牛大力总黄酮提取工艺及不同萃取物的抗氧化活性研究

为了考察牛大力乙醇提取物中总黄酮的含量及抗氧化活性。通过L16(45)正交实验,超声波辅助提取牛大力中总黄酮,得到最佳工艺,再测试乙醇提取物和四个萃取物对羟基自由基(.OH)和DPPH自由基(DP-PH.)的清除效果。最佳工艺为:φ(EtOH)=75%、m(牛大力,g)∶V(EtOH,mL)=1∶25、温度60℃、时间60min,该条件下,牛大力总黄酮得率可达2.14mg.g-1。其中,牛大力乙醇提取物中氯仿萃取物中黄酮含量最高,为5.52mg.g-1;而且氯仿萃取物对DPPH.的清除效果最好,其半数抑制浓度(IC50)为40.97μg.mL-1;乙酸乙酯萃取物对羟基自由基的清除效果最好,其IC50值为90.5μg.mL-1。牛大力乙醇提取物中石油醚、氯仿、乙酸乙酯萃取物都有很好的抗氧化活性,且稳定性、重复性好。     

星点设计-响应面法优化麦冬总黄酮提取工艺及其抗氧化活性的研究

在单因素试验的基础上,利用星点设计-响应面法来优化酶提取法提取麦冬总黄酮的提取工艺,同时利用DPPH法和Fenton法测定总黄酮提取液清除1,1-二苯基-2-三硝基苯肼自由基和羟基自由基的能力.结果表明麦冬总黄酮酶提取法的最佳提取工艺条件:酶用量为46.61 mg,酶解时间为4.14 h,酶解温度为55.56℃,提取率...     

超声波法提取紫甘薯叶总黄酮的工艺研究

采用超声波提取法,以总黄酮含量为考察指标,利用单因素试验法对影响总黄酮提取率的因素进行了分析,然后通过正交试验确定紫甘薯叶总黄酮的最佳工艺条件。研究表明,影响紫甘薯叶总黄酮提取率的主次因素为:溶剂pH值溶剂的浓度料液比提取时间。紫甘薯叶总黄酮的最佳提取工艺为:乙醇体积分数80%,料液比1∶40(W/V),提取时间30 min,提取溶剂pH 9。在此条件下甘薯叶中总黄酮提取率为8.22%。     

响应面法超声辅助优化巨大口蘑多酚的提取工艺及其体外抗氧化活性研究

以巨大口蘑为研究对象,采用超声波辅助乙醇提取法,以乙醇浓度、料液比、提取时间及提取次数为单因素进行实验,在此基础上,以提取率为响应值,利用Box-Behnken方法优化多酚提取条件,并对其体外抗氧化活性进行研究。结果表明,巨大口蘑多酚提取工艺的最佳条件为:乙醇浓度为39%、液料比21∶1(mL·g^-1)、提取时间40min、提取次数2次,该条件下巨大口蘑中多酚的含量为(9.4072±0.013)mg·g^-1,巨大口蘑多酚的自由基清除能力与多酚浓度呈现出很好的剂量相关性,其中清除DPPH自由基的IC₅₀值为0.032 mg·mL^-1、清除ABTS自由基的IC₅₀值为0.063 mg·mL^-1,在质量浓度为0.1mg·mL^-1时,巨大口蘑多酚的铁离子还原能力为0.364。本研究将为巨大口蘑进一步的开发利用提供重要参考依据。     

甜樱桃色素的提取及抗氧化活性

采用溶剂浸提法从成熟甜樱桃中提取了甜樱桃色素,并通过C18柱分离纯化,HPLC／光电二极管阵列检测器分析色素的主要成分,同时测定了甜樱桃色素体外清除二苯代苦味肼基自由基（DPPH）和羟基自由基的活性．结果表明,甜樱桃色素含有新绿原酸和对-香豆酰奎宁酸两个主要成分,对DPPH和·OH自由基具有较强的清除能力,且随色素浓度的增大而增强．研究认为,甜樱桃色素是一种具有良好抗氧化活性的功能性天然色素．     

