Structure-activity relationship of neuroprotective and reactive oxygen species scavenging activities for allium organosulfur compounds

The neuroprotective and antioxidative activities of five organosulfur compounds with a thioallyl structure (-S-CH2CH=CH2) were characterized in terms of structure-activity relationships. Among five organosulfur compounds, only S-allyl-L-cysteine (SAC) having the alanyl group (-CH2CH-NH2-COOH) and lacking the oxo (O=) group with in between molecular properties, was effective in protecting cell death induced by both oxygen glucose deprivation and global cerebral ischemia. Conversely, lipophillic organosulfur compounds including diallyl sulfide, diallyl disulfide, and diallyl trisulfide were devoid of in vitro and in vivo neuroprotective activities. Furthermore, a significant correlation was only found between the in vivo neuroprotective activity and the OH- scavenging activity (gamma = 0.55 and p = 0.032) among reactive oxygen species scavenging activities. These results indicate that the presence of the alanyl group and the absence of the oxo group are essential for the manifestation of neuroprotective activity against ischemic insults and scavenging of OH radical, with SAC surfacing as a potent neuroprotectant.     

氮素不同形态配比对菜用大豆生长、种子抗氧化酶活性及活性氧代谢的影响

通过蛭石盆栽试验,研究了氮素不同形态配比对菜用大豆[Glycine max (L.) Merr.]品种"理想95-1"生长、种子抗氧化酶活性及活性氧代谢的影响。结果表明,营养液中适宜的硝铵比(75∶25)有利于菜用大豆的生长发育,植株具有最大生物量;在高比例的硝态氮(100%)和铵态氮(75%)处理下,植株的干重、鲜重及产量均显著降低,以硝铵比为25∶75处理下尤为显著。在适宜的硝铵比(75∶25和50∶50)处理下,菜用大豆种子具有较低的抗氧化酶活性,活性氧代谢产物O2、过氧化氢(H2O2)和膜脂过氧化产物丙二醛(MDA)含量也较低,表明植株受到的氧化胁迫程度较低;而在硝铵比为25∶75处理中,抗氧化酶活性最高,O2生成速率、H2O2和MDA含量也最高,表明过多的铵态氮对细胞膜造成了伤害,所受的氧化损伤程度较重。     

Characterization of free radicals in soluble coffee by electron paramagnetic resonance spectroscopy

EPR spectra of soluble coffee display single-line free radical signals in both the solid state and aqueous solution, along with signals from the paramagnetic ions Fe(III) and Mn(II). The intensity of the free radical signal in the pure solid was estimated to be ca. 7.5 x 10(16) unpaired electrons/g, and there was no significant change on dissolution in water. In aqueous solutions, however, the free radical signal declined rapidly over ca. 10-15 min in the temperature range 20-65 degrees C, after which only slow changes were observed. This decline, which was essentially independent of atmosphere, was greatest for the lowest temperatures used, and the intensity after 1 h fitted well to an exponential curve with respect to temperature. The free radicals responsible for the single-peak EPR signal did not react with any of the spin traps tested in the present experiments, but unstable free radicals with parameters consistent with adducts of C-centered radicals were detected in coffee solutions in the presence of PBN and 4-POBN spin traps. The presence of oxygen in the solutions increased the initial rate of formation of these free radical adducts. No adducts were detected when DEPMPO was used as spin trap. However, *OH adducts of DEPMPO were shown to be unstable in the presence of coffee, a fact which illustrates the strong free radical scavenging ability of coffee solutions.     

Promoting effect of Nano-Se on tobacco growth and reactive oxygen species metabolism

Abstract

Se is beneficial to plants’ growth and it is an essential mineral for animals and humans. However, relatively little is known about the relationship between nano-Se concentrations and plant antioxidant activity. In this work, a pot experiment was carried out using two cultivars of tobacco and increasing nano-Se concentrations. The changes of plant biomass, root growth, chlorophyll content, nutrient accumulation and reactive oxygen species (ROS) content in tobacco leaves after being sprayed with nano-Se were studied. The results indicated that the growth of tobacco can be promoted by applying nano-Se in an appropriate concentration. In addition, our research proves that there is cultivars variation in the response of tobacco to increased concentrations of nano-Se. The biomass, root growth characteristics, chlorophyll content and N accumulation of E'yan 1 were increased significantly and were the highest at 5.0?mg L^?1 of nano-Se. On the other hand, the above mentioned indicators for K326 reached the maximum value at 2.5?mg L^?1 and decreased at 5.0?mg L^?1 of nano-Se. The antioxidant enzymes activity were increased by the application of nano-Se, however cultivars variation was detected. The application of nano-Se reduced the amount of thiobarbituric acid reactive substances (TBARS) and ROS at 5.0?mg L^?1 for both cultivars. This study confirms that nano-Se affects positively the growth and oxidative status of tobacco plants. However, this study points out that more research is needed to understand the interaction phenomena observed here between tobacco cultivars and concentrations specifically for the anti-oxidant status of the plant.     

