首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
Rubratoxin were recovered from cultures of Penicillium rubrum after the mold grew in natural substrates, a semi-synthetic medium, and a glucosemineral salts broth. Substrates that contained rubratoxins were extracted with: diethyl ether, ethyl acetate-benzene, ethanol (100%), ethanol-acetone, acetonitrile, or diethyl ether with refluxing at 45 degrees C. Extracts were screened for rubratoxins by thin-layer chromatography. Some extracts were partially purified with a column of silicic acid using acetone as the eluant. Other extracts were purified (primarily removal of pigments) using columns of silica gel plus Celite and gradient solvent elution. Most rubratoxin B (1.9 mg/g or 0.77 mg/ml) was recovered when corn, rice, or glucose-salts broth were extracted successively with diethyl ether, ethyl acetate-benzene, and diethyl ether or when samples were adjusted to pH 1.5 before refluxing with diethyl ether at 45 degrees C for 1--4h. Most rubratoxin A (0.1--0.15 mg/ml or 1.0 mg/g) was obtained from samples of corn extracted twice each with ethyl alcohol, acetone, and ethyl acetate; from glucose-mineral salts broth extracted with diethyl ether; or from yeast extract sucrose broth extracted with diethyl ether and refluxed for 4 h at 45 degrees C. Large amounts of fairly pure rubratoxin A (up to 400 mg) and rubratoxin B (greater than lg) were obtained with a combination of preparative thin-layer and column chromatography.  相似文献   

2.
The objective of this study was to evaluate the antioxidant and binding effects of gooseberry, a less-studied berry, and to compare with blueberry and cranberry in the model of interaction with human serum albumin (HSA). The relationship between the scavenging properties of dietary polyphenols of the selected berries and their affinities for HSA were investigated by fluorescence analysis. In order to perform the extraction and identification of the antioxidants present in the samples, different types of extraction solvents were used, such as water, ethyl acetate, and diethyl ether. The polyphenols, tannins, anthocyanins and ascorbic acid contents, and the total antioxidant capacities (TACs) of the berry extracts were assessed by using ESI–MS, FTIR, and radical scavenging assays. The contents of bioactive compounds and the levels of TACs in water extracts differed significantly and were the highest in water extracts in comparison with other extracts in all the investigated berries (P < 0.05). Gooseberry water extracts contained: polyphenols (mg GAE/g DW)—5.37 ± 0.6, tannins (mg CE/g DW)—0.71 ± 0.2, anthocyanins (mg CGE/g DW)—12.0 ± 1.2, ascorbic acid (mg AA/g DW)—5.15 ± 0.5, and TACs (μMTE/g DW) by ABTS and FRAP assays were 15.53 ± 1.6 and 6.51 ± 0.7, respectively. In conclusion, the bioactivity of gooseberry was lower than blueberries and cranberries. The antioxidant and binding properties of gooseberries in comparison with widely consumed blueberries and cranberries can be used as a new source for food supplementation.  相似文献   

3.
Uronic acid soluble in ethanol/water (4:1 v/v) increased from 9 ± 1 mg kg?1 fresh weight in pulp of unripe banana fruit. Musa (AAA Group, Cavendish subgroup) ‘Williams’, to 53 ± 13 mg kg?1 fresh weight in fruit ripened for 13 days. This increase began within the first 2 days of ripening. Uronic acid soluble in phenol/acetic acid/water (2:1:1 w/v/v) increased from 15 ± 5 to 86 ± 17 mg kg?1 fresh weight during the first 8 days of ripening, accompanied by a decrease in cell wall uronic acid from 10·2 ± 0·8 to 4·4 ± 0·4 g kg?1 fresh weight. Most or all of the uronic acid in extracts of ripe pulp cochromatographed with monogalacturonic acid. The results were consistent with hydrolysis of cell wall polyuronides by exopolygalacturonase (EC 3.2.1.67).  相似文献   

