溪黄草提取物成分预试及对羟自由基的清除作用

目的初步测定溪黄草提取物的化学成分类型及其对羟自由基的清除作用。方法用水、乙醇和石油醚对溪黄草进行提取,根据颜色反应及沉淀反应初步判断所含化学成分的类型,利用结晶紫作显色剂的分光光度法研究各提取物对羟自由基的清除作用。结果溪黄草水提取物对Fenton反应产生的羟自由基具有清除作用,而乙醇和石油醚提取物对羟自由基的清除作用不明显。结论溪黄草中的水溶性成分对羟自由基具有清除作用。     

艾叶多糖的提取、含量测定及对羟自由基清除作用的研究

目的:探讨艾叶多糖的提取、含量测定及其对羟自由基(·OH)的清除作用.方法:采用热水浸提法提取艾叶多糖并进行初步纯化;苯酚-硫酸法测定其含量;·OH清除实验观察艾叶多糖对·OH的作用.结果:样品中多糖含量为2.56%,回收率为98.45%,RSD = 0.391%(n = 5),其纯度和产率均较高;艾叶多糖溶液对由Fenton体系产生的·OH有一定的清除作用,随着艾叶多糖浓度的增加,对·OH自由基的清除能力也增强.结论:艾叶中含有一定量的多糖;艾叶多糖对·OH具有较好的清除作用,在一定范围内呈现良好的量效关系.     

生化汤捕获自由基·OH作用考察

目的研究生化汤对自由基.OH的清除作用。方法采用Fenton法对3种不同工艺及主药配伍比例变化获得的生化汤提取物对羟基自由基的清除能力进行考察。结果生化汤对自由基.OH的清除能力与提取物含量相关(P<0.01),3种不同工艺获得的生化汤提取物对自由基.OH的清除作用有差异。当归剂量变化对自由基.OH清除作用与生化汤浓度之间的正相关性有较大影响。结论生化汤对自由基.OH具有较好的捕获作用。     

2种西番莲叶中黄酮的抗氧化活性研究

目的:研究紫果和黄果西番莲叶中黄酮提取物的抗氧化作用。方法:以芦丁、Vc为对照,测定紫果和黄果西番莲叶中黄酮提取物对超氧阴离子自由基(O2-·)、羟自由基(·OH)及二苯代苦味酰基苯肼(DPPH·)自由基的清除率。结果:2种西番莲叶中黄酮提取物均具有不同程度的清除自由基能力,其中黄果西番莲提取物对·OH的清除率优于Vc和紫果西番莲提取物;2种西番莲提取物对O2-·和DPPH·自由基有清除效果,但总体偏低。结论:2种西番莲叶中黄酮均具有不同程度的抗氧化能力。     

薄荷中总黄酮的提取及其对羟自由基的清除作用

目的 探讨薄荷中总黄酮的提取、鉴别及其对羟自由基的清除作用.方法 采用超声波乙醇浸提法提取薄荷中的黄酮类物质,用分光光度法测定含量,并做黄酮类物质的羟自由基清除作用试验.结果 测得样品中总黄酮的含量为0.325mg·mL-1,回收率为99.53%,其纯度和产率均较高.结论 超声波乙醇浸提法是提取薄荷中黄酮类物质的有效方法.薄荷中总黄酮提取液对Fenton体系产生的·OH有很好的清除作用.     

安吉白茶黄酮抗氧化活性的体外实验研究

目的通过研究安吉白茶黄酮对自由基的清除作用及抗脂质过氧化作用来系统阐明安吉白茶黄酮的抗氧化活性。方法应用化学发光法和分光光度法系统评价了安吉白茶黄酮对超氧阴离子自由基(O-2·)、羟基自由基(·OH)、二苯代苦味酰基自由基(DPPH·)和H2O2的清除作用。采用小鼠肝脏为研究对象,评价了安吉白茶黄酮对自发及诱导性脂质过氧化模型的抑制作用。结果安吉白茶黄酮对O-2·、·OH、DPPH·和H2O2均有较强的清除能力,其清除作用与黄酮浓度呈明显的剂量依赖关系。安吉白茶黄酮可以以剂量依赖方式抑制小鼠肝脏脂质过氧化。结论安吉白茶黄酮在体外具有高效的自由基清除作用,并具有较强的抗脂质过氧化活性。     

