两种药食同源植物总生物碱的提取及其抗氧化作用

通过考察两种药食同源植物总生物碱提取率及抗氧化作用,为两种植物作为天然抗氧化剂的应用提供一定理论依据。采用超声波破碎法提取两种植物(马齿苋、蒲公英)的总生物碱,考察乙醇浓度、料液比、提取溶剂pH值、超声时间、超声功率和超声温度对两种植物总生物碱提取率的影响,确定两种植物总生物碱适宜提取条件。在两种植物适宜的总生物碱提取条件下,考察两种植物总生物碱提取率及抗氧化作用。试验结果表明,两种植物总生物碱提取率相差不大,马齿苋总生物碱提取率为20.48%,蒲公英总生物碱提取率为20.19%;通过考察不同质量浓度两种植物总生物碱提取物的总抗氧化能力,对ABTS+·、DPPH·、超氧阴离子、羟基自由基的清除能力和总还原能力,发现这两种植物总生物碱提取物都具有良好的抗氧化活性,可作为潜在的天然抗氧化剂在食品中应用。     

Quantitative UPLC‐MS/MS analysis of chlorogenic acid derivatives in antioxidant fractionates from dandelion (Taraxacum officinale) root

While qualitative studies have identified chlorogenic acids in antioxidant extracts, particularly ethyl acetate‐derived extracts, of Taraxacum officinale, quantitative analysis of these phenolic compounds remains largely unreported for this species. In this study, bioactivity‐guided fractionation of an antioxidant crude ethyl acetate extract (DPPH = 295.481 ± 0.955 mg TE g^?1 extract) from T. officinale root resulted in a number of reverse‐phase fractions that demonstrated high antioxidant activity (DPPH = 1058.733–1312.136 mg TE g^?1 extract), stronger than that of the synthetic antioxidant Trolox^®. UPLC‐MS/MS screening of these fractions for the presence of selected mono‐ and di‐caffeoylquinic acids revealed large quantities of 1,5‐dicaffeoylquinic acid present in several fractions (853.052–907.324 μg mg^?1), respectively. Due to the antioxidant potency and high levels of 1,5‐dicaffeoylquinic acid observed in these fractions, it was concluded that specifically this chlorogenic acid derivative is a major contributor to the antioxidant efficacy of dandelion root.     

Protective effect of HV-P411, an herbal mixture,on carbon tetrachloride-induced liver fibrosis

This study was performed to examine the anti-fibrotic activity of HV-P411, an herbal mixture of seeds of Vitis vinifera, Schisandra chinensis and Taraxacum officinale extract, against carbon tetrachloride (CCl₄)-induced liver fibrosis. Hepatic fibrosis was induced by intraperitoneal injection of CCl₄ (0.5 ml/kg, twice weekly) for 8 weeks. Rats were treated orally with HV-P411 at 50, 100, 200, and 400 mg/kg once a day. After chronic exposure to CCl₄, the levels of hydroxyproline were markedly increased; these were significantly reduced by HV-P411 at all dose levels. The level of serum aminotransferases and lipid peroxidation were increased after the CCl₄ treatment, while reduced glutathione was decreased. These changes were attenuated by HV-P411. In addition, HV-P411 attenuated CCl₄-induced raised serum concentration of transforming growth factor-β1, and the levels of matrix metalloprotease-2 and tissue inhibitor of metalloprotease-1 mRNAs. Our results suggest that HV-P411 may prevent liver fibrosis by modulating fibrogenesis and fibrolysis.     

基于Event-B和Rodin开展形式化软件工程教学

形式化软件工程是软件工程的重要组成部分。Event-B方法是一种软件形式化开发方法,Rodin是支持Event-B方法的开放工具集。基于Event-B方法和Rodin开展形式化软件工程教学,有益于学生正确理解精化等重要的软件工程概念,理解并掌握开发可信软件的方法,是软件工程教学的重要补充。     

