Natural antioxidants and antioxidant capacity of Brassica vegetables: A review

Dietary antioxidants, such as water-soluble vitamin C and phenolic compounds, as well as lipid-soluble vitamin E and carotenoids, present in vegetables contribute both to the first and second defense lines against oxidative stress. As a result, they protect cells against oxidative damage, and may therefore prevent chronic diseases, such as cancer, cardiovascular disease, and diabetes. Brassica vegetables, which include different genus of cabbage, broccoli, cauliflower, Brussels sprouts, and kale, are consumed all over the world. This review focuses on the content, composition, and antioxidant capacity both lipid- and water-soluble antioxidants in raw Brassica vegetables. The effects of post-harvest storage, industrial processing, and different cooking methods on stability of bioactive components and antioxidant activity also are discussed.     

几种常见果蔬抗氧化活性与多酚和维生素C的关系

目的:探索几种常见果蔬的抗氧化活性与多酚、维生素C的相关关系。方法:运用二苯代苦味酰基自由基法（DPPH法）、硫代巴比妥酸反应物法（ABTS法）、血浆高铁还原能力分析能力（FRAP法）、羟自由基和超氧阴离子自由基5种抗氧化方法评价10种常见果蔬的抗氧化活性,并采用Folin-Ciocalteu法和2,4-二硝基苯肼法分别测定了果蔬中多酚和VC的含量,并对多酚、VC的含量与抗氧化活性进行相关性分析。结果:DPPH、ABTS、FRAP、超氧阴离子、羟自由基抗氧化活性最强的依次为豆角、豆角、橘子、香蕉、橘子,最弱的依次为西瓜、西瓜、西瓜、胡萝卜、卷心菜。DPPH、ABTS和FRAP测定果蔬粗提液抗氧化活性与多酚的含量的相关性强于VC。结论:多酚的含量对果蔬抗氧化活性的影响强于V_C。      

Influence of heating on the polyphenolic content and antioxidant activity of grape seed flour

Abstract: The production of grape seed flour (GSF) from a waste product generated during winemaking, is of interest in product development applications due to its potential health benefits. However, before GSF can used in baking as a source of additional antioxidants, research on its heat stability is required. The overall objective of this study was to assess changes in phenolic content and antioxidant activity of GSF during heating. Merlot GSF was heated at 5 temperatures (120 to 240 °C) for 0 to 90 min. At each time/temperature combination, total phenolic content (TPC), total flavanoid content (TFC), Trolox equivalent antioxidant capacity (TEAC), 2,2 diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging, and ferric ion reducing antioxidant power (FRAP) of the extracts were determined. Specific polyphenolic compounds, including catechin, gallocatechin, epicatechin, and gallic acid were also measured. Results showed that when Merlot GSF was heated to ≥180 °C, significant decreases in the TPC and antioxidant activity, measured using FRAP, DPPH, and TEAC, were observed. Longer heating times also caused a reduction in antioxidant capability. Catechin and epicatechin content decreased with increasing heating temperature while gallocatechin and gallic acid content increased. Both catechin and epicatechin content had strong positive correlations (r > 0.91) with TPC and TFC, as well with FRAP and TEAC, suggesting that the GSF antioxidant activity is related to the presence of these particular compounds. Overall, while a decrease in antioxidant content was observed during heating, this occurred at higher baking temperatures. Thus GSF may be suitable for use as an ingredient in baked goods to bolster antioxidant content. Practical Application: In order for Merlot grape seed flour (GSF) to be used in baking as a source of additional antioxidant compounds, the impact of heating on the polyphenolic compounds in the GSF needed to be examined. Thermal treatment of Merlot GSF caused significant decreases in the TPC, antioxidant power, and specific polyphenolic compounds when heated ≥180 °C. Thus while antioxidant content decreased with higher heating temperatures, this occurred at higher baking temperatures. Thus, GSF may be suitable for use as an ingredient in baked goods to bolster antioxidant content.     

