Gold nanoparticles (AuNPs) are promising for biomedical applications, but their synthesis often requires toxic reagents. “Green” methods utilizing biopolymers offer a sustainable alternative. This study presents a novel synthesis of stable gold nanoparticles using a disulfide-crosslinked derivative of alginic acid (AA–S–S–AA) as both a reducing agent and stabilizer. The S–S-cross-linked alginate was synthesized with a degree of substitution of ~4.2% and reacted with HAuCl4 in water at room temperature for just 10 min to give stable and polysaccharide in situ modified gold nanoparticles (AA-AuNPs). The resulting AA-AuNPs were characterized by a surface plasmon resonance peak at 539 nm and exhibited good colloidal stability over 14 days. Electron microscopy revealed spherical nanoparticles with a bimodal size distribution (10 nm and 75–100 nm) and a visible polysaccharide shell (5–9 nm), confirming effective stabilization. X-ray photoelectron spectroscopy confirmed the presence of metallic gold (Au0) and Au1+. NMR analysis indicated the oxidation of disulfide groups to sulfonic acid during synthesis. The nanoparticles demonstrated a high negative zeta-potential of −53.9 mV, attributable to the polyanionic alginate corona, ensuring strong electrostatic stabilization. This work establishes sulfur-modified alginic acid as an efficient platform for the rapid synthesis of stable, hybrid nanoparticles for potential use in catalysis and biomedicine.

Phytoecdysteroid 20-hydroxyecdysone (20E, 1) has been isolated from the plant Serratula coronata L. (Asteraceae). Acetonide (2) and short-chain (3) derivatives of 20E, along with lithocholic acid and cholesterol, were used as starting materials for the synthesis of their triphenylphosphonium salts (TPP+). These compounds were screened for cytotoxicity and selectivity against several human non-small cell lung (NSCLC) cancer cell lines and non-cancerous (mesenchymal stem cell (MSCs)) lines using the MTT assay. The results demonstrated that the parent compounds - (ecdysteroids (1-3), lithocholic acid (8), and cholesterol (9) - were non-toxic to all tested cell lines. In contrast, all synthesised derivatives, particularly TPP+ salt of lithocholic acid (12), exhibited preferential cytotoxicity against NSCLC cell lines at micromolar concentrations (IC50 1-1.7 µM). The AnnexinV/7-AAD flow cytometry assay confirmed the selective cytotoxicity of all TPP+ derivatives towards NSCLC cells, with minimal effects on non-cancerous MSCs.

Chiral ansa-η5-complexes of transition metals have shown remarkable efficacy in organometallic synthesis and catalysis. Additionally, enantiomerically pure ansa-complexes hold promise for the development of novel chiral materials and pharmaceuticals. The discovery and synthesis of a diverse range of group IVB and IIIB metal complexes represents a significant milestone in the advancement of stereoselective catalytic methods for constructing metal-C, C-C, C-H, and C-heteroatom bonds. The synthesis of enantiomerically pure metallocenes can be accomplished through several strategies: utilizing optically active precursors of η5-ligands, separation of diastereomers of complexes with enantiomerically pure agents, and synthesis via the stereocontrolled reactions of enantiomerically pure σ-complexes with prochiral anions of η5-ligands. This review focuses on the analysis of various nuances of the synthesis of enantiomerically pure ansa-η5-complexes of titanium and lanthanum families. Their applicability as effective catalysts in asymmetric carbomagnesiation, carbo- and cycloalumination, oligo- and polymerization, Diels–Alder cycloaddition, reactions of zirconaaziridines, cyclization, hydrosilylation, hydrogenation, hydroamination, and other processes are highlighted as well.

Objectives: Skeletal muscle ischemia/reperfusion injury (IRI) occurs as a result of a marked reduction in arterial perfusion to a limb and can lead to tissue death and threaten limb viability. This work assessed the effects of 20-hydroxyecdysone (20E) on hindlimb skeletal tissue following tourniquet-induced ischemia/reperfusion injury. Methods: Animals were divided into 4 groups-control group (Control), Control + 20E (C + 20E), mice with IRI (IRI), and mice with IRI + 20E (IRI + 20E). IRI was modeled by applying a tourniquet to the hind limb for 2 h with reperfusion for 1 h. 5 mg/kg of 20E was administered intraperitoneally for 14 days. Afterward, the physical activity of mice, the histological structure of the quadriceps femoris, the expression of genes encoding proteins induced by hypoxia and involved in tissue adaptation to ischemia, and the functional parameters of skeletal muscle mitochondria were assessed. Results: It was shown that IRI of the limbs leads to functional disorders, depression of muscle function, accumulation of malondialdehyde (MDA) in mitochondria, and a decrease in their Ca2+ buffering capacity, as well as an increase in the expression of HIF-1 alpha, VGEF-A, PGC1 alpha and PDGF-BB genes associated with adaptation to ischemia. 20E reduced the intensity of degenerative processes in skeletal muscles, which was expressed in a decrease in the number of centrally nucleated fibers. Analysis of gene expression levels indicated a high degree of adaptation of animals to IRI. 20E reduced the level of MDA in mitochondria, but did not affect the rate of respiration and calcium retention capacity of organelles both in normal conditions and during IRI. Conclusion: 20E partially alleviates the skeletal muscle damage caused by IRI and can be used as part of combination therapy.

