Cationic peptides as promising compounds for the treatment of bacterial complications in atopic dermatitis: antibacterial activity assessment

Abstract

BACKGROUND: atopic dermatitis (AD) is a significant problem, since the chronic persistent course of the disease significantly affects the quality of life of patients and limits their capability up to disability. The decrease of the effectiveness of antibacterial drugs aggravates the therapy of AD and actualizes the development of new antimicrobial agents. AIMS: synthesis and evaluation of the antibacterial activity of cationic peptides and an aqueous solution of fullerene C60 to create drugs based on them that will have a spectrum of biological activity, including anti-inflammatory, antiallergic and antibacterial. MATERIALS AND METHODS: the objects of the research were the developed linear and dendrimeric cationic peptides, whose structure was confirmed by mass spectrometry (MALDI-TOF). An aqueous solution of fullerene C60 was obtained using a unique developed and patented technology. Analysis of the antibacterial activity was carried out by the method of diffusion into agar using disks (screening), the method of serial dilution was used to determine the minimum bactericidal concentration of the studied compounds. RESULTS: as a result, 42 cationic peptides with various structures were developed and synthesized. The molecular weight of the peptides did not exceed 5000 Da. They contained from 7 to 25 amino acids with charges from +5 to +16. The screening revealed 15 peptides that showed activity against the strain of E. coli Dh5a. Thus, it was shown that the peptides AB14, AB17 and AB18 showed bactericidal activity relative to the bacterial strain E. coli Dh5a in concentrations of 0.03, 0.15 and 0.74mM, respectively, which exceeded that of ampicillin (0.74mM) several times. The analysis of an aqueous solution of fullerene C60 did not reveal its antibacterial activity. CONCLUSIONS: a number of cationic peptides with hydrophobic and positively charged sites in their composition was obtained. The structures of the most active peptides (AB-14 and AB-17) were close to -helical. The antibacterial activity of these peptide constructs was several times higher than that of ampicillin, which acted as a positive control drug. This makes these cationic peptides promising for the further research and the development of antibacterial therapeutic agents based on them.