酸枣果三萜皂苷抑菌和抗氧化活性的研究

对纯化的酸枣果三萜皂苷进行抑菌和抗氧化活性研究。结果表明,三萜皂苷具有广谱抗菌效果,对实验所用的致病菌有较强的抑制和灭活作用。对金黄色葡萄球菌、乙型溶血性链球菌和炭疽杆菌的MIC可达0.078mg/mL。MBC值范围为0.180～0.712mg/mL,尤其对绿脓假单胞菌和白色假丝酵母菌显示明显的抑制作用。通过清除DPPH自由基、铁还原抗氧化能力法、降低能量、硫代巴比妥酸法和抑制β-胡萝卜素漂白等体外抗氧化反应来研究其抗氧化性能,并以人工合成的抗氧化剂BHT作对照,结果表明三萜皂苷具有显著的抗氧化效应。因此,酸枣果可作为食品、化妆品和药品行业的天然原料来源。     

Antimicrobial Activity of Peptide P34 During Thermal Processing

In the present work, the influence of pH and sodium chloride concentration on thermal stability of antimicrobial peptide P34 was evaluated under different time–temperature conditions by a 2² factorial design experiment. At sterilization conditions (121 °C for 20 min), maximum retention (36%) was obtained at pH between 5.5 and 8.5 and sodium chloride concentration between 0.4 and 0.75 mol/l. For boiling conditions (100 °C for 20 min), antimicrobial activity was about 100% combining pH between 6.0 and 8.0 and salt concentration in the range of 0.65 to 1 mol/l. At low temperature pasteurization conditions (30 min at 65 °C), antimicrobial activity was not affected within the pH range from 5.0 to 8.0. For the three time–temperature conditions tested, the antimicrobial activity was minimal at more acidic or alkaline pH. Sodium chloride concentration of 0.65 mol/l increased thermostability of the peptide P34. Combination of sodium chloride and slight alkaline pH may increase the stability of peptide P34, which is essential to the proper utilization of bacteriocins in food industry.     

菱茎多酚的提取工艺及其抗氧化、抑菌活性研究

目的:研究菱茎多酚的超声波辅助提取工艺及其体外抗氧化、抑菌活性。方法:以菱茎为材料,采用正交实验对菱茎多酚的提取工艺进行优化;通过测定菱茎多酚的DPPH、ABTS自由基清除力及还原力来评价其体外抗氧化活性;采用滤纸片扩散法测定菱茎多酚对6种腐败微生物的抑菌活性。结果:菱茎多酚的最佳提取工艺条件为乙醇浓度60%、pH1、提取温度70 ℃、提取时间35 min、料液比1:35 (g/mL),此工艺条件下多酚的提取得率为67.31 mg GAE/g DW;菱茎多酚对DPPH、ABTS自由基清除力和对Fe3+还原力(FRAP)的IC₅₀值分别为228.34、220.57、152.00 μg/mL;对金黄色葡萄球菌、蜡样芽孢杆菌、大肠杆菌、腐败希瓦氏菌、青霉和酿酒酵母的最小抑菌浓度(MIC)分别为6.25、3.13、0.20、0.39、1.56、0.78 mg/mL。结论:菱茎多酚具有良好的抗氧化和抑菌活性,可作为潜在抗氧化剂和抑菌剂的来源进一步开发利用。     

Antioxidant and antimicrobial activities of Polygonum cognatum Meissn extracts

The antioxidant activities, reducing powers, 2,2‐diphenyl‐l‐picrylhydrazyl (DPPH) radical‐scavenging activities, total phenolic compound contents and antimicrobial activities of ether, ethanol and hot water extracts of Polygonum cognatum Meissn were studied in vitro. The highest antioxidant activity was found in the water extract. However, there were no statistically significant differences among 15 µg ml^?1 extract‐containing samples in linoleic acid emulsion (0.02 M , pH 7.0) during 120 h of incubation (P > 0.05). The reducing power of the water extract was the highest, but its reducing power was markedly lower than that of ascorbic acid. The highest DPPH radical‐scavenging activity was found in the water extract, with 50% DPPH radical scavenging at a concentration of 100 µg ml^?1 dried water extract, while at the same concentration of dried ethanol extract the value was 12%. Surprisingly, no DPPH radical‐scavenging activity was observed in the ether extract. The concentrations of phenolic compounds found were 0.48, 0.50 and 0.01 µg ml^?1 gallic acid equivalent in 10 µg ml^?1 water, ethanol and ether extracts respectively. The ether and ethanol extracts showed antimicrobial activity against Staphylococcus aureus and Bacillus subtilis. The water extract did not show antimicrobial activity against the studied micro‐organisms. © 2002 Society of Chemical Industry     

