Various RNAs are among the most promising and actively developed therapeutic agents for the treatment of tumors, infectious diseases and a number of other pathologies associated with the dysfunction of specific genes. Some nanocarriers are used for the effective delivery of RNAs to target cells, including liposomes based on cationic and/or ionizable amphiphiles. Cationic amphiphiles contain a protonated amino group and exist as salts in an aqueous environment. Ionizable amphiphiles are a new generation of cationic lipids that exhibit reduced toxicity and immunogenicity and undergo ionization only in the acidic environment of the cell. In this work we developed a scheme for the preparation and carried out the synthesis of new cationic and ionizable amphiphiles based on natural amino acids (L-glutamic acid, glycine, β-alanine, and γ-aminobutyric acid). Cationic and ionizable liposomes were formed based on the obtained compounds, mixed with natural lipids (phosphatidylcholine and cholesterol), and their physicochemical characteristics (particle size, zeta potential, and storage stability) were determined. Average diameter of particles stable for 5–7 days did not exceed 100 nm. Zeta potential of cationic and ionizable liposomes was about 30 and 1 mV, respectively. The liposomal particles were used to form complexes with RNA molecules. Such RNA complexes were characterized by atomic force microscopy and their applicability for nucleic acid transport was determined.

Recently, due to the growth in bacterial infections resistant to antibiotics, there is an urgent need for developing alternative antibacterial drugs. Alkyl-indolyl-L-lysines are a promising class of compounds; their amphiphilic structure is crucial in antimicrobial efficacy. A scheme is developed and five new derivatives of indolylbutyric and indolylacetic acids containing a polar amino acid residue with an ethylenediamine linker binding alkyl fragments with different lengths are synthesized. The antibacterial activity of the new amphiphiles against gram-positive and gram-negative bacterial strains is evaluated. The minimum binding energy of the synthesized compounds with human serum albumin (HSA) is determined by molecular docking. A lower affinity of the studied objects in comparison with control indolmycin is shown.

Objectives. Cationic amphiphiles and antimicrobial peptidomimetics are widely investigated as antibacterial agents due to their membrane-active mechanism of action. Particular attention is focused on the rational design of compounds in this class to achieve high antimicrobial activity. The aim of the present work is to synthesize bivalent cationic amphiphiles with L-ornithine as a branching element and evaluate the effectiveness of their antibacterial action. The compounds differ in terms of hydrophobicity due to the variation of N-terminal aliphatic amino acids in the polar block and alternation of dialkyl and alkyl-hetaryl radicals in the lipophilic block.Methods. For the synthesis of nonpolar fragments of amphiphiles, methods for the alkylation of amines with alkyl bromides in the presence of carbonate salts were used. The formation of amide bonds of L-ornithine derivatives with amino acids was carried out using the carbodiimide method. For the reaction products recovery from the reaction mixture, column chromatography on silica gel and aluminum oxide activated Brockmann Grade II was used. The antimicrobial activity of the synthesized compounds against gram-positive B. subtilis 534 and gram-negative E. coli M17 bacterial strains was evaluated. Minimum inhibitory concentration (MIC) values were recorded using a serial microdilution method in a nutrient medium.Results. Developed schemes for the preparation of bivalent cationic amphiphiles based on L-ornithine derivatives are presented. Differences in the structure of aliphatic amino acids (glycine, β-alanine, γ-aminobutyric acid (GABA)), in the length of alkyl radicals (C8, C12), or in the presence of an indole moiety, were used in the design of target compounds. The high antibacterial activity of the synthesized compounds was demonstrated. The most active compounds were lipoamino acids with terminal GABA residues and asymmetrical non-polar block (tryptamyl–dodecylamine). The MIC values were 0.39 μg/mL for gram-positive bacteria and 1.56 μg/mL for gram-negative bacteria. A GABA derivative with a symmetrical lipophilic moiety based on dioctylamine demonstrated activity with an MIC of 0.78 μg/mL against B. subtilis and 3.12 μg/mL against E. coli.Conclusions. Nine new lipoamino acid cationic bivalent amphiphiles based on L-ornithine were synthesized. The structure of the obtained compounds was confirmed by nuclear magnetic resonance 1H spectroscopy and mass spectrometry data. Leading compounds in antimicrobial activity against both gram-positive and gram-negative strains of bacteria were determined. The influence of the degree of lipophilicity in the asymmetric nonpolar block on the level of exhibited antimicrobial activity is demonstrated.

