Preventive effects of black tea theaflavins against mouse type IV allergy

BACKGROUND: Tea (Camellia sinensis L.), one of the most popular beverages, contains various beneficial constituents. We investigated the preventive effects of black tea theaflavins, theaflavin‐3‐gallate (3‐TF) and theaflavin‐3,3′‐digallate (TFDG), on oxazolone‐induced type IV allergy in male ICR mice. RESULTS: Percutaneous administration of both 3‐TF and TFDG at 0.2 mg ear^?1 showed significant preventive effects against mouse type IV allergy. Oral administration of these agents at 50 mg kg^?1 body weight also showed significant preventive effects against mouse type IV allergy. Oral administration of 3‐TF and TFDG at a dose of 50 mg kg^?1 body weight prevented the increases in levels of some proinflammatory cytokines, interleukin‐12 (IL‐12), interferon‐gamma (IFN‐γ), and tumour necrosis factor‐alpha (TNF‐α), in the sera and/or ears of mice with type IV allergy. Lowering of serum antioxidant activity in mice with allergic symptoms was also prevented by oral administration of these theaflavins at a dose of 50 mg kg^?1 body weight. The anti‐allergic mechanisms of action of theaflavins involve inhibition of the fluctuations of cytokines and maintenance of antioxidant status in allergic mice. CONCLUSION: These results suggest that the theaflavins as well as catechins contribute to the anti‐allergic effects of black tea. Copyright © 2010 Society of Chemical Industry     

斑玉蕈多糖的酶辅助提取及其抗氧化活性分析

通过Box-Behnken中心组合实验设计,获得了酶辅助提取斑玉蕈多糖的最佳工艺;以DPPH自由基清除率、还原力、羟基自由基清除率为指标,评价了斑玉蕈多糖的抗氧化活性。结果表明,酶辅助提取斑玉蕈多糖的最佳工艺条件为复合酶（木瓜蛋白酶和纤维素酶按1∶1质量比例配合）添加量0.9%、酶解pH5.4、酶解温度55.6℃、提取时间2.8h,在此条件下多糖得率为4.68%。斑玉蕈多糖具有较好的抗氧化活性,在一定范围内,其抗氧化能力与多糖质量浓度呈线性正相关,斑玉蕈多糖清除DPPH和羟基自由基的IC50值分别为78.5μg/mL和170.5μg/mL。      

真姬菇JB06发酵海带废渣所得产物的抗自由基和总抗氧化能力

为了探索海带废渣高附加值利用的方法,用真姬菇JB06菌株液态发酵海带废渣,乙醇沉淀法制备发酵液上清液中多糖,用试剂盒测定了所得多糖的抗自由基和总抗氧化能力。结果表明:在多糖质量浓度为0.5mg/mL时,真姬菇JB06菌株发酵上清液中的多糖(简称JB06菌株多糖)对羟自由基的抑制率比海带废渣水溶液上清中的多糖(简称对照多糖)高了11.34%;多糖质量浓度为8mg/mL时,JB06菌株多糖对超氧阴离子自由基的抑制率比对照多糖高了9.52%;JB06菌株多糖的总抗氧化能力比对照多糖高出了13.20%。通过实验可以得出:真姬菇发酵海带废渣后获得的多糖的总抗氧化能力比对照多糖总抗氧化能力显著提高。     

Absorption of Calcium and Magnesium by the Fruiting Body of the Cultivated Mushroom Hypsizigus marmoreus (Peck) Bigelow from Sawdust Culture Media

ABSTRACT: Hypsizigus marmoreus was cultivated in potato‐sucrose‐agar (PSA) and in sawdust media supplemented with Ca or Mg salts. The radial growth of mycelia was determined. The mushroom spawn did not grow on PSA supplemented with Ca carbonate, Mg carbonate, or Mg hydroxide. However, the mycelia grew well on sawdust media supplemented with Ca phosphate, Ca carbonate, or Mg sulfate. Ca of the fruiting body was increased 4.0 to 5.6 times by 1% to 5% of Ca phosphate or Ca carbonate. Mg was increased 1.4 times by 0.5% of Mg sulfate or Mg chloride.     

