牛蒡子75%乙醇提取物总酚含量及抗氧化活性研究

目的本文主要测定牛蒡子75%乙醇提取物的体外抗氧化活性。方法:采用ABTS自由基、DPPH自由基清除方法以及还原法和总酚含量测定法,并利用紫外分光光度计法测定牛蒡子乙醇提取物的抗氧化活性。结果牛蒡子醇提物对DPPH、ABTS+自由基的清除率IC50值分别为0.055mg/m L、0.121 mg/m L;当浓度为1.24 mg/m L水平,其吸光度值为2.390,显示较强的还原性,其中总酚含量为48.3μg/mg。结论牛蒡子的75%醇提取物具有较好的抗氧化活性,在天然抗氧化剂的食品保鲜和药物的治疗方面,牛蒡子的醇提取物可以作为一种新的抗氧化材料,应用价值较好。     

椰子种皮油提取物的抗氧化活性研究

测定椰子种皮油提取物中的总酚含量,对羟基自由基、DPPH（1,1-二苯基-2-三硝基苯肼）自由基、ABTS（2,2连氮-双-（3-乙基苯并噻咪唑-6-磺酸）自由基清除能力和总抗氧化能力等抗氧化活性指标。结果表明,椰子种皮油提取物中含有较高的总酚含量（68 mg/g）,提取物浓度为0.1 mg/mL时对羟基自由基的清除率为56.89％,对DPPH自由基的清除率为71.0％,对ABTS自由基的清除率为96.4％,表明椰子种皮油提取物具有很好的抗氧化活性。     

甜叶菊总黄酮提取条件、成分与抗氧化活性研究

为探究甘肃酒泉产甜叶菊中总黄酮提取条件、成分与其抗氧化活性间的关系。采用乙醇超声水浴提取法,探讨提取时间、温度、料液比、功率等因素对总黄酮提取条件的影响;用HPLC柠檬酸-甲醇流动相梯度洗脱法测定甜叶菊中芦丁、圣草枸杞苷、山奈素、槲皮素、橙皮苷的含量;用FRPD和DPPH法评价甜叶菊茎叶中总黄酮提取物与抗氧化活性之间的关系。结果:通过正交试验,得出乙醇超声水浴的最佳提取条件:80%乙醇、提取功率450 W、料液比1∶20、提取时间150 min、温度85℃、提取3次,总黄酮提取率最高可达到0.88%;HPLC法检测甜叶菊茎叶中5种黄酮成分,以芦丁的含量(701.42μg/g)为最高,槲皮素含量(451.55μg/g)居其次,橙皮苷含量(297.54μg/g)与山奈素含量(241.21μg/g)较少,圣草枸杞苷含量(57.44μg/g)极微;用FRPD和DPPH法评价甜叶菊茎叶总黄酮提取物抗氧化活性,其抗氧化活性高达10.02 mg/g DW,黄酮含量与抗氧化活性二者呈较显著的正相关性(R=0.769～0.792)。这为甜叶菊中黄酮类物质的提取与进一步开发利用提供基础性研究资料。     

千层金叶片醇提物抗氧化活性的研究

为了探究千层金叶片醇提物的抗氧化活性,本文研究了千层金叶片醇提物及其不同极性部位的抗氧化活性和总多酚含量。研究结果表明：千层金叶片醇提物正丁醇相的总多酚含量最高,为(453.75±0.75) mg/g;75%甲醇粗提物及其正丁醇相对ABTS ⁺自由基的清除能力较抗坏血酸（VC）强;各组分还原力强弱顺序为VC>正丁醇相>75%甲醇粗提物>水相>乙酸乙酯相>BHT>石油醚相;正丁醇相和乙酸乙酯相对DPPH自由基的清除能力较醇提物和水相强,石油醚相最弱;千层金叶片醇提物及其不同极性部位清除ABTS ⁺自由基清除能力、DPPH自由基清除能力及还原力均与其总多酚含量呈正相关。除石油醚相外,千层金叶片醇提物及其不同极性部位均有较强的抗氧化活性,可作为一种良好天然抗氧化剂的物质来源。     

