LC-ESI-MS/MS profiling of alkaloids and antiproliferative activity of Pachypoduim lamerei drake leaves

Abstract

In the present study, evaluation of the antiproliferative activity of Pachypodium lamerei Drake leaves (family Apocyaceae) against human breast cancer cell lines MDA-MB-231 was done for the total methanolic extract, crude alkaloidal mixture and ursolic acid using the MTT colorimetric assay. The methanolic extract showed the strongest antiproliferative activity followed by ursolic acid and crude alkaloidal fraction with an IC₅₀ equal to 6.2, 14.55 and 56.3?µg/ml respectively compared to oleocanthal. It is the first record for the LC/ESI-MS/MS alkaloidal profiling of the leaves of P. lamerei. Seven alkaloids were tentatively identified according to their fragmentation patterns. Four alkaloids were related to the parent indole class and two alkaloids belong to the quinoline class in addition to one steroidal alkaloid with a pregnan nucleus. Phytochemical investigation of the methanolic extract led to the isolation of three triterpenoidal compounds including ursolic acid, 11,12-didehydroursolic acid lactone and ursolic acid lactone.     

A new lead(II)-selective PVC-coated graphite rod electrode based on a Schiff base complex.

A new lead(II)-selective electrode has been developed based on bis(acetylacetone)-p-phenylenediamine-lead(II) [LPb(NO3)2]H2O complex ionophore as a sensing material, dioctylphthalate (DOP) as a solvent mediator and PVC as a matrix. This electrode exhibits a linear Nernstian response over the concentration range of 1 x 10(-5)-1 x 10(-1) mol l(-1) of Pb(II) cation, with a cationic calibration slope of 30.0 +/- 0.2 mV/concentration decade and a detection limit of 2 x 10(-6) mol l(-1) (0.40 ppm). It has a fast response time and can be used for a period of 2 months without any divergence in potentials. The proposed electrode reveals a good selectivity for Pb(II) over a wide variety of other tested cations and could be used in the pH range of 4-8. It was successfully used for direct determination of Pb(II) concentration in some samples. The obtained results show a good agreement with those obtained by an atomic absorption spectrometric method. The average recovery obtained is 96.5 +/- 0.5% with standard deviation of 1.2% (n = 8).     

过渡金属阳离子预处理对活性炭催化性能的提高

首先将商用活性炭样品在1%的稀硝酸中处理,然后等体积浸渍在含有5%和10%(质量分数)硝酸钴、硝酸镍或硝酸铜的水溶液中,并在100℃干燥至恒重,最后将样品在Ar气氛中于400℃焙烧3 h.采用X射线衍射、N2吸附和红外光谱等分析手段对不同固体样品进行了表征,并考察了其对异丙醇催化转化和25~45℃时过氧化氢催化分解的活性.结果表明,掺杂5%或10%的过渡金属氧化物后,活性炭样品中含有结晶度很差的CoO,Co3O4,NiO,Cu2O和CuO相的纳米晶.金属氧化物预处理使活性炭的BET比表面积略有增加.这些固体样品主要用作脱氢催化剂,其选择性均高于90%.在225℃时,经5%氧化钴、氧化镍和氧化铜处理的活性炭的催化活性比硝酸处理的活性炭分别提高了6%,24.6%和40.6%.少量CoO处理后的商用活性炭对H2O2催化分解活性的提高是由参与该催化反应的活性位浓度的显著增加而引起的,该处理过程并没有改变H2O2催化分解的机理.     

Reactions with α-substituted cinnamonitriles. A novel synthesis of hexa-substituted pyridines

Whereas acetoacetanilide (II) reacted with α-cyano- and α-benzoylcinnamonitrile derivatives Ia-e to give hexa-substituted pyridines III and V, it reacted with α-carboxamido- and α-thiocarboxamidocinnammonitrile derivatives If-h to afford penta-substituted pyridines VI. One mole of acetonedicarboxylic acid dianilide (VII) reacted with two moles of each of α-cyano- and α-thiocarboxamidocinnamonitriles Ia,b,f,g to yield the dipyridyl ketones VIII and IX, respectively. On the other hand, α-benzoyl- and α-ethoxycarbonylcinnamonitriles Ic,d,i,j reacted with VII in equimolecular ratio to give the pyran derivaties X and XI, respectively. Several schemes were proposed to illustrate reactions steps. The structures of the synthesized compounds were proved by chemical and spectral methods.     

Green synthesis of titanium dioxide nanoparticles via bacterial cellulose (BC) produced from agricultural wastes

Cellulose - Bacterial cellulose (BC) produced from Achrmobacter sp. M15, was used to reduce titanium tetra isopropoxide into titanium dioxide nanoparticles (TiO2NPs) via green process. Addition of...     

Solvent extraction production of high specific activity59Fe and carrier free54Mn from irradiated iron targets

Summary Three different procedures have been worked up for the production of⁵⁹Fe and⁵⁴Mn from irradiated iron targets using tridodecylamine, tributylphosphate, and isobutylmethyl ketone. These procedures are more simple and economic than those previously reported. The yield as estimated by the standard addition technique was found to be always higher than 90%. The separated isotopes were found to be radiochemically very pure.

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Zusammenfassung Drei verschiedene Verfahren zur Herstellung von⁵⁹Fe und⁵⁴Mn aus bestrahlten Eisentargets mit Tridodecylamin, Tributylphosphat und Isobutylmethylketon wurden beschrieben. Sie sind einfacher und wirtschaftlicher als die bisherigen. Die Ausbeute war stets höher als 90%. Die erhaltenen Isotopen sind radiochemisch sehr rein.

     

Cyclohexene Hydroconversion Using Monometallic and Bimetallic Catalysts Supported on γ‐Alumina

The hydroconversion of cyclohexene (CHE) using monometallic catalysts containing 0.35wt% of Pt, Pd, Ir or Re on a γ‐alumina support, as well as bimetallic catalysts containing combinations of 0.35wt% Pt with 0.35wt% of either Pd, Ir or Re on γ‐alumina, were investigated in a plug flow‐type fixed‐bed reactor. The Cyclohexene (CHE) feed was injected continuously with a rate of 8.33 × 10^?3mole h^?1 on 0.2 g of catalyst using a simultaneous hydrogen gas flow of 20 cm³ min^?1 throughout a broad reaction temperature range of 50–400 °C. The dispersion of the metals in the catalysts was determined via H₂ or CO chemisorption. The activities of the monometallic catalysts were found to be in the order: Pd > Pt > Ir > Re, whereas those of the bimetallic catalysts were in the order: PtPd > PtIr > PtRe. Cyclohexene hydrogenation and dehydrogenation reactions using the current mono‐ and bimetallic catalysts were kinetically investigated applying the absolute reaction rate theory, whereby reaction rate constant, activation energy, enthalpy and entropy of activation were computed to explain surface variations on these catalysts.