The aim of the research is to assess various decrystallization techniques applied to honey of different biological origin, in order to reveal the processes occurring in honey during decrystallization and storage, and to assess the changing quality of honey and human allergy manifestation. The Research Tasks: 1. To investigate biological origin, physico-chemical, biochemical properties and relationship among several types of honey, to highlight the most valuable types of honey with reference to them. 2. To explore the influence of thermal and mechanical decrystallization on physical, chemical and biochemical properties of different biological origin honey. 3. To evaluate the dynamics of physicochemical and biochemical changes in differently decrystallized honey during storage. 4. To determine the optimal modes of honey thermal decrystallization friendly to honey valuable properties, the most favourable storage duration and conditions. 5. To reveal whether there is a difference in allergy caused by honey before and after heat treatment. / Darbo tikslas Įvertinti skirtingos biologinės kilmės medaus įvairių dekristalizavimo būdų galimybę, atskleisti dekristalizavimo ir sandėliavimo metu meduje vykstančius procesus, įvertinti kintančią medaus kokybę bei poveikį žmonių alergiškumui. Darbo uždaviniai 1. Ištirti skirtingų medaus rūšių botaninę-biologinę kilmę, fizikocheminius, biocheminius parametrus ir jų tarpusavio ryšius, remiantis jais išryškinti vertingiausios kilmės medaus rūšis. 2. Ištirti terminio ir mechaninio poveikio įtaką skirtingos biologinės kilmės medaus fizinėms, cheminėms bei biocheminėms savybėms. 3. Įvertinti įvairiais būdais dekristalizuoto medaus fizikocheminių ir biocheminių savybių kitimo dinamiką sandėliuojant. 4. Nustatyti optimalius dekristalizavimo režimus, tausojančius vertingąsias medaus savybes, optimalią sandėliavimo trukmę ir sąlygas. 5. Įvertinti skirtingos botaninės kilmės natūralaus bei termiškai apdoroto medaus įtaką žmonių alergiškumui.

The nutritional quality and antioxidant activity of organic and conventional green beans were compared in a series of experiments. Firmness, percent dry matter, carotenoids and chlorophyll contents, respiration rate, vitamin C and proteins were evaluated. Hydroxyl radical scavenging activity, SOD, APX and POX were also analysed. In a second experiment, organic green beans treated with hexanal formulations were stored with untreated at 12⁰C in the refrigerator for a period of three weeks during two seasons. The results of the experiment showed higher levels of most of the parameters measured in organic green beans (with significant differences in firmness, carotenoids and chlorophyll b), except for respiration, vitamin C, antioxidant activity(hydroxyl radical scavenging) and APX where conventional green beans were higher and showed significant differences in respiration and vitamin C. The storage experiment showed a decrease in firmness and fresh weight and increase in respiration during storage for both seasons. Carotenoids and chlorophyll contents showed decrease in concentrations during the first week and increased during the second week of storage.

No description available.

