The in vitro evaluation of anti-chlamydial and cytotoxic properties of dermaseptin S4 and derivatives: peptides from amphibian skin

Chlamydia trachomatis is an obligate intracellular bacterium responsible for a number of health problems, including sexually transmitted infection in humans. Efforts were made for the search of alternative therapies. Accordingly, the present study was undertaken to perform a systemic in vitro investigation on the anti-chlamydial potential of cationic peptides from frog’s skin, namely dermaseptin S 4 (S 4 ) and its derivatives. Several strains of Chlamydia trachomatis serovar E were used to detect the antimicrobial activity of the new compounds. The infections tests and the toxic effects of the new compounds were determined using McCoy cells monolayers. Our data show that S 4 exhibited a potent anti-chlamydial activity and found that these peptides blocked infection of McCoy cells and reduced the numbers of inclusion-forming units (81 %) after 48 h at low concentration (5 μg/ml). Besides, the finding revealed that increasing the number of positive charges of the peptide resulted in a reduced cytotoxicity without affecting the antimicrobial effect. Among all peptides, the derivative K 4 K 20 S 4 was the more potent to inhibit C. trachomatis growth with 96 % reduction in the number of chlamydial inclusions compared with an untreated control infection and, therefore, can be considered as potential agents for therapy of Chlamydia infectious diseases.