Profile of antioxidant and antibacterial activities of different solvent extracts from Rabdosia rubescens

The objective of this work was to investigate the antioxidant and antibacterial activities of different extracts from Rabdosia rubescens and to further evaluate the antibacterial mechanism of extracts. The results showed that 80% acetone extracts had the highest contents of total polyphenols (8.09 mg GAE g^?1) and flavonoids (5.69 mg RE g^?1) and exhibited the strongest antioxidant activities, followed by 80% methanol and 80% ethanol, and the lowest for hexane extracts. Others except for hexane extracts showed different antibacterial activities against Gram‐positive strains, while no inhibitory effects were found on tested Gram‐negative bacterial strains. Among these extracts, 80% acetone and ethanol extracts had relatively higher antibacterial activities with the lowest minimum inhibitory concentration and minimum bactericidal concentration values of 5 and 10 mg mL^?1. The antibacterial mechanism of ethanol extracts against Staphylococcus aureus might be described as it disrupts cell wall, increases cell membrane permeability and then leads to the leakage of cell constituents.     

不同类型江西名茶儿茶素含量及体外抗氧化能力比较

采用高效液相色谱法测定江西11种名茶中的5种儿茶素(儿茶素、表儿茶素、表没食子儿茶素、表没食子儿茶素没食子酸酯、儿茶素没食子酸酯)含量,并通过测定茶叶样品的DPPH自由基清除能力、铁还原抗氧化能力、ABTS+自由基清除能力和总还原能力4项体外抗氧化指标,比较11种江西名茶的抗氧化能力。研究结果表明:上述茶叶中5种儿茶素含量有较大差异,总儿茶素含量大部分差异不显著,绿茶和白茶总儿茶素和各种儿茶素含量总体比红茶高;各种类型茶叶均表现出明显的抗氧化能力,总体趋势也是绿茶和白茶强于红茶。从抗氧化、防衰老的角度来说,推荐消费者优先选择井岗翠绿、浮瑶仙芝等绿茶,资溪白茶、靖安白茶等白茶。     

Analysis of solvent effects on polyphenols profile,antiproliferative and antioxidant activities of mulberry (Morus alba L.) extracts

A systematic study about the solvent effect on the mulberry polyphenol (MP) profile, antioxidant and antiproliferation capacities against human hepatoma HepG2 cells was conducted. Results indicated that MP profiles showed significant differences as a function of solvents including AA/W (acetic acid/water), MeOH/AA/W (methanol/ acetic acid/water), EtOH/AA/W (ethanol/ acetic acid/water) and ME2CO/AA/W (acetone/ acetic acid/water). Among the solvents, EtOH/AA/W took advantage in obtaining MP with the highest yield (49.81 mg GAE g^?1 dw), and cellular antioxidant capacity in the PBS no‐wash protocol (63.2 μmolQE/100 g), as well as low cell cytotoxicity (≥50.0 mg mL^?1). ME2CO/AA/W was the best choice for extracting MP with the most various compositions (two phenolic acids, four anthocyanins and four flavonols), greatest potential in inhibiting proliferation of HepG2 cells (EC₅₀ = 28.2 mg mL^?1) and highest intracellular antioxidant activity (38.0 μmolQE/100 g). Results provide baseline information for efficient solvent extraction to obtain MP that is promising as natural antioxidants and antitumor agents.     

比较研究新疆小茴香不同溶剂提取物的抗氧化活性

研究新疆小茴香4种不同溶剂萃取物的抗氧化活性.采用DPPH、ABTS和还原能力法评估不同萃取物的抗氧化活性,并测定了萃取物中的总酚和总黄酮的含量.结果表明,各样品具有不同程度的抗氧化能力,甲醇萃取物的抗氧化活性显著强于其他溶剂萃取物.小茴香抗氧化活性的主要物质为酚类化合物,与其总黄酮的含量并没有明显的关联.     

