益智的抗氧化作用

本文探讨了益智(Alpinia oxyphylla Miquel)超临界CO2提取物及其渣的水提物、正丙醇提取物和乙酸乙酯提取物的抗氧化作用,测定了总酚含量、黄酮含量、抗氧化力、还原能力、DPPH清除率.结果表明,益智超临界CO2提取物和正丙醇提取物的总酚含量最高,均为5.53%,乙酸乙酯提取物的总酚含量为4.04%,水提物总酚含量最低,为O.89%.抗氧化力与酚含量相关(R2=0.703).四种提取物中黄酮含量顺序为:乙酸乙酯提取物(6.29%)＞丙醇提取物(5.81%)＞水提取物(4.85%)＞超临界CO2提取物(4.70%).在还原能力、清除DPPH自由基和羟自由基方面,乙酸乙酯提取物表现出了很强的抗氧化能力,呈现剂量依赖关系.     

Evaluation of free radical scavenging activity of Butea monosperma Lam

In the present study, ethyl acetate, butanol and aqueous fractions derived from total methanol extract of Butea monosperma flowers were evaluated for radical scavenging activities using different in vitro models like reducing power assay, scavenging of 2,2 diphenyl-1-picrylhydrazyl (DPPH) radical, nitric oxide radical, superoxide anion radical, hydroxyl radical and inhibition of erythrocyte hemolysis using 2, 2' azo-bis (amidinopropane) dihydrochloride (AAPH). Methanol extract along with its ethyl acetate and butanol fractions showed potent free radical scavenging activity, whereas aqueous fraction was found to be devoid of any radical scavenging properties. The observed activity could be due to the higher phenolic content in the extracts (16.1, 25.29, and 17.74% w/w in methanol extract, ethyl acetate and butanol fractions respectively). HPTLC fingerprint profile of the ethyl acetate and butanol fractions were developed which would serve as reference standard for quality control of the extracts.     

蓝莓果渣提取物总酚含量及抗氧化活性研究

研究了蓝莓果渣提取物总酚含量及其抗氧化活性。分别采用水、40%乙醇及纤维素酶辅助乙醇超声提取蓝莓果渣,并用Folin-Ciocalteu试剂对3种提取物的总酚含量进行评估;并采用DPPH清除实验及O2—.清除实验对3种提取物的抗氧化活性进行研究。实验结果表明,纤维素酶辅助超声提取蓝莓果渣的总酚含量最高,可达425.36±15.21 mg GAE.100 g-1DW,远远高于水提物(169.46±9.75 mg GAE.100 g-1DW)及醇提物(218.39±12.54mg GAE.100 g-1DW)中的总酚含量。且纤维素酶辅助乙醇超声提取物对DPPH的清除能力为2.67±0.13 gVc.100 g-1DW,对O—.2的清除能力2.48±0.14 g Vc.100 g-1DW,明显好于醇提物及水提物抗氧化活性。     

Chemical composition and antibacterial activity of Cordia verbenacea extracts obtained by different methods

The present study describes the chemical composition and the antibacterial activity of extracts from Cordia verbenacea DC (Borraginaceae), a traditional medicinal plant that grows widely along the southeastern coast of Brazil. The extracts were obtained using different extraction techniques: high-pressure operations and low-pressure methods. The high-pressure technique was applied to obtain C. verbenacea extracts using pure CO₂ and CO₂ with co-solvent at pressures up to 30 MPa and temperatures of 30, 40 and 50 °C. Organic solvents such as n-hexane, ethyl acetate, ethanol, acetone and dichloromethane were used to obtain extracts by low-pressure processes. The antibacterial activity of the extracts was also subjected to screening against four strains of bacteria using the agar dilution method. The extraction yields were up to 5.0% w/w and up to 8.6% w/w for supercritical fluid extraction with pure CO₂ and with ethyl acetate as co-solvent, respectively, while the low-pressure extraction indicates yields up to 24.0% w/w in the soxhlet extraction using water and aqueous mixture with 50% ethanol as solvents. The inhibitory activity of the extracts in Gram-positive bacteria was significantly higher than in Gram-negative. The quantification and the identification of the extracts recovered were accomplished using GC/MS analysis. The most important components identified in the extract were artemetin, β-sitosterol, α-humulene and β-caryophyllene, among others.     

