Human neutrophils generate oxygen reduction products as a consequence of membrane interactions with a number of stimuli. One oxygen-centered free radical (superoxide) has been unequivocally shown to result from this "respiratory burst," and some experimental evidence for another (hydroxyl radical) has been published, although debate remains as to its significance. The role of phagocyte-derived ...

ion, hydrogen addition or electron transfer, while superoxide anion reacts via only hydrogen abstraction and electron transfer (Section 1.2) (5). Although, hydrogen peroxide and singlet oxygen are classified as ROS, they are not radicals and do not necessarily interact with tissue through radical reactions directly (6). Hence, they are not toxic per se but in presence of free radicals or cataly...

The 2-ethoxycarbonyl-2-methyl-3,4-dihydro-2H-pyrrole-l-oxide (EMPO), an easily prepared pyrroline-N-oxide has been tested as a free radical scavenger. Spin adducts of superoxide, hydroxyl radical, and other free radicals were characterized in phosphate buffer at pH 7.0 and 5.6. At pH 7 in phosphate buffer, the EMPO/O(2)(-*) spin adduct was estimated to be about five times more persistent than i...

The pro-oxidant activities of baicalein, morin, myricetin, quercetin, and rutin were examined in various cell-containing systems including human platelets, rat vascular smooth muscle cells, human umbilical vein endothelial cells (HUVECs), human THP-1 cells, and fibroblast cells. Electron spin resonance (ESR) results showed that only baicalein generated hydroxyl radicals in a resting human plate...

Phagocytes mediate their innate immunological response by releasing products that damage invading microorganisms. These products include proteins such as lysozyme, peroxidases, and elastase as well as reactive oxygen species such as superoxide, hydrogen peroxide, hypohalous acid, and hydroxyl radical. Although it is clear that many phagocytic secretory products have direct cytotoxic potential, ...

Treatment of Chinese hamster ovary and mouse hybridoma cells with Mega-H brand silica hydride, a marketed antioxidant, after photosensitization with singlet oxygen and hydroxyl/superoxide reactive oxygen species through the use of rose bengal diacetate and malachite green resulted in an effective method of reducing free radical activity by more than 96% against singlet oxygen species and more t...

Zonisamide (ZNS), a commonly used anticonvulsant, scavenged hydroxyl radicals at a clinically relevant concentration. Reactants of ZNS with hydrogen peroxide and with hydrogen peroxide plus UV irradiation, yielding hydroxyl radicals, were analyzed by the LC/MS technique. Many small fragments were found in the both reactions, suggesting that ZNS was decomposed not only by hydroxyl radicals but a...

Microalgae have been a popular edible food, but there are no known reports on the antioxidative peptides derived from microalgae. The algae protein waste, which is normally discarded as animal feed, is a by-product during production of algae essence from microalgae, Chlorella vulgaris. Algae protein waste was hydrolyzed using pepsin, and a potent antioxidative peptide of VECYGPNRPQF was separat...

OBJECTIVE To investigate the in vitro antioxidant activity of different fractions (R1, R2 and R3) obtained from pet ether extract of black pepper fruits (Piper nigrum Linn.) MATERIALS AND METHODS The fractions R1, R2 and R3 were eluted from pet ether and ethyl acetate in the ratio of 6:4, 5:5 and 4:6, respectively. 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical, superoxide anion radical, nitri...

ethanolic extract of leaves of elaeocarpus ganitrus was analyzed for their total antioxidant capacity, reducing power, metal chelating, abts+ (2, 2-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical scavenging and hydroxyl radical scavenging activities. the extract at 500 ?g/ml showed maximum iron chelating activity (76.70%) followed by the scavenging of the abts+ radical (55.77%) at the sa...