昆仑雪菊提取物对α-葡萄糖苷酶的抑制作用

目的：探讨昆仑雪菊提取物对α-葡萄糖苷酶的抑制活性。方法：将昆仑雪菊干燥花序粉碎,分别用水提法和乙醇法制备5种提取物。采用α-葡萄糖苷酶体外活性抑制模型,测定昆仑雪菊的5种提取物对α-葡萄糖苷酶的抑制活性。结果：这5种提取物对α-葡萄糖苷酶活性有较强的抑制作用,抑制活性均高于阿卡波糖。其中提取物Ⅰ的抑制活性最强,IC50=28.2 mg/L。结论：昆仑雪菊提取物具有较高的α-葡萄糖苷酶抑制活性,提示昆仑雪菊在抗糖尿病产品开发方面具有很好的应用前景。     

黄连提取物对α-葡萄糖苷酶抑制作用研究

利用体外α-葡萄糖苷酶抑制模型对黄连不同部位提取物进行活性评价,并与阳性对照Acarbose比较,发现黄连不同部位均有一定的α-葡萄糖苷酶抑制活性.其中,黄连根茎乙酸乙酯提取物的抑制活性最高(IC_(50)=20.72 μg/mL),黄连种子石油醚部位(IC_(50)=40.86 μg/mL)和黄连叶石油醚部位(IC_(50)=62.85 μg/mL)的活性次之.3个部位的提取物活性均远大于阳性对照Acarbose(IC_(50)=1081,27 μg/mL).不同部位比较,根茎对α-葡萄糖苷酶抑制活性最好,这3种提取物抑制活性均比阳性对照高;同一部位不同提取物比较,石油醚和甲醇提取物α-葡萄糖苷酶抑制活性一般要高于乙酸乙酯提取物.     

石榴皮多酚提取物及纯化物对α-葡萄糖苷酶的抑制作用研究

采用紫外分光光度法研究了石榴皮多酚提取物及其2种纯化物(P-1和P-2)对α-葡萄糖苷酶体外抑制作用以及纯化物对该酶的抑制作用类型.结果显示,石榴皮多酚提取物和纯化物对α-葡萄糖苷酶活性均表现出较强的抑制作用,且其作用大小与浓度呈明显的剂量-效应关系;3种多酚样品中,纯化物P-2的抑酶活性最强,纯化物P-1次之,提取物最弱,它们对α-葡萄糖苷酶的半数抑制浓度(IC50,mg/mL)分别为0.045、0.185和0.278.石榴皮多酚纯化物P-2对α-葡萄糖苷酶抑制作用类型为反竞争性抑制;浓度为0.01 mg/mL时该纯化物对α-葡萄糖苷酶的抑制常数Ki为1.22 μg/mL.     

高效液相色谱法测定灰兜巴对α-葡萄糖苷酶的抑制作用

研究灰兜巴醇提石油醚萃取、醇提乙酸乙酯萃取、醇提正丁醇萃取、醇提萃取剩余部分和水提部分对于α-葡萄糖苷酶活性的抑制作用,并通过高效液相色谱检测在药物与酶反应过程中振荡对于α-葡萄糖苷酶抑制率的影响。结果显示,灰兜巴各提取部分均表现出良好的α-葡萄糖苷酶抑制活性,为一种良好的α-葡萄糖苷酶抑制剂,且振荡对其抑制率的影响较大,在反应过程中应使酶与药物充分结合。     

帽蕊木α-葡萄糖苷酶抑制活性研究

利用体外抑制α-葡萄糖苷酶模型,首次对植物帽蕊木叶、皮提取物和从中分离得到的化合物进行活性评价,并与阳性对照Acarbose 进行比较.结果表明帽蕊木叶和皮提取物都具有很高抑制α-葡萄糖苷酶活性,且叶的活性要好于皮,同一部位的正丁醇和乙酸乙酯提取物的活性要好于石油醚提取物;从帽蕊木中得到的化合物莨菪内酯(scopletin)的α-葡萄糖苷酶抑制活性(IC50=35.03 μg/mL)高于阳性对照Acarbose(IC50=1081.27 μg/mL)约为其活性的30倍.     