Various solvent effects on phytochemical constituent profiles,analysis of antioxidant and antidiabetic activities of Hopea parviflora

The current research has been designed to assess the phytochemical composition, antioxidant and antidiabetic properties of Hopea parviflora, sequentially extracted with petroleum ether, chloroform, ethyl acetate, ethanol and methanol. All the five extracts were tested for qualitative and quantitative phytochemicals. DPPH, Superoxide, FRAP, ABTS and metal chelating antioxidant activities were evaluated. Antidiabetic potentials of all the five extracts were tested using standard in vitro α- amylase and α - glycosidase inhibition assays. Qualitative phytochemical screening showed the presence of alkaloids in all the extracts except petroleum ether and ethyl acetate. Steroids were present in the petroleum ether, ethyl acetate and chloroform extracts whereas glycosides were present in all the extracts, except ethanol. The total phenol, flavonoid, tannin and saponins contents varied from solvent to solvent, with the highest values being 18.9, 18.2, 0.98 and 39.9 mg/mL, respectively. Methanolic extract showed the highest antioxidant activities in DPPH, FRAP and superoxide assays. Moreover, effective results were observed for the ethanol and ethyl acetate extracts in the ABTS and metal chelating assays. The methanolic extract showed potential antidiabetic activities with the IC₅₀ values of 230.2 and 308.2 μg/mL in α- amylase and α -glycosidase inhibition assays, respectively.     

库克诺你果汁提取物体外清除自由基及抗氧化活性研究

本文对诺你果汁多糖、乙醇溶出物和乙酸乙酯萃取物体外对超氧阴离子(O2·)、羟自由基(·OH)、DPPH和脂质过氧化(LPO)的抑制作用进行了研究。超氧阴离子(O2·)由邻苯三酚自氧化产生;羟自由基(·OH)由Fenton反应产生;利用Fe2 诱发卵黄脂蛋白产生丙二醛(MDA),TBA法测定。所有测定均为分光光度法。结果表明,与已知抗氧化剂L抗坏血酸相比,乙醇溶出物和乙酸乙酯萃取物均有明显的捕捉自由基和抗氧化能力,而多糖捕捉自由基和抗氧化能力很低,且对O2·没有抑制作用,反而会增加其生成速度。     

酿酒葡萄皮渣中白藜芦醇的抗氧化活性研究

本文利用甲醇溶剂对酿酒葡萄皮渣进行浸提,得到白藜芦醇粗提物.粗提物通过硅胶柱层析进行纯化.然后,研究了白藜芦醇的氧自由基、超氧阴离子自由基、羟自由基、DPPH自由基的清除能力.结果显示:白藜芦醇具有很强的自由基清除能力和抗氧化能力,并且随着浓度的增加,抗氧化能力增强.     

桦褐孔菌提取物抗氧化活性研究

以乙酸乙酯和甲醇为提取剂,采用索氏提取法,剩余残渣采用热水浸提,最终得到桦褐孔菌不同极性提取物,对其DPPH自由基、羟基自由基及超氧阴离子自由基清除活性作用进行了研究,确定桦褐孔菌的抗氧化能力,为深入研究和开发桦褐孔菌功能性食品奠定理论基础。实验结果表明桦褐孔菌具有较好的抗氧化活性,其中乙酸乙酯提取物的DPPH自由基清除率、羟基自由基清除率和超氧阴离子自由基清除率均高于其他两组分及BHT,桦褐孔菌提取物有望成为功能性食品组分中合成抗氧化剂的天然替代品。     

