Antioxidant properties and composition of Majorana syriaca extracts

Majorana syriaca is an important food‐flavouring ingredient in the Middle Eastern culture known commonly as Za'atar. The components of the plant were extracted in a Soxhlet apparatus sequentially with solvents of increasing polarity, specifically with petroleum ether (P), diethyl ether (D), ethyl acetate (EAc), and ethanol (E). The activity of the extracts to scavenge the 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH^?) followed the order D > E > EAc > P. Moreover, the antioxidant activity in corn oil at concentrations of 200, 500 and 1000 ppm was monitored through peroxide value and conjugated hydroperoxide measurements and revealed that D and E extracts resulted in the highest protection followed by EAc and P extracts. Increasing the concentration from 200 to 500 ppm depressed peroxide formation, while a further increase had no effect. The main components of the P extract according to GS‐MS analysis were thymol (42.89%) and carvacrol (42.75%). The remaining extracts comprise flavonoids and phenolic acids that provide the antiradical and antioxidant activity.     

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.     

草果不同极性萃取物总黄酮、总多酚含量与其抗氧化活性的相关性

以草果为原料,通过50%乙醇、水、乙酸乙酯、丙酮、正丁醇、甲醇和石油醚不同极性溶剂萃取活性物质,探讨萃取物中总黄酮和总多酚含量与总还原能力及对DPPH自由基清除率、ABTS⁺自由基清除率、OH^-自由基清除率、NO^-₂清除能力的相关性。结果表明:50%乙醇萃取物总黄酮和总多酚含量均最高,各萃取物均有抗氧化能力,且呈明显的量效关系,其中50%乙醇萃取物总还原能力、清除ABTS⁺和DPPH能力最强,石油醚萃取物清除OH^-和NO^-₂能力最强。相关性分析表明,草果萃取物中总黄酮含量与ABTS⁺清除能力呈极显著相关,与DPPH清除能力呈显著相关,总多酚含量与ABTS⁺和DPPH的清除能力呈极显著相关,可为草果作为天然抗氧化剂提供理论依据。     

Antioxidant activity of evening primrose phenolics in sunflower and rapeseed oils

Crude ethanol/ethyl acetate extracts of industrial evening primrose (Oenothera biennis L.) seed meal were separated into six fractions using the Sephadex LH‐20 column chromatography and 96% aqueous ethanol as a mobile phase. Their antioxidant activities were tested in sunflower and rapeseed oils by using an Oxidograph apparatus at a temperature of 110 °C. Only the fractions III and IV displayed a pronounced antioxidant activity while the other fractions were either inactive or even pro‐oxidative. The active fractions contained phenolic acids and their esters; gallic acid, methyl and ethyl gallates, protocatechuic acid and its methyl ester were identified by GC/MS. Catechin was present, too, but exhibited only moderate antioxidant activity in sunflower oil.     

海滩植物厚藤（Ipomoea Pes-caprae）抗氧化活性研究

采用加速溶剂萃取技术(ASE)快速制备厚藤活性提取物,并以DPPH法对厚藤茎叶不同溶剂提取物抗氧化活性进行评价。抗坏血酸抗氧化能力乙酸乙酯提取物抗氧化能力乙醇提取物抗氧化能力甲醇提取物抗氧化能力石油醚提取物抗氧化能力,其IC50值分别为0.203 4、0.836 2、0.868 8、1.867 5、6.628 3 g/L。结果显示,厚藤茎叶提取物具有一定的抗氧化活性,且以乙酸乙酯为提取溶剂时,效果最佳。     

海南核果木抗氧化活性研究

将海南核果木干燥枝叶用乙醇浸提,对总提物分别用石油醚、乙酸乙酯、正丁醇萃取,并以DPPH法和FRAP法对总提物及各萃取物的抗氧化活性进行评价。结果显示,在DPPH法中海南核果木总提物(DH)、石油醚萃取物(DHMSO)、乙酸乙酯萃取物(DHEtOAC)、正丁醇萃取物(DHNBA)、水相(DHH2O)的IC50分别为77.3、115.2、51.4、342.9、205.7 mg/L,其FRAP值分别为(11 712.2±931.8)、(10 820.9±690.5)、(14 386.4±568.8)、(1 157.6±63.3)、(5 584.1±182.3)μmol Fe2+/g。且抗坏血酸(Vc)和BHT的IC50分别为10.7、47.1mg/L,FRAP值分别为(18 022.8±63.3)、(14 568.7±137.0)μmol Fe2+/g,并通过多元聚类分析表明DH、DHMSO、DHEtOAC与BHT、Vc具有类似强度的抗氧化活性,可归为同一类型,且DHEtOAC抗氧化活性与BHT无显著性差异,说明其粗提物具有较强的抗氧化活性。     