黄麻韧皮纤维活性物质鉴定及抑菌效果分析

采用溶剂法从黄麻韧皮纤维中提取黄酮、多糖、生物碱3种成分,并对提取物的化学组分及抑菌效果进行测定分析。结果表明,3种提取物中总黄酮、总多糖、总生物碱含量分别为17.36 mg/g、3.57 mg/g、61.01μg/g。高效液相色谱法(HPLC)检测出黄酮类提取物主要包括异槲皮素(167.47μg/g)、槲皮素(12.35μg/g)、木犀草素(6.41μg/g)、山奈酚(6.26μg/g)等;多糖类提取物中的单糖组分有半乳糖(0.41 mg/g)、半乳糖醛酸(0.43 mg/g)、阿拉伯糖(1.03 mg/g)等;生物碱类提取物主要组分为盐酸小檗碱(9.97μg/g)。纸片扩散法、二倍稀释观察法、扫描电镜分析显示,3种提取物对金黄色葡萄球菌、大肠杆菌、痢疾杆菌均能产生不同程度的抑制效果。综上,黄麻韧皮纤维中的活性物质较为丰富,且具有良好的抑菌性能。     

嘉宝果嫩叶提取物不同极性部位抗氧化及抑制α-葡萄糖苷酶活性研究

从植物中寻找天然的抗氧化剂和α-葡萄糖苷酶抑制剂对糖尿病患者具有重要的意义。采用比色法对嘉宝果嫩叶醇提物不同极性部位进行总多酚和总黄酮含量、抗氧化活性及α-葡萄糖苷酶活性抑制活性研究,以期为嘉宝果嫩叶有效提取部位在食品、化工及医学领域的应用提供一定的参考依据。结果表明,乙酸乙酯相的总多酚含量（33.92 mg/g及总黄酮含量（13.35 mg/g）最高,其次为正丁醇相（总多酚31.11 mg/g;总黄酮12.93 mg/g）及水相（总多酚17.04 mg/g;总黄酮11.18 mg/g）;石油醚相及二氯甲烷相均未检测到总多酚及总黄酮。乙酸乙酯相与正丁醇相对DPPH及ABTS ⁺自由基的清除能力相当,明显高于其他极性部位。对酵母源和小鼠小肠源α-葡萄糖苷酶活性抑制活性大小依次分别为乙酸乙酯相>正丁醇相>水相>石油醚相>二氯甲烷相和乙酸乙酯相>正丁醇相>水相>二氯甲烷相>石油醚相。以上结果表明嘉宝果嫩叶乙酸乙酯相与正丁醇相总多酚及总黄酮含量较高,抗氧化活性及对α-葡萄糖苷酶活性的抑制作用较强,是挖掘抗氧化及抑制α-葡萄糖苷酶活性物质的主要极性部位。     

苦丁茶不同提取物抗氧化活性比较及其GC-MS分析

利用气相色谱-质谱联用技术（GC-MS）,对苦丁茶超声辅助不同有机溶剂（乙醇、乙酸乙酯、石油醚）提取物及超临界CO₂萃取物的体外抗氧化活性（DPPH自由基清除能力、羟基自由基清除活性、超氧阴离子自由基清除活性和ABTS ⁺自由基清除能力）进行比较分析。结果表明,苦丁茶不同提取物DPPH清除能力和超氧阴离子自由基清除活性依次为：超声-乙醇提取物>超临界CO₂萃取物>超声-乙酸乙酯提取物>超声-石油醚提取物,羟基自由基和ABTS ⁺自由基清除能力依次为：超声-乙醇提取物>超声-乙酸乙酯提取物>超临界CO₂萃取物>超声-石油醚提取物。GC-MS结果显示,苦丁茶不同提取物中主要有5类物质,共有49种化学成分,7种共有成分。     