铁、镁、锌营养胁迫对植物体内活性氧代谢影响机制

活性氧是植物体内常见的一类自由基,对植物有很强的伤害。本文总结了铁、镁、锌元素胁迫影响植物体内活性氧代谢机制。铁对于催化植物体内的Haber-Weiss反应产生活性氧具有重要作用。镁诱导植物体内活性氧代谢失调与光氧化有密切关系。缺锌条件下,植物体内活性氧含量升高,其机制是多方面的:NADPH氧化酶氧化能力提高,O2产生增多;体内铁浓度升高,增强了铁诱导的活性氧的产生;光氧化伤害加重;清除系统活性降低。     

不同机械伤处理对香蕉果皮活性氧代谢的影响

为探究不同机械伤处理对香蕉果皮活性氧代谢的影响,该研究以\     

Evaluation of the antioxidant properties of free and bound phenolic acids from native and malted finger millet (ragi, Eleusine coracana Indaf-15)

Free and bound phenolic acids were isolated from native and malted finger millet (ragi, Eleusine coracana Indaf-15), and their antioxidant properties were evaluated. Protocatechuic, gallic, and caffeic acids were found to be the major free phenolic acids. A 3-fold decrease was observed in protocatechuic acid content, whereas the decrease was marginal in the case of caffeic acid upon 96 h of malting. However, the contents of other free phenolic acids such as gallic, vanillic, coumaric, and ferulic acids increased. Ferulic, caffeic, and coumaric acids were found to be the major bound phenolic acids, and a 2-fold decrease was observed in their contents upon 96 h of malting. The antioxidant activity of a free phenolic acid mixture was found to be higher compared to that of a bound phenolic acid mixture. An increase in antioxidant activity coefficient was observed in the case of free phenolic acids from 770.0 +/- 7.8 to 1686.0 +/- 16.0, whereas the same was decreased from 570.0 +/- 6.0 to 448.0 +/- 4.5 in bound phenolic acids upon 96 h of malting. Therefore, the antioxidant capacity of phenolic acids changes during the malting of ragi.     

外源NO对不同作物种子萌发、幼苗生长及抗氧化酶活性的影响

以浓度分别为0、0.01、0.1、1.0 mmol/L的硝普钠（Sodium nitroprusside, SNP; NO供体）处理玉米、小麦、花生、小白菜、萝卜、黄瓜的种子和幼苗,研究了以上几种浓度的SNP对作物种子萌发和幼苗生长及抗氧化酶活性的影响。结果表明:SNP对多数种子萌发影响表现为低浓度（0.01 mmol/L和0.1 mmol/L）促进,高浓度（1.0 mmol/L）抑制,其中对萝卜发芽率的促进作用最显著;低浓度SNP可有效促进植物幼苗地上部的生长,其中对小麦、黄瓜的促进效果最显著,同时可显著促进根系的伸长,其中对萝卜的促进效果最显著,且对植物幼苗生长的影响与作物种类有关;SNP对多数植物的根系活力有明显的促进作用,其中对萝卜的促进效果最显著;适宜浓度的SNP可以提高作物CAT、POD和SOD活性以及可溶性蛋白含量,并降低MDA含量,不同作物SNP的适宜浓度不同,其中0.1 mmol/L SNP对多数作物处理效果最好。     

