芒果叶总黄酮含量及抗氧化作用测定

目的 研究芒果叶总黄酮(MLF)的体外抗氧化作用.方法 采用超声辅助乙醇浸提方法提取芒果叶中的黄酮类化合物,评价芒果叶总黄酮的体外清除自由基能力及抗脂质过氧化活性.结果 芒果叶提取物中总黄酮的含量为38.35％,对羟自由基和超氧阴离子自由基具有一定的清除能力;维生素C和芒果叶总黄酮对羟自由基的半数清除浓度(IC50)分别为0.546 9、2.973 9 mg/mL,对超氧阴离子自由基清除的IC50分别为0.253 0、3.861 2 mg/mL,清除能力与浓度有明显的量效关系;芒果叶总黄酮浓度(x)与抑制率(y)之间拟合曲线,得出回归方程为:y=5.263 9 ln(x)+50.947,R2=0.982 1,表明芒果叶总黄酮在1～10 mg/mL剂量范围内能有效抑制肝组织自发性脂质过氧化.结论 芒果叶总黄酮具有清除自由基及抗脂质过氧化和红细胞溶血作用.     

冬枣提取物对羟自由基诱导氧化损伤的抑制作用

冬枣(Zizyhpus Jujuba. cv dongzao)为鼠李科枣属植物,主要分布在山东、河北等地.据报道冬枣富含黄酮类物质,大量研究表明黄酮类化合物具有较强的抗氧化活性[1].目前国内的研究报道,主要集中在枣树的栽培管理以及果实的贮藏、加工[2,3].本文通过体外试验研究冬枣乙醇提取物(WJE)对活性氧自由基清除和脂质过氧化抑制作用,以期为冬枣资源的开发利用提供科学依据.     

响应面优化黄皮叶中的活性因子超声提取工艺及其抗氧化活性研究

目的优化黄皮叶中活性因子总黄酮的超声提取工艺条件,并测定其抗氧化活性。方法以乙醇体积分数、超声时间及料液比为影响因子,以黄皮叶总黄酮得率为评价指标,在单因素试验基础上,采用响应面法优选黄皮叶总黄酮超声提取工艺,并测定黄皮叶总黄酮体外清除1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-1-picryl hydrazyl,DPPH)自由基、羟自由基和总抗氧化的活性。结果黄皮叶总黄酮的最佳提取工艺条件为乙醇体积分数18%、超声时间73 min、料液比31∶1(m L/g)。在此条件下,黄皮叶总黄酮得率达到(1.300±0.006)%。黄皮叶总黄酮得率大小的主次因素为乙醇体积分数>超声时间>料液比,其中超声时间与料液比因素之间的交互作用显著。黄皮叶总黄酮体外清除DPPH和羟自由基的IC50值分别为0.282 mg/m L、1.152 mg/m L,用三价铁还原抗氧化能力(ferric-reducing antioxidant power,FRAP)法测得1 mg/m L黄酮的FRAP值为533.3μmol/L。结论该所选工艺合理、可行,可用于黄皮叶总黄酮的超声提取;三种测定方法均说明黄皮叶总黄酮在一定浓度下有抗氧化活性。     

芫荽中总黄酮的提取及其对羟自由基的清除作用

目的为充分利用芫荽植物资源,探讨芫荽中总黄酮的提取、鉴别及对羟自由基清除作用。方法采用超声波乙醇浸提法从芫荽中提取黄酮类物质,对所提取的黄酮类物质进行验证,并用分光光度法测定含量,用芫荽中总黄酮对羟自由基清除作用进行试验。结果测得样品中总黄酮的含量C=0.42 g/L,回收率为102.3%,其纯度和产率均较高。结论该方法采用全物理过程,无任何污染,是提取芫荽中黄酮类物质的有效途径。芫荽中总黄酮提取液对Fenton体系产生的·OH自由基有很好的清除作用。     

