广东石豆兰不同溶剂提取物抗氧化及与总黄酮、总酚含量的关系

为明确广东石豆兰的抗氧化能力及抗氧化成分,以鳞茎为材料,以甲醇、乙醇、丙酮和乙酸乙酯为提取剂得到4种提取物,测定了4种提取物中总黄酮、总酚含量及其抗氧化活性,并分析了两者之间的关系。结果表明,石豆兰总酚含量高于总黄酮,乙醇为总酚和总黄酮2种物质的最佳提取溶剂;甲醇提取物对羟基自由基清除力和对Fe²⁺的螯合力最强,对DPPH自由基清除效果最差;丙酮提取物具有最强的总还原力和清除超氧阴离子的能力,而清除羟基自由基能力最弱;乙酸乙酯提取物清除DPPH自由基的能力最强,但总还原力、清除超氧阴离子的能力、Fe²⁺的螯合力最弱。此外,除了DPPH自由基外,其他4个抗氧化指标与总黄酮或总酚含量呈正相关(0.185<r<0.969),总还原力与总黄酮含量呈显著相关。本研究结果为广东石豆兰抗氧化物质的提取及进一步开发利用提供了参考依据。     

黑水虻幼虫蛋白质的制备及体外抗氧化活性

本文主要研究黑水虻幼虫蛋白质的制备及其体外抗氧化活性。以黑水虻幼虫为原料,采用碱提酸沉法提取黑水虻幼虫蛋白质,并于等电点沉淀,沉淀复溶后再浓缩、透析、冻干。分别测定了其总还原力,超氧阴离子自由基清除活性、羟基自由基清除活性、DPPH自由基清除活性、ABTS自由基清除活性、金属离子螯合能力及脂质体系中抗氧化能力,并将其体外抗氧化能力与维生素C(测定金属离子螯合能力时与EDTA)和卵清白蛋白进行比较。结果显示:BSFLP的等电点在4.8左右,并且该法所提蛋白纯度较高,表明利用碱提酸沉法对黑水虻幼虫进行蛋白的提取的方法可行。BSFLP的总还原力约是VC的0.013倍,是OVA的1.319倍;BSFLP的超氧阴离子自由基清除活性强于OVA,而弱于VC;其清除羟基自由基、清除DPPH自由基、清除ABTS自由基、螯合亚铁离子、亚油酸体系中抑制过氧化的IC50分别为2.577、3.965、0.228、0.876、5.050 mg·m L-1,也均介于VC(或EDTA)和OVA之间,说明BSFLP具有较高的体外抗氧化活性。本文为黑水虻的进一步研究与综合利用及抗氧化功能蛋白食品的研发提供了一定的依据。     

超微粉碎对青稞麸皮粉多酚组成及抗氧化活性的影响

为评价超微粉碎对青稞麸皮多酚、体外抗氧化活性和淀粉消化酶抑制活性的影响。该研究制备了3种粒径分别为335.94、72.52、22.69μm的青稞麸皮粉体,对3种粉体的多酚、黄酮含量及其组成、体外抗氧化活性与淀粉消化酶活性抑制率进行测定。结果表明:与粗粉相比,2种微粉的多酚(游离酚、结合酚)、黄酮和总酚含量均显著高于粗粉(P0.05)且粒径越小,含量越高;青稞麸皮粉共检出19种酚酸,其中游离酚以阿魏酸和藜芦酸为主,结合酚以阿魏酸和苯甲酸为主;随着粒径的减小,粉体多酚提取物的抗氧化活性(DPPH·自由基清除能力、FRAP还原能力、ABTS~+·自由基清除能力)及对α-葡萄糖苷酶、α-淀粉酶抑制率均显著增强(P0.05);粉体多酚组成及含量与体外抗氧化活性及淀粉消化酶活性抑制率存在一定的相关性。相关分析结果表明:青稞麸皮游离酚提取物中2,4-二羟基苯甲酸、藜芦酸是清除DPPH·自由基、抑制α-葡萄糖苷酶活性的主要贡献物质,阿魏酸是抑制α-葡萄糖苷酶及α-淀粉酶活性的主要物质;结合酚提取物中2,4-二羟基苯甲酸是抑制α-淀粉酶活性的主要物质。该结果显示超微粉碎一定程度上可提高青稞麸皮中多酚含量、体外抗氧化活性及淀粉消化酶抑制率,可作为青稞麸皮食品的一种有效前处理加工手段。     

