二硫化碳氧化性自由基对生物靶分子损伤机理研究

利用脉冲辐解技术研究了二硫化碳(CS2)被氧化生成的阳离子自由基,以时间分辨瞬态吸收光谱方法获取CS2阳离子自由基的特征吸收谱。同时,研究了CS2阳离子自由基损伤生物靶分子的机理,测定了相关的反应动力学常数。结果发现,CS2阳离子自由基能与DNA、dGMP、酪氨酸和色氨酸反应产生新的产物,在CS2对生物靶分子的氧化损伤中可能起着重要的作用。

鸟嘌呤核苷酸与核黄素氧化性自由基之间的电子转移研究

应用 ２４８ ｎｍ激光光解时间分辨吸收方法，研究了 ２’－鸟嘌呤核苷酸与核黄素氧化性自由基之间的单电子转移机理，给出了电子转移的直接证据。改变溶液的酸碱性，探讨了不同形式自由基之间电子转移的可行性。

新温室气体SF_5CF_3的汇

SF_5CF_3本身不会吸收190nm以上波长的紫外光而发生解离,同时,SF5CF3在大气中非常稳定,和大气中存在量比较丰富的氧化性自由基——O(1D)、·OH、·NO3不发生反应.初步推断SF5CF3在对流层及平流层中不存在与氧化性自由基反应引起的汇.

Antioxidant phenanthrenes and lignans from Dendrobium nobile

To study the antioxidant constituents from the stems of Dendrobium nobile, and to discuss theft structure-activity relationship. Compounds were isolated from a 60% ethanolic extract by various chromatographic techniques and were identified by spectral analysis. The antioxidant activities of compounds were evaluated by DPPH free radical scavenging assay. Five phenanthrenes and four lignans were obtained from the active fractions ofD. nobile. Their structures were identified as fimbriatone （1）, confusarin （2）, flavanthrinin （3）, 2,5-dihydroxy-4,9-dimethoxyphenanthrene （4）, 3,7-dihydroxy-2,4-dimethoxyphenanthrene （5）, syringaresinol （6）, pinoresinol （7）, medioresinol （8） and lirioresinol-A （9）, respectively. Compounds 2 and 6 exhibited more potent DPPH scavenging activities than vitamin C. All the above compounds were reported from this plant for the first time, and compounds 3, 4 and 9 were reported for the first time from the genus of Dendrobiurn. For all phenanthrenes and lignans, an electron-donating methoxyl group in the ortho position to the phenolic hydroxyl group exhibits enhanced antioxidant activities.

Factors Influencing the Effects of Theabrownin in Pu-erh Tea on Scavenging DPPH Radicals

[Objective] This study aimed to explore factors influencing the effects of theabrownin in Pu-erh tea on scavenging DPPH radicals. [Method] Taking Pu-erh tea as main research object, theabrownin in Pu-erh tea from tea piles with different times of mixture, stored for different years and processed by both the old and new techniques were extracted and isolated. And DPPH method was used to study the effects of theabrownin solution and tea liquor on scavenging radicals and their antioxidant activity. [Result] The result showed that the theabrownin content in Pu-erh tea from tea piles with one to four times of mixture revealed a first declining and subsequently rising trend. Under different pH conditions, the rates of DPPH radical scavenging of 1 mg/ml theabrownin solution made from tea piles with different times of mixture decreased gradually with the increase of pH, and all the rates were lower than that of the control vitamin C solution; the rates of DPPH radical scavenging of theabrownin from tea samples stored for different years and produced by different techniques dropped slowly within pH range 3.0-6.0; when pH was higher than 6.0, the rates of DPPH radical scavenging of theabrownin from tea samples produced by both new and traditional techniques in 2001 declined obviously, while the declining trend was not obvious in either the black tea or the Pu-erh tea produced by new technique in 2005. Under different theabrownin concentrations, the rates of DPPH radical scavenging of theabrownin solution made from tea piles with different times of mixture ascended as the concentration increased and the highest rate occurred in tea pile with four times of mixture, reaching up to 46.56%±0.88%; for tea samples stored for different years and produced by different techniques, the rates of DPPH radical scavenging of theabrownin rose gradually with the increase of the theabrownin concentration; the rate of radical scavenging of theabrownin in the black tea ascended obviously and that in Pu-erh tea was decreasing within the concentration range of 0.04 -0.06 mg/ml. At pH6.0, the DPPH radical scavenging ability of theabrownin in 0.1 mg/ml theabrownin solution and tea liquor containing 0.1mg/ml theabrownin from tea piles with different times of mixture ascended with the time of mixture; solution made from tea samples produced by different techniques in different years, the DPPH radical scavenging ability of theabrownin solution and tea liquor followed： Pu-erh tea produced by the new technique in 2001 ﹥ Pu-erh tea produced by the old technique in 2001﹥ Pu-erh tea produced by the new technique in 2005. And the DPPH radical scavenging ability of theabrownin in tea liquor containing 0.1 mg/ml theabrownin was higher than that in 0.1 mg/ml theabrownin Solution made from tea samples either with different times of mixture or produced by different techniques in different years. The above results indicated that many factor influenced the effects of theabrownin on eliminating DPPH radicals, including the time of fermentation, fermentation technique, years of storage, concentration and pH all had great influence on the effects of theabrownin on eliminating radicals. To ensure a good effect on scavenging radicals, it is better to prepare theabrownin at pH6.0 with concentration between 0.08 and 0.1 mg/ml for drinking. [Conclusion] Results of this study provide a basis for developing functional products of theabrownin from Pu-erh tea in the future.