4.
董蕊  孙昌霞 《食品工业科技》2018,39(8):56-60,66
目的:对木贼的乙醇提取物不同萃取部位进行总酚酸、黄酮含量测定及抗氧化活性比较,以探知木贼抗氧化活性物质基础。方法:木贼经70%乙醇超声提取浓缩后,采用有机溶剂萃取法依次得到石油醚、乙酸乙酯、正丁醇、水相4个部位萃取物;利用紫外-分光光度法比较各萃取部位总黄酮、酚酸含量差异;以抗坏血酸为阳性对照,比较不同萃取部位还原能力、羟自由基(·OH)、1,1-二苯基-2-三硝基苯肼(DPPH·)、2,2'-联氮-双(3-乙基苯并噻唑-6-磺酸)二铵盐(ABTS+·)清除率的差异,评价各部位抗氧化能力强弱。结果:木贼各萃取物总黄酮含量在5.70~61.55 mg/g 范围内,总酚酸含量在4.07~19.10 mg/g 范围内,乙酸乙酯萃取物总黄酮与酚酸含量明显高于其他萃取物,其还原能力、羟自由基、DPPH·、ABTS+·清除率也明显高于正丁醇、石油醚和水相萃取物,乙酸乙酯萃取物对羟自由基、ABTS+·、DPPH·清除能力IC50值分别为:(0.321±0.0026)、(0.213±0.0010)和(0.169±0.0014) mg/mL。结论:经各相溶剂萃取后木贼有效成分得到初步分离,乙酸乙酯相萃取部位总黄酮和酚酸相对含量及抗氧化活性明显强于总提物和其他萃取部位,且其抗氧化能力呈量效关系。实验发现木贼中黄酮和酚酸类成分与其抗氧化能力密切相关。  相似文献   

5.
Petroleum ether extract from Abutilon theophrasti Medic. leaves was optimized by response surface methodology, and the optimal extraction conditions were as follows: ratio of solvent to material (20.12 mL/g), extraction time (5.45 h), and Soxhlet extraction temperature (61.32°C). And the yield of petroleum ether extract collected in August, September, and October was (2.05 ± 0.02)%, (2.39 ± 0.01)%, and (2.32 ± 0.02)%, respectively. The September and October extracts exhibited a better antioxidant activity, which was proved by DPPH·scavenging ability (IC50 value of 327.5 and 331.5 μg/mL), ABTS·+ scavenging ability (IC50 value of 170.1 and 182.1 μg/mL), and reducing power (0.31 and 0.28 mmol Fe2+/100 μg/mL). Meanwhile, the gas chromatograph-mass spectrometry analysis revealed that the main antioxidant components contained 9, 12, 15-octadecatrienoic acid and 9, 12, 15-octadecatrienoic acid, ethyl ester (Z,Z,Z) in three petroleum ether extracts. Therefore, petroleum ether extract from Abutilon theophrasti Medic. leaves can be a potential resource of natural antioxidants in pharmaceutical, medicine, food, and chemical industries.  相似文献   

6.
研究不同溶剂对洋葱皮总多酚、总黄酮和槲皮素的提取效果及其提取物的抗氧化、抑制α-糖苷酶活性。以紫色洋葱皮为原料,分别以水、40%~100%乙醇溶液、乙酸乙酯、石油醚为溶剂提取洋葱皮活性成分,分析不同溶剂对总多酚、总黄酮及槲皮素的提取效果,测定不同溶剂提取物的总还原能力、清除DPPH·、ABTS+·、O2-·能力及抑制α-糖苷酶活性,并分析提取物中总多酚、总黄酮及槲皮素含量与其生物活性的相关性。结果表明:60%乙醇对总多酚、总黄酮、槲皮素的提取效果最好,三种活性成分的提取率分别为5.5%、9.87%、3.25%,纯度分别达(33.12%±0.39%)、(59.44%±0.38%)、(19.56%±0.14%)。40%、60%乙醇提取物均具有较强总还原能力、清除DPPH·、ABTS+·、O2-·能力和抑制α-糖苷酶活性能力。洋葱皮提取物总黄酮、槲皮素含量与其抗氧化、抑制α-糖苷酶活性的相关系数均达显著或极显著水平,其中,提取物的槲皮素含量与自由基清除活性、抑制α-糖苷酶活性相关性最高。  相似文献   