红豆树种子化学成分及其抗氧化和抑菌活性研究

为研究红豆树种子的化学组成及生物活性。本文采用气相色谱-质谱联用技术(GC-MS)对其甲醇提取物的化学成分进行了鉴定,并首次采用不同极性溶剂对红豆树种子的生物活性物质进行萃取;同时,利用DPPH法、ABTS法和抑菌圈法评价红豆树种子生物活性物质的体外抗氧化及抑菌活性。结果表明,从红豆树种子萃取物中共检测出化合物12个,占萃取物总量的89.03%;种子萃取物的主要成分为5-羟甲基糠醛(52.98%)、D-阿洛糖(7.24%)、2,3-二甲氧基-10,11-二氢二苯并(b,f)恶庚英-10-醇(6.51%)、甲基丁香酚(4.53%)、2,3-二氢-3,5-二羟基-6-甲基-4H-吡喃-4-酮(4.45%)、黄樟素(3.75%)、α-松油醇(3.31%)、2,6-二甲氧基苯酚(2.01%),此8种成分占总量的84.78%。红豆树种子正丁醇、乙酸乙酯和石油醚等萃取物对DPPH和ABTS自由基均具有显著的抗氧化活性,且抗氧化活性与萃取物浓度呈线性相关。当红豆树种子正丁醇、乙酸乙酯和石油醚等萃取物浓度为10.0 mg/mL时,正丁醇萃取物对大肠杆菌、绿脓杆菌和鼠伤寒沙门氏菌的抑菌效果最佳;乙酸乙酯萃取物对枯草芽孢杆菌的抑菌效果最佳;石油醚萃取物对金黄色葡萄球菌和苏云金芽孢杆菌的抑菌效果最佳。研究结果为红豆树种子资源的开发和综合利用提供了数据支持。     

Antioxidant activity of leaf extracts from Bauhinia monandra

Bauhinia monandra Kurz. is used in Brazil for the treatment of diabetes. Since this activity may be correlated with the presence of antioxidant compounds, leaf extracts of B. monandra were evaluated for their radical scavenging capacity (RSC). An ethanolic extract was taken up in aqueous methanol and partitioned with hexane, chloroform, ethyl acetate to yield three organic extracts together with remaining aqueous extract. The RSC was determined spectrophotometrically using 1,1-diphenylpicrylhydrazyl free radical (DPPH). The chloroform and ethyl acetate extracts were the most appropriate as sources of antioxidant compounds as shown by their inhibition concentration (IC50) and inhibition percentage (IP) values. The antioxidant activity of such extracts was attributed to the presence of three compounds of different polarities (flavonoids and steroids). The chloroform and ethyl acetate extracts exhibited an IC50 of approximately 2 mg/g DPPH and IP values in the range of 60-65%. The results indicate that the extracts of B. monandra have a very potent antioxidant activity, compared with the pure catechins used as positive controls and with other plant extracts.     

Chemical characterisation,antioxidant and antimicrobial screening for the revaluation of wine supply chain by-products oriented to circular economy

Abstract

Aim of the project was the bioassay guided optimisation of extraction methods applied to wine chain by-product to obtain extracts, fractions and biologically active biomolecules with a possible use in the nutraceutical and cosmeceutical industry. Exhausted red and white grape marc were extracted using water:ethanol 50:50 with ultrasound assisted extraction and Naviglio® technology; and also with supercritical fluid extraction (SFE) and steam-distillation obtaining different phytocomplexes. Each extract was characterised by different molecular category: exhausted red grape marc (VCR) by anthocyanins, exhausted white grape marc (VCB) by flavonoids, and grapeseed (VIN) by proanthocyanins. SFE and steam-distillation, instead, highlighted the presence of fatty acids and their ester in every matrix, but terpenoids were not revealed at level major or equal than 0.1%, except for manoyl oxide in VCR (2.89%). VIN was the most abundant matrix in polyphenols (506.24?±?55.91?mg gallic acid/g dried extract), and it showed the highest antioxidant activity (IC₅₀ of 4.30?μg/mL). Regarding the antimicrobial activity, the hydroalcoholic extracts from VCR, VCB and VIN were tested but no noteworthy activities have been recorded.     

