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

Abstract

Antimicrobial peptides (AMPs), particularly those from amphibian skin secretions, offer a potential approach to combat multidrug resistance by targeting a wide range of pathogens through specific work of mode. 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. Furthermore, QUB-2116 could inhibit the proliferation of human non-small cell lung cancer cells (H838) at the concentration of only 10-5 M, underscoring its potent anti-cancer properties. This observation highlights the potential of QUB-2116 as a promising candidate for further development in the field of anti-MDR infection and anti-cancer therapeutics.

In summary, the peptide QUB-2116 exhibits bioactivities consistent with those of the published Phylloseptin family, demonstrating potent antibacterial effects against Gram-positive bacteria and mild haemolytic activity. These findings present promising opportunities for the clinical application of QUB-2116, with the potential for minor modifications to improve its effectiveness.

Thesis is embargoed until 31 December 2028.

Date of Award	Dec 2023
Original language	English
Awarding Institution	Queen's University Belfast
Supervisor	Mei Zhou (Supervisor), Tianbao Chen (Supervisor) & Yangyang Jiang (Supervisor)