Effect of Cistanoside Compounds on Oxidative Stress and Immunity

Cistanoside compounds were studied as the scavengers of hydroxyl and superoxide anion free radicals with spin trapping ESR method in vitro. Low-temperature ESR technique, experimental technique of immunotoxicology and biochemical method were used to detect the level of reactive oxygen radicals in kidney tissue of rats and SOD level and GSH-Px activity in rat serum. The results indicated that cistanoside compounds could inhibit reactive oxygen free radicals in vitro and prevent and repair the free radical damages for diabetic nephropathy. The experimental data of 揷arbon-particle detection in mouse serum?showed that cistanoside compounds could improve the phagocytotis index of macrophages (Mj) in mice blood and increase the weights of immune organs of mice.

Purification and characterization of novel antioxidant peptides of different molecular weights from mackerel Pneumatophorus japonicus protein hydrolysate

Mackerel （Pneumatophorus japonicus） proteins were hydrolyzed by five proteases： trypsin, papain, neutrase, acid protease, and flavourzyme. The hydrolysate treated by neutrase exhibited the highest antioxidant activity. Response surface methodology （RSM） was employed to optimize the hydrolysis conditions in an effort to obtain a mackerel protein hydrolysate （MPH） with the highest DPPH radical scavenging activity. The MPH was fractioned using a series of ultrafiltration membranes and five fractions, namely, MPH-I （〉10 kDa）, MPH-II （10-2.5 kDa）, MPH-III （1-2.5 kDa）, MPH-IV （0.4-1 kDa）, and MPH-V （below 0.4 kDa）, were obtained. DPPH radical scavenging activity, reducing power, hydroxyl radical scavenging activity, and the lipid peroxidation inhibition capability of these fractions were evaluated. The fractions in molecular weights 〈2.5 kDa （MPH-III, MPH-IV, and MPH-V）, which occupied 93.4% of the total fractions, showed the strongest antioxidant activity; and the antioxidant activities of the three fractions are similar to each other. Using SP Sephadex C-25 and Sephadex G-25 columns, eight fractions were obtained from the MPH （〈2.5 kDa）. The isolated peptide I （1 664 kDa） displayed the highest DPPH radical scavenging activity. Therefore, MPH is a potential source of antioxidant peptides.

Isolation and Characterization of Fucoidans from Five Brown Algae and Evaluation of Their Antioxidant Activity

In this study, we evaluated the chemical property and antioxidant activity of fucoidans isolated from brown algae, Laminaria japonica(LJF), Lessonia nigrescens(LNF), Lessonia trabeculata(LTF), Ascophyllum mackaii(AMF), and Ecklonia maxima(EMF). LJF was less in sulfate content(14.16%) and more in galactose and mannose content(1.08 and 0.68) than the documented early. EMF contained 20%–30% of sulfate and fucose, 0.97 in molar ratio which was lower than that of sulfate to other four fucoidans(1.21–1.41). AMF(162 kDa) and EMF(150 kDa) were the first two largest in molecular weight, which were followed by LJP(126 kDa), LNF(113 kDa) and LTF(105 kDa). The fucoidans isolated these algae showed a wide range of antioxidant activity in vitro. It was found that the reducing power of the isolated fucoidans was positively correlated with their sulfate content and molecular weight. In addition, LNF and LTF at low concentrations exhibited high superoxide and hydroxyl radical scavenging activity. This demonstrated that low molecular weight fucoidans may perform a high antioxidant activity.

