大豆抗氧化活性肽研究进展

自由基能够引起机体衰老、肿瘤等一系列疾病的发生,大豆抗氧化活性肽具有清除羟自由基、清除超氧阴离子自由基、抑制脂肪氧合酶活力和抑制脂质过氧化链式反应等功效。本文综述了自由基的形成、大豆抗氧化活性肽的抗氧化防御机理、制备方法和发展前景等方面近年来的研究概况。     

Antioxidative effect of cactus pear fruit (<Emphasis Type="Italic">Opuntia ficus-indica</Emphasis>) extract on lipid peroxidation inhibition in oils and emulsion model systems

The lipid peroxidation inhibitory effects of cactus pear fruit (Opuntia ficus-indica) extracts (CPFE) on fish oil, fish oil-in-water emulsion and linoleic acid were studied using conjugated diene hydroperoxides (CDH), weight gaining, peroxide value (PV), and thiobabituric acid reactive substances (TBARS) assays. A modified DPPH assay was used in the characterization of CPFE antioxidants for their thermal stability. CPFE successfully controlled lipid peroxidation at different stages of the pathway in a dose-dependent manner. Inhibition of the lipid peroxidation in oils and emulsion was successfully improved by increasing the level of CPFE from 0.01 to 0.1%. CPFE controlled conjugated diene formation from lipid radicals, demonstrating lower conjugated diene hydroperoxide values than its control counterpart. Moreover, it controlled the addition of oxygen to conjugated dienes to form lipid peroxyl radicals, resulting in lower weight gain. It also recorded a lower PV than its control counterpart, indicating its inhibitory effect on peroxyl radical formation. Such multiple and integrated effects controlled the overall lipid peroxidation, resulting in lower TBARS values than the control. Characterization of the CPFE antioxidants proved that those antioxidants are heat-resistant, although the color of the CPFE pigments disappeared rapidly.     

Activated oxygen species and oxidation of food constituents

Activated oxygen species which may be important in initiating oxidative changes in foods include singlet oxygen, hydroxyl radical, ozone, superoxide anion (perhydroxyl radical at low pH), and hydrogen peroxide. Chemical and enzymic reactions known to occur in biological materials can generate singlet oxygen, hydroxyl radical, superoxide anion, and hydrogen peroxide. Ozone is primarily a product of photoreactions in polluted air. Reactions involving singlet oxygen, hydroxyl radical, and ozone with food constituents can ultimately yield peroxides which decompose to initiate oxidative chain reactions. Superoxide anion and hydrogen peroxide are relatively inert toward organic molecules but can decompose to produce the more reactive singlet oxygen and hydroxyl radical. Inhibition of reactions initiated by reactive oxygen species in foods should be very important in preserving the oxidative stability of foods. The generation, detection, measurement, reaction, and inhibition of reactions of active oxygen species are surveyed in this review.     

Activated oxygen species and oxidation of food constituents.

Activated oxygen species which may be important in initiating oxidative changes in foods include singlet oxygen, hydroxyl radical, ozone, superoxide anion (perhydroxyl radical at low pH), and hydrogen peroxide. Chemical and enzymic reactions known to occur in biological materials can generate singlet oxygen, hydroxyl radical, superoxide anion, and hydrogen peroxide. Ozone is primarily a product of photoreactions in polluted air. Reactions involving singlet oxygen, hydroxyl radical, and ozone with food constituents can ultimately yield peroxides which decompose to initiate oxidative chain reactions. Superoxide anion and hydrogen peroxide are relatively inert toward organic molecules but can decompose to produce the more reactive singlet oxygen and hydroxyl radical. Inhibition of reactions initiated by reactive oxygen species in foods should be very important in preserving the oxidative stability of foods. The generation, detection, measurement, reaction, and inhibition of reactions of active oxygen species are surveyed in this review.     

In vitro antioxidant properties of rutin

Much work has been carried out in recent years on the beneficial effect of phenolic compounds which act as natural antioxidants and help to neutralize free radicals. We analysed the antioxidant activity of the rutin (quercetin-3-rhamnosyl glucoside) using different assays including: total antioxidant activity and reducing power, hydroxyl radical scavenging assay, superoxide radical scavenging assay, 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assay and lipid peroxidation assay which uses egg yolk as the lipid-rich source. Total antioxidant capacity was determined by the assay based on the decrease in absorbance of β-carotene by the sample. Rutin exhibited strong DPPH radical scavenging activity. At the concentration of 0.05 mg/ml, ascorbic acid (Vc), butylated hydroxytoluene (BHT) and rutin showed 92.8%, 58.8%, and 90.4% inhibition, respectively. In addition, rutin had effective inhibition of lipid peroxidation. Those various antioxidant activities were compared to standard antioxidants such as BHT and Vc.     