响应面优化蒲公英橡胶草菊糖提取工艺及其MALDI-TOF MS分析

以蒲公英橡胶草根为原料,采用超声提取的方式,通过单因素实验和响应面试验探究了超声功率、提取时间、超声温度、液料比对蒲公英橡胶草菊糖提取率的影响,得到蒲公英橡胶草菊糖提取的最佳工艺为:超声功率230 W、超声时间34 min、超声温度61 ℃、液料比30:1（mL:g）,菊糖提取率为20.14%±0.19%。采用氢氧化钙-磷酸法、三氯乙酸法、Sevage法进行脱蛋白纯化,得出氢氧化钙-磷酸法的效果最好,其蛋白清除率达90.78%,菊糖损失率为26.44%。将菊糖粗提液经蛋白纯化、脱色、旋蒸、醇沉及真空冷冻干燥后得到纯度为80.8%的菊糖,为白色固体粉末。经MALDI-TOF MS进行表征分析,确定其单体的分子量为162,端基的分子量和为179,能检测到的聚合度范围为2~30。此研究为蒲公英橡胶草的综合利用研究提供了理论依据。     

蒲公英内生真菌PG23产抗菌物质发酵培养基的优化

为了提高蒲公英内生真菌产抗菌活性物质的能力,对其液体发酵培养基的组成进行优化.以大肠杆菌为指示菌,采用单因素分析法考察最佳的碳源、氮源组成,以添加蒲公英汁模拟宿主内环境提高产抗菌物质的能力;采用Box-Behnken设计和响应面分析法对培养基组成进行优化.结果表明,PG23产抗大肠杆菌活性物质的最适培养基组成为在马铃薯浸出液的基础上,添加葡萄糖2.5％(w/v)+豆油0.5％ (w/v)为碳源,添加玉米粉0.1 5％ (w/v)为氮源,添加8％ (v/v)蒲公英浸汁模拟体内环境.优化后的蒲公英内生真菌PG23的发酵液提高了产抗大肠杆菌的能力,对大肠杆菌的抑菌直径达到了26.7mm,与优化前相比提高了29％.同时发现,蒲公英内生真菌能单独利用豆油作为碳源促进抗菌活性物质的产生.     

丁香、苦荞麦及蒲公英的复配抑菌作用

研究了丁香、苦荞麦、蒲公英3种植物的乙醇提取物的抑菌活性,并进行复配抑菌试验,测定了复配液的抑菌圈直径和最低抑菌浓度(MIC),确定了其复配的最佳配比。实验结果表明,丁香、苦荞麦、蒲公英对5种供试菌均具有较好抑菌效果;在复配抑菌的正交试验中,丁香、苦荞麦和蒲公英的最佳配比为3∶3∶2,最低抑菌浓度为5.0~7.5 mg/ml。     

蒲公英糖蛋白体外抗炎作用及对NF-κB信号通路的调控

探讨蒲公英糖蛋白(glycoprotein from Taraxacum,TG)对由脂多糖引起的RAW264.7细胞炎症的抗炎效果,并阐明其活性的基本分子机制。利用脂多糖刺激RAW264.7细胞,建立体外炎症模型,采用噻唑蓝比色法检测TG对RAW264.7细胞的增殖毒性,Griess试剂法检测了一氧化氮(nitric oxide,NO)的分泌情况,反转录聚合酶链式反应检测炎症细胞因子——白细胞介素-6(interleukin 6,IL-6)和肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)m RNA以及诱导型一氧化氮合酶(inducible nitric oxide synthase,i NOS)m RNA的表达水平,酶联免疫吸附测定法测定IL-6和TNF-α的分泌量,Western blot检测P-IκB-α蛋白的表达水平,用以研究TG对核转录因子-κB(nuclear factor-kappa B,NF-κB)信号转导通路的抑制作用。结果表明:TG能够显著甚至极显著地抑制NO的分泌,IL-6、TNF-α、i NOS的m RNA的表达,IL-6和TNF-α的分泌(P0.05、P0.01)。TG高度显著上调了IκB-α的蛋白表达(P0.001),并显著下调了P-IκB-α的蛋白表达(P0.05),且与TG质量浓度成正比。其中在TG质量浓度为250、500、1 000μg/m L时对TNF-α分泌量的抑制率分别为28.6%、65.4%、89.3%,对IL-6分泌量的抑制率分别为32.3%、54.1%、85.7%。TG间接抑制了NF-κB信号转导途径,有显著的体外抗炎效果且抗炎效果与TG的质量浓度呈剂量依赖性。