Antioxidative Activity of Polysaccharide Fractions Isolated from Tricholoma Matsutake Sing. with Ultrafiltration

Polysaccharides of Tricholoma matsutake Sing. were extracted with boilingwater, followed by precipitating with ethanol. Two membranes of different molecular weight cut-off, namely, 30 kD and 10 kD were chosen with ultrafiltration. The antioxidant activity of the purification polysaccharides was evaluated by various antioxidant assay, including DPPH （l,l-diphenyl-2-picrylhydrazyl） radical scavenging, superoxide anion radical scavenging and hydrogen peroxide scavenging. The scavenging effect on hydroxyl radical and DPPH radical, which may be comparable to Vitamin C, while the scavenging effect on superoxide anion radicals was not obvious.

Antioxidant Activity of Ethanol Extract of Pomegranate Seed

In this study, the ethanol extract of pomegranate seed was prepared and its antioxidant activities were investigated. It was found the total phenolic content in the extract was as high as 41.791 mg GAE/g. And the extract showed high antioxidant activity measured as scavenging of DPPH radicals, hydroxyl radicals. It also exhibited strong antioxidant activity in reducing power and Rancimat test. These results demonstrated Pomegranate seeds could serve as a new source of natural antioxidant.

Antihymolytic and Antioxidant Effects of Medicinal Plant Capparis spinosa L.

Capparis spinosa L. is a traditionally used plant in Algerian folk medicine to treat asthma, rheumatism and other free radicals related disorders such inflammatory. The present study was designated to study the antioxidant activity of aerial and root parts of Capparis spinosa L.. Total polyphenol content was determined, after extraction with solvents in five subfractions; methanol （CE）, Hexan （HE） chloroform （CHE）, ethyl acetate （EAE） and aqueous extracts （AE）, employing the ＂Prussian blue assay＂. The results showed that EAE containing the highest concentration of phenolic compounds and Flavonoids followed by those of CHE of aerial and root parts, repectively. The antioxidant protective effects of extracts were determined by measuring the erythrocyte membrane resistance to free radical-induced. The results demonstrated that all the extracts exhibited a protective effect against t-BHP induced oxidative damages in human erythrocytes, the most potents wer CEs and CHEs with 86.55%, 85.81%, 74.59%, and 68.70%, for aerial and root parts, respectively, which were more effective than used standards： Quercetin （65.46%） and rutin （59.62%）. In order to more clarify the previous antioxidants activity of the extracts through other mechanisms, the iron chelating ability assays were realized. The results showed that the iron chelating ability of Aerial and root extracts were very considerable; the CE showed an excellent chelating with ICs0 of 0.197 ± 0.031 μM/quercetin equivalent, higher than that used standard EDTA, with approximately 0.34 folds. These results show that Capparis spinosa L. extracts have strong anti-oxidant effects and may have some clinical benefits.

Preparation and Evaluation of High Antioxidant Talbina as a Protective and Therapeutic Meal

Functional properties of Talbina were used in ancient Arab for nutritional purpose. It was a meal made from barley flour and milk. The high antioxidant Talbina was formulated from whole flour of harley and oat, milk, date palm syrup （debis） and date palm seeds. The chemical composition, organoleptic properties and antioxidant activity of high antioxidant Talbina were determined. Sensory evaluation of traditional and high antioxidant Talbina showed that the developed product Talbina was considered as good for overall acceptability of all panelists. Also, the formulated Talbina contains high values of antioxidants components and natural nutrients. The antioxidant activity of formulated Talbina containing barley or oat may be due to presence of phenolic compounds and proanthocyanidins in the barley and oat. Increasing the antioxidant activity of high antioxidant Talbina containing barley and oat may be due to the adding of dates palm seeds which contain very high values of phenolic compounds and other antioxidants components. Date palm seeds as well as barley and/or oat give high antioxidants components which protect cells from oxidative stress and help to reduce the risk of cancer and heart disease as well as natural anti-depressant. Moreover, increasing the antioxidant activity in the formulated Talbina may play a role for reducing power, radical scavenging activity and the lipid peroxidation inhibition. In conclusion, supplementation of traditional Talbina containing barley and/or oat with date palm syrup （debis） and date palm seeds can produce simple and healthy meal to provide a good source of daily dietary antioxidants and micronutrients.

