Antioxidants in the selected plant raw materials used in prevention and treatment of diabetes

The free radicals in p‐polyphenylene and the formation of free radicals in this polymer upon pyrolysis in vacuum have been studied by means of electron spin resonance. For an unpyrolyzed series of polymer samples, a linear relationship was observed between free radical concentration and increasing carbon content. The free radicals observed in the unpyrolyzed samples did not react with NO. When samples of polyphenylene were pyrolyzed, additional free radicals were produced which did react with NO. The growth of free radical concentration upon pyrolysis was observed to be closely related to the production of volatile products from the polymer. In the temperature range 250–600°C, HCl was the principal volatile species produced. Two mechanisms were involved in HCl production: a process with an activation energy of 7.1 kcal/mole which led to the production of stable free radicals; and a process involving 75 kcal/mole which was unconnected with the production of free radicals. From 600 to 700°C, H2 was the principal volatile degradation product. The rate at which H2 was evolved showed a second‐order dependence on phenyl units bearing two or three substituents; this process had an activation energy of 79 kcal/mole. Electron spin resonance spectra indicated that this process led to the production of free radicals, and infrared spectra showed that a highly crosslinked product resulted.

P 247 - Free radical production and detoxification in complex IV deficient cancer cells

Background/Aims: The purpose of this study was to investigate the potential therapeutic roles of honey, prednisolone and disulfiram in an experimental model of inflammatory bowel disease. Another aspect of the study was to find out whether these substances have any effect on nitric oxide (NO) and free radical production. Methods: After the induction of colitis with trinitrobenzene sulfonic acid in 64 male rats, physiological saline, honey, prednisolone and disulfiram enemas were applied to the rats once daily for 3 days (acute treatment groups) or 7 days (chronic treatment groups). Control groups received only saline enemas. Rats were killed on the 4th or 8th days and their colonic mucosal damage was quantitated using a scoring system. Acute and chronic inflammatory responses were determined by a mucosal injury score, histological examination and measurement of the myeloperoxidase (MPO) activity of tissues. The content of malonylaldehyde (MDA) and NO metabolites in colon homogenates was also measured to assess the effects of these substances on NO and free oxygen radical production. Results: Estimation of colonic damage by mucosal injury scoring was found to be strongly correlated with the histologic evaluation of colon specimens. On the other hand, mucosal injury scores were not correlated with MPO, MDA or NO values. There were significant differences between the MPO results of chronic-control and chronic-honey groups, as well as chronic-control and chronic-prednisolone groups (p = 0.03 and p = 0.0007). The acute honey, prednisolone, and disulfiram groups had significantly lower MDA results compared to the acute control group (p = 0.04, p = 0.02, and p = 0.04). In terms of NO, there was no significant difference between the treatment and control groups. NO was found to have a strong relationship with MDA (p = 0.03) and MPO values (p = 0.001). On the other hand, MPO results were not found to be correlated with MDA values (p > 0.05). Conclusions: MPO activity is not directly proportional to the severity of the inflammation, but it may only determine the amount of neutrophil in the tissues. Inflammatory cells are not the sole intensifying factor in colitis. Therefore, mucosal injury scores may not correlate well with MPO activities. In an inflammatory state NO and MPO levels have a strong relationship, since NO is released from the neutrophils. In an inflammatory model of colitis, intrarectal honey administration is as effective as prednisolone treatment. Honey may have some features in the treatment of colitis, but this issue requires further investigation. Honey, prednisolone and even disulfiram also have some value in preventing the formation of free radicals released from the inflamed tissues. Prednisolone may also have some possible benefits in the inhibition of NO production in colitis therapy.