甘松不同溶剂提取物的抗氧化活性研究

采用DPPH、ABTS、羟自由基、超氧阴离子和还原力五种体外抗氧化测定方法对甘松95%乙醇提取物以及石油醚萃取物,乙酸乙酯萃取物,正丁醇萃取物和水萃取物等4个不同极性部位的抗氧化活性进行评价,同时分析抗氧化活性与其总多酚和总黄酮含量的相关性。研究结果表明,除水和石油醚萃取物外,甘松其他3个萃取物均表现出一定的抗氧化活性,且与总多酚和总黄酮含量呈显著相关。其中,乙酸乙酯萃取物中总黄酮和总多酚含量最高,分别为(157.22±1.89)mg·g-1和(99.43±1.23)mg·g-1,其清除DPPH、ABTS、超氧阴离子和羟自由基的IC50分别为(0.20±0.02)mg·mL-1、(0.15±0.01)mg·mL-1、(0.29±0.02)mg·mL-1和(0.35±0.02)mg·mL-1。甘松的乙酸乙酯萃取物具有显著的抗氧化活性,可以成为天然抗氧化活性化合物的良好来源。     

绳江蓠多糖的提取及抗氧化活性研究

本文采用NaOH水溶液对海南绳江蓠进行超声浸提制备绳江蓠粗多糖(GCP),通过单因素实验和正交试验,考察得出GCP最佳提取工艺条件为NaOH溶液质量浓度1.5%,提取温度70℃,液料比1∶40,提取时间水浴4h,超声1h,提取率为20.01%,总糖含量为26.00%。对绳江蓠粗多糖进行乙醇沉降分级纯化,得到3种多糖组分GCP20、GCP40、GCP50,凝胶渗透色谱结果表明三种组分数均分子量分别为117kDa、116kDa和113kDa。电子自旋共振法测试GCP20、GCP40、GCP50对·OH的清除活性,三种组分均有很好的自由基清除能力,20mg·mL-1GCP20的羟基清除率达81.4%。紫外可见分光光度计在734nm波长下测试GCP20、GCP40、GCP50对ABTS+·的清除活性,浓度为20mg·mL-1时,三种组分对ABTS+·清除率均接近100%,表明这三种组分均有很好的抗氧化活性。     

天然植物抗氧化活性成分的提取及检测方法

天然抗氧化剂能有效地清除自由基从而保护机体健康,从自然界中寻求高效、廉价、低毒的天然抗氧化剂成为目前抗氧化剂发展的一个必然趋势。总结了几种天然植物抗氧化活性成分的提取和测定方法的研究进展,为天然植物抗氧化活性成分的开发利用提供参考。     

洋葱色素的提取及抗氧化活性的测定

分别用芬顿（Fenton）反应法和1,1-二苯-2-苦肼基（DPPH）法测定了洋葱色素的抗氧化作用。结果表明,洋葱色素对羟自由基和DPPH自由基均有一定的清除作用,其清除率大小依次为42．4％,58．2％。洋葱色素是十分具有开发利用价值的天然色素。     

柠檬汁总黄酮的提取纯化工艺研究

利用超声波辅助提取柠檬汁中总黄酮,分光光度法测定总黄酮类化合物含量,利用单因素实验,找出了最佳提取工艺条件70%乙醇、料液比1∶1.5、超声温度55℃、超声时间60 min。通过对比实验找出了最佳纯化方法二氯甲烷在1∶1.5比例下萃取、大孔树脂吸附18 h、70%乙醇洗脱,洗脱液除醇后所得的黄酮浓度最高达1.851 mg/m L。     

Response surface optimized ultrasonic-assisted extraction of flavonoids from Sparganii rhizoma and evaluation of their in vitro antioxidant activities

