吕梁红枣提取物的抗氧化性研究

以浸提法用80％vol乙醇提取吕梁红枣中的非酶类抗氧化物质,从总酚含量、DPPH自由基清除能力、还原能力以及清除羟基自由基能力4方面对其抗氧化活性进行检测,评价吕梁红枣提取物的体外抗氧化作用。红枣非酶类抗氧化物质溶液浓度设置为：1．34mg／mL、2．69mg／mL、5．38mg／mL、10．75mg／mL、21．5mg／mL。结果表明：红枣乙醇提取物总酚含量为3．22mg／g;DPPH自由基清除能力随提取物质量浓度增大清除自由基能力增强,且高于BHT;还原能力也是随提取物质量浓度增大而增强,明显高于BHT;清除羟基自由基能力随提取物质量浓度增人清除自由基能力呈明显的增强趋势,范围从15．25％增强至62．74％。     

黑莓果渣不同溶剂提取物抗氧化活性研究

黑莓果渣经不同溶剂(水、pH3水、60%乙醇、80%乙醇、95%乙醇、正丁醇、乙酸乙酯)在室温下振摇提取,得到黑莓果渣不同溶剂提取物。分别采用总抗氧化能力测定体系、DPPH·(1,1-二苯基-2-苦基肼)自由基体系、羟基自由基体系、超氧阴离子自由基体系,对黑莓果渣不同溶剂提取物总抗氧化能力、清除DPPH·、O2-·和·OH的活性进行测定,并与VC进行比较。结果表明,黑莓果渣不同溶剂提取物均有不同程度抗氧化能力;酸性溶剂提取效果优于非酸性溶剂;60%乙醇为最佳的提取溶剂,其提取物总抗氧化能力、清除DPPH·和O2-·活性均弱于VC,而清除·OH活性较强且高于VC。     

连翘叶不同溶剂提取物体外抗氧化活性研究

比较连翘叶不同提取溶剂提取物的抗氧化活性。分别以水、60%乙醇、80%乙醇、无水乙醇、乙酸乙酯为溶剂制备连翘叶提取物,测定不同提取物中多糖、总酚和黄酮含量;以BHT为阳性对照,采用DPPH自由基(DPPH·)、羟基自由基(·OH)、超氧阴离子(O_2~-·)、ABTS自由基(ABTS~+·)清除活性和铁离子还原能力(FRAP)法考察各溶剂提取物的抗氧化活性;考察提取物中活性物质含量与其活性的相关性。连翘叶不同溶剂提取物均具有抗氧化活性,均呈一定的量效关系,且不同溶剂提取物的抗氧化活性强弱顺序随评价方法的不同而不同。连翘叶不同溶剂提取物中总酚含量和黄酮含量均与·OH清除活性和铁离子还原能力具有较高的相关性,黄酮含量还与O_2~-·清除活性具有较高的相关性。连翘叶80%乙醇提取物和60%乙醇提取物抗氧化活性相对较高。     

金银花不同提取物抗氧化活性的研究

初步研究金银花不同提取物的抗氧化活性。将金银花药材用石油醚脱脂后,分别用无水乙醇、95%乙醇、90%乙醇、80%乙醇、70%乙醇、60%乙醇和50%乙醇提取,采用紫外-可见分光光度法对不同溶剂提取物的绿原酸、总黄酮和总酚含量进行分析,并测试各提取物对羟基自由基(·OH)和二苯代苦味酰基自由基(DPPH·)的清除作用以对其抗氧化活性进行比较。结果表明:金银花95%乙醇提取物绿原酸、总黄酮和总酚含量最高,分别为123.99、242.62和48.76 mg/g;95%乙醇提取物清除·OH和DPPH·能力也最强,清除率分别为90.69%和65.64%。可见,金银花清除·OH和DPPH·自由基的能力与绿原酸、黄酮和多酚的含量具有一定的相关性。     

