Potential Anticancer Activities and Catalytic Oxidation Efficiency of Platinum(IV) Complex

The treatment of an aqueous acetonitrile solution of chloroplatinic acid hydrate H₂PtCl₆.xH₂O and pyridine-2-carbaldehyde-oxime (paOH) in the presence of potassium thiocyanate at room temperature (25°) led to the formation of a new Pt(IV) complex with the formula [Pt(SCN)₂(paO)₂], (1). Complex 1 was fully characterized by FT-IR, UV-vis and NMR spectroscopic techniques as well as elemental analysis. The crystallographic structure of complex 1 was obtained by single-crystal X-ray diffraction. The structure of complex 1 consists of a distorted octahedral geometrical environment around the platinum center in which the coordination sites are occupied by two terminal thiocyanate ligands in trans arrangement and two bidentate paO ligands through four nitrogen atoms. In addition, the in vitro evaluation of the cytotoxicity of platinum complex 1 against four different cancer cell lines was performed. The IC₅₀ values for colon (HCT116), liver (HepG2), breast (MCF-7) and erythroid (JK-1) treated with complex 1 are 19 ± 6, 21 ± 5, 22 ± 6, and 13 ± 3 μM, respectively. In HCT116 cells treated with the IC50 dose of our title compound, apoptosis and necrosis were increased by 34% and 27.8%, respectively. Cells halted in the proliferative phase (S phase) to 21.7 % and 29.8% in HCT116 and HepG2 cells treated with complex 1 have anti-proliferative actions. Furthermore, the catalytic activity of synthesized complex 1 was examined in the oxidation reaction of benzyl alcohols in the presence of an oxidant. Finally, the luminescence behavior of complex 1 was investigated.     

Antiviral Efficacy of Selected Natural Phytochemicals against SARS-CoV-2 Spike Glycoprotein Using Structure-Based Drug Designing

SARS-CoV-2 is a highly virulent coronavirus that first surfaced in late 2019 and has since created a pandemic of the acute respiratory sickness known as “coronavirus disease 2019” (COVID-19), posing a threat to human health and public safety. S-RBD is a coronaviral protein that is essential for a coronavirus (CoV) to bind and penetrate into host cells. As a result, it has become a popular pharmacological target. The goal of this study was to find potential candidates for anti-coronavirus disease 2019 (COVID-19) drugs by targeting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) S-RBD with novel bioactive compounds and molecular interaction studies of 15,000 phytochemicals belonging to different flavonoid subgroups. A spike protein crystal structure attached to the ACE2 structure was obtained from the PDB database. A library of 15,000 phytochemicals was made by collecting compounds from different databases, such as the Zinc-database, PubChem-database, and MPD3-database. This library was docked against a receptor binding domain of a spike glycoprotein through the Molecular Operating Environment (MOE). The top drug candidates Phylloflavan, Milk thistle, Ilexin B and Isosilybin B, after virtual screening, were selected on the basis of the least binding score. Phylloflavan ranked as the top compound because of its least binding affinity score of −14.09 kcal/mol. In silico studies showed that all those compounds showed good activity and could be used as an immunological response with no bioavailability issues. Absorption, distribution, metabolism, excretion and a toxicological analysis were conducted through SwissADME. Stability and effectiveness of the docked complexes were elucidated by performing the 100 ns molecular dynamic simulation through the Desmond package.     

Development of validated RP HPLC method with fluorescence detection for simultaneous quantification of sacubitril and valsartan from rat plasma

In the present work, a sensitive, accurate and precise RP HPLC method has been established for simultaneous determination of sacubitril and valsartan from rat plasma by using irbesartan as an internal standard. Separation of analytes were carried out on monolithic column using 10?mM phosphate buffer (pH 2.6), methanol and acetonitrile in a proportion of 50:25:25 (v/v). Analytes were monitored using fluorescence detector maintained at an excitation wavelength of 249?nm and an emission wavelength was set at 380?nm till the elution of valsartan as well as internal standard and switched online to 320?nm for sacubitril. Analysis of analytes from rat plasma was carried out by protein precipitation using methanol and acetonitrile. Valsartan and sacubitril showed good linearity in the concentration range of 1–250?ng/ml and 1–200?ng/ml respectively, with good correlation coefficient (r²?≥?0.998). Further, the precision and accuracy of the proposed procedure were suitable as the percent relative standard deviation and percent relative error were well within the acceptable range. The average percent of recovery from the rat plasma was found to be 96.6% and 97.6% for valsartan and sacubitril respectively. The newly proposed method can be used for regular pharmacokinetic studies because of simplicity in sample preparation, short analysis time (<5?min) and good sensitivity.     

