Polyphenolic Profile of Callistemon viminalis Aerial Parts: Antioxidant,Anticancer and In Silico 5-LOX Inhibitory Evaluations

Five new compounds viz kaempferol 3-O-(4″-galloyl)-β-d-glucopyranosyl-(1‴→6″)-O-β-d-glucopyranoside (1), kaempferol 3-O-β-d-mannuronopyranoside (2), kaempferol 3-O-β-d-mannopyranoside (3), quercetin 3-O-β-d-mannuronopyranoside (4), 2, 3 (S)- hexahydroxydiphenoyl]-d-glucose (5) along with fifteen known compounds were isolated from 80% aqueous methanol extract (AME) of C. viminalis. AME and compounds exerted similar or better antioxidant activity to ascorbic acid using DPPH, O₂⁻, and NO inhibition methods. In addition, compounds 16, 4, and 7 showed cytotoxic activity against MCF-7 cell lines while 3, 7 and 16 exhibited strong activity against HepG2. An in silico analysis using molecular docking for polyphenolic compounds 2, 3, 7, 16 and 17 against human stable 5-LOX was performed and compared to that of ascorbic acid and quercetin. The binding mode as well as the enzyme-inhibitor interactions were evaluated. All compounds occupied the 5-LOX active site and showed binding affinity greater than ascorbic acid or quercetin. The data herein suggest that AME, a source of polyphenols, could be used against oxidative-stress-related disorders.     

Synthesis,Characterization and Investigation of Electrochemical and Spectroelectrochemical Properties of Peripherally Tetra Diethoxypropan Substituted Phthalocyanines

In this study novel peripherally tetra 1,3-diethoxy-2-propanol substituted Co(II), Cu(II), Mg(II), Ni(II) Zn(II) phthalocyanine derivatives were prepared. The characterization of the novel compounds was made by FT-IR, ¹H-NMR, UV-vis and MALDI-TOF mass. Electrochemical, in-situ spectroelectrochemical and electrocolorimetric measurements have been carried out with the aim to determine the redox properties, to illuminate reaction mechanism and the effect of substituent and metal center. Moreover, the color properties and aggregation tendency of compounds were also investigated.     

[N‐(2‐Hydroxy­ethyl)ethyl­enediamine‐κ3N,N′,O]‐cis‐bis(isothio­cyanato‐κN)copper(II)

In the novel transition metal isothio­cyanate complex of N‐(2‐hydroxy­ethyl)ethyl­enediamine (hydet‐en) with copper, [Cu(NCS)₂(C₄H₁₂N₂O)], the Cu atom lies in a distorted square‐pyramidal environment, coordinated by four N atoms in the basal plane and an apical O atom. The hydet‐en ligand is N,N,O‐tridentate, in contrast to the disposition in previously studied complexes, while the isothio­cyanate ions act as N‐atom donor ligands. The monomeric units are linked to one another by hydrogen bonds.     

Leaving group effect in the sulfonyl transfer reactions of aryl benzenesulfonates with Grignard reagents

The C–S coupling reactions of aryl benzenesulfonates with phenylmagnesium bromide in THF:toluene (7:10) at 90 °C have been studied. A Hammett-type kinetic study of the leaving group effect of aryloxy groups provides a conclusive support for a two step addition-elimination mechanism in which C–S bond formation is rate determining step.     

The Effects of High-Pressure Processing on pH,Thiobarbituric Acid Value,Color and Texture Properties of Frozen and Unfrozen Beef Mince

In this study, beef mince (approximately 4% fat longissmus costarum muscle of approximately 2-year-old Holstein cattle) was used as a material. High-pressure processing (HPP) was applied to frozen and unfrozen, vacuum-packed minced meat samples. The pH and thiobarbituric acid (TBA) values of the samples were examined during 45 days of storage. Color values (L*, a* and b*) and texture properties were examined during 30 days of storage. After freezing and HPP (350 MPa, 10 min, 10 °C), the pH value of minced meat increased (p > 0.05) and its TBA value decreased (p < 0.05). The increase in pH may be due to increased ionization during HPP. Some meat peptides, which are considered antioxidant compounds, increased the oxidative stability of meat, so a decrease in TBA may have been observed after freezing and HPP. While the color change in unpressurized samples was a maximum of 3.28 units during storage, in the pressurized sample, it exceeded the limit of 10 units on the first day of storage and exceeded the limit of 10 units on the third day of storage in the frozen and pressurized sample. Freezing and HPP caused the color of beef mince to be retained longer. The hardness, gumminess, chewability, adherence, elasticity, flexibility values of the pressurized and pressurized after freezing samples were higher than those of the unpressurized samples during storage. On the other hand, the opposite was the case for the adhesiveness values. In industrial applications, meat must be pressurized after being vacuum packed. If HPP is applied to frozen beef mince, some of its properties such as TBA, color, and texture can be preserved for a longer period of time without extreme change.     

Use of a Hydrophobic Azo Dye for the Centrifuge-Less Cloud Point Extraction–Spectrophotometric Determination of Cobalt

The hydrophobic azo dye 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR, H₂L) was studied as part of a system for the centrifuge-less cloud point extraction (CL-CPE) and spectrophotometric determination of traces of cobalt. The extracted 1:2 (Co:HTAR) complex, [Co^III(HL⁻)(L²⁻)]⁰, shows an absorption maximum at 553 nm and contains HTAR in two different acid–base forms. Optimum conditions for its formation and CL-CPE were found as follows: 1 × 10⁻⁵ mol L⁻¹ of HTAR, 1.64% of Triton X-114, pH of 7.8, incubation time of 20 min at ca. 50 °C, and cooling time of 30 min at ca. −20 °C. The linear range, limit of detection, and apparent molar absorptivity coefficient were 5.4–189 ng mL⁻¹, 1.64 ng mL⁻¹, and 2.63 × 10⁵ L mol⁻¹ cm⁻¹, respectively. The developed procedure does not use any organic solvents and can be described as simple, cheap, sensitive, convenient, and environmentally friendly. It was successfully applied to the analysis of artificial mixtures and real samples, such as steel, dental alloy, rainwater, ampoules of vitamin B₁₂, and saline solution for intravenous infusion.     

Pharmacological evaluation of benzimidazole derivatives with potential antiviral and antitumor activity

In recent years the synthesis of benzimidazole and its derivatives has attracted the attention of many organic chemists because of the compounds’ interesting biological activity and the crucial importance of the benzimidazole unit in the function of these biologically important molecules. Benzimidazole-based polyheterocyclic compounds have several interesting biological properties. Simple synthetic strategies leading to benzimidazole-based fused polyheterocyclic systems and the antiviral and anticancer biological activity of the compounds are surveyed in this review article.     

Sampling theory for Sturm–Liouville problem with boundary and transmission conditions containing an eigenparameter

In this paper, we derive the sampling theorem associated with a Sturm–Liouville problem which has two points of discontinuity and contains an eigenparameter in a boundary condition and also two transmission conditions. We establish briefly spectral properties of the problem, and then, we prove the sampling theorem associated with the problem.