板栗壳中多酚的提取及体外抗氧化性研究

研究了不同因素对板栗壳多酚提取效果的影响,并对不同条件下板栗壳多酚的抗氧化性进行了研究。结果表明,板栗壳多酚的最佳提取条件为:乙醇体积分数59.7%,料液比1∶18(g∶mL),浸提温度52.6℃,浸提次数3次。在此最优工艺条件下板栗壳多酚提取得率预测值为76.0 mg/g,实验值75.9 mg/g。板栗壳多酚具有较强的清除自由基能力,在25~200 mg/L范围内,随质量浓度升高其还原能力和清除二苯基苦基肼自由基(DPPH.)、羟基自由基(.OH)、超氧阴离子自由基(O-2.)的能力逐渐增强,当200 mg/L时其还原能力达0.841,DPPH.抑制率达89.7%,均高于同质量浓度的2,6二-叔丁基对甲酚(BHT),但低于同质量浓度Vc,对O-2.和.OH的清除率分别为93.2%和94.0%,均高于同质量浓度BHT和Vc。     

花楸果多酚物质提取及抗氧化性的研究

以花楸果为原料，对花楸果多酚进行乙醇提取，分别研究料液比、乙醇浓度、提取时间和温度对花楸果多酚物质提取率的影响，获得最佳提取工艺参数。并通过研究花楸果多酚提取物对羟自由基、DPPH自由基、过氧化氢等的清除能力，同时与相同浓度的抗坏血酸进行比较，对其进行抗氧化性的研究。由结果可知，最佳提取工艺参数为：料液比1∶25,40%乙醇浓度，40℃下提取90 min,该条件下多酚得率达6.73%。通过比较花楸果多酚提取物与相同浓度的抗坏血酸的抗氧化性，确定花楸果多酚提取物的抗氧化能力较抗坏血酸要弱，但仍具有很强的抗氧化能力。     

野生鱼腥草黄酮类化合物清除DPPH自由基的作用

以六盘水本地野生鱼腥草为原料,70%乙醇作为提取介质,提取野生鱼腥草黄酮类化合物.以抗坏血酸(VC)和VE为对照品,采用DPPH法研究野生鱼腥草黄酮提取物对自由基的清除作用.结果表明,野生鱼腥草黄酮提取物具有较强的抗氧化作用,在其浓度为51.644g/mL时其清除率可达62.27%,显著高于相同浓度下的VC和VE的清除率.因此,野生鱼腥草黄酮提取物可作为一种天然抗氧化剂.     

沙棘籽不同部位原花青素含量及抗氧化性研究

笔者采用盐酸-正丁醇法测定沙棘籽不同部位的原花青素含量,并以VC、BHT为阳性对照,对其抗氧化性进行评价。结果表明,沙棘籽不同部位的原花青素含量表现为沙棘籽壳>沙棘籽>提油沙棘籽渣。沙棘籽不同部位原花青素均具有清除DPPH自由基、羟自由基和超氧阴离子的能力,且清除能力在一定范围内和样品浓度呈正相关关系,清除效果优于常见的抗氧化剂BHT,但稍弱于VC,其中,沙棘籽壳中原花青素对羟自由基和超氧阴离子的清除效果优于VC。本研究可为沙棘籽原花青素在生物医药领域的进一步开发利用提供参考。     

超声空化效应及其对植物活性成分抗氧化性的影响

指出了超声波提取技术因具有提取率高、耗时短、温度低等优点被广泛应用于植物活性成分的提取中,从超声波提取法的原理入手,对其在植物活性成分的提取中的应用以及超声空化对活性成分的抗氧化性影响的机理进行了综述,为后续超声波提取的应用提供一定参考。     

蓖麻油粘滞特性及抗氧化性的研究

测定了蓖麻油的粘滞系数,得到其随温度变化的规律;添加抗氧化剂（BHA,TBHQ,BHT）于蓖麻油中,对其进行了抗氧化性研究,结果表明：BHA对蓖麻油的抗氧化性显示出最佳的效果。     