The values of the hydrophilic(lipophilic balance (HLB) of various amino-acid derivatives of diethylenetriamine were calculated. Compounds with HLB indices within the range of manifestation of potential antimicrobial activity were selected from the library. Cationic amphiphiles containing fragments of aromatic (L-Phe, L-Trp) and aliphatic amino acids (γ-aminobutyric acid, GABA) were synthesized. The antibacterial activity was preliminarily studied on Gram-positive B. subtilis 534 and Gram-negative E. coli M17 bacteria by the serial microdilution method. The most active compound had an aliphatic GABA amino-acid residue and an elongated diethylenetriamine derivative with a C12 alkyl chain.

The goal of the study was to estimate transfection efficacy and drug release in function of the PEG derivative in cationic liposomes and lipoplexes in both 2D and 3D in vitro models as well as in a mouse model (in vivo). For this purpose, cationic PEGylated nanocarriers based on OrnOrnGlu(C16 H33 )2 lipopeptides were fabricated and characterized. The nanocarriers were loaded with DNA plasmid pGL3 or with siRNA targeting 5'-UTR region of Hepatitis C virus, and their transfection efficacies were studied by luciferase test or by PCR technique, respectively. The pGL3-lipoplexes containing PEG derivative b (6 mol % PEG) were selected as the most promising nanocarriers for further in vivo study. In vitro cytotoxicity assay of the pGL3-lipoplexes with the PEG derivative b showed 2- and 1.5-fold enhancements of IC50 levels for HEK293T and HepG2 cells, respectively. Accumulation of the liposomes in the cells was studied by confocal microscopy using both 2D (monolayer culture) and 3D (multicellular spheroids) in vitro models. The PEGylated liposomes were found to penetrate cells more slowly than unmodified ones (without PEG). Thus, maximum liposomes in the HEK293T cells was observed after 1 and 3 h in the case of 2D and 3D in vitro models, respectively. Biodistribution study in mice showed that the PEGylated lipoplexes containing the PEG derivative b were eliminated from the bloodstream more slowly, namely with the doubled half-life time, than unmodified ones. Thus, the enhanced transfection efficacy and prolonged drug release of the PEGylated lipoplexes containing the optimal PEG derivative was demonstrated. This approach could be promising for development of novel siRNA-based drugs.

Mitochondria are the “power stations” of cells. Without them, the normal functioning of a living cell is impossible. This organelle is an attractive target for antitumor therapy because of the variety of processes in which mitochondria are involved and the differences between mitochondria in healthy and tumor cells. In this review, various approaches to the development of diagnostic and therapeutic agents selectively directed to the mitochondria of tumor cells are described. The main mitochondrial vector ligands are described, as well as their conjugation with known antitumor drugs and combination with common drug delivery systems.

This work is aimed to develop several cationic amphiphiles based on amino acid derivatives of diethanolamine as potentially membrane-active antibacterial agents. The developed compounds contain two amino acid residues in the polar block and aliphatic chains of various length in the hydrophobic domain. Amphiphiles were obtained in preparative amounts sufficient to confirm their structures and perform a study of antibacterial activity. The synthesized samples based on β-Ala (4c) and GABA (4d) with aliphatic C12 chain in the hydrophobic domain showed a promising level of antimicrobial activity against gram-positive (B. subtilis) and gram-negative (E. coli) bacteria (minimal inhibitory concentration, MIC, 1 μg/mL). Amphiphiles containing aromatic amino acids L-Phe (6a) and L-Trp (6b) in the polar head group and C8 hydrocarbon chain exhibited an antibacterial activity against B. subtilis with MIC of 1 μg/mL. The obtained data on antimicrobial activity make the selected compounds attractive for further detailed study of their mechanism of action.