新疆植物源提取物杀虫活性的初步研究

以采自新疆常见植物的石油醚、乙醇、乙酸乙酯、正丁醇和水的提取物对蚕豆蚜进行生物活性测定,结果表明辣椒的水提物和刺山柑、天仙子、莨菪的乙醇提取物具有较高的杀虫活性。     

Valorisation of waste fractions from autohydrolysis of selected lignocellulosic materials

Non‐isothermal processing of lignocellulosic materials in aqueous media (autohydrolysis reaction) under mild conditions leads to solutions containing valuable chemicals (oligosaccharides, sugars and acetic acid) and other, undesired, compounds (belonging to the extractive and acid‐soluble lignin fractions) which have to be removed in further purification treatments. Liquors obtained by non‐isothermal autohydrolysis of Eucalyptus globulus wood and corncobs under a variety of operational conditions were extracted with ethyl acetate in order to remove non‐saccharide components, and the suitability of the fraction dissolved in the organic phase was assayed for possible utilisation as an antioxidant. The yield and antioxidant activity of ethyl acetate extracts (measured by the α,α‐diphenyl‐β‐picrylhydrazyl (DPPH) radical scavenging capacity) showed a strong dependence on the autohydrolysis conditions. The antioxidant activity of extracts obtained under selected operational conditions compared well with synthetic antioxidants. © 2003 Society of Chemical Industry     

Antioxidant activity of macambo (Theobroma bicolor L.) extracts

Macambo is an edible fruit species from the Amazon Region with a high content of lipids (33%). Macambo samples were obtained from the Amazon Region, dried at 60 °C, milled (32 mesh sieve) and submitted to sequential extraction using ether, ethanol and water as solvents. The antioxidant activity of the ether, ethanol and aqueous extracts was 47%, 68% and 67%, respectively, and the antioxidant activity of the control butylated hydroxytoluene (BHT) was 64%. Three phenolic fractions were obtained with tetrahydrofuran: free phenolic acids, soluble and insoluble phenolic esters. The antioxidant activity of these fractions was 83%, 85% and 93% respectively, and the antioxidant activity of the control BHT was 64%. The phenolic acids were identified on the basis of relative retention times as compared with standards. The fractions obtained showed the presence of the following phenolic acids: salicylic, trans‐cinnamic, sinapinic, chlorogenic, protocatechinic, gallic, quinic, and p‐hydroxibenzoic acid. The presence of phenolic compounds in macambo fruit extracts may be responsible for its rather high antioxidant activity and the results obtained suggest that macambo extracts could be used as food antioxidants. Further studies are in progress to analyze the use of its extracts and phenolic fractions in edible oil shelf life.     

Selective Solvent Extraction of the Bark of Rhizophora apiculata as an Anti-Termite Agent against Coptotermes gestroi

Abstract

The anti-termite action of the bark of mangrove plant Rhizophora apiculata and four other species against the attack of the subterranean termite Coptotermes gestroi was investigated. The bark powder was extracted and partitioned into four main extracts—petroleum ether (PE), chloroform (CE), ethyl acetate (EE), and n-butanol (BE). Termite bioassay on different extracts was carried out. The total phenol content (TPC) of the extracts was determined by the Folin-Ciocalteu method and expressed as gallic acid equivalent (GAE). Butylated hydroxytoluene (BHT) and Butylated hydroxyanisole (BHA) were used as a positive control in the free-radical-scavenging activity test. It was believed that both the toxicity and antioxidant properties of extractives imparted natural resistance to the bark of R. apiculata. Considering wood weight loss, EE appeared to be the most potent inhibitor. The EE was then fractionated into three fractions (F1, F2, F3) by means of thin layer chromatography. F2 exhibited the lowest mean percentage weight loss. Through chemical and spectral analyses, we attribute the presence of bioactive constituents in the EE to a mixture of aromatic carboxylic acids or phenolics.     

陈皮提取物对α-葡萄糖苷酶的抑制作用研究

为了研究新会陈皮的降糖活性,首先制备了5年和10年陈皮的乙醇提取物,再使用5种不同极性溶剂进行萃取,分别得到石油醚层、二氯甲烷层、乙酸乙酯层、正丁醇层以及水层提取物。接着评估这些粗提物对α-葡萄糖苷酶的体外抑制活性。结果表明:5年和10年陈皮提取物的石油醚层对α-葡萄糖苷酶的IC_(50)均为0.2 mg/mL,二氯甲烷层的IC_(50)分别为8.3、8.7 mg/mL,乙酸乙酯层的IC_(50)分别为17.8、8.4 mg/mL,正丁醇层和水层无明显活性,阳性对照品阿卡波糖的IC_(50)为58.8 mg/mL。本研究表明,新会陈皮具有较好的α-葡萄糖苷酶体外抑制活性,具有开发成降糖功能食品的潜力,本研究为新会陈皮的深度开发提供了科学依据和参考。     

