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•A series of esters of diastereomeric menthols was analyzed by GC–MS.•A foolproof identification procedure for these aroma important esters was suggested.•EI Mass Spectral Libraries ...recorded on SQ and QIT mass detectors were created.•GC RI data on non-polar HP-5MS and polar HP-Innowax columns are included therein.•A collection of MS and GC data was compiled and is available as supplementary data.
A comprehensive data collection of mass spectral and gas chromatographic data of a series of esters of diastereomeric menthols (menthol, isomenthol, neomenthol, and neoisomenthol), in total 150 chemical entities, obtained by GC–MS on commonly used capillary columns of different polarity (non-polar HP-5MS and polar HP-Innowax), was created. Also, MS libraries containing electron ionization MS recorded on single quadrupole as well as on quadrupole ion-trap mass detectors together with the RIs on non-polar and polar columns were compiled (available as supplementary materials). The results point out to frequent misidentification of neoisomenthyl acetate as isomenthyl acetate in the literature, and the means of how to resolve this issue was suggested. The outcomes of this study provide chemists and food technologists with a useful tool in the field of food analysis of compounds with important food aroma properties.
A detailed chemical analysis of the essential oil of Asphodelus albus roots performed in this work, in combination with a chemical synthesis approach - the synthesis of selected compounds and their ...detailed spectral analysis - has led to the identification of a series of new natural products, the esters of furan-3-ylmethanol: furan-3-ylmethyl 2-methylpropanoate, furan-3-ylmethyl butanoate, furan-3-ylmethyl 2-methylbutanoate, furan-3-ylmethyl 3-methylbutanoate, furan-3-ylmethyl pentanoate, furan-3-ylmethyl 4-methylpentanoate, and furan-3-ylmethyl hexanoate.
Aims: The study aimed at investigating interactions between zinc(II) complexes with different geometrical structures and relevant nitrogen donor nucleophiles at physiological pH.
Background: Lack of ...clear distinction between the therapeutic and toxic doses of platinum drugs is a major challenge for the design of novel non-platinum DNA and protein targeting metal-based anticancer agents. The non-platinum antitumor complexes could be alternatives to platinum-based drugs due to their better characteristics and different mechanisms of action.
Objective: This study could provide more information regarding the design of future zinc-based anticancer drugs, providing a better understanding of the mechanism of interactions between Zn(II) complexes and nitrogen-donor nucleophiles (important from the medical point of view), and clarifying the changes in geometrical structures of zinc(II) that are referred to structure-reactivity correlations.
Methods: Mole-ratio method and UV-V is spectroscopic kinetic method have been used.
Results: The results indicated additional coordination of chlorides in the first coordination sphere with changes in coordination geometry and formation of the octahedral complex anion ZnCl4(en)2- while the excess of chloride did not affect the square-pyramidal structure of ZnCl2(terpy). The substitutions of studied complexes and relevant nucleophiles proceeded in two consecutive reaction steps that depended on the nucleophile concentration. Octahedral complex anion ZnCl4(en)2- forms rapidly and all substitution processes of this complex species should be considered. We assume that the first reaction step is accompanied by the dissociation of chloride ligands. Nucleophile 1,2,4- triazoles have shown the highest affinity toward ZnCl2(en), and rates of both steps were almost of the same value, indicating parallel reactions.
Conclusion: The different order of reactivity of relevant N-donor ligands toward ZnCl2(en) and ZnCl2(terpy) complexes for the first reaction step occurred because of the influence of different geometrical structures of complexes, while low reaction rates for the second reactions of ZnCl2(en) complex with imidazole and pyrazine were a consequence of interconversion between octahedral and tetrahedral structure during substitution processes.