Liver fatty acid binding protein (L-FABP) binds and translocates many lipophilic substrates within the cytoplasm including long chain fatty acids. Moreover it was reported that L-FABP possesses antioxidative properties within hepatocytes. However, the mechanism of L-FABP’s antioxidative activity remains to be determined. Peroxisome proliferator activated receptor (PPAR) agonists and antagonists can regulate L-FABP levels. However, it needs to be investigated how PPAR agonists and antagonists regulate L-FABP expression. And whether the altered expression of L-FABP by these agents will affect its antioxidative properties within hepatocytes remains unclear. In this thesis we employed clofibrate (PPARα agonist), MK886 (PPARα antagonist), and GW9662 (PPARγ antagonist) to elucidate the mechanism whereby PPAR regulate L-FABP expression and what effect such expression has on the antioxidant activity of L-FABP in CRL-1548 hepatoma cells. Clofibrate served to upregulate L-FABP expression while MK886 and GW9662 were employed to inhibit L-FABP expression. The principal findings revealed that clofibrate treatment enhanced L-FABP mRNA stability and transcription, which resulted in increased L-FABP levels, while MK866 and GW9662 reduced these levels. We also demonstrated that increases in L-FABP levels were associated with reduced cytosolic reactive oxygen species (ROS), while L-FABP siRNA knockdown resulted in a decrease in L-FABP expression and an associated increase in ROS levels. The antioxidant mechanism of recombinant rat L-FABP in the presence of a hydrophilic (AAPH) and lipophilic (AMVN) free radical generators was also evaluated. Recombinant rat L-FABP was produced in E. coli and its amino acid sequence was confirmed by MALDI QqTOF MS. Antioxidant activity was assayed using the thiobarbituric acid method. Ascorbic acid served as a positive control for the AAPH reaction while α-tocopherol was used as a positive control for the AMVN reaction. The antioxidant activity of recombinant L-FABP was greater when free radicals were generated with AAPH than AMVN. Oxidative modification of L-FABP included up to five methionine oxidative peptides with a total of 80 Da mass shift compared to native L-FABP. These findings suggest that the mechanism of L-FABP’s antioxidant activity involved the reaction of methionine with free radicals. In conclusion, L-FABP expression is regulated by PPAR agonists and antagonists through transcription and mRNA stability. Moreover, methionine residues appear to play an important role in the antioxidative activity of L-FABP.

Background: In breast cancer patients, the administration of Trastuzumab and Doxorubicin is associated with an increased risk of cardiotoxicity. The aim of the study was to determine if the antioxidant probucol would be useful in attenuating this drug induced cardiotoxicity. Methods: In an acute murine model of chemotherapy induced cardiomyopathy, wild-type C57Bl/6 mice received one of the following regimens: (1) control; (2) doxorubicin; (3) trastuzumab; (4) dox+trastuzumab; (5) probucol; (6) probucol +dox; (7) probucol+trastuzumab; (8) probucol+dox+trastuzumab. Serial murine echocardiography with tissue Doppler imaging was performed daily. Histological and biochemical studies were conducted at day 10 of the experiment. Results: Mice treated with prophylactic probucol demonstrated minimal cardiotoxicity compared with those treated with doxorubicin+trastuzumab. Survival rate was only 27% at day 3 of the experiment in the doxorubicin+trastuzumab group compared to 82% of mice receiving probucol+ doxorubicin+trastuzumab. Survival, apoptosis and histological remodeling were preserved in mice prophylactically treated with probucol following the administration of trastuzumab+doxorubicin. Conclusion: The synergistic cardiotoxicity of trastuzumab plus doxorubicin is attenuated by the antioxidant probucol.

Wheat bran contains a diverse collection of macronutrients, micronutrients and bioactive components, including those thought to have an important role in reducing the risk of many chronic diseases. The complication of wheat bran as a functional food relates to its high insoluble fibre content, which renders bran and its constituent bioactives largely indigestible, and hence with limited bioavailability. The main objective of this thesis research was to evaluate the effects of heat treatments of branon the antioxidant activity and chemical composition of the bran. Presumably, if the solubility of wheat bran can be enhanced by pre-treatment, its biological impact associated with its fibre and resident phytochemicals would also be enhanced. Compared to untreated bran, freeze dried water soluble extracts of thermally treated bran had substantially enhanced levels of antioxidant activity and signficantly increased concentration of a very broad spectrum of bran bioactive constituents including phenolics, minerals, phytate, B vitamins, and non-starch polysaccharide fibre compounds. Results taken together point to the development of novel wheat bran and extracts with considerable commercial potential for whole grain food use and a variety of nutraceutical applications far beyond what may be possible with whole grain wheat or normal bran. Outcomes of the research highlight the conclusion that the nutritional and functional food benefits of normal wheat bran probably represent a fraction of its potential due to the limited digestibility of wheat bran, which in turn, limits the bioavailability of its fiber and constituent bioactive compounds.

