Radical scavenging effect

It has long been recognized that ascorbate levels are low in patients with RA (Lunec and Blake, 1985) and ascorbate is predominantly found in the dehydro form. The presence of increased dehydroascorbate has been suggested to indicate its rapid oxidation by stimulated PMNs (Halliwell and Gutteridge, 1990). When ascorbate concentrations are lower than about 20 /tmol/1, as can occur in rheumatoid synovial fluid, the Fe(III) reducing effects of ascorbate outweigh its radical-scavenging effects. Ascorbate then causes increased OH formation and promotes lipid peroxidation (Blake et al., 1981). 

For the sonochemical mineralization of reactive dye Cl Reactive Black 5 with 20, 279 and 817 kHz irradiation, the discoloration and radical formation both are directly dependent upon ultrasonic frequency, acoustic power and irradiation time and indirectly on the number of free radicals thus generated, as their suppression decreased the discoloration rate due to radical scavenging effect. Although ultrasound alone is capable of decolorizing Reactive Black 5 but inefficient in mineralization as only 50% degradation was observed after 6 h of ultrasonic irradiation [121]. The sonochemical... 

When the flow through the CNC was exhausted outside of the laboratory, we observed particle formation at higher SOp concentrations as expected (Table II). To prove that the radical scavenger effect is reproducible, another radical scavenger (92 ppb nitric oxide) was used in the presence of 110 ppb SOp concentration and 2% humidity, and the supression in particle formation was observed. Another possible mechanism that supressed the particle formation is that more neutralization of polonium ions occurred at the higher humidities and thus ion-induced nucleation would be suppressed. 

Selenoureas are prepared by reaction of isoselenocyanates with amines, or by reaction of carbodiimides with a mixture of LiAlH4/Se and by reaction of cyanamides with LiAlH4/Se.267 272 The tyrosinase inhibitory activity and superoxide radical scavenger effect of selenoamides and selenoureas have been investigated (Scheme 84).273 275... 

Radical scavenging effect. Seed oil, in cell culture, was active on astrocytes vs peroxide radical scavenging, IC50 27461 ppm . Spasmogenic activity. Methanol (70%) extract of the seed, administered to guinea pigs at a dose of 1 mg/mL, was active on the uterus and ileum. The effect was abolished... 

Lou, H. et al.. Polyphenols from peanut skins and their free radical-scavenging effects. Phytochemistry, 65, 2391, 2004. 

Hatano T, Kagawa H, Yasuhara T, Okuda T. Two new flavonoids and other constituents in licorice root their relative astringency and radical scavenging effects. Chemical Pharmaceulical Bulletin. 1988 36(6) 2090-2097. 

The radical-scavenging effect of citronellal showed a strong protective activity in lipid peroxidation processes in a dose-dependent manner [139, 146,159], Also, scavenging effects have been described for neral and geranial [146, 152, 160],... 

Figure 16.14 represents a summary of the most important studies performed in the field of free radical scavenging effects. G115 inhibits lipid peroxidation in rats. It protects the rabbit pulmonary artery from free radical injury and the rat heart from ischemia reperfusion injury. Figure 16.15 illustrates the various diseases that are due to an excessive production of free radicals, such as atheroclerosis, diabetes, rheumatoid arthritis, and aging. 

D3. Desmarchelier, C., Coussio, J., and Ciccia, G., Antioxidant and free radical scavenging effects in extracts of the medicinal herb Achyrocline satureioides (Lam.) DC. ( marcela ). Braz. J. Med. Biol. Res. 31, 1163-1170 (1998). 

Some sulfated galactans, or products of their partial depolymerization, exhibit antioxidant activity.684,685 The chemistry of radical scavenging effects is not very clear, especially taking into account the fact that several products of chemical modifications of natural polysaccharides, such as oversulfated, phosphorylated, acety-lated and phthaloylated derivatives, may demonstrate stronger antioxidant activity than the raw material.685-688... 

The free radical scavenging effects of compounds 57 derived from dihydro-pyrimidines 56 (Scheme 12) was also examined by the DPPH method and by measuring hydroxyl radical scavenging activity (RSA) [33]. It was found that compounds derived from the thioureas had the best antioxidant activities. Compounds 58 and 59 were the most potent and had comparable activity to quercetol (Table 4). 

Fungus Epicoccum sp. was isolated from the marine brown alga Fucus vesiculosus. From the cultivated fungus, a new secondary metabolite 4,5,6-trihydroxy-7-methylphthalide 336 (epicoccone) was found. 336 was found to be potently active, showing 95% DPPH radical scavenging effects at 25 pg mL. It also inhibited the peroxidation of linolenic acid in the TEARS assay (62 % inhibition at 37 pg mL ). 

At present, the most preferred method developed to study radical scavenging effects of flavonoids seems to be the oxygen radical absorbing capacity (ORAC) method that utilizes a peroxyl radical (ROO ) generator and the water-soluble fluorescent indicator... 

Saint-Cricq de Gaulejac, N., Glories, Y., and Vivas, N. 1999. Free radical scavenging effect of anthocyanins in red wines. Food Res. Int. 32 327-333. 

Yoshida, T., Mori, K., Hatano, T., Okumura, T., Uehara, I., Komogoe, K., Fujita, Y., and Okuda, T. 1989. Studies on inhibition mechanism of autoxidation by tannins and flavonoids. V. Radical-scavenging effects of tannins and related polyphenols on l,l-diphenyl-2-picrylhydrazyl radical. Chem. Pharmacol. Bull. 37(7) 1919—1921. 

Imai, J., Ide, N., Nagae, S., Moriguchi, T., Matsuura, H. and Itakura, Y. (1994) Antioxidant and radical scavenging effects of aged garlic extract and its constituents. Planta Med. 60 417 120. 

Studies of ginkgolide B are also discussed in the above-cited review, with effects noted on ischemia, cerebrovascular injury, and inflammation and it is noted that the free radical scavenging effects of the flavonoid component of EGb-761 are in all probability important contributors to the overall activity of this product. It can also be noted that G. biloba extracts have other activities than those mentioned above and that these extracts also have cytostatic activities that might render them valuable adjuncts to cancer chemotherapy. ... 

It was reported licochalcone A inhibits the cytopathic activity of human immunodeficiency virus (HIV) by Okuda s group [22], A cell line named OKM-1, sensitive to the cytopathic activity of HIV, was established from the peripheral blood of a patient with adult T-cell leukemia. Giant cells due to the cytopathic activity, were formed within a day on co-culture with HIV-infected Molt-4 cell (OKM-1 OKM-4 = 3 1). Licochalcone A inhibited the giant cell formation at concentration 20 ig/ml without observable cytotoxicity. Besides, licochalcone A has a radical scavenging effect, inhibition of leukotriene synthesis in human polymorphonuclear neutrophils and xanthine oxidase. 

Antioxidative and radical scavenging effects of olive phenols... 

Antioxidative and Radical Scavenging Effects of Olive Biphenols... 

Pharmacology In vitro studies have documented antioxidant and radical-scavenging effects and increased formation of NO. Animal studies have revealed reduced blood viscosity and changes in CNS neurotransmitters. At the clinical level, ginkgo appears to have value in intermittent claudication, and it reduces markers of oxidative stress in coronary artery bypass surgery. Several studies show a mild benefit of ginkgo in Alzheimer s dementia. 

---