16种花茶对DPPH~·的清除能力及其优化配比研究

比较研究了16种花茶对DPPH.清除能力的影响,结果表明:绿茶、红茶、玫瑰花和桂花都有较强的DP-PH.清除能力,其清除率分别为59.21%、50.70%、42.72%和24.09%。选用绿茶、玫瑰花、桂花和茉莉花为原料,以DPPH.的清除能力为考察指标,采用L16(45)正交实验,研究了玫瑰花茶的最优配比。结果表明玫瑰花的比例对DPPH.清除能力影响最显著(P<0.05),玫瑰花:绿茶:桂花:茉莉花=2:6:0.8:0.3为优化配比,其提取液对DPPH.的清除率最高。     

益智的抗氧化作用

本文探讨了益智(Alpinia oxyphylla Miquel)超临界CO2提取物及其渣的水提物、正丙醇提取物和乙酸乙酯提取物的抗氧化作用,测定了总酚含量、黄酮含量、抗氧化力、还原能力、DPPH清除率.结果表明,益智超临界CO2提取物和正丙醇提取物的总酚含量最高,均为5.53%,乙酸乙酯提取物的总酚含量为4.04%,水提物总酚含量最低,为O.89%.抗氧化力与酚含量相关(R2=0.703).四种提取物中黄酮含量顺序为:乙酸乙酯提取物(6.29%)＞丙醇提取物(5.81%)＞水提取物(4.85%)＞超临界CO2提取物(4.70%).在还原能力、清除DPPH自由基和羟自由基方面,乙酸乙酯提取物表现出了很强的抗氧化能力,呈现剂量依赖关系.     

酶解鹿茸血ACE抑制活性及其与抗氧化活性关系的研究

实验采用木瓜蛋白酶和Alcalase碱性蛋白酶水解鹿茸血,在不同的时间取样,分别测定血管紧张素转化酶(ACE)抑制率、二苯代苦味肼基自由基(DPPH.)清除率和羟自由基(.OH)清除率。结果表明Alcalase蛋白酶水解产物ACE抑制活性和DPPH.清除活性较强,其水解3h的产物ACE抑制率为90.63%,DPPH.清除率为14.40%;木瓜蛋白酶水解5h的产物.OH清除率最高,为96.7%。用SPSS10.0软件分析结果,发现ACE抑制率与DPPH.清除率具有显著相关性。     

低聚壳聚糖衍生物的制备及其抗氧化性能

低聚壳聚糖(COS)经化学改性得到N-苯亚甲基壳聚糖(NBCOS)和O-2'-羟丙基三甲基氯化铵壳聚糖(OHCOS),对其结构进行表征.考察了COS及其衍生物对超氧阴离子O2¨、羟基自由基·OH、DPPH自由基的清除活性以及还原能力.结果表明:当浓度为10 mg/mL时,COS和OHCOS对O2¨的清除率分别为89.6%和85.5%,而同样浓度时NBCOS的清除率仅有6.9%;它们清除·OH和DPPH的活性大小顺序为COS>OHCOS>NBCOS,而还原能力大小顺序为COS>NBCOS>OHCOS.     

米糠蛋白抗氧化活性肽的制备

以水解度(DH％)和对DPPH自由基清除率为指标,筛选出制备米糠蛋白抗氧化活性肽的最适蛋白酶.研究最适蛋白酶的酶解条件,探讨底物浓度、蛋白酶的加入量、pH值、酶解时间等因素对水解度(DH％)和DPPH自由基清除率的影响;在单因素基础上采用Box-Behnken响应曲面中心组合设计法,对酶解米糠蛋白的工艺进行优化.试验结果表明,在加酶量13970.82 U/g,时间3.05h,底物浓度4.97％的水解条件下,米糠蛋白的水解度能够达到23.67％,活性肽对DPPH自由基清除率达到64.26％.     

细脚拟青霉不同菌株清除DPPH自由基活性研究

在初筛基础上选择不同地理来源的10株细脚拟青霉,用二苯基苦基苯肼自由基酶标仪法比较了不同提取部位的DPPH自由基清除率。结果表明在所有供试菌株中细脚拟青霉的两个菌株清除自由基活性均较高。10株细脚拟青霉间的清除自由基活性少数相似,多数差异显著;发酵液和菌丝体提取物清除自由基活性不同;菌丝体不同溶剂先后提取所得物清除率也不同,其中氯仿提后甲醇提取物无论提取量,还是活性均较高,5分钟时的清除率最少也有66.0%(Pt02菌株),最高是Pt69菌株达到93.5%,Pt57菌株的清除率为92.8%;氯仿提取量极少,活性也不高;经氯仿和甲醇提取后的水提物,得率只有甲醇的一半左右,而活性与氯仿提取物相当,在14.11%~45.3%之间。     

