The major stilbene glycoside, 2,3,5,4′-tetrahydroxystilbene 2-O-β-d-glucopyranoside (PM-SG), was purified from the ethanol extract of the roots of Polygonum multiflorum Thunb. In order to better understand the antioxidation mechanism of PM-SG, PM-SG was allowed to react with H2O2, and the reaction products were isolated by chromatography and identified by liquid chromatography–mass spectrometry and nuclear magnetic resonance. The formation of a major product, a dimer of PM-SG, indicated that the C5 phenolic group on PM-SG was more reactive toward the hydrogen abstraction.
The root of Polygonum multiflorum Thunb is an important medicinal plant and has been used for over several thousand years in China. A major stilbene glucoside, 2,3,5,4′-tetrahydroxystilbene 2-O-β-d-glucopyranoside (PM-SG) is known as the active antioxidant of this plant material. In the present study, structural determination of the oxidation products from the reaction of PM-SG with H2O2 was carried out in order to allow better understanding of the antioxidant mechanism of this compound.
Two general spectrophotometric methods were used to analyze alkylresorcinols and determine their total amounts in rye, wheat and cereal products. Alkylresorcinols were extracted from rye bran with acetone, hydrogenated to obtain a mixture of saturated homologues, subjected to preparative high-performance liquid chromatography (HPLC) to obtain individual species with the side chain ranging from 15 to 25 carbon atoms, and finally quantified by colorimetric reaction with the diazonium salt Fast Blue B (2-methoxy-4-nitoraniline) and by HPLC. The intensity of the reaction between the same weight amounts of homologues with Fast Blue B decreased in the order C15:0 > C17:0 > C19:0 > C21:0 > C23:0 > C25:0. It was demonstrated that calibration curves based on molecular concentration instead of weight amount of the particular homologues were characterized by the same regression equation and showed an acceptable linearity in the range of 5–30 nmol of homologue in a sample. This confirmed that the colorimetric reaction of alkylresorcinols with Fast Blue B is independent of the length of the aliphatic side chain. Total alkylresorcinols were accordingly determined in cereal grain materials. Two extraction systems (acetone and ethyl acetate) were used. The results of the colorimetric method and those calculated from calibration curves based on the weight amounts of the homologues C15:0 and C19:0 were different. In contrast, the results calculated from the calibration curves based on the mole amounts of the particular homologues were very similar or even identical.
The color and intensity of the reaction between alkylresorcinols and the diazonium salt Fast Blue B was independent of the length of the alkyl side chain. This feature could be helpful for the differential determination of the phenolic and resorcinolic lipids present in biological samples. Most cereal material and products contain a mixture of various homologues that is characteristic not only of the source (rye, wheat, triticate, barley), but also of the variety and the growth conditions. Therefore, for accurate calibration curves independent of the composition of homologues, they should be prepared on the basis of the mole fraction of the alkylresorcinols present, similar to the quantitation of phospholipids via phosphorus determination. This procedure will also allow the direct comparison of their amounts in different sources of alkylresorcinols. Nevertheless, simultaneous determination of the homologue composition in the samples is desirable (e.g., by reverse-phase high-performance liquid chromatography) as different homologues may have various impacts on the biological activity of alkylresorcinol
Fatty acid and lipid compositions from different tissues of Galilee Sardine important in the diet of East Mediterranean inhabitants were examined. More than 50 fatty acids were detected in freshwater fish sardines (Mirogrex terraesanctae). The muscles of this fish contained a high level of omega-3 fatty acids.
Sardines are an important commercial freshwater fish species. The lipids of different sardine tissues, fished in Lake Kinneret (the Sea of Galilee), were examined. The benefits of including omega-3 fatty acids in the diets of humans are well documented. Fatty acids play a major role in the functioning of the immune system and the maintenance of all hormonal systems in the body. Sardines (Mirogrex terraesanctae) are an excellent source of both docosahexaenoic acid and eicosapentaenoic acid. Sardines are one of the most popular treats in Israeli homes.