冬瓜籽水提取物抗氧化作用研究

研究了冬瓜籽水提取物对Fenton反应羟自由基、光照核黄素超氧自由基的清除作用,以及对脂质过氧化的抑制作用。研究表明,冬瓜籽水提取物具有优良的清除羟自由基、超氧自由基作用及抗体外脂质过氧化作用。     

新疆树莓果实营养成分及其提取物抗氧化性研究

目的分析新疆野生树莓果实营养成分,并对其提取物进行抗氧化活性测定。方法进行营养保健成分含量分析,并对果实95%乙醇提取物经石油醚脱脂后,依次用乙酸乙酯、正丁醇萃取,观察不同萃取部位对DPPH·和·OH的清除能力。结果树莓鲜果中必需氨基酸含量高达320mg%,非必需氨基酸中谷氨酸含量较高(180mg%);富含维生素C(28.04mg%)和钾(147.32mg%);有机酸含量高达1.72%,以柠檬酸为主;其它如总酚、总黄酮、鞣化酸、单宁含量分别为498、125、2.2和290mg%,SOD活性高达606.93U/ml。树莓不同提取物均显示了较好的抗氧化活性,以乙酸乙酯部分最高,与清除DPPH自由基相比,清除羟自由基能力强。结论新疆野生红树莓果富含多种营养保健成分和抗氧化活性,有很好的开发价值。     

玫瑰花渣总黄酮清除活性氧自由基及体外抗氧化活性研究

以玫瑰花渣为原料,将超声波技术和双水相萃取技术耦合用于提取玫瑰花中总黄酮,利用Fenton反应产生羟自基·OH,光照核黄素产生超氧阴离子自由基·O-2,采用分光光度法研究玫瑰花渣提取物体外清除活性氧自由基的作用;用硫代巴比妥酸(TBA)分光光度法研究玫瑰花对·OH诱发卵磷脂脂质过氧化抑制作用。结果表明:玫瑰花渣提取物能有效清除活性氧自由基,对卵磷脂脂质过氧化显著抑制作用。     

大夜关门总黄酮提纯工艺及体内体外抗氧化研究

目的研究大夜关门中总黄酮的提取工艺及体内体外抗氧化性。方法通过超声波提取法提取大夜关门中黄酮类物质,测定羟基自由基清除能力及H_2O_2-FeSO_4自由基发生系统MDA生成的抑制率。结果大夜关门总黄酮最佳提取工艺为:提取温度为70℃,乙醇体积分数为70%,固液比为1∶20,提取时间为60 min。黄酮提取物可有效地清除羟自由基,且对小白鼠肝匀浆自氧化有明显的抑制作用。结论最佳工艺下黄酮提取率为19.43%,具有明显清除自由基及体内抗氧化功能,其医药保健价值有待进一步开发利用。     

鸡骨草总黄酮提取及对羟自由基清除作用

为充分利用鸡骨草植物资源,避免资源的浪费,探讨鸡骨草总黄酮的提取、鉴别及对羟自由基清除作用。采用超声波乙醇浸提法从鸡骨草中提取黄酮类物质,对所提取的黄酮类物质进行验证,并用分光光度法测定含量,用鸡骨草总黄酮对羟自由基清除作用进行试验。测得样品中总黄酮的含量C=0.3063 mg/ml,回收率为102.2%,其纯度和产率均较高。该方法采用全物理过程,无任何污染,是提取鸡骨草黄酮类物质的有效途径。鸡骨草总黄酮提取液对Fenton体系产生的.OH自由基有很好的清除作用。     

青椒总黄酮提取及对羟自由基清除作用

为充分利用青椒植物资源,避免资源的浪费,探讨青椒总黄酮的提取、鉴别及对羟自由基的清除作用。采用超声波乙醇浸提法从青椒中提取黄酮类物质,对所提取的黄酮类物质进行验证,并用分光光度法测定含量,用青椒中总黄酮对羟自由基清除作用进行试验。测得样品中总黄酮的含量C=0.192 mg/ml,回收率为100.9%,其纯度和产率均较高。该方法采用全物理过程,无任何污染,是提取青椒黄酮类物质的有效途径。青椒中总黄酮提取液对Fenton体系产生的.OH自由基有很好的清除作用。     

