翅果油植物甾醇的提取分离与结构分析

采用薄层层析、溶剂结晶、高分辨气相色谱-飞行时间质谱联用等方法对翅果油植物甾醇的成分进行了提取分离与分析,确定了β-谷甾醇、豆甾醇、豆甾烷醇、麦角甾醇、5-氯-豆甾烷-3-醇乙酸酯、麦角甾-5-烯-3β-醇、豆甾-5,24(28)-双烯-3β-醇、豆甾烷-7,24(28)-双烯-3β-醇、豆甾烷-3,5-二烯等10种化合物。     

一株黄芪内生真菌甾醇类代谢产物的分离和鉴定

目的:研究分离自夏季黄芪根部的内生真菌AR-17-S03的次级代谢产物。方法:采用组织学的方法从恒山黄芪中分离内生真菌,真菌的鉴定采用形态学法结合分子生物学法,采用硅胶柱色谱法、薄层层析制备色谱(pTLC)、Sephadex LH-20凝胶柱色谱法和半制备HPLC色谱法分离内生真菌代谢产物,采用质谱法、核磁共振法结合物化性质鉴定分离得到的9个化合物。结果:经形态学结合分子生物学鉴定该菌株黑曲霉,为9个甾醇类化合物鉴定为麦角甾醇、过氧化麦角甾醇、胆固醇、啤酒甾醇、23-甲基麦角甾-7,22-二烯-3β,5α,9α-三醇、5α,8α-表二氧麦角甾-6,9(11),22-三烯-3β-醇、5α,8α-表二氧-23-甲基麦角甾-6,22-二烯-3β-醇、麦角甾-4,6,8(14),22-四烯-3-酮、3β,5α-二羟基麦角甾-7,22-二烯-6-酮。结论:其中,23-甲基麦角甾-7,22-二烯-3β,5α,9α-三醇、5α,8α-表二氧-23-甲基麦角甾-6,22-二烯-3β-醇、麦角甾-4,6,8(14),22-四烯-3-酮是首次从黄芪内生真菌中分离得到。     

西藏林芝地区野生黑木耳的化学成分

通过正相硅胶柱色谱、中压反相柱色谱、凝胶柱色谱、TLC及HPLC等技术从西藏黑木耳中分离、纯化得到7个单体化合物,通过MS、NMR并结合文献报道确定其结构,其中包含6麦角甾醇类化合物,分别为(22E,24R)-麦角甾-7,22-二烯-3β,5α,6β-三醇(1yy2),(22E,24R)-麦角甾-5,7,22-三烯-3β-醇(Lyy3),3β,5α,9α-三羟基-7,22-(22E,24R)-麦角甾二烯-6-酮(Lyy4),5α,8α-环氧-(22E,24R)-麦角甾-6,22-二烯-3β-醇(Lyy5),5α,8α-环氧-(22E,24R)-麦角甾-6,9(11),22-三烯-3β-醇(Lyy6),(22E,24R)-麦角甾-7,22-二烯-3β,5α,6α,9α-四醇(Lyy7);剩余一个为5-羟甲基-2-异丙-1-醇-2,3-二氢苯并呋喃(Lyy1)。这7个化合物均为首次从黑木耳中分离得到的单体化合物。     

紫红曲中的麦角甾类化合物

研究紫红曲乙醇提取物中显示细胞毒活性的醋酸乙酯萃取部位的化学成分。利用正反相硅胶、凝胶Sephadex LH-20、结合闪式(Flash)柱色谱和制备高效液相色谱等多种色谱手段进行分离纯化,借助核磁和质谱等波谱学方法进行结构鉴定。从紫红曲乙醇提取物的醋酸乙酯萃取部位中分离鉴定了5个麦角甾类化合物,分别为:麦角甾-7,22-二烯-3β,5α,6β-三醇(1),(22E,24R)-麦角甾-7,22-二烯-6-酮-3β,5α,9α-三醇(2),(22E,24R)-23-甲基麦角甾-7,22-二烯-3β,5α,6β-三醇(3),(22E,24R)-23-甲基麦角甾-7,22-二烯-6-酮-3β,5α,9α-三醇(4),麦角甾-4,6,8(14),22-四烯-3-酮(5)。上述5个化合物均为首次从紫红曲中分离得到。除化合物1外,其余化合物均为首次从红曲菌属中发现。在体外MTT法的细胞毒活性测试中,所筛选的化合物在10×10-6mol/L浓度下均未显示细胞毒的活性。     

