油橄榄叶水提物的有效成分与抗氧化活性研究

油橄榄叶多采用乙醇或甲醇提取,该研究选择水为提取溶剂,比较水提物和醇提物有效成分及抗氧化活性的差异。分别以水、44%乙醇及80%甲醇为溶剂超声提取油橄榄叶,测定总多酚、总黄酮、羟基酪醇及橄榄苦苷含量,比较各提取物对DPPH·、ABTS+·及羟基自由基的清除率与还原力。采用SPSS19.0软件进行主成分分析,评价各成分含量与抗氧化指标的相关性;经降维因子分析,找到代表提取物特征的主成分,根据特征值和方差贡献率计算主成分总分,水提物、乙醇提取物和甲醇提取物的得分分别为249.87、-136.89及-112.98。试验结果表明,油橄榄叶水提物有效成分含量及抗氧化活性显著优于醇提物,具有进一步开发为产品的潜力。     

檀香叶提取物抗氧化及抗菌活性初步研究

研究檀香(Sandalwood)叶不同溶剂提取物的抗氧化及抗菌活性,为檀香叶资源开发利用提供依据。采用4种不同溶剂提取檀香叶中抗氧化、抗菌活性成分;采用清除DPPH自由基方法测定抗氧化活性,采用平板打孔法测定抗菌活性。结果表明:檀香叶80%乙醇、水、乙酸乙酯提取物可以清除DPPH自由基;80%乙醇提取物对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌有抗菌作用,但对霉菌、啤酒酵母没有抑菌作用。乙醇提取物经不同温度、不同光照时间处理后,其抗氧化、抗菌活性较稳定。乙醇提取物经不同pH处理后,抗氧化物质在pH6～8范围内稳定,抗菌物质在pH3～7范围内稳定,碱性条件下不稳定。檀香叶乙醇提取物化学成分标识结果表明:檀香叶乙醇提取物中含有多糖、鞣质、黄酮类、酚类物、有机酸以及氨基酸、多肽、蛋白质等成分。结论:80%乙醇、水、乙酸乙酯提取物具有抗氧化活性,其中,80%乙醇提取物抗氧化活性最好。只有80%乙醇提取物具有抗菌活性。     

厚朴叶不同极性溶剂萃取物总酚含量及体外抗氧化活性研究

为研究厚朴叶抗氧化活性成分,测定厚朴叶90%乙醇提取物及其石油醚、正丁醇、乙酸乙酯、甲醇萃取物和萃余相浓缩物的1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除活性、2,2-联氮基-双-(3-乙基苯并噻唑啉-6-磺酸)二铵盐[2,2-azino-bis(3-ethylbenzthiazoline-6-sulonic acid),ABTS]自由基清除活性和总还原力,并与抗氧化剂2,6-二叔丁基-4-甲基苯酚(2,6-di-tert-butyl-4-methylphenol,BHT)、抗环血酸(VC)的抗氧化活性比较;同时测定厚朴叶乙醇提取物和不同极性部位中的总酚含量。结果发现:乙酸乙酯萃取物总酚含量最高,为(178.56±11.32)mg GAE/g,其含量高于正丁醇萃取物和90%乙醇提取物。厚朴叶乙醇提取物和不同极性部位均具有一定抗氧化活性,其中乙酸乙酯萃取物的抗氧化活性最强,DPPH自由基清除活性接近VC,显著高于BHT,其EC50为(86.27±0.02)μg/mL;对ABTS+自由基的清除活性接近VC和BHT;对Fe3+还原力较BHT低,但显著高于正丁醇萃取物。厚朴叶乙醇提取物和不同极性部位的抗氧化性与总酚含量呈显著相关性。采用薄层色谱-生物自显影法定性检测抗氧化活性,其结果与3种抗氧化测定方法的结果一致。综上,厚朴叶乙酸乙酯萃取物具有良好的抗氧化活性,可用于进一步分离抗氧化活性物质,具有发展为天然抗氧化剂的潜力。     

五种常用香料的抗氧化活性研究

用四种不同极性溶剂提取五种常用植物香料,并用福林-酚法检测提取物总酚含量,用二苯代苦味酰基自由基(1,1-diphenyl-2-picrylhydazyl,DPPH·)法检测提取物自由基清除活性,铁离子还原法检测提取物总还原力,硫代巴比妥酸(TBA)法检测提取物抑制Fe2+-半胱氨酸引发的大鼠肝微粒体脂质过氧化作用。结果表明:丁香石油醚提取物、甲醇提取物、水提取物和肉桂甲醇提取物的总酚含量较高,其抗氧化活性与常用抗氧化剂--2,6-二叔丁基-4-甲基苯酚(BHT)作用相当。总体而言,高极性溶剂提取物的总酚含量比低极性溶剂提取物的总酚含量高,抗氧化活性也比低极性溶剂提取物的强。     