红松松仁膜衣提取物体外抗氧化活性研究

本文旨在探明长白山红松松仁膜衣提取物的体外抗氧化活性。分别采用60%乙醇和50%丙酮为提取剂,提取物冻干后,用分光光度法测其总多酚和总黄酮纯度,研究其自由基清除能力和还原铁离子的能力。结果表明,松仁膜衣乙醇提取物总多酚纯度为39.02%,总黄酮纯度为10.19%;丙酮提取物总多酚纯度为44.09%,总黄酮纯度为14.59%。红松松仁膜衣提取物清除ABTS~+·、DPPH·、羟自由基(·OH)的能力和还原铁离子能力都呈现一定的剂量效应关系,且对DPPH·的清除作用和还原铁离子能力强于BHT;丙酮提取物对ABTS~+·和·OH的清除能力显著高于乙醇提取物,表明丙酮提取物的抗氧化能力强于乙醇提取物。同时,在实验范围内,红松松仁膜衣提取物的抗氧化能力与其总多酚、总黄酮的纯度存在正相关性。     

五个产地荔枝核中药饮片抗氧化活性研究

为了比较五个产地荔枝核中药饮片的体外抗氧化活性,分别采用DPPH法、ABTS法和总抗氧化能力测试法(T-AOC)对5个产地荔枝核的90%乙醇提取物进行抗氧化活性测定,同时对其中的活性成分包括多酚、黄酮和皂苷及其含量与抗氧化活性的相关性进行了初步分析。结果表明:广东惠东荔枝核中多酚和黄酮含量最高,其次为阳西荔枝核,广西灵山荔枝核多酚和黄酮含量均最低;阳西荔枝核中皂苷含量最高,其他产地皂苷含量从高到低依次为广东惠东、从化、东莞和广西灵山。各产地荔枝核提取液对DPPH自由基的清除率差异均不显著,而对ABTS+自由基的清除率差异显著,其中广东阳西荔枝核的清除能力最强,总抗氧化能力测定结果表明广东从化荔枝核抗氧化能力最强,广西灵山荔枝核最弱。活性物质与抗氧化活性相关性分析表明多酚、黄酮和皂苷均与抗氧化活性呈现一定的正相关。     

花生壳不同溶剂提取物的总酚含量及抗氧化性的比较研究

分别以水、60%乙醇、纤维素酶＋60%乙醇为提取剂,采用超声辅助提取花生壳中活性成分,研究提取物对DPPH自由基和羟自由基( ·OH)的清除能力,并测定提取物中总酚含量。结果表明：在超声辅助条件下,3种不同提取剂水、60%乙醇、纤维素酶＋60%乙醇的提取物中总酚含量依次为81.22、205.9、370.8mg/100g。3种提取物均具有较强的抗氧化能力,且以纤维素酶＋60%乙醇超声提取物最强,其对DPPH自由基的清除率为88.49%,对 ·OH清除率为 93.65%。花生壳提取物抗氧化能力与其总酚含量成正相关。     

卷丹乙醇提取物及其不同极性部位抗氧化活性的比较研究

对卷丹进行抗氧化活性研究,并筛选其主要的活性部位。采用体外抗氧化活性测试方法,以清除DPPH自由基和ABTS+ ·能力、还原Fe3+能力及抑制脂质过氧化能力为指标,评价卷丹乙醇总提取物及不同极性部位的抗氧化能力。卷丹及其乙酸乙酯部位和水饱和正丁醇提取部位具有较强的清除DPPH自由基和ABTS+ ·能力、还原Fe3+能力及抑制脂质过氧化能力。     

丝瓜花不同溶剂提取物抗氧化活性及其酚类成分分析

以无水乙醇、70%乙醇、40%乙醇和水分别对丝瓜花进行提取,并测定各提取物中总酚、总黄酮含量,采用DPPH·清除能力、超氧化物自由基清除能力、FRAP抗氧化能力和亚铁离子螯合能力等方法评价其抗氧化活性,通过HPLC分析其中酚类成分。结果表明,70%和40%乙醇提取物总酚及总黄酮含量较高,而且DPPH·清除活性、FRAP还原力最强,40%乙醇提取物、水提物分别具有最强的超氧阴离子自由基清除活性和亚铁离子螯合能力。总酚含量与DPPH·清除活性之间存在较强的相关性(R²=0.8688)。HPLC分析检出提取物中9种酚类化合物,其中含量最高的为杨梅素。试验结果说明,70%乙醇、40%乙醇可能是丝瓜花抗氧化性物质提取的较好溶剂。结果表明丝瓜花是一种较好的抗氧剂资源。     

