Antimicrobial Profile from Frog Skin Peptides

This study evaluates the antimicrobial efficacy of frog skin-derived peptides Magainin 1, Magainin 2, and Bombesin against Bacillus subtilis, Escherichia coli, and Trichoderma harzianum . Experimental setups involved uniform inoculation of the microorganisms on 20 mL agar plates, treated with varying volumes (1.5 µL, 5 µL, and 10 µL) of each peptide (10 mg/mL). For Bacillus subtilis , Magainin 2, and Bombesin demonstrated significant antibacterial activity, with inhibition zones increasing in size proportionally to the peptide volumes. Magainin 2 showed the highest efficacy, surpassing ampicillin at higher volumes. In Escherichia coli , similar dose-dependent antibacterial effects were observed, with Magainin 2 again showing superior performance, matching or exceeding the inhibition zones of ampicillin. Notably, Magainin 2, and Bombesin exhibited antifungal activity against Trichoderma harzianum with Amphotericin resistance. These antibacterial peptides show inhibitory activity on fungi, gram-positive higher than gram-negative bacteria. These findings highlight the potential of Magainin 2, and Bombesin as antimicrobial agents except of Magainin 1.