Alternative approaches were developed to introduce deuterium atoms into the steroid backbone and the side chain of a short-chain derivative of the phytoecdysteroid 20-hydroxyecdysone, poststerone acetonide, using LiAlD4 and D2O as deuterating agents.

The reaction of HAuCl4.nH2O with organoaluminum compounds (HAlBui2 or AlR3, R = Me, Et, Bui) in organic solvents, followed by hydrolysis in the presence of a tertiary thiol (5-methylundecane-5-thiol), afforded gold nanoparticles (AuNPs). Particle sizes and size distributions depended largely on the structure of the original organoaluminum reagent and the nature of the solvent. The smallest particle sizes ranging from 2 to 20 nm were observed when reducing HAuCl4 with HAlBui2. Nanoparticles have been characterized by the means of scanning transmission electron microscopy, photon cross-correlation spectroscopy, X-ray photoelectron spectroscopy, and UV–Vis spectroscopy. The proposed method may be further utilized for the deposition of metal nanoparticles onto solid supports for applications in catalysis and other fields.

Gold nanoparticles (AuNPs) are of significant interest due to their unique properties and applications in biomedicine. While hyaluronic acid (HA) has been used to modify pre-formed AuNPs, its thiolated derivative (HA−SH) has been less explored for the direct synthesis and stabilization of AuNPs. This study investigates the use of thiolated hyaluronic acid as a key component in the synthesis of AuNPs. A series of HA-AuNPs (HA-AuNP1-4) were synthesized by reacting HA-SH with HAuCl4 at different mass ratios. The resulting nanoparticles were characterized using UV-Vis spectroscopy, scanning/transmission electron microscopy (SEM/STEM), X-ray photoelectron spectroscopy (XPS), photon cross-correlation spectroscopy (PCCS), and zeta potential measurements. The chemical transformations of the thiol ligand were studied using NMR spectroscopy. The morphologies and sizes of AuNPs depended on the HA-SH-to-HAuCl4 ratio, ranging from icosahedral and triangular particles (≥146 nm) to quasi-spherical particles with a bimodal distribution (6–7 nm and 45–60 nm). XPS confirmed the presence of metallic gold (Au0) and a Au−S bond, while NMR and XPS revealed the partial oxidation of thiol groups to sulfonic acid. Zeta potential measurements showed that lower HAuCl4 concentrations resulted in higher negative charge (up to −41.5 mV), enhancing colloidal stability. This work demonstrates a versatile approach to the synthesis of hyaluronic acid-based gold nanomaterials with tunable properties for potential biomedical applications.

New nitrogen-containing fusidic acid analogues, namely bis-amidoxime, bis-tetrazole, and 1,2,4-oxadiazoles, were synthesized via chemical transformations of 3,11-bis-O-(2-cyanoethyl)fusidic acid methyl ester.

Dimers and oligomers of alkenes represent a category of compounds that are in great demand in diverse industrial sectors. Among the developing synthetic methods, the catalysis of alkene dimerization and oligomerization using transition metal salts and complexes is of undoubted interest for practical applications. This approach demonstrates substantial potential, offering not only elevated reaction rates but also precise control over the chemo-, regio-, and stereoselectivity of the reactions. In this review, we discuss the data on catalytic systems for alkene dimerization and oligomerization. Our focus lies in the analysis of how the activity and chemoselectivity of these catalytic systems are influenced by various factors, such as the nature of the transition metal, the ligand environment, the activator, and the substrate structure. Notably, this review particularly discusses reaction mechanisms, encompassing metal complex activation, structural and dynamic features, and the reactivity of hydride intermediates, which serve as potential catalytically active centers in alkene dimerization and oligomerization.

