Purification, Conformational Analysis and Cytotoxic Activities of Host-Defense Peptides from the Giant Gladiator Treefrog Boana boans (Hylidae: Hylinae)

Frogs from the extensive amphibian family Hylidae are a rich source of peptides with therapeutic potential. Peptidomic analysis norepinephrine-stimulated skin secretions Giant Gladiator Treefrog Boana boans (Hylidae: Hylinae) collected in Trinidad led to isolation and structural characterization five host-defense limited similarity figainin 2 picturin other frog species belonging genus Boana. In addition, contained high concentrations tryptophyllin-BN (WRPFPFL) both C-terminally α-amidated non-amidated forms. Figainin 2BN (FLGVALKLGKVLG KALLPLASSLLHSQ) 1BN (GIFKDTLKKVVAAVLTTVADNIHPK) adopt α-helical conformations trifluroethanol–water mixtures presence cell membrane models (sodium dodecylsulfate dodecylphosphocholine micelles). The CD data also indicate contributions turn structures. Both (GLMDMLKKVGKVALT VAKSALLP) inhibited growth clinically relevant Gram-negative Gram-positive bacteria MIC values range 7.8–62.5 µM. was potently cytotoxic A549, MDA-MB-231 HT-29 human tumor-derived cells (LC50 = 7–14 µM) but displayed comparable potency against non-neoplastic HUVEC 15 indicative lack selectivity for cancer cells.