微孔草种子油的三萜醇和甾醇成分

微孔草种子油中的不皂化物含量为0.6％。采用硅胶柱层析和硝酸银薄层层析方法,从不皂化物中分离出三萜醇和甾醇。已鉴定有4个三萜醇(β—香树脂醇、环阿屯醇、羽扇醇和24—次甲基环阿屯醇),11个甾醇[胆甾醇、Δ~7胆甾醇、菜油甾醇、24—甲基Δ~7—胆甾醇、β—谷甾醇、22—二氢菠菜甾醇、(?)子甾醇、豆甾醇、5,24(28)—豆甾烯醇、Δ~7—燕麦甾醇和7,24(28)—麦角二烯甾醇]。     

小蓟中甾体类化合物的分离及结构鉴定

对小蓟乙醇粗提物中显示细胞毒活性的石油醚萃取部位进行化学成分的研究。运用硅胶、凝胶和反相高效液相等色谱方法进行分离纯化;应用一维、二维NMR和MS等波谱学方法对纯化的物质进行结构鉴定。结果表明:从小蓟乙醇提取物的石油醚萃取部位分离鉴定了4个甾体类化合物,分别为:麦角甾-4,24(28)-二烯-3-酮(化合物1)、豆甾-4-烯-3-酮(化合物2)、豆甾醇(化合物3)和β-谷甾醇(化合物4)。化合物1和2为首次从蓟属中分离得到,除化合物4外,其余3个化合物均是首次从小蓟中分离得到;在体外MTT法的细胞毒活性测试中,所筛选的化合物在1×10-5mol/L的浓度条件下均未显示出细胞毒活性。     

特种植物油中甾醇总量及组成分析

通过气相色谱法对牡丹籽油、核桃油、南瓜籽油、葡萄籽油四种特种植物油中的甾醇总量及组成进行分析研究。结果表明,牡丹籽油甾醇总量为240.0 mg/100 g,其主要组分是β-谷甾醇、Δ5,23-豆甾二烯醇和Δ5-燕麦甾烯醇;核桃油甾醇总量为100.5 mg/100 g,其主要组分是β-谷甾醇;南瓜籽油甾醇总量为299.6~358.4 mg/100 g,其主要组分是β-谷甾醇、Δ5,24-豆甾二烯醇和Δ7-燕麦甾烯醇;葡萄籽油甾醇总量为222.5~234.9 mg/100 g,其主要组分是β-谷甾醇、菜油(芸薹)甾醇和豆甾醇。分析结果为特种植物油的开发及加工提供了基础数据及技术支撑。     

番茄籽油不皂化物成分分析与分离

采用GC-MS分析番茄籽油不皂化物成分,并通过薄层层析(TLC)对不皂化物进行初步分离。通过GC-MS从番茄籽油不皂化物中分离出42个峰,鉴定出29种物质,主要成分为β-谷甾醇、胆甾醇、豆甾醇、环菠萝烷醇、羊毛甾醇、γ-生育酚、(3β,5α)-胆甾-7-烯-3-醇、γ-谷甾醇、麦角甾醇、二十九烷、角鲨烯,其中β-谷甾醇含量最高,为15.68%;以正己烷与氯仿(7:3,V/V)为展开剂,通过TLC分离番茄籽油不皂化物,得到6条色带,利用紫外-可见光对分离物进行扫描,6种分离物最大吸收峰均不相同。     

石花菜醇提物成分分析

目的：研究石花菜的成分,为其功能食品的研发提供基础数据。方法：采用薄层色谱、液-质谱联用方法分析石花菜醇提物的化学成分的丰富度。通过硅胶柱、高效液相等色谱方法对其进行分离纯化,并用气-质谱联用、核磁结合文献确证化合物结构;并对部分化合物抗氧化活性进行测定。结果：薄层色谱、液-质谱联用分析表明石花菜醇提物中含有丰富的次级代谢产物,且很可能是甾醇类成分。采用气-质谱联用方法从中鉴定到29个化合物（5个为甾醇类化合物）,其中棕榈酸（46.76%）、棕榈酸乙酯（13.82%）、胆甾醇（7.20%）、胆甾-4,6-二烯（4.99%）为含量最高的4个化合物。经色谱分离、核磁鉴定出9个单体化合物,分别为胆甾醇（1）、1,2-二醇植烯（2）、帕格甾醇C(3)、6-羟基-胆甾-4-烯-3-酮（4）、胆甾-5-烯-7-酮（5）、胆甾-5-烯-3β,7α二醇（6）、胆甾-5-烯-3β,7β二醇（7）、胆甾-4-烯-6-酮（8）、3-羟乙基-2-甲基-马来酰亚胺（9）。其中,化合物7清除DPPH自由基和ABTS自由基能力最好,其IC50值分别为180μg/mL和12.2μg/mL。结论：首次系统研究了石花菜醇...     