蒲公英根多糖的抗氧化活性研究

目的:提取蒲公英根中多糖,测定其多糖含量和体外抗氧化作用。方法:超声波协同酶法提取蒲公英根中的多糖,苯酚-硫酸法测定多糖的含量,以维生素C为对照,采用分光光度法测定蒲公英根多糖对OH·和O-2·自由基的抑制作用,HPLC法检测DPPH·的浓度法测定蒲公英根活性多糖清除DPPH·自由基的能力。结果:蒲公英根中的多糖含量为83.31%,清除OH·、O-2·和DPPH·的IC50值分别为:0.047mg/mL,0.01mg/mL,0.154mg/mL。结论:蒲公英根多糖对OH·、O-2·和DPPH·自由基均有良好的清除能力。     

槲皮素-钼配合物对超氧阴离子和羟自由基的清除作用

目的 探讨槲皮素-钼配合物对超氧阴离子自由基(O2-.)和羟自由基(·OH)的清除作用.方法 分别用改良的邻苯三酚法和水杨酸法测定槲皮素一钼配合物对O2-.和·OH的清除作用,并与槲皮素比较.结果 配合物对O2-.和·OH均有显著的清除作用,对·OH的清除作用优于槲皮素(P＜0.05).结论 槲皮素-钼配合物具有较强的清除自由基作用.     

松花粉抗氧化活性与主要成分的关联分析

目的:研究松花粉的抗氧化活性及其主要有效部位.方法:采用紫外分光光度法测定不同来源松花粉清除DPPH和羟基自由基的能力,及其总黄酮、总甾醇和总多糖的含量,并进行多元相关分析.结果:松花粉提取液对DPPH与羟基自由基均有清除作用,且都呈明显的量效关系;松花粉与破壁松花粉清除DPPH的平均IC50分别为14.86 g·L-1、12.95 g·L-1,清除羟基自由基的平均IC50分别为20.31 g·L-1、3.45 g·L-1;松花粉总黄酮、总甾醇的含量与清除DPPH自由基、羟基自由基的IC50呈负相关,并以总黄酮的相关性最为突出,而总多糖的含量则与其关联性不显著.结论:松花粉具有一定的抗氧化活性,其有效部位为黄酮和甾醇;松花粉破壁能有效提高其清除自由基的能力及总黄酮、总甾醇的含量.     

鸡眼草3种不同溶剂提取物对ABTS自由基和羟自由基清除活性的研究

目的:研究鸡眼草3种不同溶剂提取物对ABTS自由基(ABTS·+)和羟自由基(·OH)的清除活性。方法:用冷浸法得到鸡眼草乙醇、丙酮和乙酸乙酯提取物,以UV法测定3种提取物的总黄酮含量,并测定3种提取物对ABTS·+和·OH的清除活性。结果:鸡眼草丙酮提取物的总黄酮含量最高(131.41mg·g-1),对自由基的清除效果也最好,其对ABTS·+和·OH的清除率最高可达到88.79%和95.81%。结论:鸡眼草乙醇、丙酮和乙酸乙酯提取物都具有较强的自由基清除能力,有作为天然抗氧化剂开发利用的潜力。     

溪黄草提取物抗脂质过氧化作用研究

目的研究溪黄草提取物抗脂质过氧化作用。方法采用组织匀浆MDA比色法测定不同质量浓度溪黄草水提取物及乙醇提取物对SD大鼠离体肾脏、肝脏、心脏、脾脏和肺脏组织脂质过氧化的影响。结果2种提取物均具有明显的抗脂质过氧化活性,其中水提取物活性大于乙醇提取物,在1.00g.L-1质量浓度时,水提取物对SD大鼠离体组织MDA的抑制率大小为:肾脏>肝脏>心脏>脾脏>肺脏。结论溪黄草水提取物及乙醇提取物具有抗脂质过氧化作用。     