大麦乳酸菌发酵液粉中多酚的提取及其抗氧化性研究

通过单因素和正交实验优化大麦乳酸菌发酵液粉（barley lactobacillus fermented solution,BLFS）中多酚的提取工艺条件,高效液相色谱分析鉴定多酚成分,并对其抗氧化活性进行测定。结果表明:在60%的乙醇浓度,1∶50 g/m L的料液比,60℃提取60 min的最优条件下,BLFS多酚的提取率为（18.09±0.25）mg/g;HPLC分析结果显示,经乳酸菌发酵后大麦多酚中没食子酸、香豆酸、阿魏酸和芦丁的含量显著增加（p<0.05）,香草酸和对香豆酸的含量显著减少（p<0.05）,BLFS多酚的主要成分为芦丁35.08μg/g,香草酸21.28μg/g,阿魏酸19.38μg/g,香豆酸11.36μg/g,没食子酸6.80μg/g,原儿茶酸2.99μg/g,对香豆酸0.83μg/g。BLFS多酚提取物和大麦多酚提取物清除羟自由基、1,1-二苯基-2-苦基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基和还原能力的半数有效质量浓度（EC50）分别为0.66和0.87、0.88和0.96、0.76和0.89 mg/m L,具有良好的体外抗氧化活性。BLFS多酚提取物的抗氧化活性均高于大麦多酚提取物,说明经乳酸菌发酵后大麦的抗氧化活性增加。      

The phenolic content and antioxidant activity of the aqueous and hydroalcoholic extracts of hops and their pellets

The goal of this study was to investigate how three commonly used systems (water, 50% methanol and 50% ethanol) affected the yields of phenolic substances and the antioxidant capacity of extracts prepared from hops (cv Magnum and Marynka) and their pellets (T90 and T45). The total phenolic (TPC) and total flavonoid contents (TFC), as well as antioxidant activity (ABTS^+? scavenging, reducing power and metal chelating activity) of the hydroalcoholic extracts were found to be significantly higher than those of aqueous extracts. Extraction using 50% ethanol produced the highest yield of flavonoids. In turn, aqueous–methanol extracts were a better source of chlorogenic acid. No significant differences in terms of TPC and TFC were found between extracts prepared from hops and their pellets when water was used for extraction. Aqueous–ethanol extracts of T45 pellets, regardless of the hop variety, exhibited higher TFC compared with those of T90 pellets. For aqueous and aqueous–methanol extracts, such a tendency was not observed. Extraction with water revealed that cv Marynka hops and pellets had higher TPC than those of cv Magnum, which resulted in their better antioxidant potential. Hydroalcoholic extracts, regardless of the type of alcohol and hop product, did not differ significantly in terms of antioxidant activities. Copyright © 2013 The Institute of Brewing & Distilling     

Effect of drying conditions on bioactive compounds and antioxidant activity of broccoli (Brassica oleracea L.)

The effect of air‐drying parameters on antioxidant activity and changes in antioxidant compounds of broccoli (Brassica oleracea L.) were studied. Broccoli samples were dried to 70 g kg^?1 moisture content using temperatures ranging from 50 to 100 °C and air flow‐rates from 1.20 to 2.25 m s^?1, resulting in drying times from 25 to 90 min. Temperature, owing to its positive effect on the oxidation kinetics, was negatively correlated with ascorbic acid and free and total polyphenol contents but not with kaempferol, even though the sample dried at the highest temperature showed the lowest kaempferol content. The air flow‐rate was positively correlated with the total (TPP) and free (FPP) polyphenol contents because it led to a reduction in the drying time. No correlation was found between air flow‐rate and kaempferol content. Air flow‐rate and temperature positively affected the antioxidant activity by reducing the drying time. High‐temperature, short‐time processes maximised the antioxidant activity of broccoli owing to the negative effect of drying time on antioxidant activity. The antioxidant activity of broccoli was positively and significantly correlated with the FPP content but not with TPP and kaempferol. The evaluation of hydroxymethylfurfural content as an indicator of the occurrence of a Maillard reaction in dried broccoli did not support the hypothesis of a contribution of MRPs to the antioxidant activity of dried broccoli. Copyright © 2006 Society of Chemical Industry     