分子量对酪蛋白多肽抗氧化活性的影响

在对酪蛋白酶解产物制备工艺进行优化的基础上,对不同分子量抗氧化肽(>3ku,1～3ku,<1ku)的抗氧化活性进行了评价。首先对酶的种类、酶底物比及水解时间进行了单因素实验,最终确定采用碱性蛋白酶,在pH8.0,55℃,底物浓度5%,酶底物比0.192AU/g的条件下,酶解4h所得水解物抗氧化活性最高。经过超滤和凝胶过滤层析分离获得不同分子量的抗氧化肽,并采用2,2′-连氮基-双-(3-乙基苯并二氢噻唑啉-6-磺酸)二铵盐(ABTS+.)、羟自由基和超氧自由基清除活性评价其抗氧化性。结果表明,ABTS+.清除活性与分子量呈负相关(r=-0.898,p<0.01),分子量低于1ku组分活性最强(2mg/mL,Trolox当量为2.08±0.05mmol/L);分子量低于3ku的抗氧化肽羟自由基清除活性较高(IC50:1～3ku,4.43±0.03mg/mL;<1ku,4.35±0.06mg/mL);分子量高于3ku组分主要分布在3～5ku,超氧自由基清除活最强(10mg/mL,66.1%±1.0%)。     

Antioxidant, antimicrobial, and anticancer activity of 3 Umbilicaria species

Abstract: The aim of this study is to investigate in vitro antioxidant, antimicrobial, and anticancer activity of the acetone extracts of the lichens Umbilicaria crustulosa, U. cylindrica, and U. polyphylla. Antioxidant activity was evaluated by 5 separate methods: free radical scavenging, superoxide anion radical scavenging, reducing power, determination of total phenolic compounds, and determination of total flavonoid content. Of the lichens tested, U. polyphylla had largest free radical scavenging activity (72.79% inhibition at a concentration of 1 mg/mL), which was similar as standard antioxidants in the same concentration. Moreover, the tested extracts had effective reducing power and superoxide anion radical scavenging. Total content of phenol and flavonoid in extracts was determined as pyrocatechol equivalent, and as rutin equivalent, respectively. The strong relationships between total phenolic and flavonoid contents and the antioxidant effect of tested extracts were observed. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. The most active was extract of U. polyphylla with minimum inhibitory concentration values ranging from 1.56 to 12.5 mg/mL. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method. All extracts were found to be strong anticancer activity toward both cell lines with IC₅₀ values ranging from 28.45 to 97.82 μg/mL. The present study shows that tested lichen extracts demonstrated a strong antioxidant, antimicrobial, and anticancer effects. That suggests that lichens may be used as possible natural antioxidant, antimicrobial, and anticancer agents.     

Effect of pH,heat, and light treatments on the antioxidant activity of sweet potato leaf polyphenols

In the present study, the antioxidant activity of sweet potato leaf polyphenols was measured, and the effect of different pH values (3.0, 5.0, 7.0, and 8.0), temperatures (55, 65, 80, and 100°C), and light treatments on sweet potato leaf-polyphenols was investigated. Results showed that the O₂^? scavenging activity of sweet potato leaf polyphenols from cultivar Jishu No. 04150 was 5.84 and 6.20 times of that of tea polyphenols and grape seed polyphenols, respectively, at the concentration of 20 μg/mL. The oxygen radical absorbance capacity was 1.28 and 1.27 times of that of tea polyphenols and grape seed polyphenols, respectively. Sweet potato leaf polyphenols dissolved in pH 5–7 solutions showed higher retention rates of antioxidant activity. Heat treatment at 50 and 65°C and light treatment had little effects on sweet potato leaf polyphenols. In conclusion, sweet potato leaf polyphenols possessed high antioxidant activity and processing stability, having the potential to be a new type of natural antioxidant.     