贴梗海棠α-葡萄糖苷酶抑制活性研究

对不同月份采摘的贴梗海棠叶α-葡萄糖苷酶抑制活性进行研究,发现3月和7月采集的贴梗海棠叶不同提取部位均具有一定的α-葡萄糖苷酶抑制活性。其中,7月贴梗海棠叶中乙酸乙酯部位(IC50=47.27μg/mL)的α-葡萄糖苷酶抑制活性最好,远高于阳性对照阿卡波糖(IC50=1213.38μg/mL)。7月贴梗海棠叶中乙酸乙酯部位和正丁醇部位的α-葡萄糖苷酶抑制活性均高于3月叶中相应部位,而石油醚部位低于3月叶的石油醚部位,且都高于阳性对照阿卡波糖。此外,各提取物对α-葡萄糖苷酶的抑制作用均具有剂量依赖性。     

草麻黄对α-葡萄糖苷酶的抑制作用研究

采用96微孔板法测定草麻黄抑制α-葡萄糖苷酶活性.草麻黄正丁醇(IC50=6.86 μg/mL)、乙酸乙酯(IC50 =77.28 μg/mL)和石油醚部位(IC50=190.20 μg/mL)抑制活性远高于阳性对照阿卡波糖(IC50=1081.27μg/mL).研究表明,草麻黄各部位均具有很好的α-筒萄糖苷酶抑制活性,可进行活性追踪分离活性成分.     

朱砂根抑制α-葡萄糖苷酶与抗氧化活性研究

对朱砂根抑制α-葡萄糖苷酶与抗氧化活性进行研究.利用96微孔板法筛选α-葡萄糖苷酶抑制活性;采用DPPH、ABTS和FRAP方法分析抗氧化活性.结果表明,乙酸乙酯部位抑制α-葡萄糖苷酶的活性最高(IC50=39.27 μg/mL),石油醚部位次之(IC50 =56.11 μg/mL),正丁醇部位活性最弱(IC50=62.05μg/mL),但均远大于阳性对照Acarbose(IC50=1081.27 μg/mL);乙酸乙酯部位抗氧化能力最强,正丁醇部位次之.乙酸乙酯部位清除DPPH自由基(IC50=38.55 mg/L)的能力比BHT( IC50=18.71 mg/L)低1/2,清除ABTS自由基的能力(IC50=3.60 mg/L)比BHT(IC50=7.44 mg/L)强,但比BHA(IC50=1.74 mg/L)弱,还原Fe3+的能力(FRAP=512.99 ±6.80 μmoTE/g)为BHT(FRAP=1581.68±97.41μmol TE/g)的1/3.结果显示朱砂根乙酸乙酯部位抑制α-葡萄糖苷酶和抗氧化活性最好.     

黔产青钱柳化学成分及α-葡萄糖苷酶抑制活性研究

为了阐明青钱柳中的降血糖功效成分,实验对黔产青钱柳进行了系统化学成分研究和α-葡萄糖苷酶抑制活性评价。利用各种色谱学手段和波谱学方法,从青钱柳叶80%乙醇提取物中分离鉴定出13个化合物,分别为阿福豆苷(1)、山柰酚3-O-(4″-O-乙酰基)-α-L-吡喃鼠李糖苷(2)、juglanoside J(3)、1α,2α,4β-3羟基-1,2,3,4-四氢萘酮(4)、青钱柳苷III(5)、青钱柳苷J(6)、黄体酮(7)、去酰基萝藦苷元(8)、20-乙酰氧基-4-烯-3-酮(9)、齐墩果酸(10)、5-O-P香豆酰奎宁酸甲酯(11)、亚麻酸甲酯(12)、软脂酸(13)。其中,化合物9为新天然产物,化合物2~4、7、8、11、13均为首次从该植物中分离得到。用PNPG法对化合物1~10进行了α-葡萄糖苷酶抑制活性筛选,结果显示,化合物1、2有较强的α-葡萄糖苷酶抑制活性,表明黄酮类成分是青钱柳降血糖功效的物质基础之一。     

六种花提取物抑制α-葡萄糖苷酶活性研究

采用96微孔板法对紫丁香、日本晚樱、锦带花、荆条花、疏毛绣线菊和猥实中不同提取部位对α-葡萄糖苷酶抑制活性进行评价,并与阳性对照药阿卡波糖进行了比较,发现6种花不同提取部位均具有一定的α-葡萄糖苷酶抑制活性。其中,荆条花的乙酸乙酯部位(IC50=290.57μg/mL)和日本晚樱的乙酸乙酯部位(IC50=292.72μg/mL)抑制活性最好,且都远大于阳性对照阿卡波糖(IC50=1213.38μg/mL)。不同溶剂提取物显示,紫丁香、日本晚樱、锦带花和荆条花的乙酸乙酯部位抑制活性均大于正丁醇部位;而疏毛绣线菊和猥实的正丁醇部位略大于乙酸乙酯部位,且6种花的石油醚部位活性最低。此外,各部位的抑制活性均与质量浓度呈现相关性,具有一定的浓度依赖性。     

An acetylenic epoxide and a ferulate from Coreopsis longula

The aerial parts of Coreopsis longula gave, in addition to known compounds, a new acetylenic epoxide, hepta-deca-1,9E,15E-trien-11,13-diyn-7,8-epoxide, while the roots afforded a new ferulate, coniferyl ferulate.     

