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Magnesium participates in numerous enzymatic reactions in the human body and it has essential role in the maintenance of the antioxidant system. Since several magnesium compounds have been applied in the food and pharmaceutical industry, our purpose was to investigate the antioxidant/free radical scavenging activity of some magnesium compounds in vitro. The antioxidant/prooxidant effect of inorganic salts (e.g. MgCl2) and organic complexes (e.g. Mg-gluconate) was determined with chemiluminometric method (H2O2/•OH-microperoxidase-luminol) and heme mediated LDL oxidation (LDL-heme-H2O2 ) in vitro. It has been stated that the chemiluminescence method and LDL (low density lipoprotein) oxidation measurement is applicable in the presence of magnesium salts and complexes. Most of the compounds do not generate free radicals and the antioxidant/prooxidant effect depends on the quality of the ligand and the concentration. In the concentration range used, some representatives of the magnesium compounds (MgO, Mg-gluconate, Mg-polygalacturonate) investigated showed radical generating activity measured with chemiluminescence method, whereas the LDL oxidation has not been affected. Magnesium citrate and malate proved to be antioxidants measured with the chemiluminescence method and they slightly accelerate the LDL oxidation in the system and in the concentration applied. In vitro some of the ligands of magnesium compounds showed antioxidant activities.
Dietary intake of polyphenols and vitamins before surgery may have beneficial effect on survival of the patients. Table beet (Beta vulgaris L. var. rubra) contains bioactive agents, which have a wide range of different physiologic effects. These agents have beneficial antioxidant properties. The aim in the present study was to determine the gut protecting properties of bioactive substances of table beet in a model of ischaemic-reperfusion injury of the rat liver. Chemiluminescent intensity, H-donating ability, reducing power and free SH-group concentracion were determined by luminometry and spectrophotometry in duodenum and plasma. Lyophilized table beet increased significantly the free radical scavenging property of the plasma measured by chemiluminometry. Other antioxidant parameters of the plasma increased in rats fed table beet diet, and change in reducing power was significant. Beneficial effect of the treatment was found in changes of total scavenger capacity of the duodenum during ischaemia-reperfusion injury. H-donating ability and reducing power of the gut decreased in the table beet-fed group during ischaemia-reperfusion compared to normal group with ischaemia-reperfusion. Based on these data, it can be concluded that table beet can protect the entire body from the oxidative damage caused by ischaemia-reperfusion of the liver, but the effect of table beet treatment on gut mucosa needs further investigation.
Herbal teas may be effective in adjuvant therapy for the prevention of complications of diabetes mellitus II. Agrimoniae herba, Betulae folium, Bursae pastoris herba, Foenigraeci semen, Galegae herba, Maydis stigma, Taraxaci radix, Phaseoli fructus sine seminibus, Urticae folium, and their teas were analysed by ICP-OES for element content. Concentration of the elements of crude drug samples obtained are in good agreement with the average concentrations of plants, although some significantly high concentration has been found for manganese (893 mg kg-1), zinc (275 mg kg-1) and iron (492 mg kg-1) in Betulae folium, for copper (41.2 mg kg-1) in Galegae herba, for iron (2692 mg kg-1) in Taraxaci radix, for calcium (41210 mg kg-1) and magnesium (6275 mg kg-1) in Urticae folium. The common characteristic feature of crude drugs is the relatively high concentration of chromium (0.8-16.3 mg kg-1). Ion concentrations of teas are relatively low. The quantities of metal ions do not cover the daily needs, nevertheless, they may be important as food supplements. According to U.S. Recommended Dietary Allowances (RDA), the following teas are good sources: Agrimoniae herba for chromium, Betulae folium for manganese, Taraxaci radix for copper and chromium, Urticae folium for potassium and calcium. The dissolution of elements from plant drugs varies: potassium (22.5-74.7%), sodium (1.9-60.5%), calcium (6.6-28.1%), magnesium (12.3-52.5%) and copper (3.7-51.4%) are readily dissolved. The dissolution of manganese (6.8-32.3%) and of zinc (0-31%) is lower. The dissolution of chromium from Agrimoniae herba (9.55%) is significantly higher, while the dissolution ranges from other plant drugs are between 0-5.9%.
In general, biologically active polyphenolic compounds have indirect lipid lowering effects, antioxidant properties and they can also eliminate the accumulated toxic metal elements in the liver in cases of hyperlipidemy. Because of all these, we studied the effect of Beiqishen tea on altered lipid metabolisms, redox parameters and on liver metal contents. Although it was expected, there was not any liver protecting activity of the Beiqishen tea extract in the hyperlipidemic rat model, which was proved by biochemical and morphological studies. The reason for our expectation was the significant polyphenol content of Beiqishen tea. Although, the detoxifying activity of tea polyphenols could be observed in hyperlipidemy, at the same time toxic metal element content (As, Mo, Ni, Pb and Cr) of the tea infusion accumulated in the liver in both normo- and hyperlipidemic rats.
The different methods of making herbal tea used in various cultures may decrease the efficiency of herbal tea, therefore the purpose of the present study was to examine the changes in antioxidant activity and metal ion concentration in aqueous extracts of “Tieguanyin Stomach Tea” obtained with different steeping times. Partial phytochemical examination, element analysis, and the determination of antioxidant properties were carried out. High Al, Cr, Mn, Ni, Pb and Ti content was observed in the tea drug. Aqueous extracts of the drug sample showed H-donor activity, reducing power and scavenging activity, depending on the steeping time and concentration. According to our findings, 5-min steeping was the least effective and redox parameters of the aqueous extracts did not change considerably between 15 and 120 min of steeping time.