7.
Experiments have been made with two sheep to determine their ability to synthesise hippuric acid. The titratable acidity of diethyl ether extracts of acidified urine was expressed as g benzoic acid equivalent. One sheep on a dried grass ration and one on a hay and oats ration excreted in the urine 8·06 and 4·07 g benzoic acid equivalent/24 h, respectively, the amounts conjugated with glycine being 2·63 and 2·38 g respectively. When non-toxic levels of benzoic acid and glycine were infused into the abomasum, complete recovery of infused benzoic acid was obtained in terms of increased titratable acid in ether extracts of the urine. Infusion of 9·6 g of benzoic acid for 24 h as a continuous drip resulted in an increase of 11·89 g of benzoic acid equivalent in the urine, 8·90 g of which were conjugated with glycine. The largest non-toxic dose given was 53·95 g of benzoic acid which gave rise to an increase in urinary benzoic acid equivalent of 58·47 g, 27·10 g of which were conjugated with glycine. Lethal doses for the two sheep were 1·1 and 1·8 g of benzoic acid/kg body weight. Urine collected during infusion of a toxic dose to one sheep contained a large increment in combined glucuronides. A very large increase in urinary potassium was observed in one sheep given a toxic dose of benzoic acid.  相似文献   

8.
The wood of Ilomba (Pycnanthus angolensis Exell) may seriously discolor in the log after felling and also in lumber during drying. The discoloration is associated with the occurrence of bacterial metabolites. The components responsible for the discoloration were extracted completely from the wood before discoloration with hot methanol and separating into petroleum ether, diethyl ether, ethyl acetate and water soluble and insoluble fractions. Bioassays using nutrient liquids inoculated with Pseudomonas fragi revealed that the diethyl ether soluble fraction discolored most. Chemical characterization of the individual components indicated that three different types of components could be involved which are the (?)-epicatechin and (+)-catechin, the intensely red compound and the water soluble component of the methanol extracts. Their contributions to the discoloration are discussed on the basis of their colorimetric characteristics and amounts present in the wood.  相似文献   

9.
Methods have been developed for the analysis of residues of a new soil insecticide, diethyl 1-(2,4-dichlorophenyl)-2-chlorovinyl phosphate (SD 7859, Birlane*) in a range of crops and soils. Enzyme inhibition procedures using plasma and fly-head cholinesterases and gas-liquid chromatography (GLC) can be used for the measurement of Birlane in crop and soil extracts down to a level of 0·01 μg/ml which corresponds to 0·02 ppm in the original sample at the normal sample/solvent ratios that are used. Treated soils may be stored for at least one month at ?10° without decomposition of the Birlane residues and Birlane in solvent extracts is stable for at least one month at 0°. Extraction procedures have been investigated using chloroform and acetone-hexane mixtures with different extraction times. Recoveries of Birlane average 95% from soils at the 0·2-1·0 ppm level and average 100% from a range of crops at the 0·05-0·10 ppm level. Without clean-up, blank values of soil extracts can approach 0·2 ppm (using GLC) but are generally 0·05 ppm or less in crops apart from carrots. The interference, however, can readily be removed using column chromatography.  相似文献   

10.
摘要:目的 本实验对巫山茶多酚提取物的体外抗氧化活性进行了初步评价。方法 通过使用70%乙醇提取巫山茶得到巫山茶粗提物,再依次使用不同极性溶剂萃取巫山茶粗提物得到石油醚相、乙酸乙酯相、正丁醇相和水相4个萃取相,分别测定各萃取相的总酚含量和体外抗氧化活性,选取总酚含量最高且体外抗氧化活性最强的萃取相通过HP-20大孔树脂进行富集,测定富集后的巫山茶多酚提取物总酚含量和体外抗氧化活性。结果 乙酸乙酯相的总酚含量最高,为378.1mg/g;巫山茶粗提物及其不同萃取相均具有一定的抗氧化活性,以乙酸乙酯相的体外抗氧化活性最强,DPPH?、ABTS+?、? OH的IC50值分别为0.63mg/mL、0.46mg/mL和2.35mg/mL;将乙酸乙酯相通过HP-20大孔树脂富集后得到的巫山茶多酚提取物总酚含量为637.5mg/g,总酚含量显著提高(p <0.05),DPPH?、ABTS+?、?OH的IC50值分别为0.26mg/mL、0.16mg/mL和1.05mg/mL,体外抗氧化活性显著增强(p <0.05)。相关性分析结果显示,巫山茶粗提物及各萃取相、富集后的总酚含量与其体外抗氧化活性呈正相关。结论 巫山茶多酚提取物具有较好的体外抗氧化活性,可考虑对其进行多酚成分分析和抗氧化功能研究。  相似文献   