Inhibition of Real-Time PCR in DNA Extracts from Aquifer Sediment

Variation in inhibition of real-time PCR was investigated with DNA extracts from 50 aquifer sediment core samples of 5 cm length collected through a 2.5 meter vertical profile across a landfill leachate plume. The inhibition was quantified using an internal control of the green fluorescent protein ( gfp ) gene, which was spiked into the real-time PCR reactions. The inhibition was investigated at two gfp gene concentrations: at 1.7 · 10 ⁷ gfp gene copies/g sediment (5.1 · 10 ⁴ gfp gene copies/PCR reaction) and at 1.7 · 10 ⁵ gfp gene copies/g sediment (5.1 · 10 ² gfp gene copies/PCR reaction). Despite the low TOC content of the sediment (average 0.4 mg C/g dw) the average real-time PCR response was partially inhibited, compared to a reference (pure water), at both high and low gfp concentrations. The relative amplification (reference = 1) was 0.85 ± 0.20 (high) and 0.66 ± 0.23 (low), showing significantly (P < 0.05) stronger inhibition at the lower target gene concentration. The inhibition of the real-time PCR did not show a systematic variation in the vertical profile related to plume position but variations were significant on a small scale of 5–15 cm depth intervals. One of the 50 samples failed to produce a signal with either concentration of the gfp internal control and three other samples inhibited real-time PCR at both high and low gfp concentration. These 4 samples, which were the samples with the highest inhibition, were the only DNA extracts with a visible brown colouration, indicating contents of humic-like substances. Elevated absorbance at 400 nm of these samples also indicated that humic-like substances were responsible for inhibition. However, other factors not associated with either absorbance or TOC may have contributed to the inhibition in less inhibited samples since the variation in real-time PCR response could not be sufficiently explained by absorbance or TOC. The results of this study suggest that an internal control is needed in real-time PCR reactions with DNA from environmental samples due to variation in inhibition to correctly quantify the number of target genes, especially at low target gene concentrations, when dilution of DNA extracts is not practical.     

昆仑山前山带植物群落调查及相似性初步研究

对塔克拉玛干沙漠南缘,昆仑山北坡前山带的荒漠植物群落进行调查.结果显示:(1)在调查区域内发现21种植物,参与建群种15种,其他6种为偶见种.21种植物分属于10科20属,其中菊科(Compositae)和藜科(Chenopodiaceae)植物13种;研究区5种植物群落的优势种分别为塔里木沙拐枣(Calligonum roborovskii)、琵琶柴(Reaumuria songarica)、河西苣(Hexinia polydichotoma)、蒿类植物(昆仑蒿Artemisia nanschanica+昆仑绢蒿Seriphidium korovinii)与驼绒藜(Ceratoides latens).(2)植物群落沿海拔高度变化地带性更替明显,低山砾质壤土母质上为塔里木沙拐枣和琵琶柴群落,集中分布范围分别为2 200～2 300 m和2 250～2 400 m,中部沙质土壤母质上为蒿类植物和河西苣群落,蒿类植物群落分布于海拔2 400～2 500 m,河西苣群落集中于2 500 m高大沙丘丘间低地;驼绒藜群落在砾质土壤和沙质土壤母质上均有分布,海拔范围在2 380～2 800 m.(3)群落结构简单,整体盖度小于10%,物种密度为4～13株(丛)/m2,灌木层优势种单一,密度很小(1.2株(丛)/m2),草本层冠幅水平低,盖度小(小于5%);群落间高度、盖度、密度存在不同程度差异,物种丰富度指数(dMA)和生物多样性指数(D、H′、Jsw、Jgi)差异并不明显,总体处于较低水平.(4)群落盖度、密度、高度和物种数随海拔高度变化趋势不同,生物多样性指数随着海拔高度增加呈增加趋势;群落相似性比较显示,低海拔地区植物群落间的相似性高于高海拔地区.     

Antifilarial and Antibiotic Activities of Methanolic Extracts of Melaleuca cajuputi Flowers

We evaluated the activity of methanolic extracts of Melaleuca cajuputi flowers against the filarial worm Brugia pahangi and its bacterial endosymbiont Wolbachia. Anti-Wolbachia activity was measured in worms and in Aedes albopictus Aa23 cells by PCR, electron microscopy, and other biological assays. In particular, microfilarial release, worm motility, and viability were determined. M. cajuputi flower extracts were found to significantly reduce Wolbachia endosymbionts in Aa23 cells, Wolbachia surface protein, and microfilarial release, as well as the viability and motility of adult worms. Anti-Wolbachia activity was further confirmed by observation of degraded and phagocytized Wolbachia in worms treated with the flower extracts. The data provided in vitro and in vivo evidence that M. cajuputi flower extracts inhibit Wolbachia, an activity that may be exploited as an alternative strategy to treat human lymphatic filariasis.     