甘草抗氧化物的提取工艺

对甘草甜素提取后的废渣,分别用不同浓度的乙醇进行粗提,通过活性跟踪检测,筛选出60%乙醇提取物活性最好;再用石油醚、乙酸乙酯进行梯度提取,确定乙酸乙酯提取物的活性更优,测得总黄酮含量为27.73%。并通过实验证明,该提取物与其他抗氧化剂复配后其活性均好于单个抗氧化剂。     

凤眼草抑菌活性成分的研究

对苦木科臭椿属植物臭椿的果实凤眼草(Ailanthus altissima)的95％乙醇提取液的抑菌活性进行了研究.利用系统溶剂萃取法得到了石油醚提取物、氯仿提取物、乙酸乙酯提取物和正丁醇提取物,重点研究了4种提取物对枯草芽孢杆菌、大肠杆菌和金黄色葡萄球菌的抑菌性和最低抑菌浓度.结果表明,乙酸乙酯提取物和正丁醇提取物均...     

Studies on the antioxidants: X. oxidation products of concomitantly used butylated hydroxyanisole and ethyl protocatechuate

The effects of antioxidants were studied from the viewpoints of (a) the products generated during the autoxidation process and (b) the functional mechanism of antioxidation. The chemical structure and antioxidant activity of the oxide obtained by irradiating an ethanol solution of an equal mixture of butylated hydroxyanisole (BHA) and ethyl protocatechuate (EP) with the ultraviolet (UV) ray and its secondary decomposition were studied. The oxide was identified as 2,2′-dihydroxy-3-tert-butyl-5-methoxy-5′-carboethoxy-diphenyl ether which was a dimer of free radicals generated by BHA and EP. The resulting oxide showed a strong antioxidant activity on lard and methyl oleate in the stability testing by active oxygen method (AOM).     

Antioxidant activities of selected oriental herb extracts

Antioxidant activities of methanol extracts of 180 Oriental herbs were studied by determining the peroxide values of linoleic acid during storage at 50°C. Among the herb extracts tested, 44 species showed strong antioxidant activities on the oxidation of linoleic acid. The antioxidative effects of these 44 selected herb extracts were studied further in a methyl linoleate system during storage for 35 d. Among the 44 species tested, 11 species had particularly high antioxidative effects. The effects of type of extraction solvent (methanol, petroleum ether and ethyl acetate) on the antioxidant activities of the 11 species were studied. Antioxidant activities of most herb extracts were greatly dependent on the extraction solvent used; however, some of the extracts showed strong antioxidant activities regardless of the solvents used for the extraction. Among the 11 herbs selected, based on the antioxidant activity of their methanol extracts, two (i.e.,Psoralea corylifolia L. andSorphora angustifolia Sieb. & Zucc.) were selected for further study in lard held at 75°C for 7 d. The methanol extracts ofP. corylifolia L. andS. angustifolia Sieb. & Zucc. greatly decreased the peroxide formation of lard during storage. Treatment with 0.20% methanolic extract ofP. corylifolia L. exhibited significantly stronger antioxidant effect on the oxidation of lard than treatment with 0.02% butylated hydroxyanisole (P<0.05).     

Development of Cellulose Acetate Propionate Membrane for Separation of Ethanol and Ethyl tert-Butyl Ether Mixtures

Abstract

For pervaporation separation of ethanol and ethyl tert-butyl ether mixtures, a cellulose acetate propionate membrane was chosen as the experimental membrane because of its high selectivity and good mass fluxes. The properties of the membranes were evaluated by the pervaporation separation of mixtures of ethyl tert-butyl ether/ethanol and the sorption experiments. The experimental results showed that the selectivity and the permeates depend on the ethanol concentration in the feed and the experimental temperature. With increases of the ethanol weight fraction in the feed and the temperature, the total and partial mass fluxes increased. With respect to the temperature, ethanol mass flux obeys the Arrhenius equation. The selectivity of this membrane decreases as the temperature and the ethanol concentration in the feed increase. This membrane shows special characteristics at the azeotropic composition. In the vicinity of the azeotropic point, minimum values of ethanol concentration in the permeate and in sorption solution are obtained. The swelling ratios increase when temperature and the ethanol concentration in the feed are increasing. The ethanol concentration in the sorption solution is also influenced by the temperature and the mixture's composition. When the temperature increases, the sorption selectivity of the membrane decreases.     