Cation-exchange fabric prepared by electron beam-induced graft copolymerization of binary monomer mixture

Applying the electron-beam preirradiation method in air the cation - exchange fabric (CEF) containing sulfonic acid (R-SO₃H) groups was prepared by graft copolymerization of sodium styrenesulfonate with acrylic acid onto non woven polypropylene fabric. The effect of reaction conditions on the grafting yield and reaction mechanism was examined. The ion-exchange properties towards Cu(II) and Co(II) ions of the CEF were investigated depending on the form of the CEF and a pH of the solution. It was found that the synthesized CEF contains both strong acid groups (R-SO₃H) and weak acid (R-COOH) groups in almost equal proportion. The utilization of the CEF in Na₊ form allows to make the best use of its ion-exchange capacity.     

Boiling Technique-Based Food Processing Effects on the Bioactive and Antimicrobial Properties of Basil and Rosemary

Rosemary (Rosmarinus officinalis) and basil (Ocimum sanctum Linn) are mostly used as herbal teas, made by steeping whole or ground herbs in boiling water. Hence, it is important to know the effect of boiling time on the bioactivity of these herbs. The effect of different boiling times (5, 10, and 15 min) on the antioxidant and antimicrobial properties, and some selected phenolic compounds of these herbs was examined in this study. Experimental results revealed that basil displayed the highest total polyphenol content (TPC), total flavonoid content (TFC), and antioxidant activity when it was boiled for 5 min, and the lowest TPC was obtained when it was boiled for 15 min. On the other hand, rosemary had the highest TPC, TFC, and antioxidant potential after being boiled for 15 min, while it had the lowest after being boiled for 5 min. There was no growth inhibition of rosemary extracts against gram-negative bacteria, whereas higher growth inhibition was observed against gram-positive bacteria. The MIC and MBC of rosemary ethanolic extract against Listeria monocytogenes were 5 and 5 mg/mL and against B. subtilis were 10 and 10 mg/mL, respectively. While MIC and MBC of methanolic extract against L. monocytogenes were 5 and 5 mg/mL and against Bacillus subtilis were and 5 and 5 mg/mL, respectively. Salicylic acid was the most abundant (324.7 mg/100 g dry weight (dw)) phenolic compound in the rosemary sample boiled for 5 min, and acetyl salicylic acid was the most abundant (122.61 mg/10 g dw) phenolic compound in the basil sample boiled for 15 min.     

Multistage Segmentation of Prostate Cancer Tissues Using Sample Entropy Texture Analysis

In this study, a multistage segmentation technique is proposed that identifies cancerous cells in prostate tissue samples. The benign areas of the tissue are distinguished from the cancerous regions using the texture of glands. The texture is modeled based on wavelet packet features along with sample entropy values. In a multistage segmentation process, the mean-shift algorithm is applied on the pre-processed images to perform a coarse segmentation of the tissue. Wavelet packets are employed in the second stage to obtain fine details of the structured shape of glands. Finally, the texture of the gland is modeled by the sample entropy values, which identifies epithelial regions from stroma patches. Although there are three stages of the proposed algorithm, the computation is fast as wavelet packet features and sample entropy values perform robust modeling for the required regions of interest. A comparative analysis with other state-of-the-art texture segmentation techniques is presented and dice ratios are computed for the comparison. It has been observed that our algorithm not only outperforms other techniques, but, by introducing sample entropy features, identification of cancerous regions of tissues is achieved with 90% classification accuracy, which shows the robustness of the proposed algorithm.     

Base-catalyzed aryl halide isomerization enables the 4-selective substitution of 3-bromopyridines

The base-catalyzed isomerization of simple aryl halides is presented and utilized to achieve the 4-selective etherification, hydroxylation and amination of 3-bromopyridines. Mechanistic studies support isomerization of 3-bromopyridines to 4-bromopyridines proceeds via pyridyne intermediates and that 4-substitution selectivity is driven by a facile aromatic substitution reaction. Useful features of a tandem aryl halide isomerization/selective interception approach to aromatic functionalization are demonstrated. Example benefits include the use of readily available and stable 3-bromopyridines in place of less available and stable 4-halogenated congeners and the ability to converge mixtures of 3- and 5-bromopyridines to a single 4-substituted product.

The base-catalyzed isomerization of aryl halides is described and applied to the tandem isomerization/4-substitution of 3-bromopyridines as a strategy for achieving unconventional selectivity in nucleophilic aromatic substitution reactions.     

Enantioselective Brønsted base catalysis with chiral cyclopropenimines

Cyclopropenimines are shown to be a highly effective new class of enantioselective Br?nsted base catalysts. A chiral 2,3-bis(dialkylamino)cyclopropenimine catalyzes the rapid Michael reaction of a glycine imine substrate with high levels of enantioselectivity. A preparative scale reaction to deliver 25 g of product is demonstrated, and a trivial large scale synthesis of the optimal catalyst is shown. In addition, the basicity of a 2,3-bis(dialkylamino)cyclopropenimine is measured for the first time and shown to be approximately equivalent to the P(1)-tBu phosphazene base. An X-ray crystal structure of the protonated catalyst is shown along with a proposed mechanistic and stereochemical rationale.