Screening of antioxidant and antimicrobial activities of anise (Pimpinella anisum L.) seed extracts

In this study, antioxidant and antimicrobial activities of water and ethanol extracts of anise (Pimpinella anisum L.) seed (PAS) were investigated. The antioxidant properties of both extracts of PAS were evaluated using different antioxidant tests, including reducing power, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities. Twenty μg/ml of water and ethanol extracts exhibited 99.1 and 77.5% inhibition of peroxidation in linoleic acid system, which was greater than the same concentration of α-tocopherol (36.1%). These various antioxidant activities were compared with synthetic antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and α-tocopherol. The water extract of PAS exhibited greater antioxidant capacity than that of ethanol. Antimicrobial activity tests were carried out using disc diffusion methods with 10 microbial species.     

Chemical composition,angiotensin I-converting enzyme (ACE) inhibitory,antioxidant and antimicrobial activities of the essential oil from Periploca laevigata root barks

The present study describes the chemical composition, and antimicrobial, antioxidant and angiotensin I-converting enzyme (ACE) inhibitory activities of essential oil from Periploca laevigata root barks (PLRB), an aromatic plant widely distributed in Tunisia and used as a traditional medicinal plant. Gas chromatography/mass spectrometry was used to determine the composition of the PLRB oil. Forty-three components were identified in the essential oil and the main compounds were benzaldehyde (56%), methyl 4-methoxysalicylate (6.55%) and carvacrol (4.75%). The PLRB essential oil exhibited a dose-dependent manner of inhibitory activity toward ACE. The highest ACE inhibitory activity (54%) was observed at a concentration of 30 μg/ml. The PLRB oil was also found to possess antioxidant activities, as evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical method, β-carotene bleaching and reducing power assays. The antimicrobial activity of the essential oil was also investigated on several microorganisms. The inhibition zones and minimal inhibitory concentration (MIC) values of bacterial strains were in the range of 12–46 mm and 50–300 μg/ml, respectively. The inhibitory activity of the PLRB essential oil against Gram-positive bacteria was significantly higher than against Gram-negative. It also exhibited remarkable activity against several fungal strains.     

枫香叶精油抑菌活性及抗氧化活性研究

采用水蒸气蒸馏法提取枫香叶精油,用滤纸片法测定精油的抑菌活性,用平板涂布法测定其最低抑菌浓度(MIC),同时研究了枫香叶精油抑菌活性的酸碱稳定性、热稳定性、紫外稳定性和抗氧化稳定性。结果表明：枫香叶精油对5 种受试菌的抑制效果有较大差异,对革兰氏阳性菌和霉菌的抑制作用较强,对革兰氏阴性菌的抑制作用较弱;精油对枯草杆菌、金黄色葡萄球菌、大肠杆菌、黄曲霉、青霉的MIC 分别为1.25%、0.625%、5%、2.5%、2.5%;精油对温度和紫外照射具有良好的稳定性,在不同的pH 值条件下其抑菌活性不稳定,酸性环境下其抑菌活性强,碱性环境下抑菌活性弱;精油具有抑制食物氧化的作用,随着精油浓度增大其抗氧化性增强。     

A comparative study of caffeic acid and a novel caffeic acid conjugate SMND-309 on antioxidant properties in vitro

Caffeic acid (3,4-dihydroxycinnamic acid, CA) has been identified as an important source of natural antioxidants in various agricultural products. SMND-309, which is a degradation product of salvianolic acid B, is a novel conjugate of CA, but little information has been known about its antioxidant activities. In present study, we compared in vitro antioxidant activities of CA and SMND-309 using different assays such as DPPH radical scavenging assay, hydroxyl radical scavenging assay, superoxide radical scavenging assay, total antioxidant activity, reducing power, and lipid peroxidation assay. Butylated hydroxytoluene (BHT) and Vitamin C (Vc) were used as the standard antioxidants. At the concentration of 20 μg/ml, SMND-309 and CA exhibited 93.4% and 92.1% scavenging on DPPH radical, while BHT and Vc indicated an scavenging of 37.9% and 93.0% at the same concentration, respectively. Furthermore, SMND-309 is more effective on total antioxidant activity and hydroxyl radical scavenging than CA.     