雷竹笋总黄酮和总甾醇的抗氧化性与抑菌性

为给雷竹笋的深度开发提供参考依据,采用有机溶剂法从雷竹笋中提取总黄酮和总甾醇,就雷竹笋总黄酮与总甾醇对清除羟基自由基(·OH)与DPPH的能力和对油脂的抗氧化能力进行了测定、分析和评价,并就其对大肠杆菌、金黄色葡萄球菌及黑曲霉的抑制作用进行了试验研究。结果表明:雷竹笋总黄酮和总甾醇对羟基自由基(·OH)和DPPH均有一定程度的清除能力,总甾醇对这两者的清除能力均大于总黄酮;对羟基自由基(·OH)的清除能力,1 mg·mL~(-1)总黄酮与0.13 mg·mL~(-1)总甾醇的效力相当;而对DPPH的清除能力,1 mg·mL~(-1)总黄酮与0.60 mg·mL~(-1)总甾醇的效力相当。雷竹笋总黄酮和总甾醇对油脂的抗氧化作用均显著,其与VC、VE及柠檬酸的混合物具有协同抗氧化性,其与VC的协同抗氧化能力最强。雷竹笋总黄酮和总甾醇对金黄色葡萄球菌、大肠杆菌与黑曲霉均有一定的抑制作用,而总黄酮的抑菌效果比总甾醇的好。     

响应面法优化沙棘色素提取及抗氧化性研究

采用体积分数为95%的乙醇溶液浸提沙棘色素,在液料比、提取温度和提取时间3个单因素试验的基础上,以提取液中沙棘色素的质量浓度为评价指标,利用响应面分析法对沙棘色素的最佳提取工艺进行了研究。结果表明:最佳提取条件为:提取液料比22.4∶1(mL∶g),提取温度63℃,提取时间2.9h,沙棘色素的质量浓度为33.1mg/L。对沙棘色素的抗氧化研究表明:沙棘色素对三价铁离子的还原能力、对二苯基苦基苯肼自由基(DPPH·)和超氧阴离子自由基(O2-·)的清除作用均明显高于2,6-二叔丁基对甲酚(BHT);在质量浓度小于6.0mg/L时,沙棘色素对羟基自由基(·OH)的清除率高于BHT,而在质量浓度大于6.0mg/L时低于BHT。     

竹叶总黄酮不同提取方法的比较研究

对竹叶的不同提取方法进行比较研究。采用回流提取、超声波提取、渗漉提取、冷浸提取、微波提取和索氏提取6种不同的方法进行提取,并对提取物的收率进行比较,同时以芦丁为考察指标分别对其总黄酮进行含量测定。实验结果表明,不同提取方法所得的提取物中总黄酮的收率大小次序为:超声波法>微波法>回流法>渗漉法>索氏法>冷浸法。与其它方法相比,超声波提取法具有提取快速,不需加热,节省时间、溶剂和能源,所提取的总黄酮含量较高等优点。     

橄榄多酚的提取研究

利用溶剂浸提法、超声波辅助提取法和微波辅助提取法对橄榄中的多酚物质进行提取研究,并比较了3种方法的提取效果。结果表明:以1g橄榄果肉粉为原料,60%~70%丙酮水溶液是提取橄榄多酚的最适溶剂,最佳提取时间1h,温度20~30℃,固液比1∶20(g∶mL);超声波提取的最适功率为80W,最佳提取时间25min;微波提取的最适功率为280W,提取时间5s。3种提取方法的多酚提取得率分别为17.1%、19.3%和20.3%,与溶剂浸提法相比,超声波法和微波法提取时间短、效率高,提取效果明显优于前者,并且三者提取物的UV和HPLC检测图谱完全一致。     

Antioxidant activity of Erica arborea

The antioxidant properties of the methanol extract of leaves and flowers of Erica arborea and the ethyl acetate, butanol and water soluble fractions were investigated. The ethyl acetate extract was found to be the richest for phenolic and flavonoid content which showed the highest antioxidant activity.     

Antioxidant compounds from Ebenus pinnata

Activity-guided fractionation of the methanol extract of Ebenus pinnata aerial parts led to the isolation of ombuoside (1), kaempferol 3-O-rutinoside (2), rutin (3), catechin (4), and picein (5), along with beta-sitosterol and beta-sitosterol glucoside. Compounds 1-4 showed significant antioxidant activity in the DPPH, and TEAC, reducing power assays.     