In this work we have studied the effect of the phytoecdysteroid 20-hydroxyecdysone (20E) on the functioning of mouse skeletal muscle mitochondria. It is shown that 20E at a concentration of 100 µM or more suppresses mitochondrial respiration fueled by glutamate and malate (substrates of complex I of the respiratory chain) or succinate (substrate of complex II of the respiratory chain). This effect of 20E is accompanied by a decrease in the mitochondrial membrane potential and is associated with inhibition of the activity of complex III, the total activity of complexes I + III and II + III of the mitochondrial respiratory chain. We have noted a prooxidant effect of 20E, which manifests itself in an increase in the production of hydrogen peroxide by skeletal muscle mitochondria. In addition, 20E reduces the ability of mitochondria to accumulate calcium ions in the matrix. We discuss the mechanisms of the possible toxic effect of 20E on the functioning of skeletal muscle mitochondria.

The general trend of increasing life expectancy will consistently drive the demand for orthopedic prostheses. In addition to the elderly, the younger population is also in urgent need of orthopedic devices, as bone fractures are a relatively common injury type; it is important to treat the patient quickly, painlessly, and eliminate further health complications. In the field of traumatology and orthopedics, metals and their alloys are currently the most commonly used materials. In this context, numerous scientists are engaged in the search for new implant materials and coatings. Among the various coating techniques, plasma electrolytic oxidation (PEO) (or micro-arc oxidation—MAO) occupy a distinct position. This method offers a cost-effective and environmentally friendly approach to modification of metal surfaces. PEO can effectively form porous, corrosion-resistant, and bioactive coatings on light alloys. The porous oxide surface structure welcomes organic molecules that can significantly enhance the corrosion resistance of the implant and improve the biological response of the body. The review considers the most crucial aspects of new combined PEO-organic coatings on metal implants, in terms of their potential for implantation, corrosion resistance, and biological activity in vitro and in vivo.

In continuation of our studies on modification of fusidane triterpenoids, the alkynyl moieties were introduced into fusidic acid to synthesize new compounds promising as antimicrobial and antitumor agents. Transformations of the triple bond via the CuI-catalyzed reactions afforded new 1,2,3-triazoles as well as mono- and diacetylenic derivatives.

Camphor and carvone exhibit a broad spectrum of biological activity, which determines the prospect of their use as a platform for functionalization to obtain the analogues as potential drugs. The functionalization of camphor and carvone often involves changes to the skeleton of the molecules or their fragmentation. Therefore, in modern medicinal chemistry, research aimed at the development of effective approaches to the synthesis of semi-synthetic derivatives of camphor and carvone with preservation of the native framework, demonstrating high biological activity, is in demand. The present work is aimed at the synthesis of new propynyl analogues of camphor and carvone, as well as their conjugates with mono- and disaccharides via Cu-catalyzed cycloaddition of acetylenes and azides (CuAAC). Alkylation of camphor and carvone with propargyl bromide in the presence of the base KN(SiMe3)2–Et3B in 1,2-dimethoxyethane (DME) at room temperature provides the target products with yields of 69% and 47%, respectively. Glycosyl azides were obtained by the reaction of peracetylated sugars with trimethylsilyl azide in the presence of SnCl4.The synthesis of 1,2,3-triazolyl glycoconjugates of camphor and carvone with mono- and disaccharides was carried out through Cu(I)-catalyzed 1,3-dipolar cycloaddition of azides to acetylenes (CuAAC) in the presence of Cu and CuSO4·5H2O. The structures of the synthesized compounds were determined by NMR. The new propynyl-substituted camphor and carvone, as well as their 1,2,3-triazolylglycoconjugates, can be used as promising building blocks for medicine chemistry.

A conjugate of hyaluronic acid and antimicrobial peptide LL-37 was synthesized for the first time. The hybrid compound was tested as an antimicrobial organic coating for titanium samples with an inorganic sublayer obtained by plasma electrolytic oxidation (PEO) of the surface. As a result of in vitro studies, the antibacterial effect of the hybrid molecule within the inorganic PEO coating was established, which consists of a significant (p 0.05) suppression of the ability of Staphylococcus aureus, Pseudomonas aeruginosa, Enterococcus faecium and Escherichia coli to form biofilms. The presented approach can be utilized for the subsequent design and development of non-fouling antimicrobial coatings to decrease the risk of infectious diseases caused by bacteria when using implants.

Enantiomerically enriched (38–93% ee) diastereomerically pure (99% dr) functionally substituted dimers and oligomers with the starting Me-group were obtained by the reaction of 1-hexene with AlMe3 in the presence of enantiomerically pure dichloro[(R,R)-ethylenebis(4,5,6,7-tetrahydroinden-1-yl)]- zirconium(iv). Modified methylaluminoxane MMAO-12 as the activator was somewhat superior to boron-containing compound [Ph3C][B(C6F5)4].