An efficient ultrasound-assisted extraction technique was employed to extract total flavonoids from Sparganii rhizoma. The optimum extraction conditions for the highest yield of total flavonoids were ethanol concentration 53.62%, ultrasonication time 29.41 min and ultrasound power 300 W, which were determined using response surface methodology. The extraction yields of the optimal ultrasound-assisted extraction were higher than using conventional extraction. The crude extract was then purified on a polyamide resin, whereby the flavonoids content in the purified extract increased to 94.62%. The antioxidant activities of the purified flavonoids including DPPH radical scavenging activity, ABTS+ radical scavenging activity, reducing power, hydroxyl radical scavenging activity and superoxide anion scavenging activity, were evaluated in vitro, which suggested that the flavonoids showed significant antioxidant activities. Rutin, kaempferol and formononetin were identified in the extract by comparing relative retention times and UV-Vis spectra with those of reference standards.     

不同提取方法对红茶提取物抗氧化活性影响的研究

采取沸水浴法、回流法、微波法及超声波法探讨信阳红茶和印度红茶的抗氧化性,通过测定吸光度利用Fenton反应表征提取物对羟自由基的清除率.不同的提取方法对红茶抗氧化活性有一定的影响,羟自由基的清除率与红茶的抗氧化活性成正比.结果表明:信阳红茶沸水浴法提取率较高,印度红茶超声波法提取率较高.     

Clean recovery of antioxidant flavonoids from onions: Optimising solvent free microwave extraction method

A solvent free microwave hydrodiffusion and gravity extraction (MHG) of flavonol content from onion (Allium cepa L.) was studied. Effectiveness of this innovative method in extraction of onion total phenolic content, total quercetin (TQ), quercetin aglycon (QA), quercetin-3,4′-diglucoside (QDG), quercetin-4′-monoglucoside (Q4G), quercetin-3-monoglucoside (Q3G), kaempferol (KMF) and myricetin (MRT) have been evaluated and compared with conventional solvent extraction. Microwave extraction offers important advantages like shorter extraction time (23 min), cleaner feature (no solvent or water used) and extraction of valuable onion crude juice retaining fresh organoleptic properties with higher phenolic content (58.29 mg GAE/g DW) at optimized power (500 W). Microwave extraction resulted significant yield (81.5%) with 41.9% of flavonol contents, with better retain of remaining flavonoids (55.9%) in residues of onions. QDG (239.7 mg/100 g DW) and Q4G (82.55 mg/100 g DW) have been reported the main flavonol in this study. Minor quantities of QA (traces), Q3G (4.22 mg/100 g DW) and KMF (3.99 mg/100 g DW) were also detected in microwave onion extracts.     

猫须草多酚的提取工艺优化及其抗氧化活性

研究猫须草多酚的提取工艺及其抗氧化活性。通过单因素试验探讨提取剂、乙醇体积分数、料液比、提取温度、提取时间、提取次数等因素对猫须草多酚提取率的影响,在单因素试验的基础上进行正交试验,结果表明,猫须草多酚的最佳提取工艺条件如下:10%乙醇,料液比1∶30,提取温度90℃,提取时间40min,在该条件下猫须草多酚的提取率为11.99mg·g-1。通过测定猫须草多酚清除DPPH自由基、超氧阴离子自由基、亚硝酸根离子的能力及其还原力,对猫须草多酚的抗氧化活性进行评价,结果表明,在一定质量浓度范围内,猫须草多酚清除DPPH自由基的能力及还原力优于Vc,清除超氧阴离子自由基的能力与Vc接近,但清除亚硝酸根离子的能力低于Vc。     

黄树莓叶片中黄酮类物质的提取及抗氧化性

黄酮类物质具有降血糖、降血脂、抗心律失常、抗氧化高效性与低毒性、抗衰老等生理活性1 2 。从药食两种植物中筛选出高效低毒且经济的抗氧化性强的物质 ,必将是近一步开发天然高效食品抗氧化剂的重要途径[3 5] 。黄树莓是我国北方地区小浆果树种之一 ,其中以黑龙江分布较多。黄树莓的浆果甜而芳香 ,营养丰富 ,是鲜美的生食果品 ,也可加工制成果酱、果酒、果汁和蜜饯等。它又是密源植物和药用植物 ,有止渴、痰、发汗、活血的效用。本实验以测定黄树莓叶片总黄酮含量并考察了提取物粗黄酮对猪油的抗氧化性。1　实验部分1 1　主要试剂及仪…     