天山雪菊不同溶剂提取物的抗氧化活性研究

以天山雪菊为原料,经过超临界二氧化碳萃取后,萃余物又分别采用丙酮、体积分数分别为50%、95%乙醇进行提取,获得不同溶剂提取的4种天山雪菊提取物,比较不同溶剂提取物的抗氧化活性。通过对二苯基苦基苯肼(DPPH)自由基和羟基自由基清除能力的评价,比较各种提取物的抗氧化活性,并对各种提取物中的总多酚和总黄酮的含量进行了分析。结果表明,4种提取物对DPPH自由基均具有较强清除活性,但活性弱于对照品二丁基羟基甲苯(BHT)、水溶性维生素E(Trolox)、α-生育酚和Vc;对羟基自由基的清除能力低于对照品芦丁和BHT。清除DPPH自由基的能力以体积分数为50%乙醇提取物最强,超临界浸膏最弱;清除羟基自由基的活性以体积分数为50%乙醇提取物最强,丙酮提取物最弱。     

Total Phenol Content,Antioxidant Activities and α‐Glucosidase Inhibition of Sesame Cake Extracts

Sesame cake, the byproduct obtained after the removal of oil is presently used as cattle field. Present study evaluates the α‐glucosidase, α‐amylase inhibition and antioxidant properties of black sesame cake extracts. For that purpose, defatted seeds were sequentially extracted with ethyl acetate, methanol, methanol‐water 70:30 (v/v) and water. Among the extracts tested, methanol extract demonstrated better antioxidant activities (2,2‐diphenyl‐1‐picrylhydrazyl, hydroxyl and superoxide radical) and total phenol content. But the total flavonoid content and the total reducing power was high for methanol‐water. Most active methanol extract was further screened for α‐glucosidase and α‐amylase inhibition. The extract showed strong α‐glucosidase inhibitory potential and mild α‐amylase inhibition. The study indicated that the extraction yield and the antioxidant activities were strongly dependent on the solvent, antioxidant assays and extract concentration. These results demonstrated that sesame meal can be exploited as source of protein and bioactive for the development of functional food.     

天然蜂胶对自由基的清除作用

研究不同溶剂蜂胶提取物对二苯代苦味酰自由基 (DPPH)的清除作用 ,同时用硫代巴比妥酸 (TBA)法测定其对亚油酸的抗氧化性。实验表明 ,体积分数为 95 %乙醇提取物对DPPH自由基的清除作用强于其他提取物。其最佳提取工艺为 ,体积分数 95 %乙醇于 85℃浸提 3h。初步鉴定出蜂胶中含有黄酮、查耳酮、异黄酮、黄酮醇、二氢黄酮等物质。TBA法测定的结果同DPPH法结果一致     

山西老陈醋多酚提取物抗氧化活性研究

采用不同体系研究山西老陈醋多酚提取物的体外抗氧化活性,并与没食子酸和抗坏血酸做比较。结果显示：老陈醋多酚提取物具有抗氧化功能,并且存在一定的效量关系,但在不同的体外抗氧化体系中活性有所差异。还原能力以及对羟自由基(·OH)的清除能力强弱顺序均为老陈醋多酚提取物＞没食子酸＞抗坏血酸;清除超氧阴离子自由基(O2－·)能力顺序为老陈醋多酚提取物＞抗坏血酸＞没食子酸;清除1,1-二苯基-2-三硝基苯肼自由基(DPPH自由基)能力顺序为没食子酸＞老陈醋多酚提取物＞抗坏血酸;老陈醋多酚提取物清除亚硝酸盐的能力低于抗坏血酸;总抗氧化能力(同质量浓度比较时)的顺序为没食子酸＞抗坏血酸＞老陈醋多酚提取物。     

Evaluation of the antioxidant potential of Pittosporum dasycaulon Miq. stem bark

The in vitro antioxidant properties of methanol and aqueous extracts of stem bark from Pittosporum dasycaulon Miq. were investigated. Fractions were screened for total antioxidant capacity, ferric reducing power, and radical scavenging activities. The total phenolic, flavonoid, and tannin contents of the methanol and aqueous extracts were also determined. The aqueous extract exhibited a stronger scavenging effect than the methanol extract against the DPPH free radical, the nitric oxide radical, and the superoxide radical. The methanol extract exhibited a stronger total antioxidant activity and reducing power than the aqueous extract. The free radical scavenging effect of P. dasycaulon stem bark extracts was comparable to an ascorbic acid reference antioxidant while the reducing power of the methanol extract was greater than ascorbic acid. P. dasycaulon stem bark is a potential source of natural antioxidant compounds.     

