栾树叶总多酚的超声波辅助提取工艺及其抗氧化活性北大核心

以10 g栾树叶粉末为原料,在单因素试验基础上,采用响应面法优化栾树叶总多酚超声波辅助提取工艺,以乙醇体积分数、液料比、提取时间、提取温度、超声波功率为因子,总多酚质量分数、总多酚得率为响应值,得到优化提取条件为乙醇体积分数72%、液料比25∶1(m L∶g)、提取时间15 min、提取温度60℃、超声波功率200 W以及提取3次。在此条件下,栾树叶粗提物总多酚质量分数为61.26%、总多酚得率为3.41%。抗氧化实验结果表明:栾树叶粗提物清除1,1-二苯代苦味酰基(DPPH)自由基能力显著高于BHT和Vc,IC_(50)值为103.78 mg/L;栾树叶粗提物的铁离子还原能力与BHT相当,明显高于Vc。     

马齿苋中总酚提取工艺研究

以马齿苋为原料,选取超声波辅助法对其中的总酚进行提取测定。通过单因素实验探究了超声时间、乙醇浓度、超声温度、料液比对多酚得率的影响。在单因素实验基础上,结合响应面分析法优化提取工艺。实验表明：超声时间为114 min,提取温度为66℃,料液比为1∶28(g/mL),乙醇体积分数为34%时,多酚得率最高,为44.02%。     

响应面法优化红薯叶多酚超声辅助提取工艺及其抗氧化活性研究

以红薯叶多酚提取率为评价指标,以提取温度、乙醇体积分数、料液比、提取时间为考察因素,在单因素实验的基础上,采用响应面法优化红薯叶多酚的超声辅助提取工艺,并通过测定红薯叶多酚对DPPH自由基、ABTS自由基的清除能力,评价其抗氧化活性.确定红薯叶多酚的最佳提取工艺为:提取温度61℃、乙醇体积分数72％、料液比1:21(g...     

荷叶多酚化学成分提取工艺优化研究

通过利用乙醇提取荷叶中的总多酚,采用正交试验优化乙醇体积分数、提取时间、提取温度、pH值以及料液比等提取条件,结果表明,乙醇体积分数为90％,提取温度为60℃,提取时间为90min,提取pH为5,料液比为1:45(g:mL)时,荷叶总多酚的提取率最高,可达2.395％.     

枇杷果肉总多酚提取及体外抗氧化活性研究

目的:以枇杷果肉为研究对象,辅以超声波法提取总多酚。方法:通过正交试验确定最优提取工艺条件:提取温度为60℃,料液比1:35(g·mL~(-1)),乙醇体积分数60%,超声提取时间18 min,总多酚提取率达0.94%。通过1,1-二苯基-2-苦肼基(DPPH·)清除率的测定对枇杷果肉总多酚进行体外抗氧化活性评价。结果:枇杷果肉总多酚DPPH·清除率明显高于维生素C(Vc),且枇杷果肉总多酚DPPH·半数抑制浓度(IC50=7.04μg·mL~(-1))优于Vc(IC50=7.70μg·mL~(-1))。结论:枇杷果肉总多酚是一种天然的抗氧化活性剂。     

金银花中多酚类物质的提取工艺优化

采用超声波法提取金银花中的多酚类物质。通过单因素试验研究了乙醇体积分数、料液比、超声温度和超声时间等因素对提取效率的影响。在此基础上,选择乙醇体积分数、料液比、超声温度和超声时间进行L9(34)正交试验,得出总多酚的最佳提取工艺参数:乙醇体积分数为50%,料液比为1∶25(g·mL-1),超声温度为50℃,超声时间为2.0 h,最大提取率达到2.920%。     

广玉兰叶总黄酮的提取工艺研究

以广玉兰叶为原料、乙醇为溶剂提取总黄酮,考察了提取温度、提取时间、乙醇体积分数、料液比对总黄酮得率的影响,通过L9 (34)正交实验确定广玉兰叶总黄酮的最佳提取条件为:乙醇体积分数50%,料液比1:45(g:mL),提取温度80℃,提取时间2.5 h.此时,广玉兰叶总黄酮得率为16.362 mg·g-1.     