Evaluation of Free Radicals and Antioxidant Properties of Virus Infected Food Crops in Azerbaijan

Abstract： Viral diseases are an important limiting factor in many crop production systems in Azerbaijan. Symptomatic plants in main crop-producing areas were tested by ELISA （enzyme-linked immunosorbent assay） using specific monoclonal and polyclonal antibodies. Then RCA （rolling circle amplification） of circular DNA and PCR using different specific primer pairs have indicated that the tested symptomatic plant samples were completely infected by the following viruses： Luteovirus [BLRV （Bean leaf roll virus）], Potyviruses [BCMV （Bean common mosaic virus）, BYMV （Bean yellow mosaic virus）], Bromovirus [（AMV） Alfa-alfa mosaic virus], Geminiviruses [CpCDV （ Cickpea chlorotic dwarf virus） and TYLCV （Tomato yellow leaf curl virus）] and Nanoviruses [two different FBNYV （Faba bean necrotic yellow virus） and FBNSV （Faba bean necrotic stunt virus）]. At the same time generation sites of superoxide and hydrogen peroxide radicals and activity of antioxidant enzymes were studied in the naturally infected plants.

Determined of antioxidant activity and preventing DNA damage effect of peanut polypeptides by chemiluminescence method

To estimate the antioxidant activities of Peanut polypeptides （PPs） by using a chemiluminescence （CL） method in vitro. The scavenging ability of PPs on superoxide anion, hydroxide radical, and hydrogen peroxide was determined by the Pyrogallol-Luminol system, the CuSO4-Phen-Vc-H2O2 system, and the luminol-H2O2 system, respectively. DNA damage preventing the effect of PPs was determined by the CuSO4-Phen-Vc-H2O2-DNA CL system. The results shows that PPs had good effect on the scavenging ability of superoxide anion （IC50=9.68±0.12 mg/ml）. PPs could scavenge hydroxide radical effectively （the IC50 value was 46.06±0.08 μg/ml）. PPs had a good scavenging ability on hydrogen peroxide, which had a relatively low IC50 value （0.17±0.07 mg/ml）. PPs （the IC50 value was0.72±0.11 mg/ml） were powerful on the DNA damage preventing effect. PPs possesses a good scavenging potency on ROS in different systems, but different results exist in different systems.

Determination of the Antioxidant, Phytochemical and Antibacterial Profiles of Flowers from Selected Ornamental Plants in Nueva Vizcaya, Philippines

With the increasing interest on natural products discovery, utilization of plant parts which are commonly disregarded is another breakthrough. This study sought to determine the secondary metabolites present, phenolic contents, radical scavenging activities and antibacterial properties of 10 selected ornamental flowers which were Adenium obesum, Allamanda cathartica, Bougainvillea glabra, Catharanthus roseus, Caesalpinia pulcherrima, Heliconia subulata, Ixora coccinea, Mussaenda philippica, Tecoma stans and Torenia fournieri, from Nueva Vizcaya, Philippines. The ethanolic crude extracts were subjected to thin layer chromatography （TLC） phytochemical screening. Total phenolics expressed as mg AAE/g sample were determined through Folin-Ciocalteu method. Radical scavenging activities were measured using DPPH assay. Antibacterial activities were assessed through TLC bioautography. To quantify bacterial susceptibility of C. pulcherrima, MIC and MBC were employed in the ethyl acetate sub-fraction. TLC showed different types of phenolics, alkaloids, essential oils and terpenes. T. fournieri showed the highest total phenolics with 155 mg AAE/g while H. subulatahad showed the lowest with 3.50 mg AAE/g. Measurement of IC59 showed that H. subulata had the highest antioxidant activity followed by T. fournieri with 303 ppm and 320 ppm, respectively. H. subulata having the least amount of total phenolics had greatest radical scavenging activity. This indicates that other than phenolics, other metabolites can pose great antioxidant activities. The antibacterial testing showed that M. philippica, 1. coccinea, 1-1. subulata, C. pulcherrima and A. cathartica were bioactive against Staphylococcus aureus and Escherichia coll. MIC and MBC of C. pulcherrima ethyl acetate sub-fraction is within the range of 2.5-10 mg/mL.

Analysis on the Oxidation Resistance of Jujube Saponin

In this paper, saponins were extracted from Northern Shaanxi＇ s big jujubes using organic solvent method and also the oxidation resistance of the extractives was analyzed. In the experiment, the crude extractives of the saponins from jujubes were obtained using ethyl alcohol soaking method and Soxhlet extraction method and also qualitatively tested using 3 color reactions, and the test result was positive; the oxidation resistance of jujube saponins was analyzed through DPPH, hydroxyl radical scavenging experiment and reducibility measurement, and the results showed that the capability of jujube saponins in DPPH free radical scavenging was enhanced along with the improvement of the to- be-test material concentration, so saponins played a significant role on hydroxyl radical scavenging and possessed certain reducibility. Northern Shaanxi＇ s big jujubes are rich in saponins and possess excellent antioxidant ability that will be enhanced along with the increase of saponins content. Thus, a basis is provided for the effective extension of the jujube industry chain.