盐生海芦笋来源真菌Penicillium stoloniferum发酵产物抗肿瘤活性成分研究

采用活性追踪的方法,对一株盐生海芦笋来源真菌Penicillium stoloniferum发酵产物中的抗肿瘤活性成分进行分离和鉴定。利用常压硅胶柱层析、Sephedex LH-20、半制备HPLC等分离方法从中分离得到8个单体化合物,通过理化性质分析及波谱学方法鉴定其化学结构分别为：麦角甾-7,9(11),22-三烯-3-醇、麦角固醇、菠菜甾醇、5α,8α-环二氧-(22E,24R)-23-甲基麦角甾-6,22-二烯-3β-醇、色氨酸-苯丙氨酸-环二肽、苯丙氨酸、邻苯二甲酸正丁酯、邻苯二甲酸异丁酯;以SRB法评价化合物的抗肿瘤活性,5α,8α-环二氧-(22E、24R)-23-甲基麦角甾-6,22-二烯-3β-醇、邻苯二甲酸正丁酯、邻苯二甲酸异丁酯对小鼠乳腺癌P388细胞具有强的细胞毒活性,IC50值分别为14、34、46μg/mL,其他化合物没有活性。     

Arsenic(III) oxidation by iron(VI) (ferrate) and subsequent removal of arsenic(V) by iron(III) coagulation

We investigated the stoichiometry, kinetics, and mechanism of arsenite [As(III)] oxidation by ferrate [Fe(VI)] and performed arsenic removal tests using Fe(VI) as both an oxidant and a coagulant. As(III) was oxidized to As(V) (arsenate) by Fe(VI), with a stoichiometry of 3:2 [As(III):Fe(VI)]. Kinetic studies showed that the reaction of As(III) with Fe(VI) was first-order with respect to both reactants, and its observed second-order rate constant at 25 degrees C decreased nonlinearly from (3.54 +/- 0.24) x 10(5) to (1.23 +/- 0.01) x 10(3) M(-1) s(-1) with an increase of pH from 8.4 to 12.9. A reaction mechanism by oxygen transfer has been proposed for the oxidation of As(III) by Fe(VI). Arsenic removal tests with river water showed that, with minimum 2.0 mg L(-1) Fe(VI), the arsenic concentration can be lowered from an initial 517 to below 50 microg L(-1), which is the regulation level for As in Bangladesh. From this result, Fe(VI) was demonstrated to be very effective in the removal of arsenic species from water at a relatively low dose level (2.0 mg L(-1)). In addition, the combined use of a small amount of Fe(VI) (below 0.5 mg L(-1)) and Fe(III) as a major coagulant was found to be a practical and effective method for arsenic removal.     

Iron(VI) and iron(V) oxidation of copper(I) cyanide

Copper(Il) cyanide (Cu(CN)4(3-)) in the gold mine industry presentsthe biggest concern in cyanide management because it is much more stable than free cyanide. Cu(CN)4(3-) is highlytoxic to aquatic life; therefore, environmentally friendly techniques are required for the removal of Cu(CN)4(3-) from gold mine effluent. The oxidation of Cu(CN)4(3-) by iron-(VI) (FeVIO4(2-), Fe(VI)) and iron(V) (FeVO4(3-), Fe(V)) was studied using stopped-flow and premix pulse radiolysis techniques. The stoichiometry with Fe(VI) was determined to be 5HFeO(4-) + Cu(CN)4(3-) + 8H2O - > 5Fe(OH)3 + Cu2+ + 4CNO- +3/202 + 6OH-. The rate law for the oxidation of Cu(CN)4(3-) by Fe(VI) was found to be first-order with each reactant. The rates decreased with increasing pH and were mostly related to a decrease in concentration of reactive protonated Fe(VI) species, HFeO4-. A mechanism is proposed that agrees with the observed reaction stoichiometry and rate law. The rate constant for the oxidation of Cu(CN)4(3-) by Fe(V) was determined at pH 12.0 as 1.35 +/- 0.02 x 10(7) M(-1) s(-1), which is approximately 3 orders of magnitude larger than Fe(VI). Results indicate that Fe(VI) is highly efficient for removal of cyanides in gold mill effluent.     