人心果不同溶剂提取物的抗氧化活性研究

以人心果果实为研究材料,以水、甲醇、70%乙醇、乙酸乙酯和石油醚共计5种溶剂对人心果果实部位进行提取,对5种提取剂提取的样液分别进行DPPH自由基清除活性、铁离子还原能力(FRAP)、ABTS自由基清除活性及总黄酮含量进行测定。结果表明,使用不同溶剂的人心果提取样液测定结果中存有一定的差别,样液抗氧化活性由高到低的排序为:70%乙醇乙酸乙酯甲醇水石油醚;此外,研究结果显示,人心果的抗氧化活性与总黄酮含量存在较好的相关性。     

铜藻多糖微波辅提工艺优化及其抗氧化活性研究

运用响应曲面法优化铜藻多糖(tong zao polysaccharide,TZP)微波辅助提取的工艺条件,利用分级醇沉法得到TZP30%、TZP60%和TZP80%3个多糖组分。并对其DPPH自由基、ABTS自由基、OH自由基和O2-自由基的清除能力及其还原力进行了研究。结果表明:铜藻多糖微波辅助提取的最佳条件为料液比1:65,提取温度72℃,提取时间39min,多糖提取率为12.02%(n=3);在试验浓度范围内,TZP30%组分对羟基自由基的清除能力最高达98.07%;TZP60%组分对DPPH自由基清除能力最高达85.01%;TZP80%组分对ABTS自由基清除能力较强,还原力较大。铜藻多糖具有较高的抗氧化活性,具有作为天然抗氧化剂的应用前景。     

酶解结合高剪切破壁技术对蜂花粉酚类物质及抗氧化活性的影响

为了提高蜂花粉体外抗氧化活性及其对质粒DNA氧化损伤的保护作用,该研究以荷花、枣花、茶花、油菜、玫瑰、五味子6种蜂花粉为对象,研究纤维素酶酶解结合高剪切破壁技术对蜂花粉酚类物质溶出的影响。破壁试验结果表明,采用质量分数1%~4%纤维素酶(荷花1%;枣花4%;茶花2%;油菜1%;玫瑰4%;五味子3%)结合30 s 10000~15000 r/min高剪切,6种蜂花粉均可达到90%以上破壁率。高效液相色谱-二极管阵列检测法(High Performance Liquid Chromatography-Diode Array Detection,HPLC-DAD)分析结果表明6种蜂花粉破壁后酚类物质的溶出量和种类均有不同程度增加,荷花蜂花粉没食子酸含量较破壁前增加6倍,枣花蜂花粉经破壁后山奈酚溶出,且含量较高,为10.31 mg/g,破壁后油菜蜂花粉没食子酸含量为11.59 mg/g,较破壁前提高59%。油菜蜂花粉总黄酮含量为29.6mg/g(以芦丁当量计),相较破壁前提高6.4倍,总酚含量为21.60 mg/g(以没食子酸当量计),相较未破壁提高1.5倍;体外抗氧化试验表明,破壁能够将枣花蜂花粉Fe²⁺络合力提高2.2倍,油菜蜂花粉Fe³⁺还原力提高8倍。破壁后荷花、枣花、茶花、油菜、玫瑰、五味子6种蜂花粉对pBR322质粒DNA氧化损伤的保护作用分别提高了60.5%、12.4%、287.7%、442.1%、82.5%、4.8%。结果表明,纤维素酶酶解结合高剪切破壁方法,能够促进蜂花粉酚类物质的溶出,增强体外抗氧化活性,有效预防DNA氧化损伤。研究结果为蜂花粉资源的开发与利用提供理论依据。     