Introduction: Despite ongoing findings on the relationship between liver fibrosis in nonalcoholic fatty liver disease (NAFLD) and metabolic syndrome (MetS), this association in diabetic patients ...remains unclear. Early diagnosis of liver fibrosis is important due to the easily available diagnostic tools, such as noninvasive indices that combine clinical and laboratory variables, and the possibility of preventing its complications in type 2 diabetes mellitus (T2DM) patients with MetS.Objective: This study examines the potential predictive values of non-invasive liver fibrosis indices for MetS in T2DM patients.Patients and methods: Over the course of a two-year prospective, observational, clinical study, 80 individuals with T2DM randomly selected from the Diabetes Counseling Centers of the Public Institution Health Center of Sarajevo Canton were divided into two groups: T2DM-MetS and T2DM-non-MetS, based on the development of MetS. The study included individuals with T2DM aged 30 to 60 who were clinically diagnosed without MetS, voluntarily agreed to participate, and provided complete data in the collection forms. Serum samples from the patients were assessed for levels of liver enzymes, platelet counts, total cholesterol, high-density lipoprotein cholesterol, fasting glucose, and triglycerides. Various equations were utilized to calculate liver fibrosis indices, including the Aspartate Aminotransferase to Platelet Ratio Index (APRI), Aspartate Aminotransferase to Gamma-Glutamyl Transferase to Platelet Ratio (AGPR), Aspartate Aminotransferase to Alanine Aminotransferase Ratio to Platelet Ratio Index (AARPRI), Fibrosis-4 (FIB-4) Index, Forns Index, and Gamma-Glutamyl Transpeptidase to Platelet Ratio (GPR). Receiver operating characteristic (ROC) analysis was utilized to determine the usefulness of noninvasive liver fibrosis indices for diagnosing MetS in individuals with T2DM. Logistic regression analysis was used to predict the onset of MetS in T2DM patients.Results: Significant differences in the values of APRI (p<0.001), AGPR (p<0.05), AARPRI (p<0.001), and the FIB-4 index (p=0.001) were observed in T2DM-MetS individuals compared to T2DM-non-MetS. According to ROC analysis, the area under the curve (AUC) was found to be highest for APRI (0.84), followed by FIB-4 (0.783) and AARPRI (0.747). Logistic regression analysis identified APRI as an independent positive predictor of MetS (OR 18.179, 95% CI 6.035-24.58, p=0.015).Conclusion: This research highlights the effectiveness of the APRI index as a reliable predictor of MetS development in individuals with T2DM.
ABSTRACT
The substitution reactions of the complexes {trans‐Pt(NH3)2H2O}2(μ‐1,4‐diaminobutane)4+ (I), {trans‐Pt(NH3)2H2O}2(μ‐1,6‐diaminohexane)4+ (II), and {trans‐Pt(NH3)2H2O}2(μ‐1,8‐diaminooctane)4+ ...(III), with nucleophiles L‐cysteine (L‐Cys), glutathione (GSH), guanosine‐5′‐monophosphate (5′‐GMP), L‐histidine (L‐His), and pyridine were studied in 0.1 M NaClO4 aqueous solutions at pH = 2.5. The substitutions were studied under pseudo‐first‐order conditions as a function of concentration and temperature using UV–vis spectrophotometry. At three different temperatures (288, 298, and 308 K) the reactions of the II and III complexes and 5′‐GMP were studied. The order of reactivity of study ligands is L‐Cys > GSH > 5′‐GMP > L‐His > pyridine and the order of reactivity of the complexes is I < II ≈ III. The obtained results indicate that the structure of the alkanediamine linker in the dinuclear Pt(II) complexes controls the substitution process. The negative values reported for entropy of activation confirmed the associative substitution mode. These results are discussed in order to find the connection between structure and reactivity of the dinuclear Pt(II) complexes.
Substitution reactions of square-pyramidal ZnCl2(terpy) complex (terpy = 2,2′:6′,2″-terpyridine) with biologically relevant nucleophiles such as imidazole, glutathione, 1,2,4-triazole, and pyrazine ...were investigated at pH 7.0 as a function of nucleophile concentration. The reactions were followed under pseudo first-order conditions by UV-Vis spectrophotometry. The substitution reactions comprised two steps of consecutive displacement of chlorido ligands. Different reaction pathways for the first reaction step of nucleophilic substitution were defined. The order of reactivity of the investigated nucleophiles for the first reaction was imidazole > glutathione > pyrazine > 1,2,4-triazole, while for the second reaction step it was pyrazine > 1,2,4-triazole > imidazole > glutathione.
The mole-ratio method was used to determine the metal–ligand stoichiometry between ZnCl2(en) and ZnCl2(terpy) (where en = 1,2-diaminoethane or ethylenediamine and terpy = 2,2′:6′,2″-terpyridine) and ...imidazole at pH 7.2 in the presence of different chloride concentrations. The results indicated step-wise formation of 1:1 and 1:2 complexes in the presence of 0.010 M NaCl and 1:1 complexes in the presence of 0.001 M NaCl for the ZnCl2(en) complex. These results are correlated with additional coordination of chlorides in the first coordination sphere and with changes in coordination geometry. In the presence of 0.001 M NaCl the five-coordinate complex anion ZnCl3(en)- is formed initially and then a substitution reaction with imidazole occurs. In the presence of 0.010 M NaCl the octahedral complex anion ZnCl4(en)2- is formed. Additional coordination of chloride in the ZnCl2(terpy) complex is not found and the metal–ligand stoichiometry is 1:2. The kinetics of ligand substitution reactions of zinc(II) complexes and biologically relevant nitrogen nucleophiles such as imidazole, 1,2,3-triazole and L-histidine were investigated at pH 7.2 as a function of nucleophile concentration in the presence of 0.001 M and 0.010 M NaCl. The reactions were followed under pseudo first-order conditions by UV-Vis spectrophotometry. The substitution reactions included two steps of consecutive displacement of chlorido ligands with changes only in the coordination geometry of the ZnCl2(en) complex. The order of reactivity of the investigated nucleophiles for the first reaction step towards both complexes was L-histidine > 1,2,3-triazole > imidazole, while in the presence of 0.010 M NaCl the most reactive ligand was 1,2,3-triazole towards the ZnCl2(en) complex.