Peptidomimetics are small molecules that are able to mimic the functional and structural features of peptides. The application of rational design during the development process allows their use as effective antibacterial agents with improved pharmacokinetic properties. In this study, we have constructed a series of cationic amphiphiles based on the alkyl-indole derivative of L-serine, differing in the amino acid composition in the polar block, with potential antimicrobial activity. A universal preparation scheme, which makes it possible to obtain target compounds in the quantities necessary for the further study of biological properties, is developed. Based on the analysis of antimicrobial activity, it is found that structures with a higher lipophilicity value and a smaller polar block volume demonstrate the best results.

This paper studies the preparation of a carbohydrate derivative of lipotripeptide ( N -lactitol-Gly) 2 -LysC 16 of an irregular structure with two terminal residues of D-galactose, a branching link based on aliphatic L-lysine and its carbohydrate-free analog with 1-pyrenbutanol as a fluorescent label in a hydrophobic fragment. The developed synthesis scheme includes universal approaches of peptide chemistry and the stages of the formation of an acyclic carbohydrate based on lactose in the hydrophilic domain of amphiphile. The compounds are designed to create compositions of the vector BAS delivery systems with the ability to visualize the process of interaction with the target cells.

This work aimed to produce mixed liposomes based on natural amino acids as vehicles for delivery of anticancer drugs and nucleic acids. Liposomes were formed from cationic lipids based on L-alanine and L-serine, a cerasome-forming lipid based on L-ornithine, and phospholipids phosphatidylcholine (PC) or 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). For the developed agents, particle size, zeta potential, and stability were determined, and the biological activity was studied on the MCF-7 and HEK 293 cell lines. Liposomes based on L-serine demonstrated the ability to accumulate in the endoplasmic reticulum of cells within 1 h, and their transfection activity significantly exceeded that of the commercial drug Lipofectamine-2000. At the same time, the proposed system had a slight toxic effect (IC50, 0.475 mg/mL and the safe working concentration, 0.24 mg/mL). Thus, the results suggest that mixed liposomes based on L-serine can serve as an efficient delivery system of drugs into cells.

A series of new cationic amphiphiles based on diethanolamine esters with Gly, βAla, GABA, Lys, Orn amino acid residues in the hydrophilic block were prepared. The sample containing the Lys residue showed the best activity against gram-positive and gram-negative bacteria. For model membranes comprising combinations of DOPC, DOPG and DOPE phospholipids, the sample can electrostatically bind to the surface of a bacterial cell and destroy it by formation of through defects.

Low molecular weight RGD peptides and RGD mimetics are widely studied as ligands targeting the corresponding receptor in the diagnosis and therapy of cancer, as well as in the field of bone tissue regeneration. Some of them are undergoing preclinical trials. The aim of this study is to select the optimal variants of the ligand structure based on an aliphatic RGD mimetic. By methods of molecular modeling (blind docking and active site docking), the most advantageous constructions for the formation of a stable complex with the integrin αVβ3 are determined. A scheme is developed and two lipotripeptides Gnd-GABA-Gly-Asp(C16)2 and Gnd-β-Ala-Gly-Asp(C16)2 with the potential ability to inhibit this receptor on the surface of tumor tissues are synthesized.