昆仑山北坡4种优势灌木的气体交换特征

在自然条件下对昆仑山北坡四种灌木塔里木沙拐枣（Calligonum roborowasikii）、驼绒藜（Ceratoides latens）、合头草(Sympegma regelii)和昆仑绢蒿(Seriphidium korovinii)的气体交换、水势的季节变化特征及生长季末δ13C值进行了比较研究。结果表明：驼绒藜、塔里木沙拐枣和合头草气体交换日变化为单峰曲线,昆仑绢蒿为双峰曲线;其中塔里木沙拐枣属高光合高蒸腾型,水分利用效率最高,合头草属低光合低蒸腾型,驼绒藜属高光合低蒸腾型,昆仑绢蒿属低光合高蒸腾,水分利用效率最低。驼绒藜光合速率8月日变化,10：00-12：00,16：00-20：00两个时段,Pn下降,主要决定因素均为非气孔因素。沙拐枣6月光合速率日变化,12：00-14：00时,Pn下降,主要受气孔导度因素影响;16：00-20：00时,Pn下降,可能是同时受气孔和非气孔因素的影响。从耐旱机理可以将4种灌木归类：塔里木沙拐枣和昆仑绢蒿属于高水势延迟脱水耐旱机理;驼绒藜和合头草属于低水势忍耐脱水机理。用δ13C表征植物水分利用效率时,只有部分物种有很好的一致性。     

椰子种皮油提取物对低密度脂蛋白氧化的抑制作用

本文研究了椰子种皮油提取物对低密度脂蛋白氧化的抑制作用,以水溶性VE(Trolox)作为对照,测定椰子种皮油提取物的总酚含量,总抗氧化能力,检测提取物对低密度脂蛋白的氧化易感性,硫代巴比妥酸反应产物(TBARS)值及铜络合能力的影响。结果表明,椰子种皮油提取物的总酚含量为68.6 mg/g,总抗氧化能力也随着浓度增大而加强,说明该提取物具有较好的抗氧化活性。浓度为0.5 mg/mL的提取物能将低密度脂蛋白的延滞时间延长了两倍,丙二醛(MDA)含量也明显下降,表明椰子种皮油提取物对低密度脂蛋白的氧化具有一定的抑制作用。     

三种中药提取物对黄嘌呤氧化酶的抑制作用

分别用水、60%乙醇和95%乙醇为提取溶剂,对泽泻、青风藤和白芷进行提取,通过测定黄嘌呤氧化酶(XOD)-黄嘌呤反应体系终产物尿酸的吸光度,得出各提取物对XOD的抑制率,并判断其抑制机制。实验结果显示,在一定浓度范围内,泽泻和青风藤两种醇提物对XOD的抑制率较高,泽泻60%乙醇提取物抑制率最高达86%,青风藤95%乙醇提取物抑制率最高为71.2%,白芷水提取物对XOD抑制率较高,最高为72.7%。结果表明,三种中药的提取物均具有较强的体外抑制XOD活性的作用。     

牡丹花水提液对氧自由基的清除作用

牡丹花水提液加入O 2和·OH的产生及检测系统中,能显著降低介导的氮兰四唑(NBT)的光化学还原和·OH作用下的水杨酸羟基化作用.这提示牡丹花水提液具有显著的清除氧自由基的活性,红色牡丹花水提液清除氧自由基的效能高于浅色花.     

Inhibition of Japanese Encephalitis Virus Infection by the Sulfated Polysaccharide Extracts from Ulva lactuca

Japanese encephalitis virus (JEV), a neurotropic flavivirus, is one of the major causes of acute encephalitis in humans. After infection, inflammatory reactions and neurological diseases often develop. Still there are no effective drugs available against virus infection. Recently, extracts of algae have been shown to possess a broad range of biological activities including antivirus activity. In this study, we identified that the sulfated polysaccharide extracts from Ulva lactuca can inhibit JEV infection in Vero cells. Mechanistic studies further revealed that the Ulva sulfated polysaccharide extracts can block virus adsorption and thus make the virus unable to enter cells. The Ulva sulfated polysaccharide extracts also effectively decrease the production of pro-inflammatory cytokines in the JEV-infected primary mixed glia cells. In an animal study, the JEV-infected C3H/HeN mice appeared to have neurobehavioral abnormalities on the fifth day and died on the seventh day post infection. However, the JEV-infected mice pretreated with the Ulva sulfated polysaccharide extracts can delay the onset of hind limb paralysis and thereby prevent mice from death.