Antioxidant activity of Litsea cubeba

The antioxidant activity of Litsea cubeba was studied in terms of three different assay systems: DPPH assay, peroxidase/guaiacol assay, and TBA test. The L. cubeba methanol extract and its fractions showed remarkable antioxidant activity in comparison with alpha-tocopherol and ascorbic acid.     

Antioxidant activity of banana flavonoids

The antioxidant activity of flavonoids from banana (Musa paradisiaca) was studied in rats fed normal as well as high fat diets. Concentrations of peroxidation products namely malondialdehyde, hydroperoxides and conjugated diens were significantly decreased whereas the activities of catalase and superoxide dismutase were enhanced significantly. Concentrations of glutathione were also elevated in the treated animals.     

Antioxidant activity of Catalpa bignonioides

Antioxidant activity of methanolic extracts from inflorescence rachises, corollas, calyxes, leaves, valves of capsules and hypertrophied placenta of Catalpa bignonioides by 1,1-diphenyl-2-picrylhydrazyl reduction (DPPH) and tyrosine nitration inhibition induced by peroxynitrite was tested.     

Antioxidant flavonoids from Epimedium wushanense

Two new flavonoids, wushanicaritin (1) and wushankaempferol (2), along with 24 known flavonoids were isolated from the whole herb of Epimedium wushanense T.S. Ying (Berberidaceae). On the basis of NMR and ESI-MS spectroscopic analysis, structures of compounds 1 and 2 were elucidated as 8-γ-hydroxy-γ,γ-dimethylpropyl-3,5,7-trihydroxy-4′- methoxyflavone and kaempferol 3-O-α-l-[2,3-di-O-β-d-(6-E-p-coumaroyl) glucopyranosyl]-rhamnopyranosyl-7-O-α-l-rhamnopyranoside, respectively. DPPH radical scavenging activity tests indicated that 1 (IC₅₀ 35.3 μM) exhibited antioxidant activity comparable to Vitamin C (IC₅₀ 32.0 μM), while 2 (IC₅₀ 443.7 μM) showed weak activity.     

Antioxidant activity of Agaricus blazei

The ethanolic extract of Agaricus blazei and ethyl acetate and hydroalcoholic fractions were evaluated for their antioxidant activity.     

Antioxidant activity of Pyrrosia petiolosa

The ethanol extract of Pyrrosia petiolosa showed an antioxidant activity as determined by free radical scavenging, superoxide radical scavenging, lipid peroxidation, and hydroxyl radical-induced DNA strand scission assays.     

Antioxidant flavanes from Livistona chinensis

Three new flavanes and eight known flavonoids were isolated from the fruits of Livistona chinensis. The structure of the new flavanes were established as 2S,3S-3,5,7,3′,5′-pentahydroxyflavane (1), 2R,3R-3,5,6,7,8,4′-hexahydroxyflavane (2) and 2R,3R-3,5,6,7,8,3′,5′-heptahydroxyflavane (3), respectively, on the basis of chemical and spectroscopic data. The antiproliferative activity against four human tumor cell lines (HL-60, Mata, HepG2 and CNE-1) was evaluated. 1 had significantly antiproliferative effects against HL-60 and CNE-1 with the IC₅₀ of 0.2 ± 0.01 and 1.0 ± 0.1 μM, respectively, overpowering the reference compound in the assay (cisplatin). Most compounds also exhibited potent antioxidant activity.     

Antioxidant activity of Filipendula hexapetala flowers

The antioxidant activity of the methanol extract of Filipendula hexapetala flowers was assessed by the assay for ferric-reducing antioxidant power (FRAP), the assay for DPPH free radical scavenging ability (DPPH) and the assay for the influence of lipid peroxidation in liposomes, induced by Fe(2+)/ascorbate system and measured by the TBA test (LP). The activity of the investigated extract in all test-systems was found to be significant. The principal constituent responsible for the observed effects was isolated and identified as spiraeoside.