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Selected Publication:
Gurtner, E.
Combination of alpha-ketoglutarate and 5-HMF inhibits protein carbonyl formation by reactive oxygen and nitrogen species during exposure of cigarette smoke.
Humanmedizin; [ Diplomarbeit ] Medical University of Graz; 2014. pp. 61
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- Authors Med Uni Graz:
- Advisor:
- Greilberger Joachim
- Matzi Veronika
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- Abstract:
- Background: Exposure of human plasma to gas phase and whole cigarette smoke leads to oxidative stress and formation of peroxynitrite, as one of the most potent oxidizing and nitrating reagent produced from cigarette smoke. Reactive species are able to initiate or promote oxidative modifications of proteins, lipids, carbohydrates and DNA, which generally leads to various degenerative pulmonary and cardiovascular diseases like bronchitis, chronic obstructive pulmonary disease (COPD), emphysema, myocardial infarction and chronic inflammation as well as lung cancer and other malignancies. It was the primary goal of this thesis to answer the question if alpha-ketoglutarate and 5-HMF protect against oxidative damage of proteins exposed to the gas phase of cigarette smoke and if these substances are able to act as scavengers for peroxynitrite compared to ascorbic acid. Methods: In order to determine the level of oxidative protein damage, photometric measurement of carbonyl proteins has been carried out. In a first step, measurement of the reduction of carbonyl proteins through a BSA-solution with both substances, alpha-ketoglutarate and 5-HMF in combination, compared to ascorbic acid, using concentrations of 0.568 mmol of each substances, was executed. In a second step, measurement of inhibitory effects on carbonyl protein formation of each substance alone (alpha-ketoglutarate, ascorbic acid, 5-HMF) and in comparison to each other, in different concentrations (0.284 mmol, 0.426 mmol, 0.568 mmol), was done. In order to answer the question if alpha-ketoglutarate, 5-HMF and ascorbic acid are able to act as scavengers for peroxynitrite, peroxynitrite scavenging measurements by chemiluminescence technique were accomplished. Effects of different concentrations of alpha-ketoglutarate, 5-HMF and ascorbic acid (0.16mM, 0.8mM, 4mM, 20mM, 200mM) on the oxidation of luminol through ONNO- during chemiluminescence were analyzed. The results were treated and analyzed statistically and presented graphically. Results: Due to the examinations carried out on inhibition of carbonyl protein formation, it could not only be shown that the combination of alpha-ketoglutarate and 5-HMF had the strongest inhibiting effect on carbonyl protein formation, but also that it was clearly superior in its effect to ascorbic acid. Investigating the antioxidative potency of each substance alone against one another, it could be demonstrated that alpha-ketoglutarate was superior to ascorbic acid, whereas 5-HMF showed the weakest effects on reduction of protein carbonyl formation. By analysis of the inhibiting effects on the luminol reaction through the compounds under investigation it could be figured out, that ascorbic acid showed the strongest antioxidative potential compared to alpha-ketoglutarate and 5-HMF. The second strongest antioxidative potential could be attributed to alpha-ketoglutarate and again 5-HMF showed the weakest antioxidative potential of all three substances. Conclusion: Oxidative stress plays an important role in the development of many diseases. In the prevention and treatment of numerous diseases there is a need for multimodality concepts, e.g. to reduce the occurrence of oxidative stress. The generated data of this diploma thesis documented the radical scavenging effect through alpha-ketoglutarate and 5-HMF and supports the hypothesis that there could be achieved a significant reduction of oxidative stress by means of smoking. Reduction of oxidative stress through the use of alpha-ketoglutarate and 5-HMF may therefore be one further step towards introducing a multimodality approach in the prevention and treatment of several diseases caused or contributed to oxidative stress.