Active substances: Amoxicillin
This was achieved by introducing basic amino acid - lysine - into the lipopeptide structure and had a hydrophobic fatty acid chain attached.
Lipopeptides were subjected to microbiological tests using reference strains of Gram-negative bacteria: Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, Pseudomonas aeruginosa, Gram-positive bacteria: Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Enterococcus faecalis, and fungi: Candida albicans, Candida tropicalis, Aspergillus brasiliensis.
The toxicity toward human cells was determined by hemolysis tests via minimum hemolytic concentration MHC determination. The effect of the trifluoroacetic acid TFA counter ion on the antimicrobial activity of lipopeptides was also examined by its removing and performing the antimicrobial tests using counter ion-free compounds.
The study shows that lipopeptides are more potent against Gram-positive than Gram-negative strains. The hemolytic activity of lipopeptides strongly depends on amino acid composition of the hydrophilic portion of the molecule as well as fatty acid chain length.
Compounds endowed with a greater positive charge were more toxic to human erythrocytes.
This should be considered during new lipopeptide molecules design. Our studies also revealed the TFA counter ion has no significant effect on the antimicrobial behavior of cationic lipopeptides. Introduction Most naturally occurring antimicrobial peptides are positively charged and their amino acid sequences form an amphipathic structure.
These structural conditions seem to be mandatory for the occurrence of high levels of antimicrobial activity Hancock and Diamond,; Brown and Hancock,; Hancock and Sahl,.
Therefore, antimicrobial peptide molecule design and the synthesis of positively charged antimicrobial peptide compounds are often achieved by introducing basic amino acids.
In turn, the condition of amphipathicity is provided by introducing amino acids with hydrophobic side chains. It is also possible to create amphiphilic peptide-like molecule by replacing a few hydrophobic amino acid residues with one, also hydrophobic, fatty acid chain.
Makovitzki et al. A large group of potent antimicrobial lipopeptides have been generated this way. Some of them.
The emergence and spread of multidrug resistant MDR microorganisms causes that a development of a new antibiotics is nowadays one of the most important challenges of pharmaceutical chemistry Ventola,.
Due to the issue of researching of an effective antibiotic therapies is urgent, we decided to synthesize a group of potentially antimicrobial cationic lipopeptides and study their antibacterial and antifungal potency.
They were never intended for recreational use, and this type of misuse can lead to erectile problems down the road! Ious busulfan toxicity!