Structural Characterization and Investigation of the Biological Potential of Figainin-2-BA: An Antimicrobial Peptide from Boana albopunctata.

The increasing spread of antimicrobial resistance represents a major public health challenge, highlighting the need for new therapeutic molecules. Antimicrobial peptides (AMPs) found in amphibian skin secretions stand out due to their structural diversity and broad spectrum of activity. This study investigated the structural and biological properties of Figainin-2-BA, isolated from the skin secretion of Boana albopunctata, focusing on its potential antimicrobial, antitumor, and immunomodulatory effects, as well as its cytotoxicity. The peptide was purified by high-performance liquid chromatography (HPLC), and its conformation was evaluated by circular dichroism in the presence of sodium dodecyl sulfate (SDS) and trifluoroethanol (TFE), used as membrane-mimetic systems. Antimicrobial activity was investigated against Gram-positive and Gram-negative bacteria, including a multidrug-resistant clinical isolate of carbapenemase-producing Klebsiella pneumoniae (KPC). Bacterial morphological alterations were analyzed by scanning electron microscopy. Antitumor activity was evaluated in MCF-7 and HeLa cell lines, while hemolysis and neutrophil chemotaxis assays were performed to investigate cytotoxicity and immunomodulatory potential. Figainin-2-BA showed a tendency to adopt an alpha-helical conformation in membrane-mimetic environments and exhibited activity against Gram-positive and Gram-negative bacteria. Scanning electron microscopy revealed morphological alterations consistent with possible damage to the bacterial surface. Preliminary assays also indicated reduced tumor cell viability and low hemolytic activity. Additionally, the peptide modulated neutrophil migration, suggesting immunomodulatory potential. These findings indicate that Figainin-2-BA is a promising molecule for pharmacological and biotechnological investigations, particularly in the context of antimicrobial resistance. Further studies are needed to clarify its mechanisms of action, investigate possible synergistic effects with conventional antimicrobials, and evaluate its efficacy and safety in preclinical and in vivo models.