3种热带果树叶子甲醇粗提物的抗氧化活性比较

为了研究热带果树的抗氧化活性,以木菠萝、人心果和龙眼叶为原料,经75%甲醇超声辅助提取,得到3种提取物。分别采用Folin-Ciocalteau法和分光光度法测定总酚和类黄酮含量;以维生素C为对照,分别测定各提取物对1,1-二苯基-2-三硝基苯肼自由基(DPPH·)、自由基阳离子(ABTS+·)、铁离子和钼离子的还原能力及金属螯合能力。结果表明:人心果叶、木菠萝叶和龙眼叶都具有较强的清除DPPH和ABTS自由基能力、对铁离子和钼离子还原能力和金属螯合能力,其中人心果叶活性最强,龙眼叶最弱,且抗氧化活性与总酚含量存在显著的相关性。人心果叶、木菠萝叶和龙眼叶是较好的抗氧化原料,将具有广阔的应用价值和利用前景。     

山核桃仁多酚组分分析及抗氧化研究

以山核桃仁多酚为原料,通过酸水解分析仁多酚内可能含有的有机酸成分,结果表明,仁多酚干物质经脱糖苷之后,可以形成自由的酚酸,检测到没食子酸及绿原酸含量分别为18.2mg·g-1及246.7mg/g干物质;同时山核桃仁多酚干物质进行体外抗氧化分析表明,仁多酚具有较高的抗氧化活性,对DPPH自由基和·OH自由基清除率较高,其抗氧化能力一定范围内与VC及BHA相当.     

黔产草珊瑚中黄酮类提取物的体外抗氧化研究

目的:研究黔产草珊瑚中黄酮类化合物的体外抗氧化活性。方法:采用铁氰化钾还原法、DPPH自由基、羟基自由基和超氧阴离子自由基清除试验,研究黔产草珊瑚黄酮的体外抗氧化活性。结果:黔产草珊瑚黄酮还原能力随着其质量浓度的增加而增强;对DPPH自由基清除能力强于V_C弱于BHT;对·OH清除能力弱于BHT,同VC清除能力相当;对O_2-·清除能力同V_C相当,而弱于BHT。结论:黔产草珊瑚黄酮具有较强的体外抗氧化活性。     

银杏花粉黄酮组分分离纯化及其清除DPPH自由基能力

为了分离纯化银杏花粉中具有潜在抗氧化活性的黄酮组分及研究其潜在抗氧化活性,该文对银杏花粉的总黄酮进行提取和分步萃取,采用1,1-diphenyl-2-picrylhydrazyl(DPPH)自由基清除率检测和组分分析锁定待纯化萃取相。通过DPPH-HPLC-PAD技术筛选目标清除自由基组分,并采用制备型液相色谱技术分离纯化这些组分,然后采用紫外可见吸收光谱、质谱、核磁共振氢谱、碳谱等技术进行结构鉴定,最后通过测定DPPH自由基清除率初步研究其潜在抗氧化活性。结果显示,银杏花粉粗提物具有清除DPPH自由基活性,对DPPH的半抑制率(IC50值)为1.32 mg/m L,乙酸乙酯相和正丁醇相的IC50值为0.46、0.84 mg/m L,分别是粗提物的34.85%和63.64%。可见,乙酸乙酯相的清除DPPH活性最高。进一步研究显示,乙酸乙酯相富集了6种主要银杏花粉黄酮,而且均具有清除DPPH活性。经纯化和结构鉴定分别为山奈酚-3,4’-双-O-β-D-葡萄糖苷(1)、山奈酚-3-O-β-D-葡萄糖基-7-O-α-L-鼠李糖苷(2)、山奈酚-3-O-β-D-葡萄糖苷(3)、山奈酚-3-O-α-L-鼠李糖苷(4)、柚皮素(5)和山奈酚(6)。其清除DPPH自由基的活性由高到低依次为:化合物6化合物2化合物3化合物4化合物1化合物5。其中山奈酚清除DPPH的IC50值为0.017 mg/m L,与维生素C及芦丁相比没有显著性差异(P0.05)。上述研究为银杏花粉功能成分的深入研究奠定了基础。     

Effects of extraction solvent mixtures on antioxidant activity evaluation and their extraction capacity and selectivity for free phenolic compounds in barley (Hordeum vulgare L.)

