Antioxygenic Activity of <i>Solanum nigrum L.</i>Leaves in Sunflower Oil Model System and Its Thermal Stability

The antioxygenic activity of Solanum nigrum L. leaves and its various solvent extracts were evaluated using sunflower oil model system. Leaf powder and its methanol/water (80:20) soluble fraction showed strong antioxygenic activity in refined sunflower oil. On the other hand, ethyl acetate fraction exhibited marginal antioxygenic activity, whereas the water soluble fraction was practically devoid of any activity in refined sunflower oil. Thermal stability of different extracts of Solanum nigrum L. leaves heated at 80?C in refined sunflower oil also indicated the strong efficacy of methanol/water (80:20) extract to inhibit thermal oxidation. Solanum nigrum L. contain high levels of magnesium (239.0 mg/100g) and phosphorous (80.3 mg/100g). Fatty acid analysis of the lipid extracted from Solanum nigrum L. leaves indicated the presence of linoleic (59.1%) as a major fatty acid. The result of this study confirmed the presence of antioxygenic compounds in leaves, in particular its methanol/water (80:20) extracts showed great potential as a natural antioxidant to inhibit lipid peroxidation in foods.

Effect of Tocopherol on Antioxygenic Properties of Green Lubricating Oil

Based on the needs of green motor oil, and in order to improve the antioxidation properties of green lubricating oil, the effect of tocopherol antioxidation properties of rapeseed oil was studied. Experiments of high temperature oxidation, antiwear and infra-red spectrum analysis were accomplished, the results show that the rapeseed oil including tocopherol can still keeps steady structure after high temperature oxidation, with a small variety of acid number, whose antioxygenic properties are improved evidently. Meanwhile, both thiocarbamate and vitamin C play an assistant role in tocopherol, which can make rapeseed oil to have better oxidation stability and keep excellent antiwear properties after high temperature oxidation.

<i>In Vitr</i>Antioxygenic Activity of Ridge Gourd (<i>Luffa acutangula</i>) Pulp, Peel and Their Extracts on Peroxidation Models

Ridge gourd pulp and peel powders as well as their various solvent fractions were evaluated for antioxygenic activity using different methods. Ridge gourd pulp and peel powders at 2% level and their ethanol/water soluble extracts exhibited strong antioxygenic activity in sunflower oil stored at 37?C. The water soluble extract devoid of any antioxygenic activity in sunflower oil. Ridge gourd pulp and peel powders as well as their extracts were evaluated for their antioxygenic activity using linoleic acid peroxidation, β-carotene-linoleic acid bleaching and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) methods. Ethanol/water extracts from ridge gourd pulp and peel showed highest antioxygenic activity followed by water extracts, while the petroleum ether extract showed moderate antioxygenic activity. Ridge gourd peel powder and its extracts showed slightly higher antioxygenic activity than ridge gourd pulp powder and its extracts. This may be attributed to the presence of higher amounts of phenolics and flavonoids which have been reported as potential antioxidants.

纤细席藻对重金属镍胁迫的响应研究

实验研究了纤细席藻Phormidium tenue对重金属镍胁迫的光合生理响应及外源抗氧化剂的保护作用,结果发现:在不同浓度Ni^(2+)短期处理纤细席藻时,其荧光产量随处理时间先发生急剧下降,随后有所回升;荧光产量随着Ni^(2+)浓度的增加而明显降低,在100 mg/L Ni^(2+)浓度下荧光曲线的O、J、I、P相完全消失,光合活性(Fv/Fm)丧失.经抗氧化剂抗坏血酸(ASC)和N-乙酰半胱氨酸(NAC)分别预处理的纤细席藻荧光产量有一定程度恢复,且ASC抗氧化作用相比NAC更加明显,但其保护作用均随着时间增加而逐渐减弱.在不同浓度的Ni^(2+)长期胁迫时,1d内抑制作用显著,叶绿素a、光合活性及电子传递链光合参数(ET0/ABS、ET0/TR0、RC/CS0)下降显著,SOD活性升高.实验结果表明:镍对纤细席藻的光合生理活性具有较强的抑制作用,而外源抗氧化剂可以短期内有效缓解重金属镍胁迫造成的损伤,因此在吸附去除重金属时可有效提高藻类的吸附效率和循环利用.

抗氧化治疗对妊高征预测阳性孕妇疗效和血流动力学指标影响

目的观察抗氧化治疗对妊高征预测阳性孕妇疗效和血流动力学指标的影响,并总结其规律性。方法使用MP-01型妊高征监测仪对孕妇进行普查,检测阳性孕妇随机分组治疗,干预组(176例)服用抗氧化药物(维生素C、E)加用钙剂(氨基酸螯合钙片),对照组(177例)仅给予对症治疗,两组孕妇治疗前后均接受妊高征监测仪检测。结果一般疗效比较中,干预组妊高征监测转阴例数和转阴率明显高于对照组,而前者妊高征发病例数和发病率明显少于后者(P均<0.05～0.01)。治疗前后血流动力学指标比较中,两组孕妇治疗前各种血流动力学指标分布接近(P均>0.05),两组孕妇治疗后2、4周及临产前MAP、TPR、CI、V、K等大部分检测值明显优于治疗前,而干预组2、4周及临产前MAP、TPR、CI、V、K等大部分检测值还明显优于对照组同期结果(P均<0.05～0.01)。结论抗氧化治疗可改善妊高征预测阳性孕妇血流动力学指标,有较好的临床疗效,值得临床推广和应用。

土壤水分和氮素对春小麦叶片抗氧化系统的影响

植物的抗逆性与其清除活性氧(ROS)的能力相关,提高抗氧化代谢水平是增强植物胁迫耐性的有效途径。以抗旱性不同的3个品种为材料,研究土壤水分和氮素水平及其耦合效应对春小麦叶片抗氧化系统的影响,以探讨水、氮对春小麦抗氧化系统的影响规律及抗氧化系统与抗旱性间的关系。结果表明:干旱胁迫使春小麦叶片丙二醛(MDA)含量升高,膜质过氧化程度加重,同时叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性和抗坏血酸(ASA)、还原性谷胱甘肽(GSH)含量升高,以减缓氧化伤害。高氮高水条件下,春小麦叶片细胞膜的氧化损伤最小;高氮低水处理下,抗氧化系统的活性最强,施氮能提高春小麦叶片抗氧化系统的活性。3个供试品种中,宁春4号对水分胁迫最敏感,和尚头和宁春4号对氮敏感;和尚头耐旱性及抗氧化能力最强,旱地品种定西35号次之,宁春4号耐旱性最差。

龙眼叶片活性氧代谢和抗氧化系统对La^(3+)的响应

以一年生龙眼小苗为材料,研究了La3+对龙眼叶片活性氧代谢和抗氧化系统的影响,探讨La3+提高植物抗逆境能力作用机制。龙眼小苗喷施10,20,30,40,50 mg.L-1的La(NO3)3两次,通过检测叶片的自由基含量、抗氧化酶活性和抗氧化物质含量来分析La3+提高龙眼抗氧化的作用。结果表明:20～30 mg.L-1La3+处理可明显清除龙眼叶片的.O2-和H2O2,减少MDA生成量;显著提高叶片SOD和CAT酶活性,降低POD活性,提高AsA-GSH循环运行效率及相关代谢酶APX,MDAR,DHAR和GR的活性,保证AsA和GSH再生,显示稀土离子La3+对龙眼抗性具有显著的正调节作用。