Antioxidant Potential,Lipid Peroxidation Inhibition and Antimicrobial Activities of Satureja montana L. subsp. kitaibelii Extracts

The antioxidant activity of different Satureja montana L. subsp. kitaibelii extracts was tested by measuring their ability to scavenge reactive hydroxyl radical during the Fenton reaction, using ESR spectroscopy. Also, the influence of these extracts on lipid peroxyl radicals obtained during lipid peroxidation of: (I) sunflower oil (37 ºC, 3h) induced by 4,4′-azobis(4-cyanovaleric acid) (ACVA) and (II) liposomes induced by 2,2′-azobis(2- amidino-propane)dihydrochloride (AAPH) was studied. n-Butanol extract had the best antioxidant activity (100% at 0.5 mg/mL in Fenton reaction system; 89.21% at 5 mg/mL in system I; 83.38% at 5 mg/mL in system II). The antioxidant activities of the extracts significantly correlated with total phenolic content. The antimicrobial activity of Satureja montana L. subsp. kitaibelii extracts was investigated. Petroleum ether, chloroform and ethyl acetate extracts expressed a wide range of inhibiting activity against both grampositive and gram-negative bacteria.     

A first pilot study to produce a food antioxidant from sunflower seed shells (Helianthus annuus)

This article explains a laboratory procedure to produce an antioxidant from grinded, dehulled and partially defatted sunflower seeds. Initially, a solvent suitable to extract phenols was searched among different solutions of water mixed with ethanol, methanol and acetone at 40% (vol/vol) (each tested at pH 5, 7 and 9). Both the ethanol/water 60:40 (vol/vol) and the acetone/water 60:40 (vol/vol) mixtures proved to be suitable for the dephenolization of sunflower seed shells, but in the next steps of this research, the mixture ethanol/water 60:40 (vol/vol) at pH 5 was used. Secondly, the procedure to obtain the antioxidant product was defined, which consisted in hydrolysis of sunflower seed phenols with 1.25 N NaOH at room temperature for 60 min and finally the recovery of caffeic acid formed from chlorogenic acid with ethyl acetate. From 25 g of partially defatted sunflower shells, around 90 mg of powdery antioxidant product, consisting of 58% caffeic acid, was obtained. The antioxidant product, the caffeic acid standard and propyl gallate were added to different edible fats at the same dose of 240 AU (antioxidant units) per kg fat. A Rancimat test, at 130 °C and an air flow of 20 L h^?1, demonstrated that the effectiveness of the sunflower antioxidant product was essentially similar to that of the caffeic acid standard, but 15–20% lower than that of propyl gallate. In conclusion, dephenolization of sunflower seeds could be economically convenient, not only because a useful antioxidant can be produced, but also because the raw material composition can be improved for other uses.     

Preparative Isolation of Antioxidant Flavonoids from Small Black Soybeans by Centrifugal Partition Chromatography and Sequential Solid-Phase Extraction

Unlike other members of the leguminous family that are generally used as food, Rhynchosia volubilis, a small soybean with a black seed coat, is used as a folk medicine in Korea. Using an on-line high performance liquid chromatography-2,2?-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation screening system, one peak in the ethyl acetate fraction exhibited outstanding antioxidant capacity. To purify and determine the antioxidant compounds associated with this peak, we developed a centrifugal partition chromatography (CPC) method. The ethyl acetate fraction (500 mg) was subjected to CPC using a two-phase solvent system of n-hexane–ethyl acetate–ethanol–water (0.1:8:2:7, v/v) with a dual-mode CPC (descending-ascending order) in a bid to separate glycitin (3.1 mg), daidzin (14.4 mg), 6??-O-acetyl genistin (6.9 mg), 6??-O-acetyl daidzin (5.3 mg), and a mixture of epicatechin and genistin. The mixture was further separated through solid-phase extraction to yield epicatechin (6.8 mg) and genistin (23.5 mg), respectively. Structural identification of the R. volubilis flavonoids was performed by NMR and ESI-MS.     

肿柄菊粗提物对线虫毒杀活性的研究

为评价肿柄菊粗提物毒杀线虫的潜力,利用石油醚、乙酸乙酯、二氟甲烷浸泡粉碎的肿柄菊枝叶混合物,经旋转蒸发获得粗提物,通过浸渍法检测了不同粗提物的毒杀线虫活性。结果表明：当浓度为10mg·mL^-1时,石油醚、乙酸乙酯和二氟甲烷粗提物24～72h内对线虫的毒杀效果较弱;当浓度为20mg·mL^-1时,二氯甲烷粗提物毒杀线虫活性最好,处理72h的线虫校正死亡率可达50．6％,乙酸乙酯粗提物和石油醚粗提物毒杀线虫活性均较弱;当浓度为40mg·mL^-1时,毒杀线虫活性大小依次是乙酸乙酯粗提物〉石油醚粗提物〉二氯甲烷粗提物,其中乙酸乙酯粗提物处理72h的线虫校正死亡率达73．6％。表明,对肿柄菊粗提物进行合理的处理、分离、纯化,有望开发出高效低毒、绿色环保的新型杀线虫农药。