Four kinds of solvent extracts from three Chinese barley varieties (Ken-3, KA4B, and Gan-3) were used to examine the effects of extraction solvent mixtures on antioxidant activity evaluation and their extraction capacity and selectivity for free phenolic compounds in barley through free radical scavenging activity, reducing power and metal chelating activity, and individual and total phenolic contents. Results showed that extraction solvent mixtures had significant impacts on antioxidant activity estimation, as well as different extraction capacity and selectivity for free phenolic compounds in barley. The highest DPPH* and ABTS*+ scavenging activities and reducing power were found in 80% acetone extracts, whereas the strongest *OH scavenging activity, O2*- scavenging activity, and metal chelating activity were found in 80% ethanol, 80% methanol, and water extracts, respectively. Additionally, 80% acetone showed the highest extraction capacity for (+)-catechin and ferulic, caffeic, vanillic, and p-coumaric acids, 80% methanol for (-)-epicatechin and syringic acid, and water for protocatechuic and gallic acids. Furthermore, correlations analysis revealed that TPC, reducing power, DPPH* and ABTS*+ scavenging activities were well positively correlated with each other (p < 0.01). Thus, for routine screening of barley varieties with higher antioxidant activity, 80% acetone was recommended to extract free phenolic compounds from barley. DPPH* scavenging activity and ABTS*+ scavenging activity or reducing power could be used to assess barley antioxidant activity.     

菜籽蛋白加工废液中多酚和多糖同步提取工艺优化

为开发利用菜籽蛋白加工废液中的生理活性物质,该研究在单因素试验基础上,采用Box-Behnken响应面试验设计法,对菜籽蛋白加工废液中多酚和多糖提取工艺条件进行优化,同时探究两种物质的体外抗氧化活性。结果表明,影响菜籽蛋白加工废液中多酚和多糖得率的因素大小顺序为:乙醇体积分数浸提温度浸提时间,最佳提取工艺为:浸提温度60℃、乙醇体积分数65%、浸提时间31 min,在此条件下多酚得率为2.19%,多糖得率为8.14%;多酚提取物对DPPH·具有较强清除能力,其半抑制质量浓度为0.20 mg/mL,多糖提取物对DPPH·和·OH均具有较强的清除能力,其半抑制质量浓度分别为1.45、2.38 mg/mL;高效液相色谱法初步检测表明,菜籽蛋白加工废液中含有香豆酸、丁香酸、对香豆酸、芥子酸和苯甲酸。研究结果为菜籽蛋白加工废液的再利用提供参考。     

Variation in phenolic composition and antioxidant activity during flower development of safflower (Carthamus tinctorius L.)

This work was aimed to study the effect of extraction solvent system with varying polarities on polyphenol, flavonoid and proanthocyanidin contents and DPPH scavenging activity. Obtained results showed that phenolic contents and antioxidant activities varied considerably as function of solvent polarity. The extraction with acetone/water (2:8) showed the highest flower polyphenol content (15.09 mg GAE/g DW). Moreover, antiradical capacities against DPPH, chelating power and lipid peroxidation assay were maximal in acetone/water (2:8) of flower extract. Significant variation in antioxidant properties was observed between different development stages of Carthamus tinctorius flowers; the highest antioxidant activity was observed at stage III (full flowering) while phenolic composition reached its maximum at stage II (flower formation). Gallic acid was the most abundant phenolic compound in C. tinctorius orange flowers, accounting for about 102.57 (μg/g DW). Findings underline the potential health benefits as a result of consuming C. tinctorius flowers and suggest that it could be used as valuable flavor with functional properties for food or nutraceutical products on the basis of the high polyphenol contents and antioxidant activities.     