Intervarietal Variation in Proximate Composition and Antioxidant Potential of Dry Peas （Pisum sativum L）

The present research work was carried out to investigate the proximate composition and antioxidant capacities of newly invented varieties of dry peas. The proximate composition in terms of moisture （7.00-8.50%）, ash （3.85-4.97%）, fiber （3.8-12.3%） and protein （17.3-18.8%） contents varied significantly with respect to various cultivars. Total phenolic contents （TPC）, total flavonoids contents （TFC）, percentage inhibition of peroxidation of linoleic acid system, reducing power and DPPH free radical scavenging capacity of different dry peas extracts were found in range of 0.651-0.684 g/100g of GAE, 0.021-0.041 g/100g of CE, 0.713-0.895, 40.051-84.608%, 18.097-24.591 mg/mL, respectively. The amount of TFC, and percent inhibition of per oxidation in linoleic system of different dry peas extracts varied significantly among various cultivars and solvents. From the results of present investigations it is reasonable to say that 80% methanolic extracts of dry peas have exhibited varying degree of antioxidant activity.

TGF-b and Diabetes Mellitus

Diabetes mellitus is categorized as a major metabolic disease. Hyperglycemia is the populest mediator. The oxygen radicals＇ production or the peroxide production in the mitochondria is preceded as a possible mechanism. TGF-beta is characterized as the main protagonist. TGF-b is a molecular mediator with adherent and hypertrophic properties in diabetic nephropathy. 20 Balb/c male and female mice were used. They were separated in two age groups, one of 4 weeks old （childhood, n= 10） and one of 6 weeks old （puberty, n=10）. An immunochemical study for TGF-beta was undertaken. The basal petal of the external membrane of Bowmen is thickened. In significant percentage the basal membrane was thickened and the peduncles merge together. Mature sperm cells were not normal. The two age groups did not present significant differences in morphology of the exocrine pancreatic cells. The augmented levels of TGF-beta expression promote the increased proliferation of the pancreatic glandular cells, the derangement of differentiation and the apoptosis rhythm. The renal function is diminished sooner than the clinical manifestations. The testicles are less influenced concerning principally the spermiogenesis.

Flavonoid Content and Antioxidant Properties in Different Extracts of Calluna vulgaris （L,） Flowers

This study evaluated the effect of four different solvent, i.e., water, ethanol, water-ethanol mixture and ethyl acetate, on the antioxidant activities of wild and cultivated heather （Calluna vulgaris （L.） Hull） plant. The highest values for total flavonoid content were obtained for samples extracted using ethanol-water mixture and ethyl acetate. Cupric reducing antioxidant capacity （CUPRAC） method, scavenging ability on 1,1-diphenyl-2-pirylhydrazyl radicals （DPPH） radicals and chelating activity on Fe2~ ions have been used for evaluation of antioxidant activity of the extracts. Ethanolic fraction exhibited the lowest reducing capacity, despite a heather sample used. The extracts of cultivated heather exhibited significant scavenging effect on DPPH radicals, and ethanol and ethanol-water fractions were found to be the most effective. The metal-chelating effect of the extracts increased in the order： ethanol 〈 ethyl acetate 〈 ethanol-water 〈 water. The results may be helpful for better utilization of heather flowers extracts as potential pharmaceutical and nutraceutical ingredient.

HPLC-UV Analysis and Antioxidant Potential of Phenolic Compounds from Endemic Shrub of Arid Environment Tamarix pauciovulata J, Gay

This research presents complete phenolic compounds and biological activity of Tamarix pauciovulata J. Gay, an endemic Saharan species. The antioxidant assays revealed that crude extract showed strong DPPH scavenging activity （IC50 = 49.357 μg/mL） but in reducing power and hydrogen peroxide scavenging activity, butanolic and ethyl acetate fractions have a potent ferrous ion-chelating ability in particularly the butanolic fraction （63.18% reduced power at 50 μg/mL） and a powerful scavenging activity on hydrogen peroxide in particularly ethyl acetate fraction （IC50 = 0.205 μg/mL）. The phenolic compounds of Tamarix pauciovulata leaves were analyzed by HPLC-UV. The major phenolic of leaf extracts are syringic acid （1.07 g/100g）, quercetin （34.1 mg/100g）, kaempferol （5.77 mg/100g）, isorhamnetin （5 mg/100g）. Others phenols were identified such as isoquercetin, catechin, epicatechin and its derivatives. Results indicated that the leaves extracts from Tamarix pauciovulata have great capacities to prevent diseases caused by the overproduction of radicals and can become important source of dietary compounds with health protective potential.