Evaluation of antioxidant activity of marine Agrobacterium SP. 1202

The three water-soluble polysaccharides （PI, PII and Pill）, the ethyl acetate extraction （EA） and its five fractions of petroleum ether （PeF）, ethyl acetate （EaF）, butanol （BuF）, methanol （MeF） and water （WtF） from marine agrobacterium 1202 were prepared and then subjected to antioxidant activity evaluation. The antioxidant activity was tested using the 1, 1-Diphenyl-2-picryl-hydrazyl （DPPH） free radical-scavenging assay, the hydrogen peroxide-induced luminot chemiluminescence （CL） assay and hydroxyl free radical-initiated chemiluminescence （CL） assay. All the fractions exerted significant inhibitory effects on hydrogen peroxide and hydroxyl free radical. The extracts of EA, EaF and BuF could also showed inhibition on DPPH. Among of them, the extracts of EaF showed full of antioxidant activity on the three tested system. The result suggested that the marine agrobacterium 1202 is a potential source of natural antioxidantagent.

丹酚酸B清除DPPH有机自由基活性及影响因素研究

目的探讨丹酚酸B清除DPPH自由基的活性及其影响因素。方法运用自由基反应模型观察丹酚酸B对DPPH自由基的淬灭效应。结合高效液相色谱技术分别研究温度和pH值对丹酚酸B清除DPPH能力的影响。结果在设定的反应体系下,丹酚酸B能有效清除DPPH自由基。相同浓度下其清除能力高于二丁基羟基甲苯(BHT)和抗坏血酸(AsA)。热处理后,丹酚酸B含量和清除DPPH自由基能力有不同程度下降。pH=3时丹酚酸B含量相对稳定,其清除能力较其它环境显著增加。结论丹酚酸B具有清除DPPH自由基的能力。温度对其含量和抗氧化能力有较大影响。酸性条件有利于丹酚酸B的稳定性和清除能力的增强。

三种小麦麸皮总黄酮的体外抗氧化活性

研究不同溶剂(乙醇、甲醇、丙酮)提取的3种不同品种小麦麸皮(豫教5号、郑麦7698、西农979)黄酮类化合物的抗氧化活性。结果表明,3种不同的有机溶剂对小麦麸皮的总黄酮提取能力顺序为:乙醇>甲醇>丙酮。其中乙醇提取的总黄酮的总还原力和清除羟基自由基的能力最强。细胞实验结果显示,乙醇提取3种不同品种的小麦麸皮中黄酮类化合物能使人胃腺癌细胞(adenocarcinoma cell line,AGS)内活性氧水平下降,显示良好的抗氧化活性,且活性与总黄酮含量呈正相关性。总的来说,乙醇提取的西农979小麦麸皮的总黄酮的抗氧化能力最好。该研究结果为更好利用979小麦麸皮中黄酮类物质提供了参考依据。

Synthesis of Hydroxystilbene Derivatives and their Antioxidant Activity by DPPH Method

Five hydroxystilbene derivatives were synthesized and their structures were determined using high-resolution mass spectrometry, ^1H NMB, and IR. In this study, the antioxidant activities of eight hydroxystilbenes （five synthesized hydroxystilbene derivatives and three other compounds） were evaluated with the free radiced scavenging model 1,1-diphenyl-2-picrylhydraxyl. It was observed that there exists a very significant linear rehtionship between the reciprocal of the EC50 value of each of the compounds and the maximum wavelength of the ultraviolet absorption peaks, It is believed that this result will be helpful for the further synthesis of such antioxidants.

西兰花提取物抗氧化性研究的意义

西兰花含有许多抗氧化性,可使人体避免受到自由基的伤害,降低疾病发生机率。利用DPPH法对西兰花提取物的抗衰老、抗疾病能力进行了测定。

Phytochemical characterization of polyphenolic compounds with HPLC–DAD–ESI–MS and evaluation of lipid-lowering capacity of aqueous extracts from Saharan plant Anabasis aretioides(Coss & Moq.) in normal and streptozotocin-induced diabetic rats