Effect of heat treatment of camelina (Camelina sativa) seeds on the antioxidant potential of their extracts

The effect of different heat treatments of camelina (Camelina sativa) seeds on the phenolic profile and antioxidant activity of their hydrolyzed extracts was investigated. The results showed that total phenol contents increased in thermally treated seeds. Heat treatment affected also the quantities of individual phenolic compounds in extracts. Phenolics in unheated camelina seeds existed in bound rather than in free form. A temperature of 160 °C was required for release of insoluble bound phenolics, whereas lower temperatures were found to be optimal to liberate those present as soluble conjugates. The best reducing power and alkyl peroxyl radical scavenging activity in the emulsion was expressed by phenolics which were bound to the cell wall, whereas the best iron chelators and 2,2-diphenyl-1-picrylhydrazyl (DPPH?) radical scavengers were found to be those present in free form. The heat treatment of seeds up to 120 °C increased the reducing power and DPPH? radical scavenging ability of extracts, but negatively affected iron chelating ability and their activity in an emulsion against alkyl peroxyl radicals.     

Evolution of phenolic compounds and antioxidant activity during malting

Two barley varieties, Gan4 and Hamelin, were malted to investigate the evolution of phenolic compounds and antioxidant activity during malting. The antioxidant activity was evaluated with DPPH radical scavenging activity, ABTS radical cation scavenging activity, reducing power, and metal chelating activity. Results showed that malting had significant influences on individual and total phenolic contents as well as antioxidant activities of two barley varieties. The contents of some phenolic compounds and the antioxidant activities decreased significantly during steeping and the early stages of germination and then increased remarkably during the later stages of germination and subsequent kilning. The most phenolic compounds identified in barley were (+)-catechin and ferulic acid, which both changed significantly during malting. Moreover, results from the Pearson correlation analysis showed that there were good correlations among DPPH radical scavenging activity, ABTS radical cation scavenging activity, reducing power, total phenolic content and sum of individual phenolic contents during malting.     

Determination of antioxidant and antimicrobial activities of Rumex crispus L. extracts

The antioxidant activities, reducing powers, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities, amount of total phenolic compounds, and antimicrobial activities of ether, ethanol, and hot water extracts of the leaves and seeds of Rumex crispus L. were studied. The antioxidant activities of extracts increase with increasing amount of extracts (50-150 microg). However, the water extracts of both the leaves and seeds have shown the highest antioxidant activities. Thus, addition of 75 microg of each of the above extracts to the linoleic acid emulsion caused the inhibition of peroxide formation by 96 and 94%, respectively. Although the antioxidant activity of the ethanol extract of seed was lower than the water extract, the difference between these was not statistically significant, P > 0.05. Unlike the other extracts, 75 microg of the ether extract of seeds was unable to show statistically significant antioxidant activity, P > 0.05 (between this extract and control in that there is no extract in the test sample). Among all of the extracts, the highest amount of total phenolic compound was found in the ethanol extract of seeds, whereas the lowest amount was found in the ether extract of seeds. Like phenolic compounds, the highest reducing power and the highest DPPH scavenging activity were found in the ethanol extract of seeds. However, the reducing activity of the ethanol extract of seeds was approximately 40% that of ascorbic acid, whereas in the presence of 400 microg of water and ethanol extracts of seeds scavenging activities were about 85 and 90%, respectively. There were statistically significant correlations between amount of phenolic compounds and reducing power and between amount of phenolic compounds and percent DPPH scavenging activities (r = 0.99, P < 0.01, and r = 0.864, P < 0.05, respectively) and also between reducing powers and percent DPPH scavenging activities (r = 0.892, P < 0.05). The ether extracts of both the leaves and seeds and ethanol extract of leaves had shown antimicrobial activities on Staphylococcus aureus and Bacillus subtilis. However, none of the water extracts showed antimicrobial activity on the studied microorganisms.     