青海亚麻籽中木脂素含量测定及抗氧化活性分析

目的:为促进青海地区亚麻籽及其加工副产物的高值化利用.方法:以青海省20种不同产地、品种亚麻籽为原料,采用反相高效液相色谱法测定其木脂素开环异落叶松酚葡萄糖苷和开环异落叶松脂素含量,并以DPPH自由基和ABTS自由基清除能力评价其抗氧化活性.结果:青海省不同产地、品种的亚麻籽中木脂素含量差异显著(P＜0.05),开环异...     

南疆12种植物抗氧化成分的测定及其清除自由基作用研究

测定南疆阿拉尔地产12种植物中多糖、黄酮和多酚类抗氧化成分及其抗氧化活性,明确三种主要成分与其抗氧化活性的相关性。采用紫外光度分析法测定抗氧化成分的含量,采用DPPH自由基清除法测定其抗氧化能力。结果表明,供试植物中多糖、黄酮和多酚类物质含量丰富,具有较强的清除DPPH自由基的能力,其中清除能力较强的植物为灰绿藜（IC50=77．29±4．80μg／mL）、紫花苜蓿（IC50=85．27±6．10μg／mL）和车轴草（IC50=94．16±4．62μg／mL）。就活性成分而言,多糖对DPPH自由基的清除能力极显著,多酚的清除能力显著,黄酮的清除能力不显著。供试样品醇提液对DPPH自由基的清除能力均呈现剂量依赖性。不同属植物的有效成分含量及清除DPPH自由基能力均有差异。     

Microwave drying of ginger (Zingiber officinaleRoscoe) and its effects on polyphenolic content and antioxidant activity

The effects of microwave (MW) drying on the total polyphenol content (TPP) and antioxidant properties of ginger extract (column extraction using 50% ethanol at room temperature) were evaluated using the Folin–Ciocalteau's method, 2, 2′‐diphenyl‐1‐picryl‐hydrazyl assay, reducing power, antioxidant capacity and ferric reducing ability of plasma assay. The results were compared to that of the convective cross‐flow drying (CD) at 50 ± 4 °C. Extract yield, TPP content (59–80 mg GAE per g) of the MW‐dried samples increased with increase in MW power levels (PL 40, 60, 80 and 100), which might be as a result of MW energy causing breakdown of cellular constituents. The MW‐dried (PL100, 800W) extract showed the highest quantity (1.5 fold) in TPP, [6]‐gingerol content and antioxidant activity, when compared to the CD extract. Hence, it might be concluded that the optimal MW PL for drying of ginger slices with respect to retention of nonvolatiles such as TPP including [6]‐gingerol was PL 100.     

Effect of different solvents on the chemical composition,antioxidant activity and alpha‐glucosidase inhibitory activity of hawthorn extracts

The aim was to investigate chemical composition of different extracts prepared from hawthorn fruit using 80% ethanol, 80% methanol, 80% acetone and pure deionised water, and evaluate their antioxidant and anti‐alpha‐glucosidase activities. The highest alpha‐glucosidase inhibitory activity was determined in 80% acetone extract, while the highest DPPH scavenge capacity and ferric reducing power both exhibited in deionised water extract. In the correlation analysis, polyphenols, triterpenoids, protocatechuic acid and epicatechin all contribute to the alpha‐glucosidase inhibitory activity, while flavonoids, polyphenols, vanillic acid, gallic acid, catechin and chlorogenic acid all contribute to the antioxidant activity. By HPLC‐MS, thirty six compounds were identified, and fifteen of them were found from hawthorn fruits for the first time. Our results would provide a good reference for the further study on the antidiabetes activity of hawthorn, and also support that deionised water extract has the potential to be used as ingredients of functional food products.     