Production of volatile compounds by the edible fungus Rhizopus oryzae during solid state cultivation on tropical agro-industrial substrates

When Rhizopus oryzae was grown on medium containing cassava bagasse plus soybean meal (5:5 w/w), CO2 production was at its highest (200 ml.l–1) while highest volatile metabolite production was with amaranth grain as substrate (282.8 ml.l–1). In the headspace, ethanol was the most abundant compound (more than 80%). Acetaldehyde, 1-propanol, ethyl acetate, ethyl propionate and 3-methyl butanol were also present. CO2 and volatile metabolite productions reached their maxima around 20 h and 36 h, respectively. © Rapid Science Ltd. 1998     

鄂西北产鱼腥草提取物体外抗氧化性的四种化学方法评价

采用α-脱氧核糖法、邻苯三酚自氧化法、DPPH法、铁氰化钾还原法等4种国内外常用的体外抗氧化活性检测方法,对鄂西北产鱼腥草石油醚提取物、无水乙醇提取物、乙酸乙酯提取物、三氯甲烷提取物的抗氧化性进行化学评价,结果表明鱼腥草提取物具有一定抗氧化性,其浓度与其抗氧化活性强弱顺序一致。     

Analysis of antioxidant metabolites by solvent extraction from sclerotia of Inonotus obliquus (Chaga)

Introduction – The sclerotia of Inonotus obliquus (Chaga) are effective therapeutic agents to treat several human malignant tumours and other diseases without unacceptable toxic side‐effects. Objective – To investigate solvent effects on metabolic profiles and antioxidant activities of extracts of Chaga. Methodology – Chaga was extracted by petroleum ether, chloroform, ethyl acetate, acetone, ethanol and water. Solvent effects on metabolites in the extracts were assayed by NMR‐based metabolomic analysis. Antioxidant activities were indicated as capacities for scavenging superoxide anion, DPPH and hydroxyl radicals. Results – Petroleum ether and chloroform extracts contained primarily lanostane‐type triterpenoids (LT), whereas the extracts of ethyl acetate, acetone and ethanol were characterised by the predominant presence of hispidin analogues and LT, and water extracts by polysaccharides and phenolic compounds. The ethyl acetate, acetone, ethanol and water extracts revealed remarkable potential for scavenging the tested radicals, while those of petroleum ether and chloroform did not. Polyphenols are the major contributors for quenching the tested free radicals, while in LT only compounds 16 , 17 and 22 participated in scavenging hydroxyl radicals. Conclusion – Polyphenols in Chaga are the principles for quenching free radicals while polysaccharides and a few LT compounds contribute partially in scavenging DPPH and hydroxyl radicals, respectively. NMR‐based metabolomic analysis is a useful method by which to correlate ¹H‐NMR spectra of Chaga extracts with their antioxidant activities, and this allows the prediction of potentials for scavenging free radicals by ¹H‐NMR spectroscopy. Copyright © 2011 John Wiley & Sons, Ltd.     

香露兜叶的抗氧化活性(英文)

本文评价了香露兜叶的乙醇提取物以及石油醚、乙酸乙酯、正丁醇和水相组分的抗氧化活性。在体外测定了提取物和组分的总抗氧化活性,二苯代苦味肼基(DPPH)自由基清除活性,超氧阴离子自由基清除活性和铁离子还原能力,并利用分光光度法测定了其总酚和总黄酮的含量。结果表明,所有的提取物和组分均表现出抗氧化和自由基清除活性。抗氧化活性的大小如下:正丁醇部分>乙酸乙酯部分>乙醇提取物>水部分>石油醚部分。总酚含量的顺序和其相似,说明提取物和组分中的酚类化合物使其具有抗氧化活性。香露兜叶提取物可能会成为有价值的天然抗氧化资源,并将在保健品和食品中得到应用。     

Recovery of phenolic antioxidants from wine industry by-products

The recovery process of the phenolic compounds contained in the wine industry by-products and their antioxidant activity were examined in this work. To this purpose, a combined process of liquid and supercritical solvent extraction was employed. At first the effect of various process parameters of the liquid solvent extraction--the type of solvent and the pretreatment of the raw material (composition (skins, seeds, stems) and crushing)--on the antioxidant activity of the extract was examined. It was shown that an extract of a higher antioxidant activity was obtained by using ethyl acetate as solvent and raw material free of stems. These extracts were further treated with supercritical carbon dioxide (SC CO(2)) at various extraction pressures, which resulted in their significant enrichment in phenolic compounds and the improvement of their antioxidant and organoleptic properties, especially at pressures higher than 100 bar. The antioxidant activity of the products was determined by using the Rancimat method, as well as a simple and not time-consuming free radical method. It was proved that both the ethyl acetate extracts and those treated with SC CO(2) had antioxidant activity comparable to that of antioxidants commonly used in industry, that is butylhydroxytoluene (BHT), a synthetic antioxidant, and Rosemary extract, a widely known natural one.     