Antioxidant activity of methanolic extract of emblica fruit (Phyllanthus emblica L.) from six regions in China

The phenolic contents of methanolic extracts of emblica (Phyllanthus emblica L.) fruit from six regions in China were measured in this work. The antioxidant activities of these extracts were also evaluated. Total phenolic content was ranged from 81.5 to 120.9 mg gallic acid equivalents (GAE)/g and the flavonoid content was varied from 20.3 to 38.7 mg quecetin equivalents (QE)/g, while proanthocyanidin content was ranged from 3.7 to 18.7 mg catechin equivalents (CE)/g. Among all the methanolic extracts analyzed, the Huizhou sample exhibited a significantly higher phenolic content than other samples (P<0.05). The antioxidant activities were evaluated by in vitro experiments using scavenging assays of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, hydroxyl radicals, and superoxide anion radicals, chelating ability of ferrous ion, reducing power, and inhibition capability of Fe (II)-induced lipid peroxidation, respectively. The Huizhou sample was found to have the strongest antioxidant activities in scavenging DPPH radicals, superoxide anion radicals, and had the highest reducing power, while the Chuxiong sample showed the best performance in chelating iron and inhibiting lipid peroxidation. Furthermore, the Chuxiong sample exhibited a stronger inhibition activity of the hydroxyl radicals compared with other samples. The high correlation coefficient was existed between the phenolic content and superoxide anion radical scavenging activity, but no significant correlation was found between the former and hydroxyl radical scavenging activity. Methanolic extracts of emblica fruit from some selected regions exhibited stronger antioxidant activities compared to those of the commercial compounds (quercetin and BHA). It might be considered as a potential plant source of antioxidants.     

Radical scavenging, antibacterial, and antiproliferative activities of Melissa officinalis L. extracts

The aromatic herb Melissa officinalis L. can be used as an easily accessible source of natural antioxidants and as a possible food supplement and as a phytochemical. Radical scavenging, antibacterial, and antiproliferative activities of petroleum ether, chloroform, ethyl acetate, n-butanol, and water extracts of M. officinalis L. extracts were investigated. The results of antioxidative activity, obtained by electron spin resonance spectroscopy, confirmed that investigated extracts suppressed the formation of 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, and lipid peroxyl radicals in all investigated systems in a dose-dependent manner. The maximum DPPH and hydroxyl radical scavenging activities (SA(DPPH) = SA(OH) = 100%) were achieved in the presence of n-butanol extract at concentrations of 0.4 mg/mL and 0.5 mg/mL, respectively. The highest lipid peroxyl scavenging activity (93.20%) was observed at a higher concentration (5 mg/mL) of n-butanol extract in the lipid peroxidation system. The most effective antibacterial activities were expressed by petroleum ether and ethyl acetate extracts on Sarcina lutea. Chloroform extract showed the strongest antiproliferative effect with 50% inhibitory concentration values of 0.09 mg/mL and 0.10 mg/mL for HeLa and MCF-7 cell lines, respectively. The present study demonstrated the high phenolic content and radical scavenging, antibacterial, and antiproliferative activities of extracts of M. officinalis L. originating from Serbia.     

Study on the antioxidant activity of tea flowers (Camellia sinensis)

Major chemical compounds in different extracts from tea flowers (Camellia sinensis) were analyzed. Distilled water or 70% ethanol extracts were then fractionated with chloroform, ethyl acetate and n-butanol, respectively. Each extract fraction was tested its scavenging activities on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl free radicals. The results showed that ethyl acetate fraction of ethanol-extract of tea flower (EEA) exhibited the highest quenching activity to hydroxyl radicals (SC50 11.6 mug/ml), followed by ethanol-extract (EE) of tea flower (SC50 19.7 microg/ml). Same tea flower extract showed big different scavenging activities on different free radicals. EEA quenched 80% of hydroxyl radicals generated by Fenton's reaction, however, only 40% of DPPH radical was scavenged in the Fe (II)-H2O2 -luminol system. The contents of flavones, polyphenols and catechins in EE and EEA fractions were higher than those in other fractions. We suggest that the stronger scavenging abilities to free radicals might be due to polyphenols, EGCG, ECG and flavones. However, the water extracts of tea flower and their fractions showed lower antioxidant activity for their inhibitory effect on hydroxyl radicals and DPPH radicals.     

