Design, Synthesis, and Biological Evaluation of Desmuramyl Dipeptides Modified by Adamantyl-1,2,3-triazole.

Muramyl dipeptide (MDP) is the smallest peptidoglycan fragment able to trigger the immune response. Structural modification of MDP can lead to the preparation of analogs with improved immunostimulant properties, including desmuramyl peptides (DMPs). The aim of this work was to prepare the desmuramyl peptide (L-Ala-D-Glu)-containing adamantyl-triazole moiety and its mannosylated derivative in order to study their immunomodulatory activities in vivo.

Adamantane Containing Peptidoglycan Fragments Enhance RANTES and IL-6 Production in Lipopolysaccharide-Induced Macrophages.

We report the enhancement of the lipopolysaccharide-induced immune response by adamantane containing peptidoglycan fragments in vitro. The immune stimulation was detected by Il-6 (interleukine 6) and RANTES (regulated on activation, normal T cell expressed and secreted) chemokine expression using cell assays on immortalized mouse bone-marrow derived macrophages. The most active compound was a α-D-mannosyl derivative of an adamantylated tripeptide with L-chirality at the adamantyl group attachment, whereby the mannose moiety assumed to target mannose receptors expressed on macrophage cell surfaces.

Targeted Delivery of Adamantylated Peptidoglycan Immunomodulators in Lipid Nanocarriers: NMR Shows That Cargo Fragments Are Available on the Surface.

We present an in-depth investigation of the membrane interactions of peptidoglycan (PGN)-based immune adjuvants designed for lipid-based delivery systems using NMR spectroscopy. The derivatives contain a cargo peptidoglycan (PGN) dipeptide fragment and an adamantyl group, which serves as an anchor to the lipid bilayer. Furthermore, derivatives with a mannose group that can actively target cell surface receptors on immune cells are also studied.

Design, synthesis and biological evaluation of immunostimulating mannosylated desmuramyl peptides.

Muramyl dipeptide is the minimal structure of peptidoglycan with adjuvant properties. Replacement of the -acetylmuramyl moiety and increase of lipophilicity are important approaches in the preparation of muramyl dipeptide analogues with improved pharmacological properties. Mannose receptors present on immunocompetent cells are pattern-recognition receptors and by mannose ligands binding they affect the immune system.

Synthesis and In Vitro Screening of Novel Heterocyclic β-d-Gluco- and β-d-Galactoconjugates as Butyrylcholinesterase Inhibitors.

The development of selective butyrylcholinesterase (BChE) inhibitors may improve the treatment of Alzheimer's disease by increasing lower synaptic levels of the neurotransmitter acetylcholine, which is hydrolysed by acetylcholinesterase, as well as by overexpressed BChE. An increase in the synaptic levels of acetylcholine leads to normal cholinergic neurotransmission and improved cognitive functions. A series of 14 novel heterocyclic β-d-gluco- and β-d-galactoconjugates were designed and screened for inhibitory activity against BChE.

Adamantyl pyran-4-one derivatives and their in vitro antiproliferative activity.

Pyran-4-one (maltol, kojic acid and chlorokojic acid 1) esters of adamantan-1-ylacetic acid were prepared through efficient synthetic routes in good yields and evaluated for their in vitro antiproliferative activity on four cancer cell lines: K562 (chronic myelogenous leukemia), HeLa (cervical cancer), Caco-2 (colorectal adenocarcinoma) and NCI-H358 (bronchioalveolar carcinoma). The results indicate that the presence and the position of the adamantyl acyl group or chlorine atom are the necessary requirement for antitumor activity of pyranone systems. Derivatives of kojic acid with either free (compounds 1 and 8) or acylated 5-OH group (compounds 2 and 9) have shown good-to-moderate activity (IC values ranging from 13.

A comprehensive evaluation of novel oximes in creation of butyrylcholinesterase-based nerve agent bioscavengers.

A well-considered treatment of acute nerve agents poisoning involves the exogenous administration of butyrylcholinesterase (BChE, EC 3.1.1.

Mannosylated N-aryl substituted 3-hydroxypyridine-4-ones: synthesis, hemagglutination inhibitory properties, and molecular modeling.

Structural alterations of the aglycon portions of α-mannosides influence their inhibitory potency toward type 1-fimbriated Escherichia coli. The aim of our work was to prepare and explore inhibitory properties of novel mannosylated N-aryl-substituted 3-hydroxypyridine-4-ones because they possess needed structural characteristics as possible FimH antagonists. Hemagglutination inhibitory tests showed that the examined 3-hydroxypyridine-4-one α-mannosides exhibited better inhibitory activity than methyl α-d-mannopyranoside used as a reference compound.

Influence of mannosylation on immunostimulating activity of adamant-1-yl tripeptide.

