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[en] Complete text of publication follows. Ascorbic acid, AsA (vitamin c), has been widely studied as an antioxidant or as an initiator of some technological processes, for example polymerization or nanoparticles formation. AsA can be easily oxidized to ascorbyl radical, in the first stage, and to dehydroascorbic acid, DHA, in the second stage. It has been found that several different ascorbyl radicals are formed during AsA oxidation but the main radical exists as the anion with the unpaired electron delocalized on a highly conjugated tricarbonyl system. Absorption spectrum of ascorbyl radical shows two bands with maxima at 300 and 360 nm, however only that at 360 nm is proportional to the dose and thus this wavelength was chosen for observations. We studied the oxidation of AsA by the following oxidizing radicals generated by the pulse radiolysis method ·OH, (SCN)2-·, Cl2-·, N3· and NO2·. The observed dependence of the yield and the formation rate of the AsA radical on the reduction potential of the oxidizing radical is discussed. The results obtained in water are compared with those obtained with AsA enclosed in the water pools of reverse micelles formed by AOT in n-heptane or by Igepal CO-520 in c-hexane. Somewhat surprising observation of different ascorbyl radical in pulse irradiated reverse micelles containing DHA is also commented.
[en] Eight compounds were identified in ethanol extracts prepared from the branches of C. turczaninowii. The compounds, besides 5 and 6, were isolated for the first time from this woody plant. Pyracrenic acid (4) and quercitrin (8) showed potent DPPH free radical scavenging activities with SC50 values of 55.2 and 62.4 μM, respectively, where ascorbic acid (SC50 43.5 μM) was used as a positive control. Compounds 4, 5, 6 and 8 showed strong activities in ABTS+ radical scavenging assay, with SC50 values of 34.1, 42.1, 45.8 and 29.6 μM, respectively. These activities are comparable in potency to ascorbic acid (SC50 31.6 μM). Based on these results, C. turczaninowii extracts are expected to be useful antioxidative agents, potentially applicable in food or cosmetic industries, based on the results of further studies. Korean hornbeam Carpinus turczaninowii is a deciduous woody plant belonging to the family Betulaceae. This flora is endemic to Korea, and can reach a height of 15 m. In the autumn, the fallen leaves of C. turczaninowii display a beautiful orange-red color and the tree is commonly used for bonsai in Korea. The wood is very hard, dense and fine textured, and has been used for making agricultural tools and furniture. Previous chemical investigation on this plant indicated only the existence of flavonoids such as naringenin and quercetin glycosides from the leaves. We have recently reported the isolation diarylheptanoids possessing anti-inflammatory activities from the ethanol extract of C. turczaninowii
[en] A simple and rapid spectrophotometric method for the determination of ascorbic acid is proposed. Ascorbic acid reduces iron (III) to iron (II) which forms a red colored complex with dimethylglyoxime in the presence of pyridine. The absorbance of the resulting solution is measured at 514 nm and a linear relationship between absorbance and concentration of ascorbic acid is observed up to 14 μg ml-1. Studies on the interference of substances usually associated with ascorbic acid have been carried out and the applicability of the method has been tested by analysing pharmaceutical preparations of vitamin C
[it]Si propone un rapido e semplice metodo spettrofotometrico per la determinazione dell'acido ascorbico. L'acido ascorbico riduce il ferro(III) a ferro(II) che forma con la dimetilgliossima, in presenza di piridina, un complesso colorato in rosso. L'assorbanza della soluzione risultante e' misurata a 514 nm e si ottiene una relazione lineare tra assorbanza e concentrazione dell'acido ascorbico fino a 14 μg ml-1. Si sono condotti studi sugli interferenti usualmente associati all'acido ascorbico ed e' stata valutata l'applicabilita' del metodo all'analisi di preparati farmaceutici di vitamina C
[en] The role of ascorbate as an antioxidant in the prevention and cure of disease that result from free radicals has been of considerable interest and controversy lately. As an antioxidant, we can expect it to protect against radiation damage caused by free radicals that are produced when radiation, especially sparsely ionizing radiation, interacts with living tissues. The plasma and whole blood concentration of ascorbate was analyzed before and just after the radiation therapy for the purpose of estimating the consumption amount of ascorbate during radiotherapy. Whole blood ascorbate was decreased from 1.82 mg/dl to 1.58 mg/dl, plasma ascorbate was decreased from 1.13 mg/dl to 1.08 mg/dl, and urine ascorbate was decreased from 9.33 mg/dl to 6.96 mg/dl after radiotherapy. Although the difference was not significant statistically, further human study should be followed to define the role of ascorbate as a radioprotector
[en] Full text:Pollution of atmosphere air and lands is happening with transportation to be felt. Atomic energy enterprises throws up to the air radionuclide of heavy metals, which is more dangerous such as- 551Cr, 554Mn, 555Fe, 559Fe, 558Co, 660Co, 665Zn, 990V, 991V, 995Zn, 999Mo, 103Ru, 106Ru. These heavy metals don't create so threat according to their chemical structure, as their radioactivity. Air, water, land does not lose the low-activity, will be felt for years in the soil remained at the level of radioactive background by increasing the level of radiation is also increased. Life activity of plants undergone to the influence of the harmful geese in the atmosphere air is violated. Even small amounts of radiation and toxic ingredients influence to the plants negative. Thus, plants carry out the function of the indicator. For more information about the extent of human impact on plants recently test-systems are used in the search. As a result of analyzes of physiological active compounds that are studied, for example, pigments entozoan stress in plants are collected as an answer to the condition. Ascorbic acid takes part in cell immunities and plants to increase the sustainability of unfavorable conditions.
[en] Recovery of platinum group metals and transition element such as palladium, rhodium, ruthenium and technetium in SNF are becoming important issues around the world, due to their economic values of noble metals and also radio toxicity of technetium. Precipitation is reportedly one of the possible methods to recover platinum group metals. Especially, an ascorbic acid is reviewed as a promising precipitant for palladium recovery. Also some successful results were reported with relation to the selective precipitation of palladium ion in the simulated fission product solution. However, since most of them are qualitative results with limited data and considering that the purity of noble metal is crucial for its value, quantitative data depending on the various experimental variables are also required. In this study, precipitation behaviors for palladium by ascorbic acid were investigated to obtain the qualitative precipitation data depending on the coexisting ions and other operation variables
[en] The present study was conducted to evaluate the quality of sun dried tomatoes in comparison with fresh tomatoes. Fresh fully ripen tomatoes were washed and cut in thin slices with sterilized stainless steel knife and divided into two lots, one was taken as control and other was dipped in 3% potassium meta bisulfite solution for 5 minutes. The samples were spread over stainless steel trays covered with muslin cloth and kept in solar dehydrator for 5 days at 55 +- 2 deg. C. The physicochemical analyses were carried out in both dried and fresh (control) tomatoes. They were also analyzed microbiologically for bacterial and fugal count. Results showed that sun dried tomatoes are microbiologically safe. The values of moisture content and vitamin C of fresh and sun dried tomatoes statistically differ from each others at probability level of 5 %. The nutrient which is highly affected by sun drying is vitamin C. In fresh tomatoes it was 32.5 mg/100 g which is reduced to 24.6 mg/100 g after sun drying and further reduced to 15.86 mg/100 g during three months storage. The moisture content of the fresh tomatoes was 94.4% which decreased to 8.15% after drying, and then slowly increased to 9.95% in the three months storage. Statistically no major difference was found in the other nutrients during storage, which indicates that sun drying is nutritionally and microbiologically safe and can be used to preserve tomatoes and other fruits and vegetables for off season use. (author)