Current Topics on Chemistry and Biochemistry Vol. 1

The study of coordination chemistry of these amino acids with metals can provide under- standing the coordination chemistry for the protein at large. Many proteins within the body need metal ions and they are activated or deactivated by metal ions. Eight chromium(II) complexes of type, [Cr(L)(H2O)x]·xH2O (where L= Schiff base ligand) have been synthesized and characterized on the basis of elemental analysis IR, ¹H, ¹³C NMR, mass and electronic spectroscopy, magnetic and conductance measurements. The amino acid Schiff base ligand behaved as a octa dentate ligand. The probable structures of the chromium(II) complexes have been determined, as well as the antibacterial activity of the chromium(II) complexes, which demonstrated moderate to good activity against Gram-positive and Gram-negative bacteria. Chromium (II) complexes with amino Schiff base ligands were prepared and octahedral structures have been assigned to these complexes by analyzing elemental and spectral data.

This study has aimed at using the nature of adsorptive processes that occur during bleaching of vegetable oils using clays to characterize the bleaching of oils. The available data have shown that acid-leached clays had sites for adsorption of impurities in oils. Data obtained on residual impurities in cotton and sunflower-seed oils bleached with the same clay materials produced linear Langmuir and Freundlich isotherms. The increase in constant, k with increase in both temperature of thermal activation and concentration of acid used to leach the clay, suggests that bleaching efficiency increased. The value of n decreased with increase in temperature of activation and concentration of acid used to leach the clay suggesting that bleaching capacity increased. The mineral compositions of the clays influenced their surface, structural and bleaching properties.

Folk experiences suggest natural products in Tetradium ruticarpum can be effective inhibitors towards diabetes-related enzymes. This study evaluated the inhibition effects on protein tyrosine phosphatase 1B (PTP1B) and \(\alpha\)-glucosidase (3W37) of isolated compounds from T. ruticarpum as well as using density functional theory and molecular docking techniques as computational methods to predict the stability of the ligands and simulate the interaction between the studied inhibitory agents and the targeted proteins. The results showed that two natural products: schinifoline (1) and intergrifoliodiol (2) were isolated from the buds of T. ruticarpum. These compounds (1 and 2) possess high potentiality for the inhibition of PTP1B (IC₅₀ values of 24.3 ± 0.8, and 47.7 ± 1.1 \(\mu\)M) and \(\alpha\)-glucosidase (IC₅₀ values of 92.1 ± 0.8, and 167.4 ± 0.4 \(\mu\)M) in vitro. Docking score (DS) values and the number of interactions obtained from docking simulation highly correlate with the experimental results yielded. Furthermore, detailed investigations of the structure-activity relationship reveal that the amino acids Arg254 and Arg676 play a substantial role in the overall conformational distortion of PTP1B and 3W37 structures, resulting in the loss of enzymatic activity reported in assay-based experiments. This research calls for more research, either to produce better diabetic treatments or to confirm the role of the amino acids Arg254 and Arg676.

Chitosan (CS), an amino polysaccharide, is a rigid polymer due to the availability of two types of reactive primary and secondary hydroxyl groups (-OH). It is also biodegradable, biocompatible, non-toxic, safe, and antibacterial polymer which makes it applicable in food industry and biomedical applications. Therefore, development of biodegradable films based on poly (vinyl alcohol) (PVA) and chitosan (CS) for possible use in food packaging and biomedical applications are reported. The objective of this study is to develop low cost biodegradable PVA/CS film by solution casting method using glutaraldehyde as a cross linking agent. The intermolecular interactions between constituents of polymer blends and mechanical properties were studied using Fourier transform infrared spectroscopy (FTIR) and microhardness techniques, respectively. Composting was used to investigate the degradation features of PVA/CS films. The absorption bands in the FTIR spectra of PVA and PVA/CS blends varied, indicating interactions between the blend's components. The marten hardness (HM) value changed from an initial value of 83.08 MPa in the pure PVA to a value of 142.18 MPa (highest value) in 40% wt. of chitosan content. Chitosan increased the mechanical stiffness of PVA/CS blends up to 40% loading, and the ideal composition for greatest enhancement of mechanical characteristics of the blend was discovered. This is because of blending leads to an intermolecular interaction between two polymers and improves mechanical strength of the blends. The rate of degradation of blends was observed to rise as the chitosan level increased.