木奶果醇提物的抗氧化活性及其对Aβ25-35致PC12细胞损伤的神经保护作用

为了探明木奶果不同部位的总酚含量和抗氧化活性及其对Aβ25-35致PC12细胞损伤的神经保护作用的差异,以期为木奶果高价值产品开发提供理论依据。以木奶果果皮、果肉、果核3个部位醇提物为研究对象,采用Folin-Ciocalteu法、DPPH、ABTS、羟基自由基清除能力测定体外抗氧化活性,并采用Aβ25-35诱导PC12细胞成阿尔兹海默病细胞模型测定醇提物对不同浓度Aβ25-35所致PC12细胞损伤的神经保护作用。结果显示:木奶果果皮、果肉、果核3个部位的总酚含量分别为(101.03±5.99)、(16.03±1.13)、(51.27±4.02)mg GAE/g干物质;抗氧化活性与样品浓度存在剂量关系,其中果皮的抗氧化活性最强,果核次之,果肉最差;果皮醇提物对Aβ25-35所致PC12细胞损伤的神经保护作用最佳,当木奶果果皮醇提物浓度为1 mg/m L时,能将Aβ25-35诱导的PC12细胞致死率从(41.6±1.36)%降为(11.95±1.98)%;PC12细胞的凋亡率从(84.69±5.78)%降至(25.26±3.18)%。可见,木奶果醇提物对Aβ25-35所致PC12细胞氧化损伤具有很好的保护作用。     

鹿产品护肤作用的研究

目的研究鹿产品的保湿、抗氧化和抑制酪氨酸酶活性的作用。方法以梅花鹿鹿茸、鹿胎、鹿角盘为原料,分别以75%乙醇和蒸馏水为溶剂提取,冷冻干燥得到鹿产品的提取物,考察了鹿产品各提取物的保湿作用,以酶标仪测定各样品的DPPH清除率和酪氨酸酶的抑制率。结果鹿产品在不同程度上均有一定的保湿作用,其在湿度较高的条件下保湿效果更好,具有长效的保湿作用;鹿产品对DPPH自由基的清除效果从强到弱依次顺序为鹿胎水提物鹿角盘水提物鹿茸水提物鹿茸醇提物鹿胎醇提物鹿角盘醇提物;鹿产品对酪氨酸酶有一定的抑制作用,鹿茸水提物对酪氨酸酶的抑制作用最强,IC50为31.932mg/ml,鹿茸醇提物对酪氨酸酶的抑制率较低,IC50为51.530mg/ml。结论鹿产品具有保湿、抗氧化和抑制酪氨酸酶活性的作用,具备护肤作用的相关基础活性。     

油茶籽油及枯饼提取物的抗肿瘤活性研究

采用噻唑蓝(MTT)法测定7种油茶籽油(茶油)及枯饼提取物的抗肿瘤活性,并通过福林-酚法和三氯化铝法对提取物中总酚和总黄酮的含量进行测定。结果表明,7种茶油中琼海茶油(炒)总酚(151.04μg/g)和总黄酮(1.37 mg/g)含量最高,7种枯饼中总酚含量差异不显著,莆田枯饼(蒸)中总黄酮含量(5.55 mg/g)高于其他6种枯饼;7种茶油及枯饼提取物均具有明显的抗肿瘤活性,且在1~50μg/m L的剂量范围内,对人肺癌细胞株(Lewis)、黑色素瘤细胞株(B16)及乳腺癌细胞株(SCC891)的增殖有不同程度的抑制作用,呈明显的剂量依赖关系。因此,开发利用油茶抗癌活性具有潜在的医用价值和经济效益。     

Phytochemical Properties and Antioxidant Activities of Extracts from Wild Blueberries and Lingonberries