金银花不同溶剂提取物多酚含量及抗氧化活性

分别以水、70%甲醇、70%乙醇和70%丙酮为提取剂,超声辅助提取金银花中多酚,采用Folin-Ciocalteu法测定提取液中多酚量,并利用清除DPPH·、·OH和ABTS+·法评价其抗氧化活性。结果表明,金银花不同溶剂水、70%甲醇、70%乙醇和70%丙酮提取物中多酚含量分别为18.97、46.56、46.63、48.49 mg/g,以水为溶剂与以有机溶液为溶剂,金银花多酚提取量有极显著差异(p<0.01)。不同溶剂金银花多酚均具有一定的清除DPPH·、·OH和ABTS+·能力,即抗氧化活性,但其清除DPPH·和ABTS+·的能力弱于2,6-二叔丁基-4-甲基苯酚(butylated hydroxytoluene,BHT),清除·OH的能力强于BHT。不同溶剂提取的金银花多酚种类不同,对自由基的清除能力不同。     

一点红提取物体外抗氧化活性研究

目的:研究一点红提取物体外抗氧化活性。方法:通过水提醇沉、有机溶剂萃取、大孔树脂吸附纯化,得到六种不同部位的样品。以抗坏血酸和2,6-二叔丁基-4-甲基苯酚为对照,测定样品对羟基自由基和二苯基苦基苯肼自由基的清除能力,对Fe3+的还原能力,抑制油脂的氧化能力。结论:上述样品均具有一定的抗氧化活性,其中大孔树脂纯化的50%乙醇洗脱部位活性最好,但总体上弱于抗坏血酸和2,6-二叔丁基-4-甲基苯酚。     

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。     

响应面法优化竹叶黄酮萃取工艺及其抗氧化研究

利用微波提取慈竹叶中总黄酮类化合物。在单因素实验的基础上,采用响应面法研究微波提取的最佳工艺条件。结果表明,以80%的乙醇为提取溶剂,微波提取最佳条件为:提取温度70℃、提取时间10.5min、液固比为34∶1mL/g;在此工艺条件下,慈竹叶总黄酮得率为1.381%。抗氧化活性研究表明,慈竹竹叶总黄酮DPPH·清除作用较好,其IC50值为141.5mg/L,优于相同浓度的2,6-二叔丁基对甲酚(BHT)。     

‘鲁赫’刺蔷薇叶不同溶剂提取物的活性成分及抗氧化性比较

本研究以‘鲁赫’刺蔷薇叶为原料,采用超声波辅助提取法,用不同溶剂(蒸馏水、无水乙醇、20%乙醇,40%乙醇,60%乙醇,80%乙醇,正丁醇、丙酮和乙酸乙酯)对叶中总黄酮、总多酚和原花青素进行提取,测定提取液的抗氧化活性(DPPH自由基清除能力、羟基自由基清除能力及总还原力),分析不同极性溶液对活性成分的提取效率,并评价抗氧化能力与活性成分的相关性。结果表明:不同极性溶剂提取效果不同,其中60%乙醇提取物具有最高的粗提物得率(23.76±0.04)%;60%乙醇提取物的总黄酮和总多酚含量均为最高,分别为74.29±0.01 mg/g和24.02±0.2 mg/g;80%乙醇提取物原花青素含量最高(12.92±0.46)mg/g。活性成分含量与抗氧化性之间呈正相关性。总多酚和总黄酮类化合物是‘鲁赫’刺蔷薇叶提取物抗氧化活性的主要贡献者。     

两种萃取溶剂对塑料食品包装材料上有机污染物检测效果的影响

目的检测两种萃取溶剂对塑料食品包装材料上有机污染物检测效果的影响。方法分别以正己烷和无水乙醇为萃取溶剂对塑料食品包装材料上污染物进行超声提取,提取后用旋转蒸发浓缩,最后采用气相色谱-质谱联机(GC-MS)分析方法以离子化方式对浓缩的污染物进行表征。结果正己烷作为萃取溶剂能萃取出抗氧化剂2,6-二叔丁基对甲酚、增塑剂邻苯二甲酸二丁酯、油墨生产中所用的溶剂正十六烷;乙醇作为萃取溶剂能萃取出抗氧化剂2,6-二叔丁基对甲酚、油墨生产中所用的溶剂正十六烷和正二十烷。结论正己烷作为萃取溶剂的提取效果要比乙醇作为萃取溶剂提取效果好。     

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.     

