排序方式: 共有38条查询结果,搜索用时 15 毫秒
1.
Boris Pejin Kristina Tešanović Dragica Jakovljević Sonja Kaišarević Filip Šibul Milena Rašeta 《Natural product research》2019,33(5):750-754
The polysaccharide (PSH) extracts from the edible mushroom species Coprinus comatus and Coprinellus truncorum were screened in liquid for their acetylcholinesterase inhibitory (AChE) activity. Both extracts were found to display inhibition of the aforementioned enzyme reaching similar IC50 values of 0.62 ± 0.07 and 0.61 ± 0.03 mg/mL, respectively. According to the means of FTIR spectroscopy, these PSH extracts mostly contained β-glucans. However, the presence of some proteins and polyphenolics as minor ingredients were also detected. Compared with existing literature data for anti-AChE activity of the sugar samples, the findings within this study may be treated as a profound bioactivity. Consequently, this study puts some light on the possible use of the screened macrofungi in the palliative treatment of Alzheimer’s disease. 相似文献
2.
3.
A selective, sensitive, and accurate high-performance liquid chromatographic method for determination of diltiazem in plasma samples has been developed and validated. The effects of mobile phase composition, buffer concentration, mobile phase pH, and concentration of organic modifiers on retention of diltiazem and internal standard were investigated. Solid-phase and liquid–liquid extraction were examined and proposed for isolation of the drug and elimination of endogenous plasma interferences. A 5 m Lichrocart Lichrospher 60 RP-select B chromatographic column was used; the mobile phase was acetonitrile–0.025 mol L–1 KH2PO4 (pH 5.5), 35:65 ( v / v) at a flow-rate of 1.5 mL min–1. The detection wavelength was 215 nm. The calibration plots were linear in the concentration range 20.0–500.0 ng mL–1. The method has been implemented to monitor diltiazem levels in patient samples. 相似文献
4.
5.
Electrical and electrochemical properties of solid LiH2PO4 conductor were investigated in the temperature range from room temperature to 373 K. It was found that high conductivity throughout the temperature range, with activation energy 17.23 kJ/mol, originates from the movement of hydrogen ions (protons). The movement of protons in the correlation with phosphate groups rotation was considered. The slopes of Tafel lines and exchange current densities both for cathodic hydrogen and anodic oxygen evolution were determined (by means of usual electrochemical kinetic methods) at various temperatures. The energy of activation at the equilibrium potentials both for the cathodic and the anodic processes have been assessed to be 17.23 kJ/mol (0.18 eV) and 2.9 kJ/mol (0.03 eV), respectively. 相似文献
6.
Maja Karaman Ljiljana Janjušević Dragica Jakovljević Filip Šibul 《Natural product research》2019,33(10):1522-1526
This study outlines antioxidant and anti-AChE activities of the polysaccharide (PSH) extract from the mushroom species Amanita strobiliformis. Both the presence of α and ß glucans within the aforementioned extract was recorded. PSH extract displayed a profound scavenging activity of OH radicals (IC50 value, 11.86 ± 0.59 μg/mL) and high potential for reduction of Fe3+ ions (174.11 ± 8.70 mg eq. AA/g d.w.) being almost 48- and 5-fold more effective than mannitol and butylated hydroxytoluene used as a positive control, respectively. Compared with galanthamine (0.001 μg), the same extract exhibited a moderate anti-AChE activity (10 μg) in solid. Since purified PSH extract exhibited higher bioactivity (IC50 value 7.27 ± 0.31 μg/mL, 197.68 ± 9.47 mg eq. AA/g d.w. and 0.1 μg, respectively), it can be predominantly ascribed to the polysaccharide compounds. A. strobiliformis PSH extract may be considered as a promising resource of potent bioactive polysaccharides of natural origin successfully addressing both oxidative stress and lack of acetylcholine. 相似文献
7.
Absolute Configuration of Pharmaceutical Research Compounds Determined by X‐ray Powder Diffraction
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
M. Sc. Carina Schlesinger M. Sc. Lukas Tapmeyer Dr. Silke D. Gumbert Dr. Dragica Prill Dr. Michael Bolte Prof. Dr. Martin U. Schmidt Dr. Christoph Saal 《Angewandte Chemie (International ed. in English)》2018,57(29):9150-9153
The absolute configuration of active pharmaceutical ingredients (APIs) was determined by generating salts of the active pharmaceutical ingredient (API) with counterions of known chirality, and determining the crystal structures by X‐ray powder diffraction. This approach avoids the (often tedious) growth of single crystals, and is successful with very limited quantities of material (less than 1 mg). The feasibility of the method is demonstrated on five examples, and its limitations are discussed as well. 相似文献
8.