沙果多酚的提取及组成分析

采用水浴振荡辅助乙醇提取法提取沙果果干中的总多酚,对提取工艺进行优化并分析了沙果果干中的多酚种类。通过正交试验优化出沙果青果的最佳提取工艺:乙醇体积分数50%,料液比1∶25(g∶mL),水浴振荡时间50 min,水浴振荡温度30℃,此条件下多酚得率可达(7.875±0.008)mg/g;沙果熟果的最佳提取工艺:乙醇体积分数60%,料液比1∶25(g∶mL),水浴振荡时间30 min,水浴振荡温度40℃,此条件下多酚得率可达(10.259±0.020)mg/g。液相色谱分析表明:沙果青果多酚主要含有4种多酚,分别为绿原酸22.033%、原花青素B_(2)8.875%、表儿茶素5.95%和根皮苷1.259%,这4种多酚占总多酚的38.117%;沙果熟果除含有上述4种多酚(分别为41.0758%、5.6413%、8.3252%、0.4998%),还含有(+)-儿茶素(7.2444%),这5种多酚占总多酚的62.7865%,沙果中仍有大部分未知多酚未检出。沙果熟果多酚种类及含量高于青果,营养价值更丰富。     

正交试验优选刺三加茎、叶中总多酚的提取工艺及含量测定研究

以刺三加茎、叶为原料,采用超声波辅助技术提取刺三加茎、叶中总多酚。通过单因素实验和正交试验优选了刺三加茎、叶中提取总多酚类物质的最佳工艺条件。结果表明,刺三加茎中总多酚的最佳提取工艺:乙醇体积分数45%、料液比1∶35(g/m L)、提取时间50 min、提取温度45℃,总多酚平均含量为9. 42 mg/g,提取率平均值为1. 10%;刺三加叶中总多酚最佳提取工艺:乙醇体积分数45%、料液比1∶10(g/m L)、提取时间70 min、提取温度50℃,总多酚平均含量为13. 46mg/g,提取率平均值为1. 35%。刺三加茎、叶中加标平均回收率分别为98. 13%和99. 18%,相对标准偏差(RSD)分别为1. 35%和1. 68%(n=6)。该实验方法简便、可靠、准确,为进一步研究总多酚在实际生产中的应用提供了理论依据。     

响应面法优化菠菜多酚的提取工艺研究

以菠菜为原料,采用超声波辅助法提取多酚。在单因素的基础上,采用BBD实验设计原理,对液料比、乙醇浓度、提取时间和温度进行优化。结果表明,最佳提取条件为:液料比53∶1 m L/g,乙醇浓度60%,提取时间40 min,温度55℃。在此条件下,多酚的得率为40.44 mg/g(DW)。     

大孔树脂纯化栾树叶多酚工艺研究

以栾树叶多酚提取物为原料,比较了7种大孔树脂对栾树叶多酚的静态吸附与解吸效果,结果表明AB-8树脂性能最佳,其24h静态吸附量为13.74mg/g,解吸率为98.35%,3h内达到吸附平衡与解吸平衡。AB-8树脂动态吸附较佳条件为上样液质量浓度为4g/L,上样液pH值为6,在此条件下吸附率为88.21%,动态洗脱较佳条件为洗脱剂乙醇体积分数为60%,洗脱速度为1mL/min,解吸率达到89.91%,在该条件下栾树叶总多酚经AB-8树脂纯化后,质量分数由50.36%增加到72.37%,回收率为86.83%。     

Effect of evening primrose extracts on oxidative stability of sunflower and rapeseed oils

Antioxidative activities of evening primrose seed meal extracts in sunflower and rapeseed oils were compared with that of commercially used antioxidants, namely butylated hydroxytoluene (BHT), ascorbylpalmitate as well as Grindox‐118. The study was carried out under Schaal oven conditions at 60 °C and the weight gain was followed up by p‐anisidine value measurement following the oxidation. An Oxidograph apparatus monitored the oxidation of oils at 110 °C. Among the examined extracts, the ethyl acetate extract (0.2%), containing only 87 mg/g of total phenolics, exhibited a stronger antioxidant activity than BHT (0.01%) and effectively stabilised both oils. A strong antioxidative effect was also noted for the ethanol‐ethyl acetate extract (168 mg/g of total phenolics). The study showed that addition of ethyl acetate and ethanol‐ethyl acetate extracts could extend the sunflower and rapeseed oils shelf‐life by protecting oils from further decomposition that naturally occurs during thermal treatments.     