施肥和密度对杂交谷可溶性糖、可溶性蛋白及硝酸还原酶的影响

【目的】研究不同施肥条件和密度对张杂谷5号可溶性糖、可溶性蛋白及硝酸还原酶的影响,以期为杂交谷高产优质栽培提供理论依据。【方法】于2011年采用五因素二次通用旋转组合设计,研究氮、磷、钾肥、行距和株距对张杂谷5号可溶性糖、可溶性蛋白及硝酸还原酶的影响,每个因素5个水平,共32个试验处理组合。2012年选用2011年最优组合及零水平组合进行验证试验。采用SAS9.0软件对各生理指标间的相关性进行分析,通过Lingo软件采用迭代逐次逼近的方法研究因子间的交互作用并求极值。【结果】施氮量、施磷量、行距对叶片可溶性蛋白含量和硝酸还原酶活性有显著影响(P0.05),施氮量、施磷量、施钾量、行距对叶片可溶性糖含量有显著影响(P0.05)。随着施氮量和施磷量的增加以及行距的缩小,可溶性蛋白、可溶性糖和硝酸还原酶活性均呈先上升后下降的趋势。5个因子中,施钾量与株距的交互作用对叶片可溶性蛋白和硝酸还原酶活性有显著影响。【结论】综合考察三个生理指标,杂交谷可溶性蛋白、可溶性糖含量和硝酸还原酶活性均较高的施肥量和栽培方案为施氮N 187198 kg/hm2,P2O590 97 kg/hm2,K2O 55 59 kg/hm2,行距23 24 cm,株距9 10 cm。在实际生产中,建议采用窄行中密度结合增施氮、磷肥的栽培方式,以提高谷子叶片可溶性蛋白含量、可溶性糖含量和硝酸还原酶活性,从而提高产量并改善品质。     

糜子不同种植方式对土壤酶活性及养分的影响

【目的】土壤酶参与土壤中多种生化活动,是衡量土壤生产力的指标之一。本文比较分析了不同种植方式下糜子生育期间土壤酶活性的动态变化以及成熟期土壤养分含量和糜子产量,旨在探明糜子连作障碍和连作减产的产生机制,为糜子高产高效栽培提供理论依据。【方法】以西北农林科技大学农作一站小杂粮轮作连作长期定位试验为平台,设轮作(T1)、隔年种植(T2)、连作2年(T3)、连作3年(T4)4个处理,在糜子播种期、苗期、拔节期、抽穗期、灌浆期、成熟期测定0—20 cm根际土壤中过氧化氢酶、脲酶、碱性磷酸酶、蔗糖酶活性以及成熟期0—20 cm根际土壤养分含量,对同一时期不同处理间的酶活性和成熟期不同处理间土壤有机质、全氮、碱解氮、全磷、有效磷、全钾、速效钾含量以及土壤p H值进行方差分析,并分析土壤养分和酶活性以及糜子产量之间的相关性。【结果】1)土壤过氧化氢酶、脲酶、蔗糖酶活性随着连作年限的增加而降低;碱性磷酸酶在连作2年处理的活性较低。2)随着连作年限的增加土壤p H值升高,土壤速效钾严重积累,速效磷消耗较多,说明连作导致土壤盐碱化。3)过氧化氢酶、脲酶、碱性磷酸酶活性与糜子籽粒产量呈显著正相关,土壤p H值与籽粒产量呈显著负相关;蔗糖酶活性、有机质含量与产量具有一定的相关性。【结论】糜子连作改变了土壤酶活性及土壤养分含量,导致土壤腐殖化和熟化程度减慢,土壤次生盐渍化加重,土壤养分不均衡,植株生长发育受到影响,造成籽粒产量的下降。因此,在糜子生产上要进行合理的轮作倒茬,从而减缓连作障碍,实现糜子高产优质。     

谷子精少量流体排种装置的设计与试验

为解决中国北方旱地谷子播种难、播后出苗率低的问题,根据谷子免间苗精少量播种农艺要求,采用农用保水剂和水配制了谷子种粒混合悬浮液(mixed suspension),并针对其设计试制了谷子精少量流体排种装置。该文设计确定了输送泵滚轮数为6个及分合式排种管组合结构与尺寸参数,其中泵管、长弯排种管、短弯排种管、末端排种管的内径分别为4.8、4、4、4 mm,长度分别为700、100、74.4、20 mm;并阐述了流体排种装置吸种、输种、排种工作过程。以种粒数变异系数为指标对配制的谷子种粒混合悬浮液的均匀性和稳定性进行了试验测定;以种粒破碎率、穴距合格率、穴粒数合格率、空穴率为指标对流体排种装置进行了室内排种试验;以穴距合格率、穴株数合格率、出苗率为指标进行了田间播种试验。结果表明,谷子种粒混合悬浮液中保水剂、谷子种粒、水的质量比为1.1∶10∶200,其静置0.5 h后种粒数变异系数为9.8%,谷子种粒混合悬浮液在静置5 h内的种粒数变异系数为9.7%~10.4%,谷子种粒未发生沉降现象;室内排种试验种粒破碎率小于0.01%、穴距合格率大于86%、穴粒数合格率大于75%、空穴率小于4.0%;田间播种试验穴距合格率大于77%、穴株数合格率大于74%、出苗率大于87%。该研究可为小颗粒种子精少量流体播种技术与装备的研发提供参考。     