The purpose of this study was to examine the behavior of glutathione peroxidase (GPx) activities and Free Radicals (FR) production in the brain and the lung during graded hyperoxia exposure. Twenty-four adult male rats, matched with age and body weigh, were randomly assigned to four groups. The first group served as control and the second, third and fourth were exposed to hyperoxia for 24, 48 and 72 h, respectively. Following the exposure period for each group animals were sacrificed and both lungs and brain tissues were homogenized for GPx and FR determinations. GPx activity was determined by Randox protocol (Randox, UK) and FR was determined using dROM method (H and D, Italy). Results showed that mean ( ± SD) GPx activity in the lungs increased from the baseline control of 12898.33 ± 6034.77 to 20083.62 ± 2734 (U L-1) during hyperoxia exposure for 24; then dropped to 5467.77 ± 1159.53 and 8271.80 ± 1347.67 (U L-1) during hyperoxia exposure for 48 and 72 h, respectively. Whereas mean ( ± SD) GPx activity in the brain increased from the baseline control of 5467.80 ± 2852.65 to 13841.72 ± 1245.67 and 14594.82 ± 6711.44 (U L-1), during hyperoxia exposure for 24 and 48 h, respectively; then dropped to 4346.17 ± 343.34 (U L-1), during 72 h exposure. The sustained increased in GPx up-to 48 hr in the brain provided evidence of delayed protection against ROS. The average ( ± SD) FR production in the lung increased from the baseline control of 176.67 ± 33.79 to 274.33 ± 33.37, 260.00 ± 62.54 and 320.00 ± 114.91 (U L-1) during hyperoxia exposure for 24, 48 and 72 h, respectively. The average ( ± SD) FR production in the brain increased from the baseline control of 73.33 ± 20.18 to 132.17 ± 21.77 during hyperoxia exposure for 24 h and then dropped to 94.33 ± 14.56 and 65.33 ± 21.12, during 48 and 72 h, respectively. Tukey-Kramer multiple comparisons between the lung and the brain showed that the lungs had higher rate of FR formation at all levels of hyperoxia exposures, which suggest more mechanisms that had contributed to FR formation in pnueumocyte, as compared with neurocyte. Based on the results of the present study antioxidant supplements are recommended for traumatic brain injury and hypoxemia lung injury patients subjected to oxygen therapy.

Acute treatment with one large dose of ethanol, which mimics binge drinking, causes marginal fatty liver and decreases survival significantly after liver transplantation in rats, yet mechanisms remain unclear. Therefore, we evaluated the possible role of free radicals in primary nonfunction caused by acute ethanol. Female donor rats were administered ethanol (5 g/kg orally) 20 hr before explantation, and grafts were stored in UW cold storage solution for 24-42 hr before implantation. Free radicals were trapped with alpha-(4-pyridyl 1-oxide)-N-tert-butylnitrone after transplantation, and adducts were detected using electron spin resonance spectrometry. Ethanol increased a carbon-centered radical adduct in bile approximately 2-fold and elevated serum lipid hydroperoxides approximately 4-fold. Ethanol also increased transaminase release 3.7-fold and decreased bile production by 55%. Catechin, a free radical scavenger, minimized the increase in free radicals, blunted transaminase release, and elevated bile production significantly, indicating that free radical production plays an important role in ethanol-induced fatty graft injury. GdCl3 (20 mg/kg intravenously), a selective Kupffer cell toxicant, largely blocked the increases in free radical and lipid hydroperoxide production caused by ethanol. In addition, ethanol nearly doubled white blood cell adhesion after transplantation, leading to increased superoxide production in fatty grafts. GdCl3 largely blocked leukocyte adhesion as well as superoxide production. Allopurinol, an inhibitor of xanthine oxidase, also diminished free radical production, blunted transaminase release, and improved bile production in fatty grafts significantly. Taken together, we conclude that free radical formation increases in ethanol-induced fatty grafts due mainly to activation of Kupffer cells and increased adhesion of white blood cells. Antioxidants can effectively block free radical formation and minimize injury to marginal fatty grafts caused by binge drinking.

Cigarette smoke contains highly reactive free radicals thought to play an important role in tobacco smoke-induced harm. Previously, large variations in free radical and toxicant output have been observed in commercial cigarettes. These variations are likely because of cigarette design features (paper, filter, and additives), tobacco variety (burley, bright, oriental, etc.), and tobacco curing methods (air, sun, flue, and fire). Previous reports show that tobacco varieties and curing methods influence the production of tobacco smoke constituents like the tobacco-specific carcinogen nicotine-derived nitrosamine ketone (NNK). We evaluated free radical, nicotine, and NNK production in cigarette smoke from cigarettes produced with 15 different types of tobacco. Gas-phase free radicals were captured by spin trapping with N-tert-butyl-α-phenylnitrone and particulate-phase radicals were captured on a Cambridge Filter pad (CFP). Both types of radicals were analyzed using electron paramagnetic resonance spectroscopy. Nicotine and NNK were extracted from the CFP and analyzed by gas chromatography flame ionization detection and liquid chromatography-mass spectrometry, respectively. Gas-phase radicals varied nearly 8-fold among tobacco types with Saint James Perique tobacco producing the highest levels (42 ± 7 nmol/g) and Canadian Virginia tobacco-producing the lowest levels (5 ± 2 nmol/g). Nicotine and NNK levels in smoke varied 14-fold and 192-fold, respectively, by type. Gas-phase free radicals were highly correlated with NNK levels (r = 0.92, p < .0001) and appeared to be most impacted by tobacco curing method. Altogether, these data suggest that tobacco types used in cigarette production may serve as a target for regulation to reduce harm from cigarette smoking. Variations in cigarette free radical and NNK levels vary based on the tobacco variety and curing method. Reducing the ratio of high-producing free radical and NNK tobacco types offer a potential tool for regulators and producers looking to reduce toxicant output from cigarettes.