水煮和微波处理对巴西蘑菇营养品质及抗氧化能力的影响

研究了水煮和微波加热处理对新鲜巴西蘑菇营养成分及其抗氧化能力的影响。结果表明,水煮和微波加热处理不同程度上降低了总蛋白质、灰分、可溶性蛋白质、可溶性多糖、总酚和VC的含量,而对脂肪的含量没有显著性变化。另外,加热处理明显改变了巴西蘑菇氨基酸和单糖的组成,微波处理的损失率显著低于水煮处理。加热处理对巴西蘑菇的还原力和清除DPPH·能力的影响显示,水煮和微波处理不仅降低了巴西蘑菇总酚含量,而且改变了其总酚的组成,水煮处理对其抗氧化能力的破坏能力明显高于微波处理。研究可为消费者日常生活合理烹调巴西蘑菇提供科学依据。     

6种食用花卉有效成分及其抗氧化活性研究

利用超声波法对6种常见食用花卉的活性成分进行提取,并对其活性成分和抗氧化活性进行测定。结果表明,6种食用花卉中多酚、黄酮、花色苷和类胡萝卜素活性成分含量范围分别为6.20～63.17 mg GAE/g·DW,12.52～180.47mg CE/g·DW,4.17～40.91 mg CyA/g·DW,0.33～0.68mg/g·DW。DPPH自由基清除能力为45.13～1 092.49μmol Trolox(TE)/g·DW,亚铁离子还原能力(FRAP)为100.20～2 621.25μmol TE/g·DW,以及ABTS自由基清除能力为100.12～1 708.03μmol TE/g·DW。3种抗氧化活性中,DPPH自由基清除力最强的为橙色万寿菊,亚铁离子还原能力和ABTS自由基清除能力最强的均为黄色万寿菊。高效液相色谱测定6种花卉样品中主要的多酚和黄酮类化合物为阿魏酸、没食子酸和槲皮素,其中以橙色万寿菊和黄色万寿菊的活性成分含量最丰富。     

Influence of cut type on quality,antioxidant substances and antioxidant activity of fresh-cut broccoli

In order to clarify an efficient and convenient method to increase the antioxidant activity in broccoli, this study intended primarily to elucidate the effect of cutting type on the quality parameters, antioxidant substance contents and antioxidant activity of broccoli using different floret diameters of 10 × 10 cm (CS1), 5 × 5 cm (CS2), 2.5 × 2.5 cm (CS3) and shredded florets (CS4). The results showed that chlorophyll, total soluble solid, vitamin C and reduced glutathione contents of fresh-cut broccoli were decreased obviously during the storage. However, there was a significant influence of cutting type on the enzymatic activities involved in phenolic synthesis and oxidation including phenylalanine ammonia-lyase, cinnamate 4-hydroxylase, and polyphenol oxidase, which contributed to increasing phenolic content by 26.8%, 30.9%, 46.0%, and 51.3% in CS1, CS2, CS3 and CS4, respectively, and further enhanced the antioxidant activity by more than 60% in fresh-cut broccoli. Moreover, the activities of antioxidant-related enzymes, including superoxide dismutase, peroxidase and catalase, were increased significantly in fresh-cut broccoli. In conclusion, the cutting types had no significant effect on quality but clearly influenced the antioxidant substances and activities of broccoli; therefore, this study provided an efficient and convenient method to enhance the potential nutritional value of broccoli.     

橙皮苷及铜配合物的抑菌抗氧化活性研究

橙皮苷-Cu(Ⅱ)配合物属于新的物质,用牛津杯法研究了橙皮苷及其配合物对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌的抑菌活性,橙皮苷-Cu(Ⅱ)配合物对3种菌的最低抑菌浓度,以及不用pH值对配合物抑菌效果的影响。另外,还研究了橙皮苷及其配合物对.OH的清除效应。结果发现橙皮苷-Cu(Ⅱ)配合物的抑菌活性强于橙皮苷,而对.OH的清除作用则不如橙皮苷。     

Evaluation of solvent effects on the DPPH reactivity for determining the antioxidant activity in oil matrix