Objective： Anabasis aretioides （Coss ＆ Moq.）, a Saharan plant belonging to Chenopodiaceae family, is widely distributed in semi-desert areas from the Tafilalet region of Morocco. This plant is extensively used by local population against diabetes and cardiovascular disorders. The purpose of the study was to investigate the effect of the aqueous A. aretioides extract on lipid metabolism in normal and strepto-zotocin （STZ）-induced diabetic rats and to identify the polyphenolic compounds present. In addition, the in vitro antioxidant activity of the aqueous A. aretioides extract was also evaluated. Methods： The effect of an aerial part aqueous extract （APAE） ofA. aretioides （5 mg/kg of lyophilized A. are-tioides APAE） on plasma lipid profile was investigated in normal and STZ-induced diabetic rats （n = 6） after once daily oral administration for 15 days. The aqueous extract was tested for its 1,1-diphenyl-2-picrylhydrazyl （DPPH） radical-scavenging activity. Polyphenolic compounds in the extracts were defini-tively characterized by high-performance liquid chromatography-diode array detection-electrospray ionization-mass spectrometry. Results： In diabetic rats, oral administration ofA. aretioides APAE provoked a significant decrease in both plasma cholesterol and triglyceride levels from the first to the second week （P 〈 0.01）. A significant decrease on plasma triglyceride levels was also observed in normal rats （P 〈 0.01）, where the reduction was 53%. In addition, the phytochemical analysis revealed the presence of 12 polyphenolic compounds. Moreover, according to the DPPH radical-scavenging activity, the aqueous extract showed an in vitro antioxidant activity. Conclusion： Aqueous A. aretioides APAE exhibits lipid-lowering and in vitro antioxidant activities. Many polyphenols were present in this extract and these phytoconstituents may be involved in the pharmaco-logical activity of this plant.

Optimization of Extraction of Antioxidants from Turmeric(Curcuma longa L.) Using Response Surface Methodology

Turmeric is a spice widely used to enhance the taste and color of certain meats. We investigated the antioxidant capacities of turmeric ethanol soaking extracts by utilizing the scavenging properties of hydroxyl radical and 1,1-diphenyl-2-picrylhydrazyl（DPPH） free radical. The results showed that the optimum extraction parameters were： extraction time 4 h, sample-solvent ratio 1：84.12, solvent 72.34% ethanol solution, and water bath temperature 81.3 ℃. The optimum ethanol soaking extraction parameters were： extraction time 4 h, sample-solvent ratio 1：90.74, solvent 80.46% ethanol solution, water bath temperature 88.2 ℃. With these parameters, the hydroxyl radical scavenging rate and the DPPH free radical clearance of crude extracts from turmeric can reach about 93.78% and 40.69%, respectively. These results indicate that ethanol soaking extraction may be a useful method for extracting antioxidants from turmeric.

Antioxidant,phytotoxic and cytotoxic activity of methanolic extract of Trigonella foenum-graecum

Objective:To analyze the methanol extract of Trigonella foenum-graecum(T.foenum-graecum)for antioxidant,phytotoxic and cytotoxic activity.Methods:The powder of T.foenum-graecum was extracted in diluted methanol with the help of random shaking method.All extracts of the plant were measured for cytotoxic activity(beside brine shrimp and antioxidant activity vs.1,1-diphenyl-2-picrylhydrazyl free radical).Results:Various concentrations of methanolic extract of T.foenum-graecum were observed as 36.16%to 54.12%with rising concentrations of 50 to 1000μg/mL.Significantly phytotoxic activity(100 and 1000μg/mL)reduced the growth of roots(radicals)and shoots(hypocotyls)of rice when compared to control after 3 and 7 days’treatment.At a concentration of 10μg/mL,the survival rate of cytotoxic activity of brine shrimp was maximum and at a concentration of 250μg/mL,the death rate of brine shrimp was maximum.Conclusions:T.foenum-graecum has potential activity against free radical mediated sickness and thus it is possible to treat cancer.

Evaluation of antioxidant potential,total phenolic content and phytochemical screening of aerial parts of a folkloric medicine,Haplophyllum tuberculatum(Forssk)A.Juss

Objective:To quantify total phenols,flavonoids and to investigate the in vitro antioxidant power of Haplophyllum tuberculatum(H.tuberculatum)leaves extracts of varying polarities.Methods:The authenticated sample of H.tuberculatum(50 g)leaves was dried under shade,powdered and extracted exhaustively with ethanol by cold percolation method.The alcoholic extract was further partitioned into petroleum ether,acetone,chloroform and methanol to obtain the fractions of varying polarities which were subjected to qualitative phytochemical testing.Total phenolics and flavonoids content in the acetone,chloroform and methanol extracts were quantified by using standard colorimetric methods.Petroleum ether extract was omitted because it did not show the presence of either tannins or flavonoids.In vitro antioxidant activity and total antioxidant capacity were determined by using 1,1 diphenyl-2-picrylhydrazyl radical and phosphomolybdenum reagent.Ascorbic acid was used as a reference antioxidant for comparison purpose.Results:Qualitative phytochemical results of leaves extracts confirmed the presence of major secondary plant metabolites.The extraction of phenolic compounds varied considerably according to the polarity of solvent.The most polar fractions i.e.methanol were observed to have the highest phenolic content(561.22 mg/g of gallic acid equivalent)and flavonoids(165.54 mg/g of quercetin equivalent).Although the free radical scavenging activity of leaves fractions was noted to be slightly lower than the reference compound,a direct relationship was observed between phenolic content and in vitro antioxidant activity.On the other hand,leaves fractions exhibited significant total antioxidant capacity as ascorbic acid equivalent.Conclusions:The aerial part of H.tuberculatum is rich in phenolic compounds which might play a vital role in the discovery of natural antioxidants.