马占相思树皮中原花色素提取工艺及其生物活性的研究

通过正交试验优化了马占相思树皮中原花色素的3种提取方法的最佳提取工艺条件。结果显示,传统溶剂提取法的最佳工艺为：60%乙醇、70℃、70 min、料液比1∶18（g∶mL,下同）,原花色素得率为7.42%;微波辅助提取法的最佳工艺条件为：60%乙醇、微波功率200 W、微波时间8 min、料液比1∶18,得率为7.05%;超声波辅助提取法的最佳工艺为：70%乙醇、超声波温度50℃、超声波时间50 min、料液比为1∶16,得率为8.57%。超声波辅助提取法效果最好,浸提温度低,得率高。进一步对超声波提取物不同溶剂萃取物的体外抗氧化活性和抗肿瘤活性进行了研究。结果表明,乙酸乙酯萃取物对DPPH·清除效果最好,其半数抑制浓度（IC₅₀）为17.94 mg/L,低于对照样维生素C（Vc）的IC₅₀值;乙酸乙酯萃取物对人肝癌细胞Bel-7404具有明显的抑制效果,IC₅₀值为4.86 mg/L,与抗肿瘤药依托泊苷效果相当。     

Methods and pitfalls of extracting condensed tannins and other phenolics from plants: Insights from investigations onEucalyptus leaves

Optimal conditions for extraction of tannins and other phenolics from tree foliage and their subsequent storage rarely have been investigated. We investigated methods of drying leaves, optimal solvents, and the effects of light and temperature on the extractability and stability of condensed tannins (proanthocyanidins) and total phenolics from leaves ofEucalyptus trees. Aqueous acetone was a better solvent than aqueous methanol for condensed tannins and total phenolics, but condensed tannins were less stable in aqueous acetone than aqueous methanol. Stability of condensed tannins also was decreased substantially by room temperature versus 4°C and by exposure to indirect sunlight, although the assay for total phenolics was unaffected. For quantitative estimation of condensed tannins, extraction with 50% acetone was better than methods of direct analysis of leaf tissue. The highest estimates of total condensed tannins were obtained by exhaustive extraction with 50% acetone followed by direct analysis of the residue. Lyophilization of fresh leaf increased yield of condensed tannin (although usually by less than 10%). Lyophilization and subsequent storage of extracts had little effect on assays for condensed tannins or total phenolics.     

Antioxidant activity of strawberry (Fragaria × ananassa Duch.) leaves

Antioxidant activity of aqueous extracts from two cultivated strawberry leaves, Senga Sengana and Mount Everest, obtained by maceration, reflux extraction and ultrasonic extraction, was investigated. Antioxidant activity of extracts was assessed by DPPH, FRAP, FIC and H₂O₂ test; total phenolics and flavonoids were assessed by Folin–Ciocalteu and aluminium chloride methods, respectively. Extract obtained from Senga Sengana by reflux extraction, containing higher amounts of extractive matter, total phenolics and flavonoids, has shown higher antioxidant activity (EC_50(DPPH) = 10.4 μg/mL; FRAP = 258.61 mgFe²⁺/g dry extract.; FIC activity = 62.6% in concentration of 2 mg/mL; H₂O₂ scavenging = 25.43% in concentration of 0.5 mg/mL) compared to extracts obtained by other extraction techniques. Rutin, coumaroyl-galloyl-glucopyranoside, hydroxyphenylethyl-coumaroyl-glucopyranoside, derivates of hydroxyphenylethyl-coumaroyl-glucopyranoside, chlorogenic acid and p-coumaroylhexose have been identified by UHPLC–DAD–HESI–MS analysis.     