Using optically active (R)-3-cyclohexenecarboxylic acid as a template in the reaction with (AlMe3)2, the stable adduct Me2Al(µ-O-CMe2C6H9)(µ-Me)AlMe2 and methylaluminoxane (MAO) were synthesized. It is demonstrated that the activity of obtained MAO in the reaction of 1-hexene di- and oligomerization, catalyzed with zirconocenes (Cp2ZrCl2, Ind2ZrCl2, raс-EB[THI]ZrCl2), is comparable with commercial MMAO-12. The use of chiral templated MAO in a catalytic system provides a significant change in the stereoselectivity of the reaction. Therefore, the stereoselectivity of the oligomerization process can be influenced by the activator structure, underscoring the importance of taking into account the activator counterion during the alkene insertion into the catalytically active sites.

C30-quaternized derivatives of lupane triterpenoids (31 examples) were synthesized with a yield of 85–95% via a one-pot functionalization of a double bond under the action of organic tribromides and pyridines.

Mannich bases (8 examples) were synthesized via aminomethylation of fusidane propargyl esters. In vitro antimicrobial screening against key ESKAPE pathogens showed that the fusidic acid based Mannich products exhibit a high antimicrobial effect against Gram-positive bacteria Staphylococcus aureus and the fungus Cryptococcus neoformans. Moreover, the cytotoxic effect of fusidic acid and its analogs, which showed high antibacterial activity, was determined by MTT assay on cancer HepG2, HCT-116, SH-SY5Y, MCF-7, A549 and conditionally normal cells HEK293. A remarkable cytotoxic activity of fusidic acid propargyl ester and its aminomethylene derivatives against cancer and nontumoral HEK293 cells with IC50 values within 4.2-25 µM was found.

Despite large-scale investigations of homogeneous single-site metallocene catalysts and systems based on them, there are still unsolved problems related to the control of their activity and chemo- and stereoselectivity. A solution to these problems is required to develop efficient methods for the synthesis of practically useful products of alkene transformations, such as dimers, oligomers, and polymers. Here we studied the catalytic activity of structurally diverse zirconocenes (L2ZrCl2, L = Cp, C5Me5, Ind, L2 = Me2CCp2, Me2SiCp2, Me2C2Cp2, rac-Me2CInd2, rac-H4C2Ind2, BIPh(Ind)2, H4C2[THInd]2), and co-catalysts activating the system, namely HAlBui2, MMAO-12, and (Ph3C)[B(C6F5)4], at low activator/Zr ratios in a 1-hexene oligomerization reaction. The influence of catalyst structure and system composition on the alkene conversion, the type of products, and the reaction stereoselectivity were investigated. The composition of hydride intermediates formed in the L2ZrCl2–HAlBui2–activator system (L2 = ansa-Me2CCp2, Ind) was studied by NMR spectroscopy. Participation of the bis-zirconium hydride complex as the precursor of catalytically active sites of the alkene dimerization reaction was shown.

Fusidic acid (FA) is an antibiotic with high activity against Staphylococcus aureus; it has been used in clinical practice since the 1960s. However, the narrow antimicrobial spectrum of FA limits its application in the treatment of bacterial infections. In this regard, this work aims both at the study of the antimicrobial effect of a number of FA amines and at the identification of their potential biological targets. In this way, FA analogues containing aliphatic and aromatic amino groups and biogenic polyamine, spermine and spermidine, moieties at the C-3 atom, were synthesized (20 examples). Pyrazinecarboxamide-substituted analogues exhibit a high antibacterial activity against S. aureus (MRSA) with MIC ≤ 0.25 μg/mL. Spermine and spermidine derivatives, along with activity against S. aureus, also inhibit the growth and reproduction of Gram-negative bacteria Escherichia coli, Acinetobacter baumannii, and Pseudomonas aeruginosa, and have a high fungicidal effect against Candida albicans and Cryptococcus neoformans. The study of the membrane activity demonstrated that the spermidine- and spermine-containing compounds are able to immerse into membranes and disorder the lipidsleading to a detergent effect. Moreover, spermine-based compounds are also able to form ion-permeable pores in the lipid bilayers mimicking the bacterial membranes. Using molecular docking, inhibition of the protein synthesis elongation factor EF-G was proposed, and polyamine substituents were shown to make the greatest contribution to the stability of the complexes of fusidic acid derivatives with biological targets. This suggests that the antibacterial effect of the obtained compounds may be associated with both membrane activity and inhibition of the elongation factor EF-G.