Evaluation of antioxidant activity of olive leaf extract obtained by ultrasound-assisted extraction and their antimicrobial activity against bacterial pathogens from food

The aim of the present study was to evaluate and compare the phenolic content and antioxidant and antimicrobial properties of olive leaf extracts obtained by ultrasound-assisted extraction (UAE) and conventional extraction (CSE). UAE of olive leaf extracts yielded a higher total phenolic content (TPC) and total flavonoid content (TFC) of 14.31% and 19.50%, respectively. Higher antioxidant activities were found from the extracts prepared with UAE (for 18.5%, 12.5%, 10.9% and 17.6% higher determined by DPPH, ABTS, FRAP and CUPRAC methods, respectively). Good antibacterial inhibitory activity (as MIC and MBC) was observed against both Y. enterocolitica and S. aureus (1.40 ± 0.40 mg mL⁻¹ and 4.00 ± 1.60 mg mL⁻¹, respectively) with the extract prepared with UAE. In conclusion, olive leaf extracts prepared with UAE exhibited higher antioxidant and antimicrobial activities against common food-borne pathogens than CSE extracts and thus could be beneficial in ensuring food quality and food safety.     

大叶紫薇叶提取物抗氧化性能的研究

采用不同溶剂对大叶紫薇叶进行浸泡提取,计算提取率,并用FolinCiocalteu方法测定总酚含量;采用DPPH分析法和FRAP分析法评估了不同溶剂提取物的抗氧化活性,选出抗氧化活性最高的提取物添加到猪肉中,于4℃光照下贮存12d,通过测定贮存期间猪肉的TBARS值、pH值和亨特L、a、b值,评估了提取物抗脂质氧化、防腐保鲜和护色作用,并与BHT、VE、茶多酚比较。结果表明,不同溶剂提取物显示出不同的抗氧化活性,其中甲醇提取物抗氧化活性最高(高于BHT),其提取率和总酚含量也最高。大叶紫薇叶甲醇提取物在生猪肉中具有明显的抗脂质氧化和防腐保鲜的作用,且随着提取物含量的增大,抗氧化的效果增强,有明显的量效关系。     

Composition and antioxidant activity of raisin extracts obtained from various solvents

Experiments were conducted to determine if the contents of phenolics and browning reaction products and antioxidant activity of raisin extracts were closely dependent on the extraction solvent. Enhanced extraction yields were obtained from solvent containing higher water concentrations. However, total phenolic content (TPC) was highest for extracts obtained from solvent to water ratios of 60:40 (v/v), whereby the extract obtained from ethanol:water (60:40, v/v) had the highest TPC of 375 mg gallic acid equivalents (GAE)/100 g extract. HMF content was highest in extracts obtained from 60% solvent, regardless of solvent type. The extract obtained from 60% methanol had the highest HMF content at 199 μg/g extract. Although the 60% solvents provided extract with high antioxidant components, the antioxidant activity of raisin extracts obtained from 80:20 (v/v) solvent/water was significantly higher than other raisin extracts obtained from different solvent concentrations. Phenolic acids, HMF, and low-molecular-weight flavonoids were responsible for the antioxidant activity, but not the high-molecular-weight flavonoids.     

Radiation-induced enhancement of antioxidant activity in extracts of rosemary (Rosmarinus officinalis L.)

Dry rosemary leaf powder was subjected to 30 kGy of gamma ray irradiation, followed by solvent extraction with methanol, ethanol or water. The antioxidant activity of the extracts was assessed using the DPPH radical-scavenging method and the reducing power test. EC₅₀ values, using the radical-scavenging method, indicate a 22% increase in the antioxidant activity of ethanol and water extracts as a result of irradiation treatment. EC₅₀ values in the reducing power test show an increase of 45% and 28% for the ethanol and water extracts, respectively. The antioxidant activity of methanol extracts of irradiated rosemary remained the same as in the controls in both types of test. A high correlation was found between the EC₅₀ values obtained in the DPPH radical test and those from the reducing power test. Total phenolic content (Folin–Denis test) increased by 35% in the water extracts as a result of irradiation but remained the same in the methanol and ethanol extracts. The methanol extract showed the highest antioxidant activity and the highest amount of total phenolic compounds. Radiation reduced the good correlation between antioxidant activity and total phenolic content.     

辣木叶提取物的制备及抗氧化活性

采用16 种提取方法制备辣木叶提取物,考察不同提取方法对辣木叶蛋白、糖类、多酚类物质提取率和抗氧化剂溶出率的影响。采用乙酸乙酯萃取辣木叶提取物,研究水相中蛋白（水解蛋白）、糖类和乙酸乙酯相中多酚类物质相互作用对辣木叶提取物抗氧化活性的影响。结果表明：采用酶法以及酶法耦合乙醇提取法可以制备蛋白（水解蛋白）、糖类和多酚类物质含量高且抗氧化活性强的辣木叶提取物。采用Ns37071蛋白酶、胰酶时,所得辣木叶提取物蛋白、糖类、多酚类物质提取率最高,抗氧化活性最强。蛋白（水解蛋白）和糖类物质对辣木叶提取物抗氧化活性的贡献大于多酚类物质,是辣木叶提取物发挥抗氧化活性的重要物质基础。此外,辣木叶提取物中蛋白（水解蛋白）、糖类、多酚类物质存在协同增效或拮抗作用。     