Scavenging capacity of berry crops on superoxide radicals, hydrogen peroxide, hydroxyl radicals, and singlet oxygen

The antioxidant activities against superoxide radicals (O(2)(*)(-)), hydrogen peroxide (H(2)O(2)), hydroxyl radicals (OH(*)), and singlet oxygen ('O(2)) was evaluated in fruit juice from different cultivars of thornless blackberries (Rubus sp.), blueberries (Vaccinium spp.), cranberries (Vaccinium macrocarpon Aiton), raspberries (Rubus idaeus L. and Rubus occidentalis L.), and strawberries (Fragaria x ananassa Duch.). Among the different cultivars, juice of 'Hull Thornless' blackberry, 'Earliglow' strawberry, 'Early Black' cranberry, 'Jewel' raspberry, and 'Elliot' blueberry had the highest antioxidant capacity against superoxide radicals (O(2)(*)(-)), hydrogen peroxide (H(2)O(2)), hydroxyl radicals (OH(*)), and singlet oxygen ('O(2)). In general, blackberries had the highest antioxidant capacity inhibition of O(2)(*)(-), H(2)O(2), and OH(*). Strawberry was second best in the antioxidant capacity assay for these same free radicals. With regard to 'O(2) scavenging activity, strawberry had the highest value, while blackberry was second. Cranberries had the lowest inhibition of H(2)O(2) activity. Meanwhile, blueberries had the lowest antioxidant capacity against OH(*) and 'O(2). There were interesting and marked differences among the different antioxidants in their abilities to scavenge different reactive oxygen species. beta-Carotene had by far the highest scavenging activity against 'O(2) but had absolutely no effect on H(2)O(2). Ascorbic acid was the best at inhibiting H(2)O(2) free radical activity. For OH(*), there was a wide range of scavenging capacities from a high of 15.3% with alpha-tocopherol to a low of 0.88% with ascorbic acid. Glutathione had higher O(2)(*)(-) scavenging capacity compared to the other antioxidants.     

硅对水稻病程相关蛋白活性和酚类物质含量的影响及其与诱导抗性的关系

为阐明硅提高水稻抗稻瘟病的生理机制,采用室内溶液培养试验,研究了硅对接种稻瘟病菌后水稻叶片的几丁质酶和β-1,3-葡聚糖酶活性以及总可溶性酚和木质素含量的影响。结果表明,接种稻瘟病菌能诱导几丁质酶活性的快速上升,不施硅处理的几丁质酶活性在第2 d达到第一个峰值后就开始下降,而施硅处理的几丁质酶活性则继续上升直到第4 d才开始下降,从第4～8 d显著高于不施硅处理。β-1,3-葡聚糖酶活性在接种后的第4 d之前均上升缓慢,处理间差异不显著;第4 d后开始上升,到第8 d达到最大值;不施硅处理上升更快,显著高于施硅处理。接种稻瘟病菌能诱导水稻叶片总可溶性酚含量快速上升,施硅处理和不施硅处理分别在接种后的第3和第4 d达到峰值,并开始快速下降;施硅能显著提高总可溶性酚含量。水稻叶片中的木质素含量在接种后的第1 d快速上升,并维持较高水平,施硅处理显著高于不施硅处理;但在感病后期（第6 d）,施硅处理开始显著低于不施硅处理。     

Scavenging of free radicals, antimicrobial, and cytotoxic activities of the Maillard reaction products of beta-lactoglobulin glycated with several sugars