Rosa roxburghii, also known as "Burr Rose" or "Chestnut Rose", originated in southwest China and was introduced to the botanic garden in Calcutta around 1824. It was named after William Roxburgh who was the superintendent. The extract of fruit of the Rosa roxburghii plant is the base ingredient of a range of products that is commercially sold under the Cili Bao label. The extract is composed of a wide range of substances of nutritional value, in particular a relatively high amount of antioxidants such as ascorbate and plant phenols. It has been reported before that supplementation with the fruit extract resulted in increased red blood cell superoxide dismutase, catalase and the reduced form of glutathione. An enhancement of the antioxidant status could contribute to the protection against several diseases where oxidative stress is a major factor in the pathology, such as atherosclerosis, cancer and immunity stress. Several anecdotal reports with little (published) scientific support claim that human supplementation of the Rosa roxburghii extract to the diet has a protective effect against several diseases, including the above mentioned. Medicinal and herbal plants are used in large sections in developing countries for primary care and there is now also an increase in the use of natural therapies in developed countries. However, plant extracts can also consist of anti-nutritional and possible toxic components, such as oxalic acid and nitrates, which could express cytotoxic and genotoxic activities. Therefore, understanding the health benefits but also the potential toxicity of these plants is important. The objective of this study was to investigate the beneficial properties of Rosa roxburghii extract from an antioxidant potential perspective and in particular to investigate the safety of the product for human consumption. For this purpose in vitro evaluation of the cellular toxicity, mutagenicity and genotoxicity was performed. In addition, specific biochemical parameters relating to the antioxidant status of the product, i.e. antioxidant capacity, oxidative stress prevention and glutathione redox state profiles were investigated in vitro as well as in vivo. The results indicated that Rosa Roxburghii fruit extract was not mutagenic when tested with Salmonella typhimurium strains TA 98, TA 100 and TA 102 in the Ames test. The results, however, pointed towards an antimutagenic effect of the extract in these strains against metabolic activated mutagens 2- acetylaminoflurorene (2-AAF) and aflatoxin B1, and the direct-acting mutagen, methanesulfonate (MMS). In primary rat hepatocyte, Rosa roxbughii extract did not elicit double or single strand DNA damage and cell viability loss using the single cell gel electrophoresis (Comet assay), lactate dehydrogenase leakage test or the mitochondria1 conversion test of MTT to formazan (MTT test). Again the opposite effect was observed: pre-treatment of hepatocytes with Rosa roxbughii extract significantly reduced the effect of oxidative stress-induced cellular- and genotoxicity. These results point to a protective effect against oxidative stress which is reflected in an increase of the antioxidant capacity and glutathione redox state (GSH/GSSG) in vitro (lymphoblasts) and in vivo (humans) reported in this study. This study underlines the previously suggested potential of this plant extract as a natural and safe antioxidant supplement. / Thesis (M.Sc. (Biochemistry))--North-West University, Potchefstroom Campus, 2004.

Selenenic acids and other organoselenium compounds are important both in organic and biochemistry. In organic chemistry, syn-elemination of selenoxides is used to prepare alkenes, giving a selenenic acid by-product. In biochemistry, selenocysteine is catalytically active in a variety of selenoenzymes, which have antioxidant properties, and is oxidized to a selenenic acid intermediate. For example, glutathione peroxidase (GPx) plays a role in fighting oxidative damage by catalyzing the reduction of hydroperoxides. Previous studies have shown that the lighter chalcogen analogue of selenenic acid, sulfenic acid, is a powerful antioxidant and that the known antioxidant activity of garlic is attributable to the 2-propenesulfenic acid derived from the compound allicin. This has prompted questions concerning the role of selenenic acid in the antioxidant activity of organoselenium compounds. In order to study the physiochemical properties of selenenic acids –a functional group about which little is known—and to evaluate their potential as antioxidants, a persistent selenenic acid is needed. Herein, the model compound, 9-triptyceneselenenic acid, is prepared by a previously reported procedure and a new pathway is designed, such that its properties and reactivity can be studied. The oxidation of thiols is important in cell signalling, leading to the disulfide bonds implicated in post-translational modification, among other biological roles. While this reaction is presumed to occur through the reaction of thiol with an oxidant that forms sulfenic acid, and from a subsequent reaction of sulfenic acid with another thiol, sulfenic acids are so reactive that they are not usually seen as intermediates. Given the stability of the 9-triptycenesulfenic acid previously synthesized, preliminary kinetic study of the oxidation of 9-triptycenethiol to its corresponding sulfenic acid is made possible.