In vitro antioxidant and free radical scavenging activity of Cyperus rotundus

Cyperus rotundus (Family Cyperaceae) is used both as a functional food and as a drug. In this study, the antioxidative potential of a hydroalcoholic extract of C. rotundus (CRE) was evaluated by various antioxidant assays, including antioxidant capacity by the phosphomolybdenum method, total antioxidant activity in linoleic acid emulsion systems, 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide, hydroxyl radicals, and nitric oxide (NO) scavenging. We further evaluated the reducing potential of the extract as well as Fe(2+)/ascorbate-induced lipid peroxidation in rat liver homogenate. These various antioxidant activities were compared to standard antioxidants such as butylated hydroxytoluene, tocopherol, L-ascorbic acid, and catechin. Total phenolic and flavonoid content of CRE was also determined by a colorimetric method. The extract exhibited high reduction capability and powerful free radical scavenging, especially against DPPH and superoxide anions as well as a moderate effect on NO. CRE also showed inhibited lipid peroxidation in rat liver homogenate induced by Fe(2+)/ascorbate and prevented deoxyribose degradation in both non-site-specific and site-specific assays showing the hydroxyl radical scavenging and metal chelating activity of the hydroalcoholic extract. Moreover, the peroxidation inhibiting activity of CRE was demonstrated in the linoleic acid emulsion system. These results clearly established the antioxidative potency of C. rotundus, which may account for some of the medical claims attributed to this plant.     

Anti-oxidant, anti-glycant, and inhibitory activity against α-amylase and α-glucosidase of selected spices and culinary herbs

Aqueous and methanol extracts of dry sage, rosemary, basil, parsley, chili, garlic and onion were analyzed to investigate their anti-oxidant and anti-glycant activities and in vitro inhibitory potential against enzymes involved in glycemic regulation. The aqueous extracts of rosemary and sage were the richest in phenolic compounds and showed the highest ability in binding iron and inhibiting DPPH, superoxide radicals and advanced glycation end-product production, lipid peroxidation, and the activity of α-glucosidase and α-amylase. On the other hand, the methanol extracts of both these Labiatae were less efficient than those of garlic, onion, parsley and chili in scavenging hydroxyl radicals. As far as protein glycation is concerned, methanol extracts were more effective in inhibiting the production of Amadori compounds and the aqueous ones in preventing advanced glycation end-product formation. Therefore these spices may be preventive not only against cardiovascular diseases but also type 2 diabetes.     

Resistance of Lactobacillus plantarum KCTC 3099 from Kimchi to oxidative stress

The antioxidative capacity of two lactic acid bacteria isolated from Kimchi, a Korean fermented food, was evaluated by measuring the resistance to reactive oxygen species (ROS) and compared with that of Lactobacillus rhamnosus GG as a positive control. Both intact cells and cell-free extracts of Lactobacillus plantarum KCTC 3099 exhibited higher antioxidative activity in inhibiting lipid peroxidation among the strains evaluated with an inhibitory level of 38.6% and 48.5%, respectively. To evaluate the resistance of the two lactic acid bacteria to ROS, we tested their survival in the presence of 1 mM hydrogen peroxide, 0.4 mM hydroxyl radicals, and superoxide anions induced by 10 mM paraquat. L. plantarum KCTC 3099 was viable even after 8 hours in the presence of both 1 mM hydrogen peroxide and 0.4 mM hydroxyl radicals. Moreover, the survival of L. plantarum KCTC 3099 was not affected by superoxide anions generated by using paraquat, indicating that it has resistance to superoxide anions. To define the antioxidative mechanism, superoxide dismutase (SOD) and metal ion chelating activities were determined. L. plantarum KCTC 3099 presented little SOD activity, but had the higher level of chelating activity for both Fe2+ and Cu2+ metal ions at 13.6 ppm and 23.9 ppm, respectively. These results suggested that the antioxidative capacity of L. plantarum KCTC 3099 is apparently caused by chelating metal ions rather than by SOD activation.     