Structure-function analysis of the radioprotective and antioxidant activity of flavonoids

The recombination kinetics of a series of flavonoids with stable DPPH radicals are studied. Flavonols are the most reactive. Polarization of the carbonyl in flavones reduces the reactivity. Substitution on C-7 and the B ring has practically no effect on the reactivity. Glycosylation of C-3 reduces the reactivity if the sugar can form two intramolecular H-bonds. The reactivity of the flavonoid phenol hydroxyls, with the exception of the hydroxyl on C-5, is proportional to their number. The most promising antioxidants are lespedin, kaempferitrin, kaempferol, kaempferol-7-rhamnoside, kaempferol-3-robinobioside, and robinin.I. G. Kutateladze Institute of Pharmacochemistry, Georgian Academy of Sciences, Tbilisi, fax (99532)-25-00-26. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 42–46, January–February, 2000.     

火棘黄酮的提取及美白功效研究

采用循环超声提取法提取火棘黄酮,通过正交试验确定其最佳工艺,用D101大孔树脂将其纯化,测定了火棘黄酮的马铃薯酪氨酸酶抑制率。并制备了火棘黄酮美白霜,通过人体实验,评价其美白功效。结果表明:火棘黄酮最佳的提取条件为乙醇体积分数为70%,料液比(g∶m L)为1∶15,提取温度60℃,提取时间为30min。火棘黄酮对马铃薯酪氨酸酶具有明显的抑制作用,抑制率达到50%时火棘黄酮浓度(IC50)为10.36 mg·m L-1,是熊果苷的2倍。火棘黄酮制成的美白霜有一定的美白能力,能显著降低皮肤黑色素含量和增加皮肤亮度而美白皮肤。结果说明火棘黄酮具有一定的美白功效,可以作为天然的美白化妆品添加剂。     

Study of antioxidant properties of flavonoids by voltammetry

Flavonoids are a large group of natural phenolic compounds contained in high concentrations in vegetables, fruits, etc. Antioxidant and redox properties of some flavonoids such as catechin, quercetin, dihydroquercetin, and rutin were investigated in this work. Optimal concentration and time of action of flavonoids were obtained. To determine the more effective range of antioxidant activity, mathematical models and the response surfaces of investigated flavonoids were determined using methods of experiment design. Oxidation potentials of the compounds were also obtained, E?=?0.3?÷?0.4?V. Moreover, the antioxidant activity of flavonoids depends on the redox properties and the structure of the flavonoids. The antioxidant activity of flavonoids, which is correlated to reversible potentials for this compound is good. Finally, the use of these substances as antioxidants with therapeutic effects has been recommended in human diet.     

Study on ionic liquid-based ultrasonic-assisted extraction of biphenyl cyclooctene lignans from the fruit of Schisandra chinensis Baill

The ionic liquid-based ultrasonic-assisted extraction (ILUAE) has been successfully applied in extracting four biphenyl cyclooctene lignans from the fruit of Schisandra chinensis Baill. Seventeen different types of ionic liquids with different cations and anions have been investigated. 0.8 M 1-lauryl-3-methylimidazolium bromide ([C12mim]Br) solution was selected as solvent. In addition, the ultrasonic parameters including ultrasonic power, time for ultrasonic treatment and solid–liquid ratio have been optimized by Response Surface Method (RSM). Compared with the conventional solvent extraction, the efficiency of the approach proposed in this work is about 3.5 times as much as that of the conventional solvent extraction method. With the proposed extraction method, the extraction time has been reduced to 30 min, whereas the conventional extraction method requires about 6.0 h. The experimental results presented in this work indicate that the ILUAE is a simple and efficient technique for sample preparation. The proposed method is reproducible.