The novel heteronuclear complexes {cis‐PtCl (NH3)(μ‐pyrazine)ZnCl (terpy)}(ClO4)2 (Pt‐L1‐Zn) and {cis‐PtCl (NH3)(μ‐4,4′‐bipyridyl)ZnCl (terpy)}(ClO4)2 (Pt‐L2‐Zn) (where terpy = ...2,2′:6′,2′′‐terpyridine, L1 = pyrazine, L2 = 4,4′‐bipyridyl) were synthesized and characterized. The pKa values were determined, and based on them it was established that the π‐acceptor ability of the pyrazine bridging ligand is more affective on lower pKa values. The kinetic measurements of the substitution reactions with biologically relevant ligands, such as guanosine‐5′‐monophosphate (5′‐GMP), inosine‐5′‐monophosphate (5′‐IMP) and glutathione (GSH), were studied at pH 7.4. The reactions were followed under pseudo‐first‐order conditions by UV–Vis spectrophotometry. The order of reactivity of the investigated biomolecules for the first reaction is 5′‐GMP > 5′‐IMP > GSH, while for the second is 5′‐IMP > GSH. Pt‐L1‐Zn complex is more reactive than Pt‐L2‐Zn. The cytotoxic activity of heteronuclear Pt‐L1‐Zn and Pt‐L2‐Zn complexes was determined on human colorectal cancer cell line (HCT‐116) and human breast cancer cell line (MDA‐MB‐231). Both complexes significantly reduced cell viability on tested cell lines and exerted significant cytotoxic effects, with better effect on HCT‐116 cells than cisplatin, especially after 72 hr (IC50 < 0.52 μM). The Pt‐L2‐Zn complex showed higher activity against human breast cancer cells (MDA‐MB‐231) than cisplatin after 72 hr. The higher reactivity toward DNA constituent and significant cytotoxic activity may be attributed to the different geometry, Lewis acidity of different metal centers, as well as, to choice of bridging ligands.
The heteronuclear complexes containing metals centers with different Lewis acidity, geometry and kinetic characteristics, connected with π‐acceptor bridging ligands, could give promising antitumor activity.
The aim of this study was to develop a kinetic-spectrophotometric method for 2-methyl-4-chlorophenoxy acetic acid (MCPA) determination and apply it for pesticide determination in baby tea and baby ...food samples, using solid-phase extraction (SPE) followed by the kinetic-spectrophotometric method and the high-performance liquid chromatography (HPLC) method. This method is based on the inhibited effect of MCPA on the oxidation of sulfanilic acid (SA) by hydrogen peroxide in the presence of Co
2+
ion as catalyst in alkaline medium. The reaction was monitored spectrophotometrically by measuring the increase in absorbance with time of the reaction product at 368 nm. Under the experimental conditions used, MCPA showed a linear dynamic range of 0.14 to 2.0 μg mL
−1
, and from 2.0 to 20.00 μg mL
−1
with relative standard deviations (RSD) from 1.07 to 4.35%. The limit of detection and the limit of quantification were 0.052 and 0.107 μg mL
−1
. The method was successfully applied to determination of MCPA residues in baby tea and baby food samples. Solid-phase extraction (SPE) was used for extraction of MCPA from samples using Chromabond® C
18
cartridges. The HPLC method was used as a comparative method to verify the results of kinetic method. The results obtained by two different methods showed good agreement. The proposed method is highly sensitive, simple, easy, requires cheap reagents, and leads to good recovery levels. It is linear, precise, and accurate. It can be successfully used for the routine analysis of MCPA in baby tea samples, and baby food samples.
The cover image is based on the Full Paper Novel heteronuclear Pt (II)‐L‐Zn (II) complexes: synthesis, interactions with biomolecules, cytotoxic properties. Two metals give promising antitumor ...activity? by Tanja V. Soldatović et al., https://doi.org/10.1002/aoc.5864.
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