The effect of polyphenolic bioactive substances, especially resveratrol (12.03 mg l−1), of an often consumed Hungarian red wine was investigated in a short term rat experiment. Male young Wistar albino rats were treated with high volumes of red wine (matching one bottle of wine/day for a 85 kg man) (N=5) and another alcoholic drink of the same alcohol concentration (N=5), corresponding to the circumstances of alcoholism, and 5 rats were in the control group. A total of 7 routine laboratory parameters were measured from the sera by kits.
The changes of redox homeostasis (H-donor activity, induced chemiluminescence, diene-conjugates, GSHPx) were studied in blood plasma and/or in liver homogenates by spectrophotometric and luminometric methods. Transmethylation property of the liver was measured by overpressured layer chromatography (OPLC) technique. It was proven with in vitro OPLC analytical study that resveratrol reacted with methyl groups, and resveratrol was demonstrated to influence transmethylation processes as well as redox homeostasis. Red wine compounds do not protect from the harmful effects of alcohol, and even by high doses of resveratrol, the liver further deteriorates and the negative effect of alcohol increases. It has been confirmed that high doses of resveratrol do not provide protection against liver damage in those suffering from alcoholism.
The metabolic alteration of fatty liver causes significant changes in the composition of bile fluid secreted by epithelial liver cells. These processes include both organic molecular and inorganic ion content changes in bile juice as well. In this work ion concentration differences of bile fluid in experimental hyperlipidemic rats compared to normal ones were monitored. Fatty liver in young male Wistar albino rats was induced by 2% cholesterol, 20% sunflower oil and 0.5% cholic acid added to the normal food and 3% alcoholic water was administered to rats for 9 days. The development of hyperlipidemy was detected by measuring serum parameters and fatty liver was proved by morphological investigations. The ion concentrations of bile fluid samples were determined by ICP-OES (inductively coupled plasma optical emission spectrometry). The bile fluid samples were digested with a mixture of HNO3 and H2 O2 . The results show that the concentration of calcium and phosphorus in bile juice increased significantly in hyperlipidemic rats compared to the control. Significant concentration changes have also been detected for chromium and manganese. The changes in metal ion metabolism also point to the damage of liver cells owing to metal complex evacuation.
Chronic gastrointestinal diseases are mostly attached to inflammation as well as modified redox homeostasis. These diseases cause remarkable health problems in the northern regions of Europe, but as the climate becomes colder, the harvesting of fruit with notable antioxidant content becomes harder. In these regions, polyphenol-rich berries, which can handle the climate, may have pivotal role in the diet. The aim of our study was to determine antioxidant properties of watery extracts of blueberry, Vaccinium corymbosum L., bilberry, V. myrtillus L., and lingonberry, V. vitis-idaea L. that may have role in the redox homeostasis of the gastrointestinal region. Data show that these berries notably inhibit the lipid peroxidation, underpinned by reducing power, total polyphenol and ascorbic acid content. The study demonstrates that berries can play a remarkable role in northern European diet, especially when redox homeostasis is imbalanced.
Abstract
Non-alcoholic fatty liver disease is one of the most common chronic liver diseases with unclarified pathomechanism and without evidence-proven therapy. Dietary polyphenols, targeting oxidative stress, are at the center of investigations. Our aim was to examine the effects of a polyphenol rich extract on metal element homeostasis and transmethylation ability in non-alcoholic fatty liver model. A ten-day rat model was used (control group, hyperlipidemic group with fat-rich diet, hyperlipidemic group with fat-rich diet and polyphenol supplementation, N = 8 in each group). The hyperlipidemic diet increased the concentration of the majority of the elements with significantly higher contents of B, Co, Cu, Fe, Mg, Mn, Na, Ni, P, Se, Si, and Zn in the liver. Further elevation of Al, Pb, and Sn concentrations could be observed in polyphenol supplemented animals. The polyphenol supplement unexpectedly decreased the transmethylation ability of the liver (132.00 vs. 114.15 vs. 92.25 HCHO μg g−1) further. The results emphasize the possible role of altered metal and non-metal element concentrations and decreased transmethylation ability in the pathomechanism of fatty liver disease. Dietary supplementation with natural compounds may have undesirable effect as well, there is the necessity to improve the efficacy of polyphenol formulations because of their low oral bioavailability.
ICP-OES (inductively coupled plasma optical emission spectrometry) was used to determine the element content of red wines. Development of the method involves various procedures of sample handling as well as repeatability and reproducibility measurements. Measurements were made for the following 16 elements: Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, P, Sr and Zn. The relative standard deviation of repeatability ranged from 0.41% (potassium) to 27% (cadmium) and that of reproducibility varied between 0.73% (boron) to 52% (cobalt). Recovery of the elements was determined by standard addition with results ranging from 90.6% (phosphorus) to 116.2% (boron). After that, 15 red wine samples were measured. Significant differences were found in the Al, B, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, P, Sr and Zn (P<0.001) concentration of wine samples. Correlation studies revealed parallel changes in phosphorus-potassium, phosphorus-magnesium and zinc-manganese concentrations (r=0.857, 0.875, 0.838). According to principal component analysis, measurements of zinc-, sodium-, boron-, copper- and strontium content gave almost the same results as obtained with 16 different elements. According to a two dimensional non-linear map of absolute values of principal component analysis, wines from Szekszárd and Eger could be differentiated, whereas the analysis of wines from Villány, the Mátra Mountains and Lake Balaton showed overlapping results.