11.
洋甘菊各萃取相抗氧化活性及其有效成分分析   总被引:1,自引:0,他引:1  
目的:筛选洋甘菊醇提物抗氧化活性最强的萃取组分,并对该组分抗氧化活性的有效成分进行研究。方法:采用DPPH·、ABTS+·、O2-·自由基清除能力和FRAP抗氧化功能测试方法,对比研究了洋甘菊醇提物不同极性萃取组分的抗氧化活性,并运用HPLC等方法对抗氧化能力最强萃取组分进行有效成分分析。结果:洋甘菊乙酸乙酯萃取组分的抗氧化能力最强,对DPPH·、ABTS+·和O2-·的IC50分别为25.6、30.6和83.3 mg/mL,总抗氧化能力(以trolox计)为16.7 mg/mL。成分分析表明,乙酸乙酯萃取相中总酚和总黄酮含量分别为25.84%和14.93%,在检测到的10种多酚或黄酮类化合物中,木犀草素、蒙花苷和木犀草素-7-葡萄糖含量较丰富。结论:洋甘菊醇提物的乙酸乙酯萃取组分具有良好的抗氧化能力可能与其富含的多酚和黄酮成分有关。  相似文献   

12.
为比较覆盆子不同极性溶剂提取物的抗氧化活性,分别用正丁醇、乙酸乙酯、丙酮、去离子水、50%乙醇和石油醚进行萃取,测定各提取物总多酚和总黄酮的含量,并通过清除DPPH自由基、ABTS自由基、羟基自由基和总还原能力4种体系对其体外抗氧化活性进行评价。结果显示,乙酸乙酯提取物中总多酚含量最高,50%乙醇提取物中总黄酮含量最高;50%乙醇提取物清除DPPH自由基能力和ABTS自由基能力最强,水提取物清除羟基自由基能力最强,丙酮提取物总还原能力最强。结果表明覆盆子不同极性溶剂的提取物均有抗氧化活性,可作为天然抗氧化剂开发。  相似文献   

13.
Skin, outer pericarp, inner pericarp and core, respectively comprised 4·8, 43·7, 45·0 and 6·5% of a mean whole kiwifruit weight of 111·3 ± 1·3 g. Kiwifruit weights ranged from 99·0 to 125·3 g. Vitamin C content per 100 g edible flesh ranged from 37·8 to 53·6 mg with means of 43·7 ± 1·7 mg for total vitamin C,41·9 ± 1·5 mg for ascorbic acid (AA) and 1·7 ± 0·4 mg for dehydroascorbic acid (DHA). Vitamin C contents were found to be at least half previously reported contents, possibly due to losses during storage and transportation from New Zealand. Total vitamin C concentrations per 100 g of skin, outer pericarp, inner pericarp and core were 41·7 ± 3·1 mg, 42·9 ± 2·0 mg, 45·5 ± 2·3 mg and 42·3 ± 2·6 mg, respectively. Outer and inner pericarp contained similar concentrations of both AA with 40·7 ± 1·7 mg and 42·7 ± 2·1 mg, and DHA with 2·1 mg and 2·8 ± 0·7 mg per 100 g tissue, respectively. Skin and core contained lower concentrations of AA with 28·1 ± 2·4 mg and 31·1 ± 2·2 mg, and correspondingly higher contents of DHA with 13·5 ± 2·4 mg and 11·2 ± 1·3 mg per 100 g tissue, respectively. Whole fruit weight correlated with DHA concentration in both skin (r = ?0·644) and core (r = ?0·693).  相似文献   