To investigate the effect of compound Danshen injection on lipopolysaccharide (LPS)-induced rat mesenteric microcirculatory dysfunctions and the underlying possible mechanism by an inverted intravital microscope and high-speed video camera system. LPS was continuously infused through the jugular artery of male Wistar rats at the dose of 2 mg/kg per hour. Changes in mesenteric microcirculation, such as diameters of arterioles and venules, velocity of RBCs in venules, leukocyte rolling, adhesion and emigration, free radicals released from post-capillary venules, FITC-albumin leakage and mast cell degranulation, were observed through an inverted intravital microscope assisted with CCD camera and SIT camera. Meanwhile, the expression of adhesion molecules CD11b/CD18 and the production of free radical in neutrophils, and the expression of intercellular adhesion molecule 1 (ICAM-1) in human umbilical vein endothelial cells (HUVECs) were quantified by flow cytometry (FACS) in vitro. The continuous infusion with LPS resulted in a number of responses in microcirculation, including a significant increase in the positive region of venule stained with Monastral blue B, rolling and adhesion of leukocytes, production of oxygen radical in venular wall, albumin efflux and enhanced mast cell degranulation in vivo, all of which, except for the leukocyte rolling, were attenuated by the treatment with compound Danshen injection. Experiments performed in vitro further revealed that the expression of CD11b/CD18 and the production of oxygen free radical in neutrophils, and the expression of ICAM-1 in HUVECs were increased by exposure to LPS, and they were attenuated by compound Danshen injection. These results suggest that compound Danshen injection is an efficient drug with multi-targeting potential for improving the microcirculatory disturbance.

IN VIVO ASSESSMENT OF FREE RADICAL ACTIVITY DURING SHOCK WAVE LITHOTRIPSY USING A MICRODIALYSIS SYSTEM: THE RENOPROTECTIVE ACTION OF ALLOPURINOL

Oxidative stress in clinical situations - fact or fiction?

CNS trauma has been associated with an increase in free radical production, but the cellular sources of this increase or the mechanism involved in the production of free radicals are not known. We, therefore, investigated the effects of trauma on free radical production in cultured neurons, astrocytes and BV-2 microglial cells. Free radicals were measured with the fluorescent dye DCFDA following in vitro trauma. At 30 and 60 min following trauma, there was a 132% and 64% increase, respectively, in free radical production in neurons when compared to controls. In astrocytes, there was a 94% and 133% increase at 30 and 60 min, respectively. Microglial cells, however, displayed no significant increase in free radicals at 30, 60 or 120 min following trauma. Since trauma can induce the mitochondrial permeability transition (MPT), a process associated with mitochondrial dysfunction, we further investigated whether cyclosporin A (CsA), an agent known to block the MPT, could prevent free radical formation following trauma. In neurons CsA did not block free radical production at 30 min but blocked it by 90% at 60 min. In contrast, in astrocytes CsA completely blocked free radical production at 30 min but did not block it at 60 min. Our results indicate that a differential sensitivity to trauma-induced free radical production exists in neural cells; that the MPT may be involved in the production of free radical post-trauma; and that the CsA-sensitive phase of free radical production is different in neurons and astrocytes.

