Identification and bioactivity evaluation of a novel peptide, QUB-2116, from the skin secretion of the frog, Phyllomedusa hypochondrialis

In this study, a novel peptide QUB-2116, was isolated from the skin secretion of Phyllomedusa hypochondrialis using the technique of molecular cloning. As a newly identified member of the Phylloseptin family, QUB-2116 demonstrated significant antimicrobial activity against S. aureus, with a minimum inhibitory concentration (MIC) value of only 4 µM and minimum bactericidal concentration (MBC) value of 8 µM. Nevertheless, the MIC value of QUB-2116 against E. coli was determined up to 64 µM and the MBC value was 128 µM. The antimicrobial effect against fungi exhibited a noteworthy decrease in comparison to the other tested organisms.

The findings indicated the MIC value of 128 µM and the MBC value of 128 µM for QUB-2116 against C. albicans. Additionally, QUB-2116 exhibited a half cytotoxic concentration (HC50) value of 41 µM, indicating moderate haemolysis activity in horse erythrocyte tests. These findings provide a foundation for further investigation into the therapeutic potential of the Phylloseptin family.