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Abstract

Oxygen free radicals (OFR) are implicated in the pathogenesis of stress, chemically induced gastric lesions, and gastrointestinal injury. The concentration-dependent scavenging abilities of bismuth subsalicylate (SBS), colloidal bismuth subcitrate (CBS), and selected OFR scavengers, including superoxide dismutase (SOD), catalase, mannitol, and allopurinol were examined against biochemically or chemically generated superoxide anion, hydroxyl radical, and hypochlorite radical plus hypochlorous acid based on a chemiluminescence assay. Furthermore, both gastric (GM) and intestinal mucosa (IM) were individually exposed in vitro to these free radical generating systems, and the concentration-dependent protective abilities of SBS and CBS against lipid peroxidation (LP) were compared with selected OFR scavengers. In addition, 24-hr fasted rats were orally treated with the necrotizing agents 0.6 M HCl, 0.2 M NaOH, 80% ethanol, and aspirin (200 mg/kg). The extent of tissue injury in the GM and IM was determined by assessing LP, DNA fragmentation, and membrane microviscosity. Dose- and time-dependent in vivo protective abilities of CBS (100 mg/kg) and SBS (15 mg/kg) were also assessed. Following incubations with superoxide anion and hydroxyl radical generating systems in the presence of 125 mg SBS/liter, approximately 47% and 61% inhibitions were observed in the chemiluminescence response, respectively, while 48% and 46% inhibitions were observed with 125 mg CBS/liter. SBS and CBS exerted similar abilities towards hypochlorite radical plus hypochlorous acid. Approx. 3.1- and 3.7-fold increases in LP were observed in the GM and IM of rats following oral administration of 0.6 M HCl. Pretreatment of the rats with SBS and CBS decreased 0.6 M HCl-induced LP in the GM by approx. 39% and 27%, respectively, with similar decreases in LP in the IM. SBS exhibited better protective abilities towards 0.6 M HCl and 0.2 m NaOH-induced GM and IM injury as compared to CBS. SBS and CBS provided similar protection towards 80% ethanol-induced gastric injury, while CBS exerted a superior protective ability towards aspirin-induced gastric injury. The results demonstrate that both SBS and CBS can scavenge reactive oxygen species and prevent tissue damage produced by OFR.

Low Intracellular Zinc Impairs the Translocation of Activated NF-κB to the Nuclei in Human Neuroblastoma IMR-32 Cells

“…These findings were unexpected, as we and other investigators have demonstrated that a low zinc status is associated to a condition of oxidative stress (9,10,(25)(26)(27)(28)(29)(30)(31)(32)(33)(34). NF-B is recognized to be activated by different oxidant species, by conditions that induce the intracellular production of oxidants and by oxidative-degradation products (35-38).…”

Comparing metabolic effects of six different commercial trivalent chromium compounds

“…DNA fragmentation in control samples is expressed as percentage of total DNA appearing in the supernatant fraction. Treatment effects are reported as percent of control fragmentation [22].…”

Catechins and Proanthocyanidins: Naturally Occurring O-Heterocycles with Antimicrobial Activity

“…Accordingly, the proanthocyanidins in grape seed extracts have been suspected to have free-radical scavenging abilities and to decrease the susceptibility of healthy cells to toxic and carcinogenic agents [48][49][50]. Analogously, in vitro and in vivo studies have demonstrated that these compounds exhibit the ability to scavenge reactive oxygen and nitrogen species [51], as well as inhibiting the progression of arteriosclerosis and preventing the increase of LDL cholesterol in high-cholesterol-fed rats [52].…”