The Maillard reaction occurs during many industrial and domestic thermal treatments of foods. It is widely used because of its role in creating colors, flavors, textures, and other functional properties in foodstuffs. Proteins glycated without the use of conventional chemical reagents have improved technofunctional properties such as heat stability, emulsifying, and foaming properties. The present study was carried out to determine the extent to which this reaction can convey antioxidant, antimicrobial, or cytotoxic activities to beta-lactoglobulin (BLG) and to its tryptic and peptic hydrolysates. BLG was modified with six different sugars in solution at 60 degrees C. Antiradical properties were estimated using a radical scavenging activity test. Antimicrobial activities against different bacterial strains were studied with a diffusion disk method. Cytotoxic tests were performed using two cell lines and the 3-(4,5-dimethylthiazoyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT) rapid colorimetric assay. Glycation induced a radical scavenging activity to BLG, the intensity of which depended on the sugar used for modification. Proteins modified with ribose and arabinose showed the highest radical scavenging activities depicted by about 80 and 60% of 2,2-diphenyl-1-picrylhydrazyl (DPPH) absorption decrease at 515 nm. No antimicrobial effect of any glycated form of BLG against Escherichia coli, Bacillus subtilis, Listeria innocua, and Streptococcus mutans was observed. The MTT test showed no enhancement of cytotoxicity by modified proteins and peptides against COS-7 and HL-60 cells. Thus, glycated proteins could be used in formulated food as functional ingredients with a radical scavenging activity able to delay deterioration due to oxidation. This use could be even more advisable considering the lack of toxicity to eukaryotic and prokaryotic cell cultures demonstrated in this work.     

Inhibitory effect of known antioxidants and of press juice from herring (Clupea harengus) light muscle on the generation of free radicals in human monocytes

Reactive oxygen species (ROS) can cause oxidative stress, which has been linked to various diseases. It has been suggested that antioxidant-rich foods can reduce such oxidative stress. However, the lack of suitable model systems to screen for in vivo effects of food-derived antioxidants has prevented a clear consensus in this area. In this study, the aim was to use a single-cell model system (human monocyte) to evaluate whether certain pure antioxidants and complex muscle extracts (herring light muscle press juice, PJ) could prevent ROS formation under in vivo like conditions. ROS were excreted from the monocytes upon stimulation with phorbol myristate acetate and were then detected as isoluminol-enhanced chemiluminescence (CL). Adding 2000 units of catalase and 50 units of superoxide dismutase to the monocytes model lowered the CL response by 35 and 86%, respectively. Ascorbate (14.1 mM) lowered the response by 99%, alpha-tocoperhol (188 microM) by 37%, and Trolox (50 microM) by almost 100%. Crude herring PJ gave a dose-dependent reduction in the CL response. At 10, 100, and 1000 times dilution, the PJ reduced the CL signal by 93, 60.5, and 10.6%. PJ fractionated into low molecular weight (LMW) (<1000 Da) and high molecular weight (>3500 Da) fractions decreased the CL response by 52.9 and 71.4%, respectively, at a 100-fold dilution. Evaluation of the PJ samples in the oxygen radical absorbance capacity test indicated that proteins may be the primary radical scavenging compounds of PJ, whereas the ROS-preventing effect obtained from the LMW fraction may also be attributed to other mechanisms. Thus, this study proved that the monocyte assay can be a useful tool for studying whether food-derived antioxidants can limit ROS production under physiologically relevant conditions. It also showed that herring contains numerous aqueous compounds demonstrating antioxidative effects in the monocyte model system.     

Concentration of isoflavones and other phenolics in the aerial parts of Trifolium species

Some species of the genus Trifolium are well-known for their content of isoflavones, which are natural compounds showing health-promoting activities. Until recently, only a few species of this genus have been characterized with respect to their composition. In the present study, 57 Trifolium species have been analyzed for their contents of isoflavones, phenolic acids, flavonoids, and clovamides. The cluster analysis of experimental data allowed us to identify a number of species, which should be of interest as potential sources of these metabolites. The isoflavone contents of the three species ( T. heldreichianum, T. scabrum, and T. subterraneum) had extremely high amounts of these compounds, reaching 7-9% of dry matter, and the concentration in a number of other species was higher or at least comparable to the amounts occurring in T. pratense, one of the major isoflavone sources for the nutraceutical industry. Several species contained high amounts of all four analyzed groups of phenolics (isoflavones, phenolic acids, flavonoids, and clovamides). These species may also be of great interest as the association of several groups of active molecules is highly desired for effective disease prevention.     