响应面法优化碱蒿黄酮提取工艺及其体外抗氧化作用

用响应面法优化野生碱蒿黄酮类化合物的提取条件,通过羟自由基、超氧阴离子自由基、总还原力及脂质抗氧化实验测定碱蒿黄酮的体外抗氧化作用,并与抗坏血酸的抗氧化能力进行比较。结果表明提取工艺最佳条件为：提取温度80℃、提取时间1.75h、液料比27.5:1(mL/g)、提取2次,该条件下黄酮提取率预测值3.002%,验证值2.996%。对碱蒿黄酮的抗氧化研究表明,碱蒿黄酮对超氧阴离子自由基的清除作用与抗坏血酸比相对较弱,但对清除羟自由基、抗脂质体过氧化及还原能力均表现出较好的效果,是一种天然有效的抗氧化剂。     

蓝莓花色苷抗氧化活性的研究

采用4种体外实验模型对蓝莓花色苷抗脂质体过氧化、还原力和清除羟基自由基、超氧阴离子自由基进行了研究,并与抗坏血酸进行比较。结果表明:蓝莓花色苷具有抗脂质体过氧化能力,还原能力和清除羟基自由基、超氧阴离子自由基能力。蓝莓花色苷抗脂质体过氧化能力强于抗坏血酸;还原能力和清除超氧阴离子自由基不如抗坏血酸;低浓度时,花色苷清除羟基自由基和抗坏血酸接近,高浓度时强于抗坏血酸。蓝莓花色苷抗脂质过氧化、清除羟基自由基和超氧阴离子自由基的IC_(50)分别为165.97、141.12、345.71μg/mL。     

肉桂精油抗氧化性能及清除自由基能力的研究

对肉桂精油(CEO)的抗氧化和清除游离基活性的比较是基于总体抗氧化能力、清除超氧阴离子自由基能力、清除羟基自由基能力、抗亚油酸脂质过氧化能力、清除DPPH自由基5个方面,并与其他的合成抗氧化剂如BHT、PG做比较。实验结果表明,在一定浓度范围内,CEO的羟自由基清除能力强于BHT和PG;清除超氧阴离子自由基的能力强于PG;清除DPPH自由基能力、抗氧化活性比BHT和PG弱;CEO抑制亚油酸的过氧化能力比BHT和PG略弱。实验表明了CEO在某些方面具有良好的抗氧化效果。     

油菜蜂花粉酶解物抗氧化性能的研究

对油菜蜂花粉酶解物和水提物进行了体外抗氧化实验。结果表明,花粉酶解物具有良好的抗氧化功能,在50mg/ml浓度下对超氧阴离子自由基、羟自由基和脂质过氧化的抑制率分别达到87．4%、61．2%和95．9%。比较酶解物和水提物抗氧化性能可知,酶解物清除羟自由基和超氧阴离子自由基的能力明显高于水提物,在50mg／ml时,对羟自由基的抑制率比水提物高约30%,清除超氧阴离子自由基的能力高约20%,而抑制脂质过氧化的能力与水提物之间无明显差异。     

Effects of hydroperoxide in lipid peroxidation on dough fermentation

The effects on dough fermentation of hydroperoxides produced by lipid peroxidation through lipoxygenase induction were studied. The mechanism by which hydroperoxides accelerated dough fermentation was also investigated. Dough with lipoxygenase had a significantly increased amount of hydroperoxides after 90 min of fermentation, while dough without lipoxygenase had less generation of hydroperoxides until 30 min, after that time hydroperoxide generation decreased gradually. A hydroperoxide concentration of 30–40 mM had the greatest effect on accelerating dough fermentation. In the dough with hydroperoxides, the maximum expansion rate occurred with a 1% yeast concentration and a gluten concentration of 60%. The mechanism of dough fermentation using lipid peroxidation by lipoxygenase induction is discussed in detail. Gluten is formed from gliadin and glutenin. Gluten was denatured by hydroperoxides, which makes the gluten molecule grow larger (molecular weight of approximately 53 kDa). Fermentation is promoted by this phenomenon. This information provides new information for the bread-making industry.     