Among Vaccinium species, blueberries (Vaccinium myrtillus L.) and lingonberries (Vaccinium vitis-idaea) are popular in the human diet. In this study, total phenolic, total flavonoid and total monomeric anthocyanin contents in the ethanol-water extracts of blueberry and lingonberry fruits grown wild in the forests in the central region of Poland were assayed. Antioxidant activities of the extracts from each plant were also evaluated for scavenging ability on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and reducing power by cupric reducing antioxidant capacity (CUPRAC) method. Total phenolics in the blueberry extracts ranged from 4.58 to 5.28 mg GAE CE/g fw. The extracts from lingonberry fruits contained higher total contents of phenolic compounds (5.82–7.60 mg GAE/g fw) as well as total flavonoids (5.22–6.47 μmol CE/g fw) than those from blueberries (3.74–4.18 μmol CE/g fw). For the total monomeric anthocyanin contents, the blueberry extracts presented significantly higher values (3.01–3.93 mg cyanidin-3-glucoside (C3G) equivalent/g fw) in comparison to the lingonberry extracts (0.32–0.47). Blueberry extracts exhibited higher antioxidant activity measured by both assays in comparison to lingonberry extracts. Water extracts from fresh and dried fruits also exhibited significant antioxidant activities for both types of berries. Considering the health benefits that have been associated with polyphenolic consumption, these fruits could appear as a good source of this group of phytochemical compounds for their direct consumption or their use as ingredients for the design of new food products or food supplements.     

Optimization of extraction conditions of antioxidants from sunflower shells (Helianthus annuus L.) before and after enzymatic treatment

The effects of three independent variables: solvent polarity, temperature and extraction time on the antioxidant capacity, total phenolic content and phenolic acid composition in extracts obtained from sunflower shells before and after enzymatic treatment were studied. Response surface methodology based on three-level, three-variable Box-Behnken design was used for optimization of extraction parameters and evaluation of their effect on antioxidant capacity and total phenolic content in shell extracts.The average antioxidant capacities of extracts from sunflower shells without enzymatic treatment (368.1-1574.4 μmol TE/100 g) were higher than those for cellulolytic and pectolytic enzymes-treated shells (222.7-1419.0 and 270.7-1570.7 μmol TE/100 g, respectively). The content of total phenolic compounds ranged between 58.2-341.2 mg CGA/100 g, 26.7-277.3 mg CGA/100 g and 51.4-301.5 mg CGA/100 g for extracts obtained from shells without enzyme and treated with cellulolytic and pectolytic enzymes, respectively. Total phenolic content (TPC) in the studied shell extracts correlated significantly (p < 0.0001) positively with their antioxidant capacity determined by the ferric reducing antioxidant power (FRAP) method (r = 0.9275). Results of FRAP, TPC and phenolic acid composition in the studied shell extracts depend on the extraction conditions (solvent polarity, temperature, time), but they are independent on the addition of enzyme solutions. The antioxidant capacity and total phenolic content in the resulting extracts increased with a line in extraction temperature and solvent polarity.     

Antioxidant, antibacterial, and antiviral effects of Lactuca sativa extracts

Antioxidant, antibacterial and antiviral effects of aqueous and methanol extracts of Lactuca sativa var longifolia leaves were investigated. The antioxidant activity was evaluated using the DPPH assay. The effect of the extracts against 5 Gram-positive and 6 Gram-negative bacteria was tested. The antiviral activity was determined against human cytomegalovirus (HCMV) strain AD-169 (ATCC Ref. VR 538) and coxsackie B virus type 3 (CoxB-3) using a cytopathic effect (CPE) reduction assay. The methanol extract had the highest total phenolic contents (235.31 mg CE/g extract). It exhibited a significantly (p < 0.05) greater hydroxyl radical-scavenging activity (IC₅₀ = 3.5 μg/ml) than the aqueous extract (4.1 μg/ml). It was also the most effective extract with the lowest MIC (2.5 mg/ml) against all Gram negative and Gram positive bacteria. Methanol and aqueous extracts exhibited antiviral activity against HCMV and Cox-B3 viruses with IC₅₀ of 200 μg/ml.     