锌素营养对春玉米内源激素与氧自由基代谢的影响

采用田间试验、植株化学分析和生理测定方法 ,研究了锌肥用量对春玉米内源激素与氧自由基代谢的影响。结果表明 ,土壤缺锌条件下 ,玉米子粒形成期间穗叶锌素含量不施锌处理 (对照 )始终处于亏缺状态 ,而供锌充足处理此阶段均不缺锌。土壤缺锌条件下吲哚乙酸 (IAA)和赤霉素 (GA3)的生物合成减少 ,施锌有利于提高生长后期穗叶超氧物歧化酶 (SOD)活性 ,降低丙二醛 (MDA)含量 ,从而降低氧自由基的伤害。     

Immunomodulatory and antitumor activities of grape seed proanthocyanidins

Proanthocyanidins are naturally occurring compounds that are widely available in many kinds of plants; particularly, the grape seeds are a rich source of proanthocyanidins. Grape seed proanthocyanidins (GSPs) have been demonstrated to possess a wide range of health beneficial properties. This study was carried out to elucidate the molecular mechanisms involved in the antitumor therapeutic and immunomodulating effects of GSPs through in vivo and in vitro models. The results showed that GSPs could significantly inhibit the growth of Sarcoma 180 tumor cells in vivo and remarkably increase thymus and spleen weight of Sarcoma 180-bearing mice and upgrade the secretion level of tumor necrosis factor-α (TNF-α) in serum. Moreover, GSPs could stimulate lymphocyte transformation, enhance lysosomal enzyme activity and phagocytic capability of peritoneal macrophages, and remarkably promote the production of TNF-α. These results suggested that GSPs could improve functional activation of the immune system, and the antitumor effects of GSPs were achieved by immunostimulating properties.     

Ca(NO3)2胁迫对嫁接番茄生长、抗氧化酶活性和活性氧代谢的影响

以“影武者”为砧木,“宝大903”为接穗,在营养液栽培条件下,对80 mmol/L Ca(NO3)2胁迫下番茄嫁接苗和自根苗的生长、叶片抗氧化酶活性、活性氧代谢以及渗透调节物质含量进行了比较。结果表明,Ca(NO3)2胁迫明显抑制植株生长,显著提高植株抗氧化酶活性,显著增加植株O2.-生成速率以及H2O2、MDA、脯氨酸和可溶性蛋白含量,但胁迫后嫁接苗的生物量显著高于自根苗,抗氧化酶活性、脯氨酸和可溶性蛋白含量均显著高于自根苗,而O2.-生成速率、H2O2和MDA含量则显著低于自根苗。以上结果表明,Ca(NO3)2胁迫下较高的抗氧化酶活性和渗透调节物质含量以及较低的氧化损伤与番茄嫁接苗耐盐性增强有关。     

Identification and in vitro biological activities of hop proanthocyanidins: inhibition of nNOS activity and scavenging of reactive nitrogen species

Oligomeric proanthocyanidins constitute a group of water-soluble polyphenolic tannins that are present in the female inflorescences (up to 5% dry wt) of the hop plant (Humulus lupulus). Humans are exposed to hop proanthocyanidins through consumption of beer. Proanthocyanidins from hops were characterized for their chemical structure and their in vitro biological activities. Chemically, they consist mainly of oligomeric catechins ranging from dimers to octamers, with minor amounts of catechin oligomers containing one or two gallocatechin units. The chemical structures of four procyanidin dimers (B1, B2, B3, and B4) and one trimer, epicatechin-(4beta-->8)-catechin-(4alpha-->8)-catechin (TR), were elucidated using mass spectrometry, NMR spectroscopy, and chemical degradation. When tested as a mixture, the hop oligomeric proanthocyanidins (PC) were found to be potent inhibitors of neuronal nitric oxide synthase (nNOS) activity. Among the oligomers tested, procyanidin B2 was most inhibitory against nNOS activity. Procyanidin B3, catechin, and epicatechin were noninhibitory against nNOS activity. PC and the individual oligomers were all strong inhibitors of 3-morpholinosydnonimine (SIN-1)-induced oxidation of LDL, with procyanidin B3 showing the highest antioxidant activity at 0.1 microg/mL. The catechin trimer (TR) exhibited antioxidant activity more than 1 order of magnitude greater than that of alpha-tocopherol or ascorbic acid on a molar basis.