紫皮甘蔗天然红色素功能活性研究

从紫皮甘蔗中提取甘蔗红色素,研究该色素对超氧阴离子自由基、羟自由基、DPPH 自由基及NO2 的清除作用,以及在动物油和植物油中的抗氧化能力,以此来评价红色素的功能活性。结果表明：甘蔗红色素对超氧阴离子自由基、羟自由基和DPPH 自由基均有良好的清除作用,对NO2 的清除作用不太显著;在油脂中具有一定的抗氧化能力,在猪油中的抗氧化能力强于在豆油中的抗氧化能力。     

Reactive oxygen species responsible for beta-glucan degradation

The presence of iron(II) in beta-glucan in solution causes the formation of hydroxyl radical, which further oxidises the polysaccharide. This degradation can be enhanced by the presence of a reducing agent, such as ascorbic acid. In this study we investigated the effect the iron(II) concentration on the hydroxyl radical-mediated degradation of beta-glucan and identified the intermediate species involved in the formation of hydroxyl radicals. An increase in the iron(II) concentration did not have a significant effect on the degradation in the presence of a reducing agent (ascorbic acid), while in the mere presence of iron(II) it accelerates the degradation. The addition of catalase and superoxide dismutase (SOD) prevented the hydroxyl radical driven-degradation of beta-glucan induced by iron(II) or ascorbic acid/iron(II), demonstrating the involvement of both superoxide and hydrogen peroxide in the hydroxyl radical formation. SOD, which catalyses the dismutation of superoxide into hydrogen peroxide, should have stimulated the formation of radicals, since these radicals are generated from the reaction between hydrogen peroxide and iron(II). In the present study, we hypothesise the mechanism of the inhibition of beta-glucan degradation by superoxide dismutase.     

甘薯糖蛋白的体外抗氧化作用研究

经水溶提取、乙醇沉淀、凝胶过滤层析，从广薯98中提取甘薯糖蛋白，并研究了甘薯糖蛋白对超氧阴离子自由基、羟基自由基的清除作用，以及对肝微粒体脂质过氧化产物丙二醛的抑制作用和对H2O3引起红细胞溶血的抑制作用。结果表明，甘薯糖蛋白能有效地清除超氧阴离子自由基和羟基自由基，并能明显地抑制肝微粒体脂质过氧化产物丙二醛的生成，但不能抑制H2O2引起的红细胞溶血。     

赤魟肝脏活性蛋白体外抗氧化作用

采用硫酸铵沉淀、Sephadex G-150 柱层析的方法从赤魟肝脏分离活性蛋白,测定活性蛋白清除超氧阴离子自由基、羟自由基和抑制脂质过氧化作用。结果显示：分离得到的3 个蛋白峰P1、P2 和P3 都具有清除超氧阴离子自由基、羟自由基和抑制脂质过氧化作用,P2 和P3 的抑制作用明显大于P1,P3 的抑制作用最强。实验表明赤魟肝脏活性蛋白具有抗氧化作用。     

沙棘籽蛋白酶解物抗氧化作用初探

研究了沙棘籽蛋白酶解物的抗氧化能力。以沙棘果籽为原材料,制备沙棘籽蛋白酶解物,测定其还原能力、抗脂质过氧化活性以及羟基自由基引起DNA损伤的保护作用;测定其对超氧阴离子自由基、羟基自由基和DPPH自由基的清除率。结果表明:沙棘籽蛋白酶解物具有较强的还原能力,对光照核黄素产生的超氧阴离子自由基、羟自由基和DPPH自由基均有较强的清除作用;具有抗脂质过氧化的活性和羟基自由基引起DNA损伤的保护作用。研究表明,沙棘籽蛋白酶解物是一种优良的天然抗氧化剂。     

Antioxidative activities of bran extracts from twenty one pigmented rice cultivars

Ethanol–water (70:30, v/v) extracts from the bran of rice seeds from twenty one pigmented and one nonpigmented rice cultivars were evaluated for antioxidative activities using the following tests: inhibition of peroxidation of linoleic acid; inhibition of peroxidation of rabbit lipid erythrocyte membranes; reduction of potassium ferricyanide, and scavenging of superoxide anions and hydroxyl radicals. With some exceptions, extracts from the pigmented rice seeds had higher antioxidative activity than did the nonpigmented variety. The following pigmented cultivars had the highest antioxidative activities in all tests: Jumlalocal-1, Parnkhari 203, DZ78, LK1-3-6-12-1-1, and Elwee. A significant correlation was also noted between reducing power, inhibition of erythrocyte ghost membrane peroxidation, and superoxide anion and hydroxyl radical scavenging. The results suggest that: (a) ferricyanide reducing power might be a useful and simple index for large-scale evaluation of antioxidative potencies of natural products present in rice; (b) pigmented rice varieties with high antioxidative activities provide a source of antioxidants and a genetic resource to develop new health-promoting rice cultivars.     