溪黄草黄酮类化合物抑制亚硝化反应活性的研究

目的研究溪黄草黄酮类化合物对亚硝化反应的抑制作用。方法根据最佳提取工艺条件提取得到3个主要的黄酮类化合物,研究其对亚硝化反应的抑制作用。结果溪黄草总黄酮提取率可达91.98%,水溶性部分阻断亚硝胺的合成及清除亚硝酸盐作用较强,分离得到的3个黄酮类化合物中芦丁的抑制作用较强,对亚硝胺的合成的最大阻断率可达91.5%,对亚硝酸盐的最大清除率可达89.2%。结论溪黄草黄酮类化合物具有抑制亚硝化反应的活性。     

Synthesis and biological evaluation of novel benzyl-substituted flavones as free radical (DPPH) scavengers and α-glucosidase inhibitors

Pharmacologically motivated natural product investigations have yielded a large variety of structurally unique lead compounds with interesting biomedical properties, but the natural roles of these molecules often remain unknown. In the present investigation, a series of benzyl substituted-flavone derivatives have been synthesized from the lead compounds and were screened against 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and α-glucosidase inhibitory properties. The resulting activity profiles of these flavone derivatives were compared for degree of similarity to the profile of 1-3. Most of the synthesized derivatives displayed potent activities when compared to the parent compounds. Maximum potencies for DPPH free radical scavenging activity were observed only in compounds containing the 4-hydroxyl substitution and 3-methoxyl group on the phenyl ring. While the 2- and 4-hydroxyl group substitutions on the phenyl ring seem to be crucial for the intestinal α-glucosidase inhibitory activity.     

Synthesis and biological evaluation of novel benzyl-substituted flavones as free radical (DPPH) scavengers and α-glucosidase inhibitors

Pharmacologically motivated natural product investigations have yielded a large variety of structurally unique lead compounds with interesting biomedical properties, but the natural roles of these molecules often remain unknown. In the present investigation, a series of benzyl substituted-flavone derivatives have been synthesized from the lead compounds and were screened against 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and α-glucosidase inhibitory properties. The resulting activity profiles of these flavone derivatives were compared for degree of similarity to the profile of 1–3. Most of the synthesized derivatives displayed potent activities when compared to the parent compounds. Maximum potencies for DPPH free radical scavenging activity were observed only in compounds containing the 4-hydroxyl substitution and 3-methoxyl group on the phenyl ring. While the 2- and 4-hydroxyl group substitutions on the phenyl ring seem to be crucial for the intestinal α-glucosidase inhibitory activity.     

刃天青法对溪黄草抗菌活性部位的筛选

目的初步确定溪黄草抗茵活性的有效部位。方法采用刃天青法测定溪黄草石油醚部位、氯仿部位、正丁醇部位和水部位的最低抑茵浓度（MIC）。结果溪黄草氯仿部位对临床常见的致病菌均有良好的抑制作用。结论初步判定氯仿部位为溪黄草的抗茵活性部位。刃天青法作为一种快速的检测细胞活性的方法,可用于中药抗茵作用的研究,为抗茵有效部位的筛选与开发提供了新思路。     

维吾尔药牛舌草提取物抗氧化活性研究

目的研究维吾尔药牛舌草提取物的抗自由基作用及体内抗氧化功能。方法采用体外分析法观察牛舌草提取物对DPPH·及超氧自由基的清除作用,并进一步针对牛舌草大孔树脂洗脱部位GZB-3及GZB-AB80的提取物,以小鼠血清SOD、GSH-Px的活性和MDA的含量变化,探讨牛舌草提取物在小鼠体内的抗氧化能力。结果牛舌草各提取物具有体外抗自由基功能,其中牛舌草GZB-3及GZB-AB80提取物有较好的清除DPPH·及超氧自由基的作用;牛舌草提取物可显著增强小鼠血清SOD、GSH-Px活性,降低MDA含量,其中GZB-AB80提取物有较好的体内抗氧化能力。结论体内外抗氧化实验表明,牛舌草提取物具有明显的抗自由基作用及抗氧化功能。     

