Molecular cloning, synthesis and bioactivity study of a bioactive peptide from the skin secretion of the Burmeister's leaf frog, <i>Phyllomedusa burmeisteri</i>

This study investigated the antimicrobial, anticancer, and toxicity properties of a bioactive peptide, QUB-1962, a phylloseptin-family peptide derived from the skin secretion of Burmeister's leaf frog, (Phyllomedusa burmeisteri), with a focus on its potential therapeutic applications. The peptide was first identified via molecular cloning, then synthesised by solid-phase peptide synthesis, and subsequently purified and characterised by HPLC and mass spectrometry.

Its bioactivity was assessed through antimicrobial assays, haemolysis tests, and cell viability/toxicity assays. QUB-1962 exhibited broad-spectrum antimicrobial activity, showing the strongest efficacy against Staphylococcus aureus with a MIC of 8 μM, while also inhibiting Escherichia coli and Candida albicans. In anticancer assays, the peptide significantly inhibited the proliferation of human lung cancer cells with an IC₅₀ of 26.98 μM; however, it demonstrated a comparable level of cytotoxicity against normal human lung cells, indicating a lack of selectivity.