紫甘蓝色素抗氧化能力的研究

从还原能力、抗脂质过氧化和对自由基清除能力等方面对紫甘蓝色素的抗氧化能力进行了试验研究和评价，并对花色苷的含量进行了测定。结果袁明紫甘蓝色素具有一定的还原能力，对脂质过氧化、DPPH（1，1-二苯基-2-苦肼基）自由基均具有较强的抑制和清除作用，且在试验浓度范围内其最大抑制率和清除率分别为对亚油酸的抑制率为54．39％；对DPPH自由基的清除率为93．2％。表明，紫甘蓝色素作为具有抗氧化功能的天然色素，有广阔的应用前景。     

Cladonia lichens and their major metabolites as possible natural antioxidant,antimicrobial and anticancer agents

The aim of this study is to investigate in vitro antioxidant, antimicrobial, and anticancer activities of the acetone extracts of the lichens Cladonia furcata, Cladonia pyxidata and Cladonia rangiferina and their atranorin and fumarprotocetraric acid constituents. Antioxidant activity was evaluated by free radical scavenging, superoxide anion radical scavenging, reducing power, and determination of total phenolic and flavonoid compounds. As a result of the study atranorin had largest free radical scavenging activity with IC₅₀ values 131.48 μg/mL. Moreover, the tested samples had effective reducing power and superoxide anion radical scavenging. Total content of phenol and flavonoid in extracts was determined as pyrocatechol equivalent, and as rutin equivalent, respectively. The strong relationships between total phenolic and flavonoid contents and the antioxidant effect of tested extracts were observed. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. The most active was fumarprotocetraric acid with minimum inhibitory concentration values ranging from 0.031 to 0.125 mg/mL. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method. All samples were found to be strong anticancer activity toward both cell lines with IC₅₀ values ranging from 10.97 to 41.23 μg/mL.     

扇贝边水解蛋白制备及其抗氧化活性测定

以水解度(DH)为测定指标,通过正交实验,对扇贝边水解蛋白制备工艺进行优化。并对产物的分子量和抗氧化活性进行测定。结果表明,pH7.0～8.0,液固比3:1,酶解温度45℃,枯草杆菌中性蛋白酶0.6%,胰蛋白酶0.3%,酶解时间7h,蛋白质水解度可达37.6%。SDS-聚丙烯酰胺凝胶电泳证实酶解产物为14.4ku以下的多肽分子。体外抗氧化活性测定该产物对羟自由基的EC50为0.2981mg/mL,并具有较强的还原能力,是一种天然有效的抗氧化剂。     

檀香叶提取物抗氧化及抗菌活性初步研究

研究檀香(Sandalwood)叶不同溶剂提取物的抗氧化及抗菌活性,为檀香叶资源开发利用提供依据。采用4种不同溶剂提取檀香叶中抗氧化、抗菌活性成分;采用清除DPPH自由基方法测定抗氧化活性,采用平板打孔法测定抗菌活性。结果表明:檀香叶80%乙醇、水、乙酸乙酯提取物可以清除DPPH自由基;80%乙醇提取物对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌有抗菌作用,但对霉菌、啤酒酵母没有抑菌作用。乙醇提取物经不同温度、不同光照时间处理后,其抗氧化、抗菌活性较稳定。乙醇提取物经不同pH处理后,抗氧化物质在pH6～8范围内稳定,抗菌物质在pH3～7范围内稳定,碱性条件下不稳定。檀香叶乙醇提取物化学成分标识结果表明:檀香叶乙醇提取物中含有多糖、鞣质、黄酮类、酚类物、有机酸以及氨基酸、多肽、蛋白质等成分。结论:80%乙醇、水、乙酸乙酯提取物具有抗氧化活性,其中,80%乙醇提取物抗氧化活性最好。只有80%乙醇提取物具有抗菌活性。     

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.     

Antioxidant activities and functional properties of tea seed protein hydrolysates (Camellia oleifera Abel.) influenced by the degree of enzymatic hydrolysis

Antioxidant activities and functional properties of tea seed protein hydrolysates (TSPH) prepared using alcalase with different (10, 20, 30 and 40%) values of the degree of hydrolysis (DH) were investigated. The effect of hydrolysis time on antioxidant activity was also investigated. As the hydrolysis time was extended, the DPPH radical scavenging activity increased and finally reached a plateau, the copper chelating capacity decreased, and the superoxide radical scavenging and iron chelating activities increased initially, then subsequently slowed. The solubility, foaming properties, and emulsification properties of TSPH were affected by pH and DH. As the DH value increased, the DPPH radical scavenging activity and the reducing power increased and the copper chelating capacity decreased. TSPH at 20 and 30% DH values exhibited higher superoxide radical scavenging and stronger iron chelating activities respectively, than TSPH at other DH values. The DH value of TSPH affected the antioxidant activity and functional properties.     