Antioxidant Properties and Evaluation of Phytochemical Composition of Salvia verbenaca L. Extracts at Different Developmental Stages

Changes in the contents and composition of polyphenolics and resulting antioxidant activities of S. verbenaca by-products were investigated at three phenological stages (flowering, early fruiting and late fruiting stages). The highest accumulation of total phenolics was detected at the flowering stage (58.36 mg GAE/g DW). HPLC analysis of methanolic extracts showed the prevalence of methyl carnosate (821.45–919.82 μg/g DW) and rosmarinic acid (544.51–649.26 μg/g DW). Phenolic diterpenes (1056.90–1148.42 μg/g DW) was the most represented class of compounds. Three complementary tests namely, DPPH^? (IC₅₀ value, 49.22 μg/mL) and ABTS^?+-radical scavenging assays (146.86 μM TE/mg) and FRAP reducing power test (188.93 mM Fe(II)/mg) were used to evaluate the antioxidant capacity and showed the best performance at the early fruiting period. The current study evidenced the significant effect of phenophase on antioxidants and contributed to valorize S. verbenaca extracts as a source of functional phenolic compounds.

     

Physicochemical assessment and bioactive properties of condensed distillers solubles,a by-product from the sorghum bio-fuel industry

Large volumes of condensed distillers solubles (CDS) are generated as by-products, from the sorghum bioethanol industry. The objective was to assess the physico-chemical and bioactive properties of CDS. The unfractionated CDS showed the highest content of phenolic compounds (16 mg GAE/g), antioxidant (522 μM Trolox/g) and antimicrobial activity (MIC 1%(w/v) against Campylobacter spp.) compared to its extracts. The water and methanol extracts also showed high levels of phenolic compounds and antioxidant activity (11.6 and 9.2 mg GAE/g and 349 and 409 μM Trolox/g respectively), followed by ethanol and acetone extractions (7.5 and 6.6 mg GAE/g; 337 and 346 μM Trolox/g respectively). A positive correlation was revealed between total phenol and antioxidant activity. The main phenolic compounds found in the extracts were protocatechuic acid, 4-hydroxybenzoic acid, taxifolin, ferulic acid, cinnamic acid and p-coumaric acid. This study indicates the potential of using CDS as a functional ingredient for other food and feed applications.     

Antioxidant activity and phenolic content of chestnut (Castanea sativa) shell and eucalyptus (Eucalyptus globulus) bark extracts

Chestnut (Castanea sativa) shell and eucalyptus (Eucalyptus globulus) bark, waste products of the food and wood industries, respectively, were analysed as potential sources of antioxidant compounds. The extraction yield, the antioxidant activity and total phenols content of the extracts were greater in chestnut shell than in eucalyptus bark for most of the extraction conditions essayed. Extraction of chestnut shell with a 2.5% Na₂SO₃ aqueous solution led to the highest extraction yield, 25.6%, total phenols, 13.4 g gallic acid equivalent/100 g oven-dried shell, and FRAP antioxidant activity, 80.7 mmol ascorbic acid equivalent/100 g oven-dried shell. Extraction with methanol:water (50:50, v/v) provided the best results for eucalyptus bark. The antioxidant activity and the total phenols content of the extracts had a positive linear correlation. FTIR spectroscopy confirmed the higher content of phenolic compounds in chestnut shell extracts compared to eucalyptus bark extracts. Chestnut shell extracts were characterized by the presence of high molecular weight species whereas lower molecular weight species were predominant in eucalyptus bark extracts.     