In this paper, we describe the synthesis of cationic amphiphiles based on aliphatic and aromatic amino acids and diethanolamine derivatives. The calculation of the hydrophilic-lipophilic balance for a number of structures makes it possible to identify the structures with potential antimicrobial activity against gram-positive and gram-negative bacterial strains. The schemes for the synthesis of mono/bivalent cationic lipoamino acids and lipopeptides are developed. Two series of amphiphiles are obtained in preparative quantities for subsequent microbiological studies and determining the minimum inhibitory concentration.

The review article traces the main trends of the synthetic approach to the solution of the problem of overcoming the resistance of pathogenic bacterial strains. The main strategies for the search of promising agents are presented, starting with natural antimicrobial peptides or “human protection” peptides, with a subsequent evolutionary transition to synthetic peptidomimetics of macromolecular or oligomeric types, as well as an approach based on membrane-active low molecular weight cationic amphiphiles. The structural diversity of peptidomimetics with a high bactericidal activity, possessing increased resistance to the action of proteolytic enzymes in comparison to natural peptides, has been shown. Much attention is paid to various aliphatic and aromatic cationic amphiphiles based on amino acids. Potential capabilities of this class of compounds as antimicrobial agents are noted. The amphiphilic structure of the synthesized compounds allows them to selectively affect bacterial membranes and does not trigger the resistance development process in bacteria.

Objectives. Resistance to antibiotics and other antimicrobial drugs is an acute problem in the world today. Therefore, the chemical and pharmaceutical industries are still in search of new antibacterial agents that can overcome the resistance of pathogenic bacterial strains. To date, it has been established that molecules with antimicrobial activity must have an amphiphilic nature, a small size, one or more positive charges, and the required degree of hydrophobicity, that is, a significant hydrophilic–lipophilic balance (HLB) value. Some examples of such structures are antimicrobial peptides or peptidomimetics. This study aimed to develop a universal scheme for synthesizing several amino acid derivatives based on diethanolamine diesters with symmetric and asymmetric radicals in a hydrophobic block and potential antibacterial activity.Methods. The progression of chemical reactions was analyzed using thin-layer chromatography (TLC) on Sorbfil plates. The obtained compounds were isolated and purified using preparative TLC on Kieselgel (Merck) 60 F254 plates and column chromatography on Merck silica gel 0.040–0.063 mm. The TLC method was used to detect substances using a 3% ninhydrin solution, followed by heating to 70 °C. The structures of the obtained compounds were confirmed by hydrogen-1 nuclear magnetic resonance (1H NMR) spectroscopy on a Bruker WM-300 pulse NMR spectrometer, with hexamethyldisiloxane serving as the internal standard.Results. The HLB values of the diethanolamine derivatives were calculated, and samples were selected for subsequent synthesis. A scheme was developed for preparing amino acid derivatives based on diethanolamine diesters with symmetric and asymmetric radicals in the hydrophobic domain, and five new compounds were synthesized. The hydrophilic blocks of these compounds included residues of amino acids such as glycine, β-alanine, L-ornithine, and L-lysine.Conclusions. The potential antimicrobial activity of the synthesized peptidomimetics was assessed by their HLB values using the ACD/Labs Log P program. New amphiphiles were synthesized using amino acids and diethanolamine, and their structures were confirmed by 1H NMR spectroscopy data. The synthesized compounds were prepared for antibacterial activity analysis.

This study is aimed at creating a number of derivatives of natural amino acids based on dioctylamine and diethanolamine diesters with potential antibacterial activity. Simple and universal schemes of the synthesis allow them to be used for obtaining a series of samples in the preparative quantities necessary for the implementation of physiochemical and biochemical studies. The synthesized sample based on glycyldioctylamide shows a promising level of antimicrobial activity (MIC) against Gram-positive and Gram-negative bacteria.

New cationic branched lipotetrapeptides based on l-amino acids and higher alkanols were prepared. Study of their physicochemical and membrane-forming properties revealed that phase transition temperature of these amphiphiles locates in the range of physiological norm. The particle sizes of liposomal dispersions with high aggregation stability are in dimension applicable to penetrate into small blood vessels.