青钱柳叶活性成分的抗氧化活性及UPLC-QTOF-MS/MS分析

利用96孔板法测定青钱柳叶不同溶剂(水、70%乙醇、乙酸乙酯和正己烷)提取物中总酚、总黄酮含量及抗氧化活性(DPPH自由基清除能力、还原能力、总抗氧化能力),考察酚类物质含量与抗氧化活性的相关性,并采用超高效液相色谱-四极杆飞行时间串联质谱(ultra performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spetrometry,UPLC-QTOF-MS/MS)分析提取物中主要活性成分。结果表明:不同提取物中总酚、总黄酮含量及抗氧化活性存在显著性差异且70%乙醇溶液提取物表现出最高的总酚(219.01 mg GAE/g)、总黄酮含量(7.23 mg CE/g)及最强的DPPH自由基清除能力(35.46 mg TE/g)和还原能力(1.89 mmol Fe SO_4/g);总酚、总黄酮含量与DPPH自由基清除能力、还原能力之间呈正相关,与总抗氧化能力呈显著负相关,表明多酚类物质是青钱柳中主要的抗氧化剂。UPLC-QTOF-MS/MS分析70%乙醇溶液提取物并初步鉴定出22种化合物,包括2种有机酸、4种酚酸、5种黄酮、8种三萜皂苷类和3种酯类,其中酚酸和黄酮类化合物是主要的抗氧化活性成分,有机酸、三萜皂苷及酯类化合物可能是潜在的抗氧化活性成分。     

Antimicrobial and Antioxidant Activities of Cichorium Intybus Root Extract Using Orthogonal Matrix Design

Solvent, impregnation time, sonication repetitions, and ultrasonic power were important factors in the process of ultrasound‐assisted extraction from chicory (Cichorium intybus) root, while there were no studies about optimizing these 4 factors for extract yield, total phenolic content (TPC), antioxidant, antibacterial, and antifungal activity of the extracts using orthogonal matrix design. The present research demonstrated that the solvent composition played a significant role in the improving extract yield, TPC, antioxidant, and antibacterial activities. The other 3 factors had inequable effect on different purposes, ultrasonic power could improve TPC and antioxidant activity, but long time of extraction lowered antioxidant activity. The TPC increased from 22.34 to 27.87 mg GAE (gallic acid equivalents)/100 g (dry extracts) with increasing solvent polarity. The half inhibition concentration (IC_50, μg/mL) of the radical scavenging activity of the chicory extracts ranged from 281.00 to 983.33 μg/mL. The content of caffeoylquinic acids of root extract, which was extracted by the optimal combination was 0.104%. Several extracts displayed antibacterial activities against Escherichia coli, Staphylococcus aureus, Bacillus thuringiensis, Bacillus subtilis, and Salmonella typhi, while Penicillium sp. and Aspergillus sp. resisted against all the extracts. Combination of 70% ethanol v/v, 24‐h impregnation time, 3 sonication rounds, and 300‐W ultrasonic input power was found to be the optimal combination for the chicory extract yield, TPC, antioxidant activity, and antibacterial activity.     

Effect of Extraction Techniques and Solvents on Antioxidant Activity of Pomegranate (<Emphasis Type="Italic">Punica granatum</Emphasis> L.) Leaf and Stem

The effect of commonly used techniques and solvents in the antioxidant activities of Pomegranate leaves and stems were studied. The extraction techniques compared were successive, individual (cold percolation), and decoction methods in both parts using solvents viz. petroleum ether, toluene, ethyl acetate, acetone, and water. The antioxidant activity of all the different solvent extracts of leaves and stem was evaluated using antioxidant assays like 2,2-diphenyl-1-picryl hydrazyl free radical scavenging assay, superoxide anion radical scavenging assay and ferric-reducing antioxidant power. Total phenol and flavonoid content was also measured. Successive extraction was a better technique to extract the antioxidants from pomegranate than other techniques evaluated in the present study. For the aqueous extraction, decoction method was found to be the best method to extract the antioxidants and it is the most convenient, exhaustive, and time-saving extraction technique for both parts of pomegranate. The results showed that the extracting solvent significantly altered the antioxidant property estimations of pomegranate leaf and stem. High correlations between phenolic compositions and antioxidant activities of pomegranate extracts were observed. High levels of antioxidant activities were detected in pomegranate leaf as compared to stem indicating that the leaf may serve as an excellent source of natural antioxidants.