蓝萼香茶菜化学成分和生物活性研究近况

蓝萼香茶菜作为1种民间抗炎草药,已被广泛应用于多种炎症和肿瘤疾病的治疗。从蓝萼香茶菜中提取的萜类、黄酮、甾体等化合物具有多种生物活性,包括抗炎、抗肿瘤、保护心血管等。综述了国内外对蓝萼香茶菜化学成分和生物活性研究近况。     

Antidiabetic and Free Radicals Scavenging Potential of Euphorbia hirta Flower Extract

The present study was carried out to evaluate antidiabetic and in vitro free radicals scavenging effects of flower extract of Euphorbia hirta. The ethanolic and petroleum ether extracts (250 and 500 mg/kg) were orally tested for 21 days in alloxan induced diabetic mice and blood glucose level was measured with glucometer. Administration of extract resulted in significant reduction in serum cholesterol, triglycerides, creatinine, urea, alkaline phosphatase levels but high density lipoprotein levels and total proteins were found to be increased after treatments. Free radicals scavenging effect of ethanolic extract was also evaluated by various antioxidant assays, including 1, 1-diphenyl-2-picryl hydrazyl free radical scavenging activity, superoxide anion radical scavenging, nitric oxide scavenging, and reducing power assay. It was compared with standard antioxidants compounds such as butylated hydroxyl anisole and ascorbic acid. All the extracts showed antioxidant activity in all the tested methods.     

Chemical characterization of Iraqi propolis samples and assessing their antioxidant potentials

Propolis samples, collected from different geographical locations in Iraq (Baghdad, Dahuk, Mosul and Salah ad-Din), were analyzed and assessed for their anti-oxidant activity. Concentrations of phenolic compounds (flavonoids, phenolic acids and their esters) in propolis were estimated using high performance liquid chromatography coupled to electrospray mass spectrometry. Thirty-eight different compounds were identified and 33 of them were polyphenols. Other compounds were tentatively identified as clerodane diterpenoids, and one was considered unknown. Semi-quantitative measurements showed that phenolic acids and their esters were the predominant constituents in propolis extracts, followed by flavones and flavonols, and then flavanones and dihydroflavonols. Propolis samples were further spectrophotometrically characterized using the Folin-Ciocalteu reagent for the determination of total phenolic compounds. The free radical scavenging activities of propolis samples were also evaluated by using the 2,2-diphenyl-1-picrylhydrazyl assay. The results revealed that propolis extracts exhibited strong free radical scavenging activity.     

桂花不同溶剂提取物对氧自由基清除作用的ESR研究

目的研究桂花不同提取物对氧自由基的清除作用。方法利用不同极性溶剂（水、石油醚、乙酸乙酯、正丁醇）浸提桂花粉后得到不同极性的提取物。通过电子自旋共振（ESR）和自旋捕集技术,以1,1-二苯基-2-三硝基苯肼自由基（DPPH）及核黄素光照条件下产生超氧阴离子O2^-自由基体系,检测桂花中各组分清除DPPH自由基及O2^-的能力。结果以维生素C为对照,桂花水提取物、石油醚提取物、乙酸乙酯提取物、正丁醇提取物及维生素C清除DPPH自由基能力IC50分别为59.63,53.93,28.33,38.89,40.93μg·mL^-1;各提取物及维生素C对超氧阴离子O2-自由基清除能力IC50分别为63.37,55.47,30.20,48.36,41.52μg·mL^-1。其中各提取物的乙酸乙酯提取物的DPPH及O2^-清除率最大。结论通过比较各组分对DPPH自由基及超氧阴离子自由基的清除能力,了解桂花中抗氧化成分在各相中的分布情况,并据此进行有目的的分离桂花中的抗氧化成分。