Neuronal cell protective effect of aerial parts of Chinese lizard’s tail (Saururus chinensis (Lour.) Baill.)

The antioxidant and neuronal cell protective effects of silica-gel open column chromatographic fractions, obtained from Chinese lizard’s tail (Saururus chinensis) methanolic extract, were investigated. The ABTS radical scavenging and ferric reducing antioxidant power (FRAP) assays indicated that the SC4 fraction (eluted with chloroform/methanol by 4:1, v/v) obtained from Chinese lizard’s tail was more potent radical scavengers and reducing agents than that of other 5 fractions. The SC4 fraction also presented protective effects against H₂O₂-induced neurotoxicity in a dose-dependent manner. Therefore, our study suggested that the SC4 fraction has strong antioxidant and neuronal protective effects which are correlated with its high level of phenolics, particularly quercitrin and quercetin.     

Effects of pH on antioxidant and antimicrobial properties of tea saponins

In order to study the effects of environmental conditions, antioxidant and antimicrobial activities of tea saponins (TS) in different pH values were evaluated. The antioxidant activity was examined by reducing power, superoxidant radical scavenging activity, metal chelating activity and so on. Antimicrobial activity was investigated using gram-negative, gram-positive bacterial and fungi. In vitro antioxidant activities exhibited pH dependency, and increased with increasing concentration of the extract. When pH was 8.0, TSs showed the best antioxidant activities, while the reversal result was found in antimicrobial measurement. At pH 8.0 and concentration 2.0 mg/mL, TSs scavenged 90.5% of superoxide radical. At pH 4.8, the minimum inhibitory concentration of TS was lower than 0.00625 % (w/v). The results indicate that TS can be an ideal antioxidant, and its antioxidant and antimicrobial activity depend on pH values.     

Effects of high pressure extraction on the extraction yield,total phenolic content and antioxidant activity of longan fruit pericarp

High pressure extraction (HPE) was carried out to extract phenolic compounds from longan fruit pericarp. The influence of different solvents, solvent concentration (25?100%, v/v), solid to liquid ratio (1:25?1:100, w/v) were individually determined using these optimum extraction conditions. HPE was carried out at various pressures (200?500 MPa), durations (2.5?30 min) and temperatures (30?70 °C). The extraction yield, total phenolic contents and scavenging activities of superoxide anion radical and 1,1-dipheny l-2-picrylhydrazyl (DPPH) radical of HPE extract were examined and then compared with those of the conventional extraction (CE). The application of HPE obtained a higher extraction yield and required a less extraction time when compared to CE. Furthermore, the total phenolic contents and the antioxidant activities of HPE extract were higher than CE extract. This study indicated that this new technology can benefit the food and pharmaceutical industries.Industrial relevanceThis study focused on the evaluations of the extraction yield, total phenolic content and antioxidant activity of longan fruit pericarp by high pressure treatment. The high pressure extraction technology provided a better way of utilizing longan fruit pericarp as a readily accessible source of natural antioxidants in food and pharmaceutical industries.     

Phenolic and antioxidant potential of olive oil mill wastes

Olive oil mill waste was subjected to conventional liquid solvent extraction and supercritical fluid extraction using different solvents and carbon dioxide, respectively. The optimum solvent extraction conditions of phenols were 180 min using ethanol, at a solvent to sample ratio 5:1 v/w, and at pH 2. Solvent and SFE extracts were tested for their antioxidant activity by the DPPH radical scavenging method and by determination of peroxide value on virgin olive oil and sunflower oil. The ethanol extract exhibited the highest antiradical activity, and no correlation was found between antiradical activity and phenol content. The SFE extract exerted good antioxidant capacity although its phenolic yield was not quite high. Moreover, the ethanol extract appeared to be a stronger antioxidant than BHT, ascorbyl palmitate and vitamin E by the Rancimat method on sunflower oil. HPLC analysis of the extracts showed that the predominant phenolic compound was hydroxytyrosol. Various phenolic acids and flavonoids were also identified.