The mannosylated derivative of adamant-1-yl tripeptide (D-(Ad-1-yl)Gly-L-Ala-D-isoGln) was prepared to study the effects of mannosylation on adjuvant (immunostimulating) activity. Mannosylated adamant-1-yl tripeptide (Man-OCH(2) CH(Me)CO-D-(Ad-1-yl)Gly-L-Ala-D-isoGln) is a non-pyrogenic, H(2) O-soluble, and non-toxic compound. Adjuvant activity of mannosylated adamantyl tripeptide was tested in the mouse model with ovalbumin as an antigen and in comparison to the parent tripeptide and peptidoglycan monomer (PGM, β-D-GlcNAc-(1→4)-D-MurNAc-L-Ala-D-isoGln-mesoDAP(εNH(2) )-D-Ala-D-Ala), a well-known effective adjuvant.

Surface modified liposomes by mannosylated conjugates anchored via the adamantyl moiety in the lipid bilayer.

The aim of the present study was to encapsulate mannosylated 1-aminoadamantane and mannosylated adamantyltripeptides, namely [(2R)-N-(adamant-1-yl)-3-(α,β-d-mannopyranosyloxy)-2-methylpropanamide and (2R)-N-[3-(α-d-mannopyranosyloxy)-2-methylpropanoyl]-d,l-(adamant-2-yl)glycyl-l-alanyl-d-isoglutamine] in liposomes. The characterization of liposomes, size and surface morphology was performed using dynamic light scattering (DLS) and atomic force microscopy (AFM). The results have revealed that the encapsulation of examined compounds changes the size and surface of liposomes.

Synthesis and immunostimulating properties of novel adamant-1-yl tripeptides.

The aim of this work was to prepare L- and D-(adamant-1-yl)-Gly-L-Ala-D-isoGln peptides in order to study their adjuvant (immunostimulating) activities. Adjuvant activity of adamant-1-yl tripeptides was tested in the mouse model using ovalbumin as an antigen and in comparison to the peptidoglycan monomer (PGM; β-D-GlcNAc-(1→4)-D-MurNAc-L-Ala-D-isoGln-mesoDAP(εNH(2) )-D-Ala-D-Ala) and structurally related adamant-2-yl tripeptides.

Adamantane-substituted guanylhydrazones: novel inhibitors of butyrylcholinesterase.

A series of novel adamantane-substituted guanylhydrazones was synthesized and used in a study of inhibitory potential toward butyrylcholinesterase. The experimental results were further supported by using docking studies to examine the behavior of the inhibitors within the active site regions of the enzyme. The enzyme-inhibitor dissociation constants K(i) were determined from Hunter-Downs diagrams using Ellman's method for cholinesterase activity determination.

Preparation of novel meta- and para-substituted N-benzyl protected quinuclidine esters and their resolution with butyrylcholinesterase.

Since the optically active quinuclidin-3-ol is an important intermediate in the preparation of physiologically or pharmacologically active compounds, a new biocatalytic method for the production of chiral quinuclidin-3-ols was examined. Butyrylcholinesterase (BChE; EC 3.1.

Novel mannosyl derivatives of peptidoglycan monomer: Synthesis and biological evaluation of immunomodulatory properties.

The aim of this work was to prepare mannosyl derivatives of peptidoglycan monomer (PGM, beta-d-GlcNAc-(1-->4)-d-MurNAc-l-Ala-d-isoGln-mesoDAP(epsilonNH(2))-d-Ala-d-Ala) in order to study the effects of mannosylation on adjuvant (immunostimulating) activity. Novel Man-OCH(2)CH(CH(3))CO-PGM isomers were substrates for N-acetylmuramyl-l-alanine amidase, like the parent PGM molecule. Adjuvant activity of Man-OCH(2)CH(CH(3))CO-PGM was tested in the mouse model using ovalbumin as an antigen.

3-Amidoquinuclidine derivatives: synthesis of compounds and inhibition of butyrylcholinesterase.

The synthesis of racemic and enantiomerically pure 3-butanamidoquinuclidines ((+/-)-Bu, (R)-Bu and (S)-Bu), (1-3) and 3-benzamidoquinuclidines ((+/-)-Bz, (R)-Bz, and (S)-Bz), (4-6) is described. The N-quaternary derivatives, N-benzyl-3-butanamidoquinuclidinium bromides ((+/-)-BnlBu, (R)-BnlBu and (S)-BnlBu), (7-9) and N-benzyl-3-benzamidoquinuclidinium bromides ((+/-)-BnlBz, (R)-BnlBz and (S)-BnlBz), (10-12) were subsequently synthesized. The interaction of the four enantiomerically pure quaternary derivatives with horse serum butyrylcholinesterase (BChE) was tested.

Synthesis, intramolecular migrations and enzymic hydrolysis of partially pivaloylated methyl alpha-D-mannopyranosides.

A series of methyl O-pivaloyl-alpha-D-mannopyranosides was synthesized using pivaloyl chloride in pyridine. The 3,6-di-O-pivaloyl derivative 6 undergoes intramolecular transesterification in neutral conditions (buffer, pH 7.2) to give its 2,6-di-O-pivaloyl analogue 5.

Synthesis and intramolecular transesterifications of pivaloylated methyl alpha-D-galactopyranosides.

Selective pivaloylations of methyl alpha-D-galactopyranoside have been studied under various reaction conditions. Partially pivaloylated products were submitted to additional acetylations. The structures were established by 1H and 13C NMR spectroscopies.