Reactivity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical in methanol, ethanol, isopropanol, isooctane, and ethyl acetate, was evaluated to assess the antioxidant capabilities in medium chain triacylglycerol. DPPH loss values were obtained over 30 min, with sampling every 5 min. Even the same concentration of antioxidants showed different DPPH reactivity depending on solvent. In methanol, 5 min was enough for α-tocopherol to react with DPPH, whereas BHT did not react with DPPH even after 30 min. Gallate series showed higher DPPH reactivity than TBHQ, sesamol, or BHA in methanol, while lower reactivity in isooctane. Antioxidants in ethanol and isopropanol reacted with DPPH less efficiently compared to those in methanol, the exception being sesamol. DPPH reactivity of gallate series in isooctane was lower than that of sesamol, TBHQ, and α-tocopherol. Combinatorial usage of methanol and isooctane for DPPH reactivity could provide reliable information on the antioxidant capacities of chemicals in edible oils.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10068-020-00874-9.     

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.     

微波加热对食品中酚类物质的含量及抗氧化活性的影响

酚类物质具有预防疾病和抗氧化等功效,在食品中应用广泛,但是食品烹调手段可能会影响酚类物质的组成和特性,微波加热是新兴的食品烹调加工方法,本文对微波引起食品中酚类物质和食品抗氧化活性的影响进行了综述,展望了酚类提取物的应用情况。      

Alterations in phenolic compound levels and antioxidant activity in response to cooking technique effects: A meta-analytic investigation

The aim of this study was to review prior studies that have evaluated the effects of cooking techniques on polyphenol levels and antioxidant activity in vegetables and to release a meta-analysis of the findings. Meta-analysis with a random effect model was conducted using the weighted response ratios (R*) that were calculated for each experiment. Baking (R* = 0.51), blanching (R* = 0.94), boiling (R* = 0.62), microwaving (R* = 0.54) and pressure cooking (R* = 0.47) techniques precipitated significant reductions in the polyphenol levels. Significant decreases in the antioxidant activity levels were noted after baking (R* = 0.45) and boiling (R* = 0.76), while significant increases were observed after frying (R* = 2.26) and steaming (R* = 1.52).     

The effect of type II and type IV resistant starch on the hydrolysis of maize and wheat gelatinised starch catalysed by pancreatic α‐amylase

The effects of resistant starch on human metabolism are considered to be beneficial because they decrease postprandial glycaemia following ingestion of starch‐rich foods. Using type II and IV resistant starches, we found a direct competitive inhibitory effect on porcine pancreatic α‐amylase action above 0.25 g/100 g affecting catalytic efficiency when wheat and maize starches were used as substrates. Because resistant starches do not gelatinise and no modifications of gelatinisation parameters were observed, we concluded that the inhibitory action of these types of polymer seem to be a consequence of impaired diffusion of enzyme, substrate or products because of an increase in branches in the two types of resistant starches used. Thus, the effects of type II and type IV resistant starches in lowering postprandial glycaemia not only involve modification of gut physiology, but also include direct inhibition of the first stage in the biochemical degradation of starch.     

Purification and identification of rambutan (Nephelium lappaceum) peel phenolics with evaluation of antioxidant and antiglycation activities in vitro

The crude rambutan peel phenolic (RPP) extracts were purified by resin adsorption technology. NKA‐9 resin with the best adsorption capacity and desorption ratio was chosen to dynamically purify crude RPP. Adsorption capacity and desorption ratio of NKA‐9 resin were 91.85 mg gallic acid equivalent (GAE) g^?1 and 90.45%, respectively. Purification processes enriched total phenolic content, and the contents in crude and purified RPP were 579.72 and 877.11 mg GAE g^?1 extract powder, respectively. Phytochemical compounds of RPP were qualitatively and quantitatively indentified by mass spectrometry. Purification of the resin as expected elevated the concentrations of major phenolic compounds, especially geraniin and ellagic acid. Antioxidant and antiglycation activities of crude and purified fractions were evaluated in vitro. Crude and purified RPP had high inhibitory effects on oxidation and glycation, and purified RPP showed stronger bioactivity than crude RPP (P < 0.05), which might be due to their differences in phenolic profiles.