The effect of industrial effluent on the oxidative stress of Puntius sophore (punti fish) tissue was investigated. Oxidative stress was determined by measuring lipid peroxide (LPO) and fatty acid profile as bioindicators. Punti fishes were collected from a river where textile mill effluent is discharged, as well as from fresh water as controls. Homogenized tissues were used for LPO, fatty acid, total cholesterol, phospholipid and protein measurements. LPO levels in both hepatic and extrahepatic tissues increased significantly in the industrial-effluent-exposed fish tissue as compared with those of the freshwater fish (control versus industrial-effluent-exposed fish: hepatic tissues, 54.0 ± 5.0 and 89.0 ± 9.0 nmol/mg protein; extrahepatic tissues, 52.0 ± 9.0 and 270 ± 16.0 nmol/mg protein). Five biologically important polyunsaturated fatty acids, docosahexaenoic acid (C22:6n-3), docosapentaenoic acid (C22:5n-3), eicosapentaenoic acid (C20:5n-3), arachidonic acid (C20:4n-6) and linolenic acid (C18:3n-3), significantly decreased, and saturated fatty acid, stearic acid (C18:0), significantly increased in the effluent-exposed fish tissue than those of the freshwater counterpart. Cholesterol level of industrial-effluent-exposed punti fish was 1.5-fold lower than those of the freshwater fish. This study thus suggests that industrial effluent poses a threat, at least partially, through oxidative insult to fish tissues.
The study reported here indicates that fish exposed to industrial effluent induce a greater risk of oxidative stress with a resultant increased level of lipid peroxides. Consequently, if these fish with increased oxidative species are ingested by humans, they may cause physiological problems such as cardiovascular diseases and cancer involving disruption of cellular homeostasis. Therefore, an investigation about the oxidative stress of fish tissue in terms of lipid peroxidation could be of considerable significance in Third World countries where consumers remain unaware about the quality of the fish sold in the local markets and are ignorant of the oxidative stress and its consequences. The information of the present investigation may help in providing some preliminary information about the impact of unplanned industrialization on aquatic ecosystem.
Many nontraditional vegetable oils have been introduced to the market relatively recently, and therefore data on their antioxidant potential have not been reported. Such data are of importance for the evaluation of the nutritional and health impact of these oils. Antioxidant properties of the methanolic extracts of cold-pressed oils such as soybean, sunflower, rapeseed, corn, grapeseed, hemp, flax, rice bran and pumpkin were studied. The methanolic extracts were obtained by solid phase extraction and separation, and identification of phenolic acids was conducted by high-performance liquid chromatography. The obtained extracts were characterized by different scavenging activities of 2,2-diphenyl-1-picrylhydrazyl radicals. The best antioxidant properties were displayed by the extract from hemp, pumpkin and rapeseed oils. The highest content of total phenolic compounds was determined for the pumpkin and hemp oils – about 2.4 mg/100 g. Rapeseed oil was characterized by the highest content of phenolic acids, especially sinapic acid. To better understand the beneficial effects of antioxidant compounds in vegetable oils, it is important to investigate whether these bioactive compounds in oils differ in their reactions with free radicals.
Phenolic compounds have been reported to be present in all vegetable oils, which is very important for the oxidative stability of the polyunsaturated fatty acids of these oils. Additionally, edible oils rich in natural antioxidants may play a role in reducing the risk of chronic diseases. Thus, the oils examined may be used in different food applications to provide nutrition and health benefits.
Synthetic chemical compounds, such as organochlorines, are known for their persistence and toxicity. The diet represents, for the general population, the main route of exposure to these contaminants, because organochlorines in food constitute a significant health risk, and olive oil has a high consumption rate among people of the producing countries; the control of residues in olive oil is of great importance. In this study, the presence of residues of hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCBs) was assessed in samples of extra-virgin olive oil from Tuscany (central Italy). The analyses revealed the presence of HCB in concentrations below the detection limit; DDT and PCBs were instead present in all samples tested, and PCB concentrations were always higher than those of DDT, from 1.24 to 29.35, and from 0.01 to 1.83 ng/g wet weight, respectively.
Because organochlorines in food constitute a significant health risk, and olive oil has a high consumption rate among people of the producing countries, the control of residues in olive oil is of great importance. For the first time here, we present data on organochlorine pollution in oil samples collected in Tuscany, and assess the intake ranges of pollutants related to consumption of the oils analyzed. Showing the low contamination levels of Tuscan olive oil, we wish to confirm the high quality of this kind of food lipid.
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