Assessment of antimicrobial, antiproliferative, and chemotactic properties of ranatuerin 2-PMe from cutaneous secretion of Lithobates palmipes (Spix, 1824) (Anura, Ranidae).

Lithobates palmipes is a frog species whose skin secretions contain peptides belonging to the ranatuerin, brevinin, and temporin families. In this study, the peptide ranatuerin-2PMe was isolated and evaluated for its antimicrobial, hemolytic, antiproliferative, and chemotactic activities. Ranatuerin-2PMe (2933.2 Da) was purified from L. palmipes skin secretions (collected via electrical stimulation) using reversed-phase high-performance liquid chromatography, and its primary structure was subsequently determined through Edman degradation. The peptide was then synthesized via solid-phase peptide synthesis. Ranatuerin-2PMe exhibited antibacterial activity against Staphylococcus aureus, Escherichia coli, Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae carbapenemase-producer (KPC), with minimal inhibitory concentrations ranging from 2 μM to 128 μM. It demonstrated low hemolytic activity (18.3 ± 1.2%) at 128 μM. Furthermore, ranatuerin-2PMe showed antiproliferative effects against HeLa and HaCaT cell lines, with IC values of 12.4 μM and 16.9 μM, respectively. Ranatuerin-2PMe induced neutrophil migration in a pattern consistent with chemotactic activity, while maintaining neutrophil viability. In conclusion, a novel peptide from the ranatuerin family was identified in L. palmipes skin secretions, demonstrating promising biomedical potential as an antimicrobial, anticancer, and immunomodulatory agent. However, its cytotoxicity toward HaCaT cells highlights the need for further studies to evaluate its selectivity and safety profile.