Current Topics on Chemistry and Biochemistry Vol. 3

Recent advances in design, sensing and binding abilities of porphyrin-based heterotopic receptors with well-defined geometries towards anions, ion pairs and neutral molecules of various natures are analyzed, summarized and classified. Synthetic approaches to the tetrapyrrolic macrocycles and methods of their functionalization are presented. General principles, mechanisms and driving forces of the formation of porphyrin-based supramolecular complexes are discussed. Most attention is on the development of effective systems for controlled recognition, selective delivery, and prolonged release of substrates of different natures to their sites of functioning.

The green synthesis of nanoparticles has gained wide attention in recent years due to their eco-friendly nature and cost-effectiveness. These nanoparticles are reported to exhibit various therapeutic functions with promising results. Though there are various biomaterials available for green synthesis, plants and plant products have proven as reliable sources for green synthesis with more cost-effectiveness and stability. As medicinal plants are well established for their potential therapeutic applications, the synthesis of nanoparticles using medicinal plants further enhances their properties. This chapter details various types of nanoparticles synthesized from different plant sources through green synthesis, emphasizing their therapeutic functions.

Methyl ethyl sulfides are used in organic synthesis and scientific research. Significant amount of ethyl methyl sulfide is emitted to the atmosphere due to biological activity in the sea, and the concentration of ethyl methyl sulfide is result of anthropogenic and human activity. Methyl ethyl sulfides has a negative effect on the atmosphere as it produces sulfuric oxides in the environment. The study of methyl ethyl sulfide oxidation products is of value to know the fate of its oxidation products in the atmosphere. The objective of this work is to find the products of oxidation of methyl ethyl sulfide under standard conditions and at different temperature using thermodynamic data. For all conceivable reaction paths of oxidation of radicals of methyl ethyl sulfide radicals, entropy and Gibb's free energy change were computed. The enthalpy change for the chemical pathways was computed as well, and the results were compared to those obtained using the CBS-QB3 DFT approach.  It has been found that the energetically favorable stable products formed from oxidation of ethyl methyl sulfide at standard conditions, 298 K and 1 atm pressure are acetaldehyde (CH₃CH=O), thioformaldehyde (CH₂=S),  thio-acetaldehyde (CH₃CH=S), and formaldehyde (CH₂=O).

The present review discusses recent findings that describe the activation of peroxisome proliferator-activated receptors (PPARs) by mycobacterial infections and their role in determining the fate of bacilli by inducing lipid metabolism, anti-inflammatory function, and autophagy. The PPAR-\(\gamma\) activation was mediated by the Middle East respiratory syndrome coronavirus (MERS-CoV)-derived S glycoprotein along with concurrent inhibition of macrophage responses and the suppression of proinflammatory cytokines. The cell wall of mycobacteria is made up of a lot of lipids with different molecular weights. To construct the cellular milieu necessary for their intracellular survival, some mycobacteria species hijack host cells and stimulate lipid droplet production. As a result, lipids are assumed to be critical for mycobacteria survival, invasion, parasitization, and multiplication within host cells. However, their physiological roles have not been fully elucidated. Mycobacteria modulate PPAR signaling and utilize host-derived triacyl-glycerol (TAG) and cholesterol as nutrient sources and for evasion of the host immune system. PPARs are important to the host-dependent mechanism of lipid metabolism and accumulation during mycobacterial infection.

The present study report a simple, one-pot procedure for the preparation of oxazolinyl-zinc complexes by the atom-efficient assembly of three reactive components: a nitrile, an amino alcohol and a zinc salt. Typically, oxazolinyl metal complexes are synthesized in two steps, where the free ligand is prepared by the condensation reaction between a functionalized nitrile and an amino alcohol in the presence of a Lewis or Brønsted acid catalyst, followed by a further reaction with metal salts to obtain the corresponding metal complexes. The yield of the two-step process is frequently low, and just a few oxazolinyl zinc complexes have been synthesised this way. It's possible that the two stages could be combined because metal-oxazoline complexes frequently comprise Lewis acidic metals.

A series of novel chiral organozinc complexes 1–15 were assembled in a single step, All crystalline compounds were fully characterized, including the report of 15 X-ray crystal structures, including a wide structural diversity.

A series of novel chiral organozinc complexes were assembled in a single step, from nitriles, chiral D/L amino alcohols, and a stoichiometric amount of ZnCl₂, with moderate to high yields (20–90%). The existence of additional donor atoms, reaction stoichiometry, and nature of the -substituent at the stereogenic centre all influence the reaction outcome, resulting in a range of coordination modes, including mono- and bis-chelate complexes. The use of too much zinc salt resulted in multinuclear complexes forming.

