Dermaseptins from Phyllomedusa oreades and Phyllomedusa distincta: Secondary structure, antimicrobial activity, and mammalian cell toxicity.

The present study reports the structural characteristics, the biological activities, and preliminary clinical investigations of three synthetic members of the dermaseptin family of antimicrobial peptides. The three peptides showed similar tendencies to form alpha-helical structures in non-polar media. The antimicrobial activity towards bacteria and fungi was determined in the micromolar concentration and the peptides did not influenced peritoneal cells viability. One of the peptides was intravenously administered in mice at concentrations similar to those of antibiotics employed in bacterial/fungal infections and it did not cause any detectable changes in cells and tissues.

The NMR-derived solution structure of a new cationic antimicrobial peptide from the skin secretion of the anuran Hyla punctata.

Amphibian skin secretions constitute an important source of molecules for antimicrobial drug research in order to combat the increasing resistance of pathogens to conventional antibiotics. Among the various types of substances secreted by the dermal granular amphibian glands, there is a wide range of peptides and proteins, often displaying potent antimicrobial activities and providing an effective defense system against parasite infection. In the present work, we report the NMR solution structure and the biological activity of a cationic 14-residue amphiphilic alpha-helical polypeptide named Hylaseptin P1 (HSP1), isolated from the skin secretion of the hylid frog Hyla punctata. The peptide antimicrobial activity was verified against Candida albicans, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, whereas no significant lytic effect was detected toward red or white blood cells.