防御活性氧保护系统在黑豆抗旱生理中的响应

以黑豆幼苗为材料,研究了水分胁迫下其非酶促保护物质和保护酶系对活性氧的清除作用。结果显示:黑豆皮红色素(17.36%)对DPPH.的清除率高达93.6%,可溶性糖(7.227%)对O2-与.OH的清除率分别为47.71%与68.16%,谷胱甘肽(0.8033mg/g)对O2-与.OH有较明显的清除作用,三种非酶促保护物质随着浓度的升高其清除能力呈逐渐增强的趋势;在水分胁迫下,黑豆幼苗超氧化物歧化酶(33~14 U.mg-1.min-1.2~6d-1),过氧化氢酶(2.87~2.01 mg.mg-1.min-1.3~6d-1)与过氧化物酶(31~14 mg.mg-1.min-1.3~6d-1)三种保护酶活性呈现先升高后降低的变化趋势。研究表明:黑豆体内清除活性氧防御系统作用十分明显,且具有较强的抗氧化、抗衰老、抗逆能力。     

赤芍总苷抗氧化活性及对大鼠肝星状细胞增殖的影响

目的:研究赤芍总苷体外抗氧化活性及对大鼠肝星状细胞HSC-T6细胞增殖的影响.方法:采用DPPH法测定赤芍总苷体外清除DPPH自由基及抗氧化活性,根据清除率曲线,确定EC50值;采用MTT法考察赤芍总苷对大鼠肝星状细胞HSC-T6细胞增殖的影响,确定起效剂量,并考察其量效关系.结果:赤芍总苷对DPPH自由基具有较强清除作用,其对DPPH的清除率的回归方程为y=7.4432x0.6111(r=.9967),EC50值为6.64mg/L;赤芍总苷对HSC-T6的增殖具有明显的抑制作用,给药浓度为1.152mg/mL时,其对HSC-T6细胞增殖的抑制率可达39.240%.结论:赤芍总苷具有较强的抗氧化活性,对肝星状细胞的增殖有一定抑制作用.     

桦褐孔菌提取物抗氧化活性研究

以乙酸乙酯和甲醇为提取剂,采用索氏提取法,剩余残渣采用热水浸提,最终得到桦褐孔菌不同极性提取物,对其DPPH自由基、羟基自由基及超氧阴离子自由基清除活性作用进行了研究,确定桦褐孔菌的抗氧化能力,为深入研究和开发桦褐孔菌功能性食品奠定理论基础。实验结果表明桦褐孔菌具有较好的抗氧化活性,其中乙酸乙酯提取物的DPPH自由基清除率、羟基自由基清除率和超氧阴离子自由基清除率均高于其他两组分及BHT,桦褐孔菌提取物有望成为功能性食品组分中合成抗氧化剂的天然替代品。     

超声波协同提取鱼腥草黄酮及其抗氧化性

研究了超声波协同乙醇提取不同部位鱼腥草黄酮的最佳工艺条件,并测定黄酮提取物对DPPH.、羟基自由基和超氧自由基的抑制效果。结果表明:鱼腥草叶中黄酮含量最高,在固液比1∶30,85%乙醇浓度,65℃下提取40min,黄酮提取率为2.36%。鱼腥草黄酮对DPPH.自由基活性、.OH自由基和超氧O2-.自由基的清除率可达72.8%、70.8%和69.8%,表明鱼腥草黄酮是一种天然有效的自由基清除剂。     

Investigation of the mechanism of temperature sensitivity of the electroreceptors of ampullae of lorenzini

In experiments on Black Sea skates (Raja clavata), the potential of the receptor epithelium of the ampullae of Lorenzini and spike activity of single nerve fibers connected to them were investigated during electrical and temperature stimulation. Usually the potential within the canal was between 0 and –2 mV, and the input resistance of the ampulla 250–400 k. Heating of the region of the receptor epithelium was accompanied by a negative wave of potential, an increase in input resistance, and inhibition of spike activity. With worsening of the animal's condition the transepithelial potential became positive (up to +10 mV) but the input resistance of the ampulla during stimulation with a positive current was nonlinear in some cases: a regenerative spike of positive polarity appeared in the channel. During heating, the spike response was sometimes reversed in sign. It is suggested that fluctuations of the transepithelial potential and spike responses to temperature stimulation reflect changes in the potential difference on the basal membrane of the receptor cells, which is described by a relationship of the Nernst's or Goldman's equation type.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov, Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Pacific Institute of Oceanology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 67–74, January–February, 1980.     

Principles of organization and evolution of systems of regulation of functions

Evolution of living organisms is closely connected with evolution of structure of the system of regulations and its mechanisms. The functional ground of regulations is chemical signalization. As early as in unicellular organisms there is a set of signal mechanisms providing their life activity and orientation in space and time. Subsequent evolution of ways of chemical signalization followed the way of development of delivery pathways of chemical signal and development of mechanisms of its regulation. The mechanism of chemical regulation of the signal interaction is discussed by the example of the specialized system of transduction of signal from neuron to neuron, of effect of hormone on the epithelial cell and modulation of this effect. These mechanisms are considered as the most important ways of the fine and precise adaptation of chemical signalization underlying functioning of physiological systems and organs of the living organism