油橄榄叶提取物抗氧化及抑菌活性研究

目的 研究油橄榄叶提取物的成分组成和生物活性。方法 采用溶剂浸提法, 以水、50%、70%、90%乙醇(V:V)为溶剂提取油橄榄叶有效成分, 通过傅里叶变换红外光谱法(fourier transform infrared spectrometry, FTIR)、气相色谱-质谱法(gas chromatography-mass spectrometry, GC-MS)等方法对所得提取物的结构特征与组成进行表征分析, 通过DPPH·清除能力、还原力以及滤纸片法分别研究了提取物的抗氧化活性和抑菌活性特征。结果 以90%乙醇为提取剂时, 提取物得率和提取物中总多酚含量最高, 提取物中酚类化合物以2,6-二叔丁基对甲酚和2,4-二叔丁基苯酚为主, 相对含量高达29.34%。提取物具有良好的抗氧化活性, 对灰葡萄孢(Botrytis cinerea)、扩展青霉(Penicillium expansum)表现出明显的抑菌活性。结论 首次发现橄榄叶提取物成分中主要酚类物质是2,6-二叔丁基对甲酚和2,4-二叔丁基苯酚, 提取物具有较强的抗氧化和抑菌活性, 为橄榄叶提取物作为抗氧化剂和抑菌剂提供了理论依据。     

柚提取物含量测定及其抗氧化、抑菌活性研究

采用水蒸气蒸馏法、超声波辅助溶剂萃取法以及酸提醇沉法分别提取柚叶、柚皮、柚肉、柚籽中精油、总黄酮和果胶,采用气相色谱-质谱（GC-MS）、Na NO2-Al（NO3）3法和咔唑-硫酸法分别对精油成分和总黄酮、果胶含量进行分析。通过精油、总黄酮和果胶的总还原力及清除1,1-二苯基-2-苦基肼（DPPH·）能力的测定实验评价其抗氧化活性,通过滤纸片扩散法评价其抑菌活性。结果表明:柚皮中精油和总黄酮含量最高;柚肉中果胶含量最高;柚皮精油共鉴定出25种化合物,其主要成分为D-柠檬烯（77.96%）,β-月桂烯（12.40%）和β-蒎烯（2.14%）;柚三种活性成分（精油,总黄酮和果胶）均具有较强的还原力,对DPPH·的IC50（清除率达到50%时的浓度）分别为1.53%、0.07%和0.21%,表现出较强的抗氧化活性;对3种受试菌（大肠杆菌、金黄色葡萄球菌和沙门氏菌）均有抑制活性,且随着物质浓度的增加,对受试菌的抑菌效果逐渐增强。该研究结果为柚资源的合理开发和回收再利用以及生物杀菌剂、天然食品抗氧化剂和防腐剂的开发提供了理论依据。      

7种苹果叶多酚的抗氧化性及抗菌性研究

为探讨苹果叶多酚抗氧化性及抗菌性,以7个品种苹果成熟叶为试材,采用Folin-ciocalteu法测定总酚含量,FRAP法、DPPH·清除法、超氧阴离子自由基清除法和ABTS+·法评价体外抗氧化活性,琼脂孔扩散法和最小抑菌浓度(MIC)评价秦冠叶对5种受试致病菌的抑菌性。结果表明:7个品种苹果叶中,秦冠、秦阳和红盖露抗氧化能力较强,密脆、富士、红星和黄元帅较弱。秦冠叶多酚对大肠杆菌、金黄色葡萄球菌、鼠伤寒沙门氏菌LT2的MIC均为25μg/m L,对志贺氏菌和阪崎肠杆菌的MIC为50μg/m L,其抑菌效果明显优于其含有的各种单酚,且抑菌性是茶多酚的3~4倍。从苹果叶中提取的多酚物质是食品抗氧化剂抗菌剂的潜在来源。