Liver fatty acid binding protein (L-FABP) binds and translocates many lipophilic substrates within the cytoplasm including long chain fatty acids. Moreover it was reported that L-FABP possesses antioxidative properties within hepatocytes. However, the mechanism of L-FABP’s antioxidative activity remains to be determined. Peroxisome proliferator activated receptor (PPAR) agonists and antagonists can regulate L-FABP levels. However, it needs to be investigated how PPAR agonists and antagonists regulate L-FABP expression. And whether the altered expression of L-FABP by these agents will affect its antioxidative properties within hepatocytes remains unclear. In this thesis we employed clofibrate (PPARα agonist), MK886 (PPARα antagonist), and GW9662 (PPARγ antagonist) to elucidate the mechanism whereby PPAR regulate L-FABP expression and what effect such expression has on the antioxidant activity of L-FABP in CRL-1548 hepatoma cells. Clofibrate served to upregulate L-FABP expression while MK886 and GW9662 were employed to inhibit L-FABP expression. The principal findings revealed that clofibrate treatment enhanced L-FABP mRNA stability and transcription, which resulted in increased L-FABP levels, while MK866 and GW9662 reduced these levels. We also demonstrated that increases in L-FABP levels were associated with reduced cytosolic reactive oxygen species (ROS), while L-FABP siRNA knockdown resulted in a decrease in L-FABP expression and an associated increase in ROS levels. The antioxidant mechanism of recombinant rat L-FABP in the presence of a hydrophilic (AAPH) and lipophilic (AMVN) free radical generators was also evaluated. Recombinant rat L-FABP was produced in E. coli and its amino acid sequence was confirmed by MALDI QqTOF MS. Antioxidant activity was assayed using the thiobarbituric acid method. Ascorbic acid served as a positive control for the AAPH reaction while α-tocopherol was used as a positive control for the AMVN reaction. The antioxidant activity of recombinant L-FABP was greater when free radicals were generated with AAPH than AMVN. Oxidative modification of L-FABP included up to five methionine oxidative peptides with a total of 80 Da mass shift compared to native L-FABP. These findings suggest that the mechanism of L-FABP’s antioxidant activity involved the reaction of methionine with free radicals. In conclusion, L-FABP expression is regulated by PPAR agonists and antagonists through transcription and mRNA stability. Moreover, methionine residues appear to play an important role in the antioxidative activity of L-FABP.

Background: In breast cancer patients, the administration of Trastuzumab and Doxorubicin is associated with an increased risk of cardiotoxicity. The aim of the study was to determine if the antioxidant probucol would be useful in attenuating this drug induced cardiotoxicity. Methods: In an acute murine model of chemotherapy induced cardiomyopathy, wild-type C57Bl/6 mice received one of the following regimens: (1) control; (2) doxorubicin; (3) trastuzumab; (4) dox+trastuzumab; (5) probucol; (6) probucol +dox; (7) probucol+trastuzumab; (8) probucol+dox+trastuzumab. Serial murine echocardiography with tissue Doppler imaging was performed daily. Histological and biochemical studies were conducted at day 10 of the experiment. Results: Mice treated with prophylactic probucol demonstrated minimal cardiotoxicity compared with those treated with doxorubicin+trastuzumab. Survival rate was only 27% at day 3 of the experiment in the doxorubicin+trastuzumab group compared to 82% of mice receiving probucol+ doxorubicin+trastuzumab. Survival, apoptosis and histological remodeling were preserved in mice prophylactically treated with probucol following the administration of trastuzumab+doxorubicin. Conclusion: The synergistic cardiotoxicity of trastuzumab plus doxorubicin is attenuated by the antioxidant probucol.