Valorization of cauliflower (Brassica oleracea L. var. botrytis) by-products as a source of antioxidant phenolics

The present study reports the development of two extraction protocols, with potential industrial applicability, to valorize cauliflower (Brassica oleracea L. var. botrytis) byproducts as a source of antioxidant phenolics. In addition, the nonionic polystyrene resin Amberlite XAD-2 was used to obtain purified extracts. The extract yield, phenolic content, phenolic yield, and correlation between the antioxidant activity and the phenolic content were studied. The water and ethanol protocols yield a phenolic content of 33.8 mg/g freeze-dried extract and 62.1 mg/g freeze-dried extract, respectively. This percentage increased considerably when the extracts were purified using Amberlite XAD-2 yielding a phenolic content of 186 mg/g freeze-dried extract (water extract) and 311.1 mg/g freeze-dried extract (ethanol extract). Cauliflower byproduct extracts showed significant free radical scavenging activity (vs both DPPH(*) and ABTS(*)(+) radicals), ferric reducing ability (FRAP assay), and capacity to inhibit lipid peroxidation (ferric thiocyanate assay). In addition, the antioxidant activity was linearly correlated with the phenolics content. The results obtained indicate that the cauliflower byproducts are a cheap source of antioxidant phenolics very interesting from both the industrial point of view and the possible usefulness as ingredients to functionalize foodstuffs.     

Antioxidant and antiradical activities in extracts of hazelnut kernel (Corylus avellana L.) and hazelnut green leafy cover

Phenolic compounds in the aqueous systems were extracted, from hazelnut kernel (HK) and hazelnut green leafy cover (HGLC), with 80% (v/v) ethanol (HKe and HGLCe) or 80% (v/v) acetone (HKa and HGLCa). The extracts were examined for their phenolic and condensed tannin contents and phenolic acid profiles (free and esterified fractions) as well as antioxidant and antiradical activities by total antioxidant activity (TAA), antioxidant activity in a beta-carotene-linoleate model system, scavenging of DPPH (2,2-diphenyl-1-picrylhydrazyl) radical, and reducing power. Significant differences (p < 0.05) in the contents of total phenolics, condensed tannins, and TAA existed among the extracts that were examined. HGLCa extract had the highest content of total phenolics (201 mg of catechin equivalents/g of extract), condensed tannins (542 mg of catechin equivalents/g of extract), and TAA (1.29 mmol of Trolox equivalents/g of extract) followed by HGLCe, HKa, and HKe extracts, respectively. Five phenolic acids (gallic acid, caffeic acid, p-coumaric acid, ferulic acid, and sinapic acid) were tentatively identified and quantified, among which gallic acid was the most abundant in both free and esterified forms. The order of antioxidant activity in a beta-carotene-linoleate model system, the scavenging effect on DPPH radical, and the reducing power in all extracts were in the following order: HGLCa > HGLCe > HKa > HKe. These results suggest that both 80% ethanol and acetone are capable of extracting phenolics, but 80% acetone was a more effective solvent for the extraction process. HGLC exhibited stronger antioxidant and antiradical activities than HK itself in both extracts and could potentially be considered as an inexpensive source of natural antioxidants.     

Antioxidative activity of protein hydrolysates prepared from alkaline-aided channel catfish protein isolates

Antioxidative activity of hydrolyzed protein prepared from alkali-solubilized catfish protein isolates was studied. The isolates were hydrolyzed to 5, 15, and 30% degree of hydrolysis using the protease enzyme, Protamex. Hydrolyzed protein was separated into hydrolysates and soluble supernatants, and both of these fractions were studied for their metal chelating ability, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability, ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and their ability to inhibit the formation of thiobarbituric acid reactive substances (TBARS) in washed tilapia muscle containing tilapia hemolysate. Both hydrolysates and supernatants were characterized using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Results showed that DPPH radical scavenging ability and reducing power of catfish protein hydrolysates decreased, whereas the ORAC value, metal chelating ability, and ability to inhibit TBARS increased, with an increase in the degree of hydrolysis. Hydrolysate samples showed higher DPPH radical scavenging ability and Fe(3+) reducing ability, and supernatant samples had higher metal chelating ability. In general, low molecular weight (MW) peptides had high ORAC values and high metal chelating ability, and high MW peptides had a higher reducing power (FRAP) and were more effective in scavenging DPPH radicals. In a washed muscle model system, the ability of catfish protein hydrolysates and their corresponding supernatants to inhibit the formation of TBARS increased with an increase in the degree of hydrolysis.