Evaluation of in vitro antioxidant activity of Sida rhombifolia (L.) ssp. retusa (L.)

Sida rhombifolia (L.) ssp. retusa (L.) is widely used in Ayurvedic medicine for the treatment of fever as well as a diuretic. The comparative antioxidant potentials of ethanol extract of roots, stems, leaves, and whole plant were studied. Estimation of total polyphenolic content and high-performance thin-layer chromatography profile were determined. Further inhibition of oxygen-derived free radicals, viz., assays for free radical scavenging, reducing power, superoxide anion scavenging, nitric oxide scavenging, and anti-lipid peroxidation, were performed. All the antioxidant activities were compared with standard antioxidants such as butylated hydroxyanisole and alpha-tocopherol acetate. Extracts were found to be good scavengers of the 1,1-diphenyl-2-picrylhydrazyl radical in the order root > leaves > whole plant > stem with 50% inhibitory concentrations of 546.1, 852.8, 983.8, and 1,222.5 microg/mL, respectively. All extracts of this plant showed effective free radical scavenging activity, reducing power, and superoxide scavenging activity. Only root extract inhibited lipid peroxidation in rat liver and brain homogenate. All these antioxidant properties were concentration dependent. In addition, total polyphenolic contents of all the extracts were determined as gallic acid equivalents. The highest antioxidant activity was observed in root extract. The results obtained from the current study indicate that S. rhombifolia ssp. retusa is a potential source of natural antioxidants.     

Free radical scavenging activity of a novel antioxidative peptide isolated from in vitro gastrointestinal digests of Mytilus coruscus

A low-molecular-weight peptide with potent antioxidative activity was obtained from Mytilus coruscus muscle protein using an in vitro gastrointestinal digestion system. The potent antioxidant peptide, which was identified as Leu-Val-Gly-Asp-Glu-Gln-Ala-Val-Pro-Ala-Val-Cys-Val-Pro (1.59 kDa), exhibited higher protective activity against polyunsaturated fatty acid (PUFA) peroxidation than the native antioxidants, ascorbic acid and alpha-tocopherol. In a free radical scavenging assay using electron spin resonance spectroscopy, hydroxyl radical formation was quenched by 75.04% in the presence of M. coruscus peptide (50 microg/mL), which was similar to ascorbic acid. In addition, the purified peptide could also quench super-oxide and carbon-centered radicals, but those activities were weaker than for ascorbic acid. This study showed that the low-molecular-weight peptide released from in vitro gastrointestinal digestion of mussel exhibited potent antioxidant potential by inhibiting the formation of reactive oxygen species formed by the peroxidation of PUFAs.     

Anti-oxidant,anti-glycant,and inhibitory activity against α-amylase and α-glucosidase of selected spices and culinary herbs

Aqueous and methanol extracts of dry sage, rosemary, basil, parsley, chili, garlic and onion were analyzed to investigate their anti-oxidant and anti-glycant activities and in vitro inhibitory potential against enzymes involved in glycemic regulation. The aqueous extracts of rosemary and sage were the richest in phenolic compounds and showed the highest ability in binding iron and inhibiting DPPH, superoxide radicals and advanced glycation end-product production, lipid peroxidation, and the activity of α-glucosidase and α-amylase. On the other hand, the methanol extracts of both these Labiatae were less efficient than those of garlic, onion, parsley and chili in scavenging hydroxyl radicals. As far as protein glycation is concerned, methanol extracts were more effective in inhibiting the production of Amadori compounds and the aqueous ones in preventing advanced glycation end-product formation. Therefore these spices may be preventive not only against cardiovascular diseases but also type 2 diabetes.