Physical, Chemical, and Antioxidant Activity Characterization of Pitaya (Stenocereus pruinosus) Fruits

Fruits with red and orange flesh of the columnar cactus pitaya (Stenocereus pruinosus) were studied to evaluate physical characteristics, total soluble solids, betalains and soluble phenols content, and antioxidant activity. Fruits had, in average, weight of 179.0 g, 9.8 °Brix, 9.4 % carbohydrates, 1.25 % protein, 0.11 % ethereal extract, 0.60 % crude fiber, and 0.62 % ash. Also, fruits resulted rich in Fe (22.8–27.8 mg/kg). Hue angle and contents of betacyanins, betaxanthins (μg/g dry sample), and total soluble phenols (mg GAE/g fresh sample) were 19.8°, 2860.0, 3210.0, and 1.6 in the red material, and 28.9°, 470.0, 2670.0, and 1.2, respectively, in the orange fruit. The antioxidant capacity was higher in the red material, since the ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) technique reported 1090.6 and 735.4 μmol of Trolox equivalents/g fresh flesh in red and orange fruits, respectively, while the oxygen radical absorbance capacity (ORAC) assay reported 7.84 and 5.16 μmol of Trolox equivalents/g fresh flesh, respectively. The chromatographic profile showed five betalains in red fruits, but only four of them were observed in those orange fleshed.     

Supercritical Fluid Extraction of Phenolic Compounds and Antioxidants from Grape (Vitis labrusca B.) Seeds

Supercritical fluid extraction (SFE) technique was applied and optimized for temperature, CO₂ pressure and ethanol (modifier) concentration using orthogonal array design and response surface methodology for the extract yield, total phenols and antioxidants from grape (Vitis labrusca B.) seeds. Effects of extraction temperature and pressure were found to be significant for all these response variables in SFE process. Optimum SFE conditions (44?~?46 °C temperature and 153?~?161 bar CO₂ pressure) along with ethanol (<7 %) as modifier, for the maximum predicted values of extract yield (12.09 %), total phenols (2.41 mg GAE/ml) and antioxidants (7.08 mg AAE/ml), were used to obtain extracts from grape seeds. The predicted values matched well with the experimental values (12.32 % extract yield, 2.45 mg GAE/ml total phenols and 7.08 mg AAE/ml antioxidants) obtained at optimum SFE conditions. The antiradical assay showed that SFE extracts of grape seeds can scavenge more than 85 % of 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals. The grape seeds extracts were also analyzed for hydroxybenzoic acids which included gallic acid (1.21?~?3.84 μg/ml), protocatechuic acid (3.57?~?11.78 μg/ml) and p-hydroxybenzoic acid (206.72?~?688.18 μg/ml).     

不同品种桑葚叶总酚含量及其抗氧化活性比较

为了研究不同品种桑葚叶的总酚含量差异及应用价值,以收集引种的40个品种桑葚叶为研究对象,采用超声波辅助提取桑葚叶中酚类物质,以总酚提取率为指标,利用单因素试验和正交试验考察各因素对超声辅助提取桑葚叶总酚提取率的影响;采用DPPH自由基清除能力评价不同品种桑葚叶提取物的抗氧化能力,同时对不同品种桑葚叶中总酚含量及其抗氧化能力进行相关性分析。结果表明：超声辅助提取桑葚叶总酚的最佳工艺条件为：超声温度65 ℃、超声时间30 min、固液比1∶45（g/mL）、乙醇浓度60%,4个因素对桑葚叶总酚提取率影响大小顺序为：超声温度>超声时间>固液比>乙醇浓度。不同品种桑葚叶总酚含量差异较大,其中‘条桑五号’总酚含量最高,为（26.35 ± 0.29）mg/g,‘滇桑’总酚含量最低,为（20.44 ± 0.15）mg/g;不同品种桑葚叶抗氧化活性也存在差异,且趋势与总酚含量基本一致,‘条桑五号’桑葚叶抗氧化活性最强,清除DPPH自由基能力IC₅₀为（77.64 ± 0.34）mg/L,总抗氧化能力（FRAP）TEAC值为（2.58 ± 0.11）mmol/g;‘滇桑’桑葚叶抗氧化活性最弱,清除DPPH自由基能力IC₅₀为（210.30 ± 0.19）mg/L,总抗氧化能力（FRAP）TEAC值为（0.73 ± 0.04）mmol/g。桑葚叶总酚含量与其提取物抗氧化能力呈正相关,选择总酚含量高的桑葚品种栽培,可提高桑葚的综合附加值。