Several studies have demonstrated the role of free radicals in causing esophagus-gastro-duodenal mucosal injury. The present study has been designed to investigate: whether acid, bile salts and a combination of bile + acid could determine the production of O2-derived free radicals by oesophageal, gastric and duodenal mucosa; which agent is capable of producing more free radicals and if O2-derived free radicals production depends on the duration of contact with acid, bile salts and their combination. Wistar rats' gastro-intestinal mucosa were perfused with bile, acid and a combination of bile + acid at pH4 and pH2 for 1 hour and 2 hours. Free radical production (FRP) was assessed by chemoluminescence. After 1 hour, the increase in FRP in comparison with control reached statistical significance (P < 0.05) at all tested pH levels in the duodenum, at pH1, 2 and 3 in the esophagus, and at pH1 in the stomach. Comparing different segments, both the esophagus and duodenum behaved similarly, producing more free radicals than the stomach at all pH values. However, this difference reached statistical significance at pH1 and 2 only. In comparison to control, FRP was increased by bile (pH7) infusion after 1 and 2 hours. There was increased FRP in all segments after the infusion of bile at pH2 and 4 in comparison to control. Infusion of bile at pH2 stimulates more FRP than infusion of bile at pH4 in all segments. This increased FRP reaches statistical significance in the esophagus after 2 hours of infusion, in the stomach after 1 and 2 hours of infusion, but in the duodenum it does not reach statistical significance. Acid, bile and bile + acid at pH2 and 4 can cause free radical production in esophageal, gastric and duodenal mucosa. Their role in producing free radicals is different according to the segment and the chemical composition of the solution.

Hyperoxia has been widely used as model for oxidative stress. Free radicals (FR), suproxide anion (*O2-) and nitric oxide anion (*NO−), are highly toxic and have detrimental effects on nitroso-redox balance in the myocyte. Myocardium is rich with β-adrenergic receptors and endothelial is the site of NO production. The authors hypothesized that graded doses of dobutamine result in hyperkinetic state, which shifts the nitroso-redox balance toward the buildup of reactive species in dose-dependent excess. The purpose of the present study was to investigate free radicals production and coronary endothelial cell pathological changes following increasing length of breathing oxygen (100% O2) and progressive doses of dobutamine. Thirty-five adult male rats, matched with age and body weight, were randomly assigned to 7 groups. The first group served as control (C) and the 2nd, 3rd, and 4th groups were exposed to hyperoxia (100% O2 breathing) for 24,48, and 72 h, whereas the 5th, 6th, and 7th groups were injected dobutamine 10,20, and 30 μg kg−1, respectively. Following the treatment condition for each group, animals were sacrificed and heart tissues were divided randomly into two parts. The first part was processed for the ultrastructure, using transmission electron microscope (TEM), and the second was homogenized for FR determination. TEM examination showed that O2 breathing for 24 h resulted in hypertrophy and proliferation of endothelial cells lining the coronary capillary, which was lodged by lymphoid cells. Distended and irregular contour of endothelium, enlarged nucleus, protrusion membrane, as well as pinocytotic vesicles were also observed. Free radicals (FR) production at all levels of hyperoxia exposures and dobutamine injections were significantly (p < .05) higher than control group. In addition, dobutamine induced higher relative FR production, as compared with hyperoxia, implying more severe myocyte injury. Based on the results of the present study, it can be concluded that O2 breathing for 24 h or higher resulted in variety of pathological changes of the endothelium of coronary capillary that were induced by the buildup of oxidants by-products. Because dobutamine caused relative higher in FR production levels, as compared with hyperoxia levels, throughout this implied it aggravated the myocyte capillaries' endothelium more heavily, which could have resulted in more intense ultrastructural deteriorations.

Diabetes mellitus is a fast-growing disease with a major influence on people’s quality of life. Oral hypoglycemic drugs and insulin are currently the main effective drugs in the treatment of diabetes, but chronic consumption of these drugs has certain side effects. Polysaccharides, saponins, flavonoids, and phenolics are the primary secondary metabolites isolated from the rhizomes of Polygonatum sibiricum Redouté [Asparagaceae], Polygonatum kingianum Collett & Hemsl [Asparagaceae], or Polygonatum cyrtonema Hua [Asparagaceae], which have attracted much more attention owing to their unique therapeutic role in the treatment and prevention of diabetes. However, the research on the mechanism of these three Polygonatum spp. in diabetes has not been reviewed. This review provides a summary of the research progress of three Polygonatum spp. on diabetes and its complications, reveals the potential antidiabetic mechanism of three Polygonatum spp., and discusses the effect of different processed products of three Polygonatum spp. in treating diabetes, for the sake of a thorough understanding of its effects on the prevention and treatment of diabetes and diabetes complications.

Reactive oxygen species are physiological mediators of the noradrenergic signaling pathway in the mouse supraoptic nucleus

Extensive production and evolution of free radicals during composting