Iron-chelating ability and antioxidant properties of phycocyanin isolated from a protean extract of Spirulinaplatensis

The invitro scavenger activities of different reactive oxygen species (superoxide radical, hydroxyl radical, hydrogen peroxide, hypochlorous acid and peroxyl radical), the effects on lipid peroxidation and the iron-chelating ability of a Spirulinaplatensis protean extract and the biliprotein, phycocyanin, isolated from this microalga were studied. S. platensis protean extract inhibited the generation of hydroxyl radical (IC₅₀ = 537 μg/ml for the system with EDTA and 1500 μg/ml without EDTA), the production of peroxyl radical (IC₅₀ = 230 μg/ml), and the lipid peroxidation process (IC₅₀ = 2320 μg/ml for the enzymatic system and 2180 μg/ml for the non-enzymatic system). Besides, phycocyanin inhibited hydroxyl and peroxyl radicals and the lipid peroxidation process. The iron ions decreased the maximum fluorescence emission spectra of S. platensis protean extract and phycocyanin and it was an indicator of the metal-chelating activity. The antioxidant properties of S. platensis and phycocyanin may arise from both radical-scavenging and metal chelation. Our results suggest that S. platensis could be used as a dietary supplement to prevent some diseases where free radicals are involved.     

Scavenging ability on ROS of alpha-lipoic acid (ALA)

The scavenging ability of alpha-lipoic acid (ALA) towards superoxide anions, hydroxyl radicals and hydrogen peroxide was evaluated by means of chemiluminescence (CL). In neutral or acid conditions, ALA could scavenge superoxide anions and its scavenging efficiency depended on its concentration. In neutral or alkaline conditions, the CL intensity of the reaction of ALA with hydroxyl radical (OH radicals) decreased after the first 10 min and then increased with time, suggesting that ALA could scavenge OH radicals at the beginning, but yielded unknown intermediate products that could lead to the increase of CL intensity at later stages. The increase of CL intensity in the reaction of hydrogen peroxide with ALA may also be due to these products.     

Antioxidant activity of natural vitamin E extracted from soybean sludge as assessed by chemiluminescence

The antioxidant activity of natural vitamin E (VE) towards superoxide anion, hydroxyl radical and lipid free radicals was investigated using a chemiluminescence technique. VE was extracted from soybean sludge, where it was present at a concentration of 600 g kg^?1 as determined by HPLC. Superoxide anions, hydroxyl radicals and lipid free radicals were generated by the pyrogallol autoxidation system, the Fenton reaction system and the AAPH‐induced γ‐linolenic acid peroxidation system respectively. VE rapidly scavenged hydroxyl radicals and lipid free radicals. The efficient concentration (EC₅₀) of VE against both was 0.1 mg ml^?1. A reaction time of 6 s was adequate to scavenge hydroxyl radicals and a reaction time of 24 s was enough to scavenge lipid free radicals. However, VE scavenged superoxide anions at a relatively low rate, and the extent of scavenging was less than 20% even after 3 min at a VE concentration of 4.3 mg ml^?1. © 2001 Society of Chemical Industry     

Antioxidant properties of Cortex Fraxini and its simple coumarins

We present the antioxidant properties of crude extract, fractions and ingredients of Cortex Fraxini (CF) and compare the antioxidant capacities of coumarin ingredients of CF and known antioxidants, including catechin, quercetin, ascorbic acid, trolox and BHT. The IC₅₀ values for CF in the DPPH and TEAC methods were 406 and 39.3 μg/ml, respectively. Among all fractions the chloroform fraction is the most active fraction in scavenging DPPH, ABTS and hydroxyl radicals, and there is a significant relationship between the antioxidant activities and the contents of the antioxidant phenolic ingredients. The contents of esculetin and fraxetin in the chloroform fraction were 8.44% and 11.1%, respectively. Esculetin and fraxetin also had good radical-scavenging capacities, and esculetin was the best, among all test compounds, against the DPPH radical. Moreover, esculetin and fraxetin had selective scavenging activity upon hydroxyl radicals and hydrogen peroxide, and this potency was better than known antioxidants and equal to quercetin in scavenging hydrogen peroxide. These results show that CF, partitioned with chloroform, gave a phenolic coumarin-enriched fraction, and that this fraction had the best free radical-scavenging activity and inhibition of Fe²⁺/ascorbate-induced lipid peroxidation, mainly due to its reducing power.