Apart from human red blood cells (RBCs), which are a common model in single cell force spectroscopy (SCFS), little is known about the parameters apparent Young's modulus (Ea) or adhesion of animal RBCs with distinct cellular characteristics. To fill this knowledge gap, we examined RBCs from chicken, horses, camels, and human fetuses, comparing the results to data from human adults. The found species-specific values can serve as a repository for further research. The first study objective was to investigate the biomechanical characteristics of certain animal RBCs used as representative models for distinct phenotypical features within one comparative approach. The second study objective was to obtain these properties under largely physiological conditions (at body temperature in autologous plasma) and to compare the outcomes with values obtained at simplified conditions (at 25°C in aqueous NaCl solution). We were interested in whether the trend by which biomechanical properties change is similar for all of our investigated RBC phenotypes or if distinct, species-specific conclusions have to be drawn. Results: Regardless of the suspension medium, Ea decreased with increasing temperature in all RBC types. Adhesion increased with higher temperatures in mammalian RBCs and scaled with reported membrane sialic acid contents. Adhesion decreased with increasing temperature only in chicken, which we attribute to a lower AE-1 concentration allowing for larger membrane undulations. At each test temperature, Ea was lower in plasma, and adhesion was completely eliminated, indicating functional cell enlargement via plasma component adsorption on the RBC surface. This elastic (solid-like) surface layer not only increased RBC size by hundreds of nanometers, but it also influenced RBC interaction with the flowing plasma. The importance of the surface layer for horse RBCs is discussed. We also found that the shear-thinning propensity of bulk blood samples in shear flow is more influenced by the shape, than by the Ea of RBCs. The study establishes the existence of an RBC surface layer and examines the significant differences between probing RBCs in physiological settings and testing cells in basic buffer.

Quinoline and 1,2,3-triazoles have received a lot of interest recently because of their biological significance. Building a single molecular framework containing quinoline and triazole rings, so-called 1,2,3-triazole-based quinolines through molecular hybridization strategy offers a suitable route to new pharmaceutical agents with potent biological proprieties. The chemistry and biology of several 1,2,3-triazole-containing quinoline hybrids are discussed in this chapter, with the goal of better understanding the physicochemical features of triazole-quinoline hybrids to develop novel bioactive chemical entities. As a result, the main Lipinski parameters, as well as an in-silico analysis, are briefly discussed and applied to a few 1,2,3-triazole-quinoline hybrids. This chapter is divided into two sections: the synthetic elements of the hybrids' manufacture utilizing Cu-catalyzed azide-alkyne cycloaddition technology, and their pharmacological aspects, with a focus on common harmful diseases like malaria, cancer, and human fungal infections.  

Many plant lectins expressed in fruits are known to possess defensive mechanism larvicidal functions. Plants respond to herbivory through various morphological, biochemical, and molecular level mechanisms to resist the effects of herbivore insect attack. The defensive compounds are either produced constitutively or in response to plant damage, and affect feeding, growth, and survival of herbivores. Present studies aimed to compare the lectin protein expression in selected cucurbit fruits to understand the resistance and susceptibility against melon fly infestation. Both susceptible (bitter gourd, snake gourd and cucumber) and resistant (chayote and bottle gourd) fruit latex sap were prepared and lectin proteins were characterized by hemo and leuco agglutination activity. Some are partially purified to identify glycocode as N-acetyl glucosamine and stability was assessed for proteases, pH and temperature. The larval growth was inhibited that are fed at low concentrations and were found dead at high concentration after incubation for about 24 hr. The histopathology indicates the lectin-induced damage to the larval gut region, indicating lectin-induced toxicity. The lectin protein induces toxicity by binding and inducing digestive impairment in larvae growth and causing mortality. The comparative observations indicate that lectin protein expressed from the fruit tissues of chayote and bottle gourd secretes latex and defends the melon fly larval infestation and provides resistance. Present investigation describe for the content of lignin in the tissue of healthy and infected cucurbit fruits which may provide the evidence for their resistance and susceptibility against melon fly infestation. If the monolignol levels or polymerized lignin units are high due to increased level of PPP (Phenylpropanoid Pathway) enzymes, this will harden the cells and make the larvae hard to break cell wall to feed on those tissues.