14.
Six colour-flowering (Scirocco, Alfred, Carola, Condor, Tina and Herz Freya) and six white-flowering (Caspar, Albatros, Gloria, Tyrol, Vasco and Cresta) cultivars of Vicia faba were studied. The crude protein contents of colour- and white-flowering cultivars were 267±13·6 and 283±18·8 g kg−1, respectively, which did not differ significantly at P<0·05. The levels of lipids, crude fibre, starch and ash varied from 14 to 22 g kg−1, 88 to 143 g kg−1, 407 to 485 g kg−1 and 32 to 42 g kg−1, respectively. The calculated organic matter digestibility (OMD) and metabolisable energy (ME) of the white-flowering cultivars were significantly higher (P<0·001) than those of the colour-flowering cultivars (OMD: 889·1±26·6 g kg−1 vs 797·5±17·1 g kg−1; ME: 13·97±0·49 vs 12·30±0·34 MJ kg−1). In all cultivars, sulphur amino acids were lower than adequate concentration when compared with recommended amino acid pattern of FAO/WHO/UNO reference protein for a 2–5-year-old child. The in vitro rumen nitrogen degradability of colour-flowering cultivars was significantly lower (P<0·01) compared to that of white-flowering cultivars (71·4±9·3% vs 88·0±11·1%). Amongst colour-flowering varieties, the contents of total phenols (TP), tannins (T) and condensed tannins (CT) were highest in Alfred (28·3, 21·0 and 35·4 g kg−1, respectively). The contents of TP and T were similar (about 15 and 10 g kg−1, respectively) in Carola, Tina and Herz Freya, and the CT were in the order: Condor>Herz Freya>Carola. The CT were not detected in white-flowering varieties, T were virtually absent and TP were extremely low (4·0–4·9 g kg−1). The activities of other antinutritional factors (white- and colour-flowering cultivars, respectively: trypsin inhibitor activity 3·05±0·34 and 1·85±0·09 mg trypsin inhibited g−1; lectin 27·2±9·4 and 27·1±5·1 mg ml−1 assay medium producing haemagglutination; phytate 15·0±2·7 and 16·6±2·3 g kg−1) were very low. A strong negative correlation (r=-0·92, P<0·001) between tannins and in vitro rumen protein degradability was observed which suggested that tannins have adverse effect on protein degradability. Similarly negative correlations between tannin levels and metabolisable energy (r=-0·89; P<0·001) and organic matter digestibility (r=-0·89; P<0·001) were observed. The correlation coefficient between trypsin inhibitor activity and tannins was negative and highly significant (r=-0·88, P<0·001), whereas between tannins and saponins it was significantly positive (r=0·96, P<0·001). ©1997 SCI  相似文献   

15.
对闪式提取红树莓总多酚的提取工艺进行研究,在单因素实验的基础上选取了溶剂体积分数、提取电压和提取时间为因素,以红树莓总多酚提取量为响应值,进行Box-Behnken中心组合实验设计,利用响应面分析法对提取条件进行优化,通过测定提取液对DPPH·和·OH清除能力,评价其抗氧化活性。结果表明,树莓总酚在四种溶剂中的提取效果顺序为:乙醇 > 水 > 石油醚 > 氯仿,最佳提取工艺参数为乙醇体积分数48%、提取电压150 V、提取时间为57 s,红树莓总酚提取量为(52.24±0.66) mg/g,此外,提取物对DPPH·清除率达到93.71%±0.70%,对·OH清除率达到84.13%±1.58%。  相似文献   

16.
The stability of selected metabolic conjugates (phenylglucuronide, phenylphosphate, and naphthylsulfate) was determined in model systems composed of water and various ratios (3:1, 1:1, 1:3) of selected solvents (hexane, chloroform, ethyl acetate, diethyl ether, or methanol) held at either 22°C or 40°C for 30 min under various pH conditions (pH 1.5, 3.2, or 6.5). Notable hydrolysis occurred only for the more polar solvents held in contact with acidic aqueous phases. Conditions were identified for minimizing hydrolysis of conjugates during extraction of fat and free alkylphenols from milk and meat products with diethyl ether. They were pH near neutral, short exposure time, near ambient temperature, presence of excess water, and saturation of aqueous phase with sodium chloride.  相似文献   