Phthalate esters, mainly di-ethylhexylphthalate (DEHP), represent a class of chemicals primarily used as plasticizers for polyvinyl chloride in a wide range of domestic and industrial applications.  These phthalate esters are low toxicity environmental contaminants.  To address these drawbacks, POLYSORB® ID 37, a blend of diesters obtained from esterification of isosorbide with plant-based fatty acids, was developed.  This article will describe the toxicological and biodegradability studies carried out to determine both the human and environmental risk assessments. Overall, all of the toxicological and biodegradability studies demonstrated that POLYSORB® ID 37 is non-toxic to mammalian life and is readily biodegradable.

Legumes have been shown to have strong nutraceutical potentials, and this made them the strong source of nutrients that protect the human health. Protection of the heart from malfunctioning is a sure way of averting the incidence of cardiovascular diseases (CVDs), which have been one of the major causes of death in middle and high income countries.  Out  of  the  17  million  premature  deaths  (under  the  age  of  70)  due  to  non-communicable diseases in 2015, 82% are in middle and high income countries, and 37% are caused by CVDs.  The most preventive measure for cardiovascular disease is primary prevention of risk factors. Most cardiovascular diseases can be prevented by addressing behavioural risk factors such as tobacco use, unhealthy diet and obesity, physical inactivity and harmful use of  alcohol  using  population-wide  strategies.    People  with  cardiovascular  diseases  or  who  are  at  high cardiovascular  risk  (due  to  the  presence  of  one  or  more  risk  factors  such  as  hypertension,  diabetes,  hyperlipidaemia  or already  established  disease)  need  early  detection  and  management  using  counselling  and  medicines,  as  appropriate. Sphenostylis  stenocarpa  (Hochst.  ex.  A.  Rich)  Harms  is  an  orphan  legume  crop  which  its  oil and milk  when  administered  to hypertensive albino rats,  significantly (p< 0.05) lowered the atherogenic index of plasma (AIP), which is a strong marker for  predicting  the  risk  of  cardiovascular  disease.  Hypertension  was  induced  in  rats  using  saturated  NaCl  solution.  The rats were treated with the extracted oil and milk at different concentrations. It was observed that Sphenostylis stenocarpa seed has low glycaemic index and that at varying concentrations and time significantly (p < 0.05) lowered the AIP.

Non-linear mathematical models were created for the empirically reported dependences of the conductivity of mouse reproductive and embryonic cells on the strength of the pulsed electric field applied, based on approximation by algebraic and transcendental functions. The usage of the least squares method was used to approximate experimental data. Approximating functions' extrema, inflections, intersections, and curvature were all found. The traditional mathematical analysis methods were utilised to determine these characteristic points. The well-known analytical geometry methods and algebraic methods for solving equations were employed for this.  The 1st and 2nd derivatives of non-linear functions were also computed in order to derive the coordinates of junction locations and curvature. During the linear rise of electric field strength applied to a cell, a relationship has been established between the estimated coordinates of characteristic spots and the modes of membrane electroporation. The intensity of a pulsed electric field may be calculated using the mathematical models of experimental conductometric curves, which is essential and enough for the application of any electro-manipulation technologies based on the phenomena of electroporation.

