenolik minuman temulawak cenderung lebih besar  dibandingkan minuman tradisional yang lain. Penambahan  rempah-rempah dapat meningkatkan kadar total fenolik  minuman dan meningkatkan kapasitas penangkapan radikal  bebas. Pembuatan minuman serbuk pada penelitian ini dapat  menurunkan kadar total fenolik tetapi tidak menurunkan aktivitas antioksidan.

scholarly journals NXY-059, the free radical trapping nitrone-based agent, reduces hemiparesis and reduces grey and white matter damage after focal cerebral ischemia in monkeys

Stroke ◽  
2001 ◽  
Vol 32 (suppl_1) ◽  
pp. 327-327
Author(s):  
J Wb Marshall ◽  
K J Duffin ◽  
A R Green ◽  
R M Ridley
Keyword(s):  
Free Radical ◽  
White Matter ◽  
Acute Stroke ◽  
Functional Disability ◽  
Focal Cerebral Ischemia ◽  
Spatial Neglect ◽  
Histopathological Analysis ◽  
White Matter Damage ◽  
Radical Trapping ◽  
Published Evidence

60 There is little published evidence for protection of white matter with neuroprotective drugs in animal models of stroke, yet white matter protection may be important in achieving clinical efficacy. We have examined the effects of NXY-059, a nitrone-based free radical trapping agent, on long-term functional disability in a primate model of stroke. We also examined histopathological effects, including analyses of grey and white matter damage. Five minutes after unilateral permanent middle cerebral artery occlusion, marmosets received a 1 ml i.v. infusion of saline (n=5) or NXY-059 (28 mg/kg) (n=6) and osmotic minipumps (model 2001D) were implanted s.c. to provide continuous drug or saline infusion for 48 h. Drug-filled pumps released NXY-059 at a rate of approximately 16 mg/kg/h. The plasma unbound drug concentration at 24 h was 76.3 ± 5.7 μM, a level well tolerated in acute stroke patients. The monkeys had been trained and tested on a variety of behavioral tasks before surgery. NXY-059-treated monkeys were significantly better at reaching with their contralesional arm than were saline-treated monkeys when re-tested 3 (p<0.01) and 10 weeks (p<0.01) after surgery. NXY-059-treatment also significantly reduced spatial neglect measured 3 weeks after surgery (p<0.01) compared with the saline group. After behavioral testing was complete, histopathological analysis showed NXY-059-treated monkeys had significantly smaller infarcts than saline-treated monkeys (F (1, 10)=5.21, p<0.05). NXY-059 reduced overall infarct size by 51%, damage to the cortex was reduced by 54%, white matter by 52%, caudate by 49%, and putamen by 33% compared with saline-treated monkeys. In conclusion, NXY-059 substantially lessened the functional disability in these monkeys. This drug protects not only cortical tissue, but also white matter and subcortical structures against ischemic damage. Together these findings bode well for advancing this drug to further clinical trials for its use in acute stroke.

scholarly journals Free Radical Trapping

Nature ◽  
1961 ◽  
Vol 190 (4775) ◽  
pp. 478-478
Author(s):  
B. BROCKLEHURST
Keyword(s):  
Free Radical ◽  
Radical Trapping

Thermolysis of α-hydroperoxyalkyl diazenes. Spin trapping of radical intermediates and spin trapping kinetics

1991 ◽  
Vol 69 (9) ◽  
pp. 1398-1402 ◽  
Author(s):  
Lukose Mathew ◽  
Emmanuel Y. Osei-Twum ◽  
John Warkentin
Keyword(s):  
Free Radical ◽  
Rate Constant ◽  
Ring Opening ◽  
Spin Trapping ◽  
Ethyl Vinyl Ether ◽  
Trapping Rate ◽  
Ethyl Vinyl ◽  
Enol Ethers ◽  
Radical Intermediates ◽  
Radical Trapping

α-Hydroperoxyalkyl diazenes (Me2C(OOH)N=NR, 1, R = CH2CF3, CH2CH2OMe, CH(Me)2, CMe3, CH2Ph, Ph, CH2CH2OPh, and c-C3H5CD2) decompose in benzene, at 50 °C or less, by a mechanism involving free radical (R•) intermediates. The radicals were trapped with 1-methyl-4-nitroso-3,5-diphenylpyrazole, 2, to afford spin adducts (nitroxyls) that were observed by ESR spectroscopy. When the solvent was ethyl vinyl ether, radicals from 1 (R = CH2CH2OPh) were trapped by the solvent and the adduct radicals so formed were spin trapped by 2. These observations support free radical mechanisms for thermolysis of 1 and for the hydroxyalkylations that occur when 1 are decomposed in solutions containing enol ethers or other unsaturated substrates. The ring-opening of cyclopropylmethyl radicals (cpm) to 3-butenyl radicals was used to estimate the rate constant for radical trapping by 2. For cpm the rate constant is given by log kcpm = (10.7 ± 0.4) − (3.9 ± 0.5)/θ where θ = 2.3 RT kcal mol−1. At 25 °C, the spin trapping rate constant has the value 6.9 × 107 M−1 s−1. Key words: hydroperoxyalkyl diazenes; radicals, spin trapping; spin trapping, rate constant.

scholarly journals New Method in Free Radical Chemistry Using 2,4-Diphenyl-4-methyl-1-pentene as Radical Trapping Agent

1997 ◽  
Vol 29 (4) ◽  
pp. 366-369 ◽  
Author(s):  
Yasumasa Watanabe ◽  
Hideyo Ishigaki ◽  
Hiroshi Okada ◽  
Shuji Suyama
Keyword(s):  
Free Radical ◽  
New Method ◽  
Radical Chemistry ◽  
Radical Trapping ◽  
Free Radical Chemistry ◽  
Trapping Agent
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