17.
以海南产槟榔鲜果为原料,制备槟榔提取物,研究槟榔提取物对小白鼠体内的抗氧化作用,通过体外实验筛选出来活性较好的提取物,将其作为受试物,以血清SOD及血清MDA水平为评价指标,进行小白鼠体内抗氧化作用研究。结果表明,槟榔粗提取物、乙酸乙酯萃取物和水溶出物三种组分对羟自由基(·OH)具有良好的清除作用,清除率均在53%以上。三种受试物的各个剂量均能显著提高小白鼠的血清SOD水平(p<0.05);而除乙酸乙酯萃取物高剂量作用效果不显著外(p>0.05),其他各受试物的各个剂量均能显著降低实验动物的血清MDA浓度(p<0.05)。槟榔提取物在小白鼠体内具有良好的抗氧化活性作用。  相似文献   

18.
用行业标准分别对文蛤原料、清洗并热烫后和冷冻0.5 h后等加工工序中文蛤细菌总数、大肠菌群数、粪大肠菌群数、副溶血性弧菌、金黄色葡萄球菌和沙门氏菌进行了检验.结果发现,湛江东海岛近海文蛤原料的细菌总数为(4.0±0.1)×105 cfu/g,清洗并热烫和再冷冻0.5 h后对细菌总数的影响不明显.文蛤原料大肠菌群数为(790.7±21.3)MPN/g,清洗并热烫后大肠菌群数明显降低至(19.4±1.3)MPN/g,再冷冻0.5 h后大肠菌群数为(18.3±1.1)MPN/g.文蛤原料粪大肠菌群数为(817.5±19.8)MPN/g,清洗并热烫后粪大肠菌群数明显降低至(194.2±10.2)MPN/g,再冷冻0.5 h后粪大肠菌群数为(180.6±11.3)MPN/g.文蛤原料、清洗并热烫后和再冷冻0.5 h后副溶血性弧菌的检验结果均为<3 MPN/g;均未检出凝固酶阳性的金黄色葡萄球菌和沙门氏菌.可见湛江东海岛近海文蛤的细菌污染主要是大肠菌群和粪大肠菌群,经清洗并热烫和再冷冻0.5h处理,能明显降低大肠菌群和粪大肠菌群数量.  相似文献   

19.
以乳苣全草为原料,75%乙醇为溶剂提取乳苣,提取液用不同极性溶剂依次萃取,得石油醚萃取物、乙酸乙酯萃取物、正丁醇萃取物和水萃取物,同时测定了各相提取物对羟自由基、超氧阴离子自由基、DPPH自由基的清除能力,并与VC进行比较。结果表明:各萃取物均具有一定的抗氧化活性,且随着浓度的增加而增强;对羟自由基的清除能力大小依次为乙酸乙酯萃取物>正丁醇萃取物>VC>水萃取物>石油醚萃取物;对超氧阴离子自由基清除能力大小依次为VC>正丁醇萃取物>乙酸乙酯萃取物>石油醚萃取物>水萃取物;对DPPH自由基清除能力大小依次为VC>乙酸乙酯萃取物>正丁醇萃取物>水萃取物>石油醚萃取物;各萃取物还原能力大小依次为VC>正丁醇萃取物>乙酸乙酯萃取物>水萃取物>石油醚萃取物。  相似文献   

20.
分别以二氯甲烷和乙醚作溶剂,同时蒸馏萃取(SDE)养殖暗纹东方鲀肉中的挥发性成分,结合气质联用(GC-MS)对挥发性成分进行定性,以2,4,6-三甲基吡啶内标定量分析,并结合主成分分析法(PCA)对挥发性成分进行数据挖掘。结果表明:乙醚为溶剂时,总共鉴定到了57种成分,含量较高的是十四醛(4 963.71ng/g)、十八醛(1 171.51ng/g)、(Z)-13-十八醛(2 007.21ng/g)、乙酸乙酯(1 148.44ng/g)、十六酸(4 639.90ng/g)等;以二氯甲烷为溶剂时,总共鉴定到了78种成分,主要是十六醛(2 381.77ng/g)、2,3-丁二酮(1 267.40ng/g)、十六酸(545.08ng/g)等。比较得出,二氯甲烷溶剂在定性方面有优势,乙醚溶剂在定量方面效果较好。2种溶剂萃取一共检测出96种化合物,其中醛类29种、酮类11种、醇类16种、含氮含硫及杂环类化合物22种、酯类7种、酸类3种、烷烃类8种。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号