Green synthesis is a trending one followed by Researchers. Instead of using chemicals as reducing agent we are using plant extract as reducing agent.  Zinc oxide nanoparticles were effectively produced with zinc nitrate as a precursor and Illicium verum extract as a reducing and stabilising agent.  The polyphenols and flavonoids present in Star anise were used as the reducing and stabilizing agents. FT-IR, UV-visible, SEM, and XRD methods were used to analyse synthesised Zinc oxide nanoparticles. UV-visible and FT-IR spectroscopy methods verified that the produced nanoparticles were zinc oxide nanoparticles. The structure and size of the generated nano-sized particles were determined using XRD data. The size was calculated to be 27.01 nm based on XRD measurements. Zinc oxide nanoparticles have a spherical and flake-like form and morphology, according to SEM examination.

Theoretical and experimental data concerning the versatile approaches for the synthesis of N-acylphenothiazines were systematized in this review. The aim of this research was to compile the literature reported worldwide in the past 20 years. The pharmacological effects of these heterocycles as one of the promising chemotherapeutic goals for modern bioorganic and medicinal chemistry were also reviewed in this article. The radical character of the acyl moiety is thought to be responsible for these moieties' immense biological potential. As a result, the current study will make a valuable contribution to the literature and will serve as a springboard for medicinal chemistry experts to conduct additional research focusing on N-acylphenothiazine moieties as potential chemotherapeutic drugs.

The present work aims to investigate the complex formation process between the pure samples of FA, isolated from natural waters   and Pb and to calculate the average stability constant of lead fulvate complex.   

Complex formation process between Pb (II) and fulvic acids was studied by the solubility method at pH=8.0. The suspension of Pb(OH)₂ was used as a solid phase. Fulvic acids were isolated from Paravani lake by the adsorption–chromatographic method. During the calculation of molar concentrations of fulvic acids, was taking into consideration the value of average molecular weight   of fulvic acids at pH=8 (Mw=6260).

It was established, that in the Pb(OH)2(solid) —Pb(II)(solution) —FA—H2O system at pH=8.0,dominates the lead dihydroxy fulvate complex with the structure 1:1,which average stability constant \(\beta\)(Pb(OH)2FA) = 9,63x106  , lg \(\beta\)=6,98.

We describe an automated luminescence sensor for measuring the insecticide thiacloprid, one of the most common neonicotinoids, in lettuce samples in this paper. The use of luminescence sensors has increased in the last decade, minimizing reagents consumption and increasing the degree of automation. To handle all solutions, a simple and automated manifold was built employing multicommutated solenoid valves. The analyte was on-line irradiated with UV light to produce a highly fluorescent photoproduct (\(\lambda\)_exc/\(\lambda\)_em = 305/370 nm/nm) that was then retained on a solid support placed in the flow-cell. A method detection limit of 0.24 mg kg^-1 was achieved in real samples, fulfilling the Maximum Residue Limit (MRL) of The European Union for thiacloprid in lettuce (1 mg kg^-1). It was possible to acquire a sample throughput of 8 samples per hour. Recovery studies were conducted at levels near to the MRL, yielding recovery yields of close to 100% and relative standard deviations of less than 5%. As a result, as an alternative to other existing approaches, this method might be used for routine quality control analyses.

To prevent residual chemicals in seafoods, it is important to strengthen the residue monitoring in these foods, and for that purpose, an accurate and efficient quantification method for each target chemical substance is required.  In the present chapter, an inexpensive, simple, rapid, and microscale technique of sample preparation followed by high-performance liquid chromatography (HPLC) coupled photodiode array (PDA) detector for simultaneous quantification of malachite green (MG) and its metabolite, leucomalachite green (LMG), in cultured eel is described.  The HPLC-PDA was carried out with an isocratic mobile phase on a C4 column. A handheld ultrasonic homogenizer was used to remove analytes from the sample, which were then purified using MonoSpin® C18 centrifugal monolithic SPE spin mini-columns. The recommended strategy has been proven to work by the analyses of spiked eel samples, resulting recoveries > 95% with relative standard deviations < 2% and total analytical time < 15 min/sample (24 samples < 4 hours).