印度块菌提取物抗氧化活性的研究

对印度块菌Tuber indicum子实体的提取物,包括55%乙醇粗提物(ECE)、石油醚提取物(PEF)和乙酸乙酯提取物(EAF)的清除DPPH自由基和羟基自由基能力、铁离子鳌合能力以及各提取物的总酚含量等进行了研究和测定,结果显示,3种提取物的清除自由基能力和铁离子鳌合能力具有显著差异(P0.05);ECE对DPPH自由基的清除活性最高,其EC50值为1.61g/L;EAF对羟基自由基及铁离子表现出较强的清除或螯合的能力,其EC50值分别为3.31g/L和0.70g/L;EAF的总酚含量(2.964mg GAE/g提取物)最高,其次是ECE,总酚含量为(2.618mg GAE/g提取物);PEF的清除自由基和铁离子鳌合能力较差,其总酚含量也最低(1.124mg GAE/g提取物);总酚含量与印度块菌提取物清除自由基以及鳌合铁离子的能力密切相关。     

怀山药醇提取物抗DPPH自由基活性研究

将怀山药乙醇提取物采用溶剂萃取的方法,分成极性不同的五个部分,并首次用DPPH(2,2-diphenyl-1-picrylhydrazyl)方法测定各部分的抗自由基活性,发现乙酸乙酯萃取部分活性最强,氯仿萃取部分次之,再其次是正丁醇和水溶性部分。乙酸乙酯和氯仿萃取部分较强的抗自由基活性主要归因于其中所含的多酚类成分。同时利用薄层层析(TLC)、紫外光谱(UV)、^13C核磁共振(NMR)技术及显色反应对酚性成分进行了定性检验,并用Folin-Denis法测定了各萃取部位中酚性成分含量,发现抗自由基活性与萃取物中多酚性成分含量有一定的相关性。因而在评价怀山药质量时,其中所含的酚性成分不应忽视。     

乳孔硫磺菌的化学成分和抗氧化活性

对乳孔硫磺菌子实体不同极性提取物进行了DPPH和ABTS自由基清除能力的测定,并对氯仿和乙酸乙酯提取物进行了分离纯化。结果表明,乳孔硫磺菌的石油醚、氯仿、乙酸乙酯和甲醇提取物均有一定的抗氧化活性,各提取物对两种自由基的清除能力均表现为甲醇提取物＞乙酸乙酯提取物＞氯仿提取物＞石油醚提取物,甲醇提取物对DPPH自由基的清除率最高可达到93.78%;对ABTS自由基的清除率最高可达到62.06%;从氯仿和乙酸乙酯提取物中分离得到10个化合物,分别是：(22E,24R)-5α,8α-过氧麦角甾-6,22-二烯-3β-醇（1）,阿里红酸 A（2）,麦角甾-7,22-二烯-3β-醇（3）,啤酒甾醇（4）,硫色多孔菌酸（5）,(4E,8E)-N-d-2′-hydroxypalmitoyl-1-O-β-d-glycopyranosyl- 9-methyl-4,8-sphingadienine（6）,麦角甾醇（7）,N-(2′-羟基二十四碳酰基)-1,3,4-三羟基-2-氨基-十八烷（8）,烟酸（9）和齿孔酸（10）。其中,化合物2、6、8和9为首次从硫磺菌属真菌中分离得到。     

沙棘果渣总黄酮提取工艺优化及抗氧化活性研究

利用果胶酶协同超声波法,对沙棘果渣有效成分总黄酮的提取工艺及其抗氧化活性进行了研究.以提取率为指标,通过酶用量、液料比、乙醇浓度、提取时间、提取温度、超声功率等单因素分析,选定酶用量、液料比、超声提取时间3个因素进行响应面试验,确定提取优化工艺条件为:果胶酶用量5.1％,液料比41∶1,超声提取时间81 min,此条件...