Rates of penetration of polyethylene glycol (PEG) molecular weight (MW) 1,000, 2,000, and 4,000 from 30% aqueous solutions
into hydrated cell walls of red pine samples following vacuum impregnation were estimated by examining retained swelling of
the samples after different post-treatment conditioning times. To model PEG diffusion into wood cell walls, a hollow cylinder
diffusion model was developed and diffusion coefficients were estimated and compared to those determined with a plane membrane
diffusion model. The models gave similar results. The diffusion coefficient of PEG MW 1,000 at room temperature was estimated
to be in the order of 10−13 m2/s, while the penetration rates of both PEG 2,000 and 4,000 were about an order lower. These findings indicate that treatments
of wood by PEG can be significantly shorter than present practices of soaking green samples in solution if the samples are
vacuum/pressure impregnated with PEG solution. 相似文献
9.
Csaba Bús Norbert Kúsz Annamria Kincses Nikoletta Szemerdi Gabriella Spengler Lszl Bakacsy Dragica Purger Rbert Berkecz Judit Hohmann Attila Hunyadi Andrea Vasas 《Molecules (Basel, Switzerland)》2020,25(24)
The occurrence of phenanthrenes is limited in nature, with such compounds identified only in some plant families. Phenanthrenes were described to have a wide range of pharmacological activities, and numerous research programs have targeted semisynthetic derivatives of the phenanthrene skeleton. The aims of this study were the phytochemical investigation of Juncus tenuis, focusing on the isolation of phenanthrenes, and the preparation of semisynthetic derivatives of the isolated compounds. From the methanolic extract of J. tenuis, three phenanthrenes (juncusol, effusol, and 2,7-dihydroxy-1,8-dimethyl-5-vinyl-9,10-dihydrophenanthrene) were isolated. Juncusol and effusol were transformed by hypervalent iodine(III) reagent, using a diversity-oriented approach. Four racemic semisynthetic compounds possessing an alkyl-substituted p-quinol ring (1–4) were produced. Isolation and purification of the compounds were carried out by different chromatographic techniques, and their structures were elucidated by means of 1D and 2D NMR, and HRMS spectroscopic methods. The isolated secondary metabolites and their semisynthetic analogues were tested on seven human tumor cell lines (A2780, A2780cis, KCR, MCF-7, HeLa, HTB-26, and T47D) and on one normal cell line (MRC-5), using the MTT assay. The effusol derivative 3, substituted with two methoxy groups, showed promising antiproliferative activity on MCF-7, T47D, and A2780 cell lines with IC50 values of 5.8, 7.0, and 8.6 µM, respectively. 相似文献
10.
Dragica M. Minić Maja T. Šumar-Ristović Đenana U. Miodragović Katarina K. Anđelković Dejan Poleti 《Journal of Thermal Analysis and Calorimetry》2012,107(3):1167-1176
The kinetics of multi-step thermal degradation of Co(II) complex with N-benzyloxycarbonyl glycinato ligand [Co(N-Boc-gly)2(H2O)4]·2H2O, in non-isothermal conditions was studied using isoconversional and non-isoconversional methods. The degradation of complex
occurs in three well-separated steps involving the loss of water molecules in first step followed by two degradation steps
of dehydrated complex. The dependence of Arrhenius parameters on conversion degree showed that all observed steps of thermal
degradation are very complex, involving more than one elementary step, as can be expected for most solid-state heterogeneous
reactions with solid reactants and solid and gaseous products. It was shown that step 1, corresponding to the dehydration,
involves a series of competitive dehydration steps of differently bound water molecules complicated by diffusion. Second step
involves two parallel reactions related to the loss of two identical C6H5CH2O– ligand fragments complicated by the presence of products in gaseous state. Further degradation in step 3 corresponds to
complex process with a change in the limiting stage, in this case from the kinetic to the diffusion regime, connected with
the presence of gaseous products diffusing through the solid product. 相似文献