樟叶木脂素的提取纯化及其抗氧化性、抗癌活性

为了优化樟叶木脂素超声波技术提取条件,探究其抗氧化性、抗肝癌活性,本文通过单因素实验考察各个因素对木脂素提取量的影响,利用响应面试验优化提取工艺并建立相应的数学模型。粗品经过浓缩、萃取、柱色谱等步骤进行分离纯化;紫外色谱、红外光谱、质谱、核磁共振等技术进行结构鉴定。利用高效液相谱（High Efficiency Liquid Chromatography, HPLC）外标法进行纯度鉴定;同时利用1, 1-二苯基-2-三硝基苯肼（1, 1-diphenyl-2-picrylhydrazyl, DPPH）法,羟基自由基清除法研究其抗氧化性; MTS （3-（4, 5-dimethylthiazol-2-yl）-5-（3-carboxymethoxyphenyl）-2-（4-sulfophenyl）-2H-tetrazolium）法研究其对肝癌细胞（HepG2）和人脐静脉内皮细胞（HUVEC）的毒性作用。结果表明:樟叶木脂素的最优超声提取条件为浸提时间78 min,超声时间3 min,料液比1:22 g/mL,乙醇浓度60%,在此条件下樟树叶中木脂素提取量为45.31 mg/g;经过纯化和结构鉴定最终得到芝麻素和松脂素-β-D-吡喃葡萄糖苷,其纯度分别为94.84%和90.14%;抗氧化实验结果表明芝麻素,松脂素-β-D-吡喃葡萄糖苷具有较好的清除DPPH自由基、羟基自由基效果,其中松脂素-β-D-吡喃葡萄糖苷清除DPPH自由基的IC₅₀为0.31 mg/mL,清除羟基自由基的IC₅₀为0.71 mg/mL;芝麻素清除DPPH自由基的IC₅₀为0.55 mg/mL,清除羟基自由基的IC₅₀为0.94 mg/mL。细胞毒性试验发现芝麻素、松脂素-β-D-吡喃葡萄糖苷均对HepG2有抑制作用,且芝麻素对肝癌细胞（HepG2）、人脐静脉内皮细胞（HUVEC）的作用大于松脂素-β-D-吡喃葡萄糖苷。综上可知响应面法可以用于樟叶木脂素的提取分离,且该提取物具有抗氧化和抗肝癌的功效。     

Manufacture and quality evaluation of purple sweet potato Makgeolli vinegar using a 2-stage fermentation

Purple sweet potato makgeolli vinegar made using a 2-stage fermentation method was evaluated. The highest alcohol concentration was 4% in a growth medium containing Acetobacter aceti ATCC 15973. Purple sweet potato makgeolli vinegar (PMV) had higher pH and lower acidity values than rice makgeolli vinegar (RMV). The total polyphenol content was 327.14 mg of GAE/L and the DPPH radical scavenging activity was 67.63% for PMV. Both values were much higher than for RMV. The total polyphenol and the DPPH radical scavenging activities of PMV decreased slowly during storage for 20 days, showing that stability of the antioxidant effect during storage was maintained.     

酶解牡丹籽粕蛋白制备抗氧化肽的工艺优化

利用制备的牡丹籽粕蛋白为原料,对其进行酶解以获得具有抗氧化活性的多肽,为牡丹籽粕的精深加工提供理论依据。首先进行蛋白酶的筛选,选取最佳的碱性蛋白酶对碱溶酸沉法制备的牡丹籽饼粕蛋白进行酶解;以水解度和DPPH自由基清除力为指标进行单因素实验,分别考察底物浓度、酶解时间、加酶量、pH和酶解温度对制备抗氧化活性肽的影响;以DPPH自由基清除力为响应值,对牡丹籽粕蛋白抗氧化肽的制备工艺进行响应面法优化,确定的最佳制备工艺为:底物浓度0.7%、酶解时间2 h、酶用量4.60%、酶解温度56℃和pH8.0。抗氧化实验结果表明,制备的抗氧化肽对DPPH自由基的清除率为52.49%;经17种水解氨基酸组成分析证明,必需氨基酸占水解氨基酸总量的32.24%,具有较高的营养价值。