表没食子儿茶素没食子酸酯的甲基化分子修饰

研究表没食子儿茶素没食子酸酯(EGCG)的甲基化分子修饰。以碘甲烷作为甲基供体,采用化学合成方法研究EGCG 的甲基化分子修饰,并通过HPLC-MS 和NMR 等对反应产物进行结构鉴定。结果表明：采用化学合成方法能有效完成EGCG 的甲基化分子修饰,并分离鉴定出5 个EGCG 甲基化衍生物,分别为4″-Me-EGCG、4′,4″-di-Me-EGCG、5,3′,4′,5′,3″,4″,5″-hepta-Me-EGCG、5,7,3′,4′,3″,4″,5″-hepta-Me-EGCG、5,7,3′,4′,5′,3″,4″,5″-octa-Me-EGCG。     

Reduction of Tc(VII) by Fe(II) sorbed on Al (hydr)oxides

Under oxic conditions, Tc exists as the soluble, weakly sorbing pertechnetate [TcO4-] anion. The reduced form of technetium, Tc(IV), is stable in anoxic environments and is sparingly soluble as TcO2 x nH2O(s). Here we investigate the heterogeneous reduction of Tc(VII) by Fe(II) adsorbed on Al (hydr)oxides [diaspore (alpha-AlOOH) and corundum (alpha-Al2O3)]. Experiments were performed to study the kinetics of Tc(VII) reduction, examine changes in Fe surface speciation during Tc(VII) reduction (M?ssbauer spectroscopy), and identify the nature of Tc(IV)-containing reaction products (X-ray absorption spectroscopy). We found that Tc(VII) was completely reduced by adsorbed Fe(II) within 11 (diaspore suspension) and 4 days (corundum suspension). M?ssbauer measurements revealed thatthe Fe(II) signal became less intense with Tc(VII) reduction and was accompanied by an increase in the intensity of the Fe(III) doublet and magnetically ordered Fe(III) sextet signals. Tc-EXAFS spectroscopy revealed that the final heterogeneous redox product on corundum was similar to Tc(IV) oxyhydroxide, TcO2 x nH2O.     

Mind the (yield) gap(s)

This paper explores the origin of the notion of ??yield gap?? and its use as a framing device for agricultural policy in sub-Saharan Africa. The argument is that while the yield gap of policy discourse provides a simple and powerful framing device, it is most often used without the discipline or caveats associated with the best examples of its use in crop production ecology and microeconomics. This argument is developed by examining how yield gap is used in a selection of recent and influential agricultural policy documents. The message for policy makers and others is clear: ??mind the (yield) gap(s)??, for they are seldom what they appear.     

Attractancy of diethyl ether extracts of Arachis hypogaea (Linnaeus) (Papilionaceae), Citrullus lanatus (Thunberg) (Cucurbitaceae) and Irvingia gabonensis var. excelsa (Baillon) (Irvingiaceae) to Oryzaephilus mercator (Fauvel) (Coleoptera: Silvanidae)

Volatiles of the diethyl ether extracts of I. gabonensis, C. lanatus and A. hypogaea attracted 1–7 and 28–42-day-old adult O. mercator when tested in a two-choice pitfall Petri dish bioassay. For both age groups, a significant difference was observed in response between fed and starved adults to the different extracts. Differences in starvation time did not affect responses of individuals in the 1–7-day-old group; a significant effect was observed in the 28–42-day-old group.

Adults, 28–42-day-old were significantly more responsive to virtually all extracts than 1–7-day-old adults. Responses of adults in each age group to the different extracts were not significantly different. The time of trial within the period 0900–1900 h did not significantly affect the response of adults in both age groups, starved for 2 days, to any extract.     