松针提取物的GC-MS分析及其复配剂对榆紫叶甲的毒杀效果

采用索氏提取法以正己烷为溶剂从樟子松和黑皮油松新鲜针叶中提取松针提取物,对提取物进行了气相色谱-质谱（GC-MS）分析,并分别研究了这2种松针提取物与松木屑木醋液的复配剂对榆紫叶甲的杀虫活性。研究结果表明：樟子松鲜针叶正己烷提取物中共鉴定出16种成分,总GC含量为65.92%,GC含量最高的化合物是2,2,4,4,6,8,8-七甲基壬烷（23.72%）,其次是苯乙酸-3-己烯酯（8.56%）。黑皮油松鲜针叶正己烷提取物中共鉴定出41种成分,总GC含量为98.06%,GC含量最高的化合物是石竹烯（23.29%）,其次是4-epi-荜澄茄油烯醇（11.24%）。这2种松针提取物复配木醋液（体积比1∶9）的5倍蒸馏水稀释液,对榆紫叶甲成虫的毒杀效果差,樟子松鲜针叶提取物复配木醋液（体积比1∶9）的5倍蒸馏水稀释液对榆紫叶甲成虫的毒杀效果优于木醋液的5倍蒸馏水稀释液。实验1~4天,松木屑木醋液的5倍蒸馏水稀释液对榆紫叶甲幼虫的毒杀效果要好于黑皮油松鲜针叶提取物复配木醋液（体积比为1∶9）的5倍蒸馏水稀释液,第5天则相反。     

广南天料木茎抗氧化活性研究

以抗坏血酸(Vc)、二叔丁基羟基甲苯(BHT)和芦丁(Rutin)为阳性对照,利用酶标仪,采用二苯代苦味肼基自由基(DPPH)法、铁离子还原总抗氧化力(FRAP)法两种微量体外抗氧化活性分析方法对广南天料木茎加速溶剂萃取物及常规溶剂提取物进行评价。研究表明,乙酸乙酯加速溶剂萃取物(ASE-EtOAc,EC50=20.8 mg/L)清除DPPH自由基的能力最强,但弱于阳性对照。二氯甲烷加速溶剂萃取物(ASE-DCM)还原Fe3+能力最强〔FRAP值=(793.3±45.7)mol TE/g〕,强于阳性对照BHT,弱于阳性对照Vc和Rutin。常规水提取物(W)清除DPPH自由基的能力和还原Fe3+能力最弱。综合比较发现,常规正丁醇提取物(NBA)抗氧化能力较强、制备简单,具有更为广阔的研究与应用前景。     

超临界CO2萃取穿心莲内酯的实验研究

Andrographis paniculata Nees has been extensively used for traditional medicine and help against fever dysentery, diarrhoea, inflammation, and sore throat. In this study, andrographolide, the main component of this plant was extracted from the leaves of A. paniculata using supercritical carbon dioxide. The operating pressures were varied from 7.50 to 20MPa, the temperatures were varied from 30℃ to 60℃, and the flow rates were varied from 0.5 to 4ml.min^-1. The best extraction condition occurred at 10MPa, 40℃, and a flow rate of 2ml.min^-1 for a 3g sample of A. paniculata ground-dried leaves. The measured extraction rate was found to be about 0.0174g of andrographolide per gram of andrographolide present in the leaves per hour of operation. The future studies must focus on the interaction between the various operating parameters such as temperature, pressure, and flow rate of supercritical carbon dioxide.     

猕猴桃根总黄酮的超声提取及抗氧化活性

以湘西"米良猕猴桃"根为原料,采用超声波辅助乙醇提取总黄酮,通过单因素及正交实验优化提取条件,考察总黄酮对羟基自由基清除效果及对油脂氧化的抑制作用,并与常用抗氧化剂作比较。结果表明,以体积分数60%乙醇按照每1 g固体30 mL液体(即料液比1∶30,下同)在60℃水浴中超声提取40 min后,猕猴桃根中总黄酮得率为1.5%。该提取物对羟基自由基清除效果随质量浓度的增大而升高,对食用油脂的氧化有较好的抑制作用。     

三明产柿叶总黄酮的微波提取研究

采用微波法提取柿叶中总黄酮,探讨了乙醇质量浓度、微波辐射功率、固液比和微波辐射时间等因素对柿叶总黄酮提取率的影响,并用UV和FTIR对提取产物进行了表征.通过单因素实验和正交实验确定最佳提取条件为:乙醇质量浓度65％,固液比1∶ 25(g:mL),微波辐射功率300 W,微波辐射时间15 min(间歇作用5次,每次3 ...