Reactivity of Pb(II) at the Mn(III,IV) (oxyhydr)oxide--water interface

In this study, the reactivity of lead (Pb(II)) on naturally occurring Mn(III,IV) (oxyhydr)oxide minerals was evaluated using kinetic, thermodynamic, and spectroscopic investigations. Aqueous Pb(II) was more strongly adsorbed to birnessite (delta-MnO1.7) than to manganite (gamma-MnOOH) under all experimental conditions. The isoteric heat of Pb adsorption (delta HT) or birnessite was 94 kJ mol-1 at a surface loading of 1.1 mmol g-1, and decreased with increasing adsorption density. This indicated that adsorption was an endothermic process and that birnessite possessed heterogeneous sites of reactivity for Pb. X-ray absorption fine structure (XAFS) spectra revealed that Pb was adsorbed as inner-sphere complexes on both birnessite and manganite with no evidence to suggest oxidation as an operative sorption mechanism. Lead appeared to coordinate to vacancy sites in the birnessite layer structure with concurrent release of Mn to solution, which resulted in a greater number of second shell Mn scatterers in Pb-birnessite when compared to Pb-manganite samples. The difference in Pb coordination apparently explained the contrasting desorption behavior between the two Mn minerals. These results have significant implications for Pb partitioning in soil environments containing solid-phase Mn(III,IV) (oxyhydr)oxides.     

羟丙基壳聚糖亚铁配合物的合成

采用壳聚糖先与Fe2+配合,再用环氧丙烷改性,研究了羟丙基壳聚糖-Fe2+的合成工艺,并用紫外和红外光谱对衍生物结构进行了表征。结果表明,在壳聚糖用量为0.1g、Fe2+起始浓度为16mg/mL、溶液pH为2的条件下,制得壳聚糖亚铁配合物。接着在壳聚糖-Fe2+∶环氧丙烷∶25%四甲基氢氧化铵为1mg∶10mL∶0.8mL条件下,制得羟丙基壳聚糖-Fe2+(HPCS-Fe2+)。位于1160～1030cm-1处有特征吸收峰,说明衍生化后得到的HPCS和HPCS-Fe2+上两个羟基上都发生了反应。     

Iron(VI) and iron(V) oxidation of thiocyanate

Thiocyanate (SCN-) is used in many industrial processes and is commonly found in industrial and mining waste-waters. The removal of SCN- is required because of its toxic effects. The oxidation of thiocyanate (SCN-) by environmentally friendly oxidants, Fe(VI) and Fe(V), has been studied anaerobically using stopped-flow and premix pulse radiolysis techniques. The stoichiometry with Fe(VI) was determined to be 4HFeO(4-) + SCN(-) + 5H2O-->4Fe(OH)3 + SO4(2-) + CNO(-) + O2 + 2OH-. The rate law for the oxidation of SCN- by Fe(VI) was found to be -d[Fe(VI)]/dt = k11([H+]/([H+] + Ka,HFeO4)) [Fe(VI)][SCN-] where k11 = 2.04 +/- 0.04 x 10(3) M-1 s-1 and pKa,HFeO4 = 7.33. A mechanism is proposed that agrees with the observed reaction stoichiometry and rate law. The rate of oxidation of SCN- by Fe(V) was approximately 3 orders of magnitude faster than Fe(VI). The higher reactivity of Fe(V) with SCN- indicates that oxidations by Fe(VI) may be enhanced in the presence of appropriate one-electron-reducing agents. The results suggest that the effective removal of SCN- can be achieved by Fe(VI) and Fe(V).     

Supercritical fluid extraction (SFE) of 4(5)-methylimidazole (4-MeI) and 2-acetyl-4(5)-(1,2,3,4)-tetrahydroxybutyl-imidazole (THI) from ground-coffee with high-performance liquid chromatographic-electrospray mass spectrometric quantification (HPLC/ESI-MS).

Two polar analytes, 4(5)-methylimidazole (4-MeI) and 2-acetyl-4(5)-(1,2,3,4)-tetrahydroxybutyl-imidazole (THI), were extracted with supercritical carbon dioxide (CO2) modified with aqueous methanol. The method was applied to a roasted coffee powder with good recovery rates. Method efficiency was compared with that of solid-phase extraction using SCX Disc cartridges and validated for spiked solid matrix. The analytes were determined using isocratic liquid chromatography-mass spectrometry (LC/MS) on an Atlantis HILIC Silica column (150 x 2.1 mm, 3 microm) with 80% methanol and 20% 0.01 mol l-1 ammonium formate as the mobile phase. The limit of quantification was around 1.5 pg for 4-MeI and 2.0 pg for THI. The linearity of the calibration curves was satisfactory as indicated by correlation coefficients of >0.999. The coefficient of variation for the intra-day and inter-day precisions was <4% (n = 6). Accuracy was in the range 98-101%; recovery rates were > or = 98 and > or = 99% for THI and 4-MeI, respectively. Several samples of Arabica coffee from various locations and commercially available 'off-the-shelf' coffee products (Arabica/Robusta mixtures) were analysed to test the method.