Bioactivity evaluation of peptide QUB-2511 from the skin secretion of the Fukien gold-striped pond frog, Pelophylax plancyi fukienensis

Abstract

Antimicrobial peptides (AMPs) have gained increasing attention in recent years due to their broad-spectrum activity and potential selectivity toward pathogenic microorganisms and cancer cells, offering promising alternatives to conventional antibiotics and chemotherapeutics. This study aimed to preliminarily evaluate the antimicrobial and anticancer activities, as well as the toxicity, of an AMP, QUB-2511, identified from the Fukien Pond frog (Pelophylax plancyi fukienensis). Sequence analysis revealed that QUB-2511 belongs to the Brevinin family and is identical to the previously reported brevinin-1P. The antibacterial and antifungal efficacy of QUB-2511 was assessed using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays against Staphylococcus aureus (S. aureus NCTC10788), Escherichia coli (E. coli NCTC10418), and Candida albicans (C. albicans NCTC1467), showing potent antimicrobial activity with low MIC/MBC values (1–8 μM). In addition, QUB-2511 exhibited strong cytotoxicity against human non-small cell lung cancer H838 cells, with an IC50 value of 3.199 μM, reducing cell viability to nearly 0% at 10 μM, suggesting promising anticancer potential. Toxicity on normal human lung fibroblasts (MRC-5) was quantified with an IC50 of 1.908 μM, while haemolysis assays yielded an HC50 value of approximately 25 μM. These data indicate that QUB-2511 possesses dual antibacterial and anticancer activity, but its selectivity toward cancer cells over normal cells remains limited. Future research should focus on elucidating the underlying mechanisms of action and modifying the peptide structure to enhance therapeutic efficacy while minimising off-target effects. This study provides a valuable foundation for rational design and development of QUB-2511-based therapeutics for infectious diseases and cancers.

Thesis is embargoed until 31 December 2030.

Date of Award	Dec 2025
Original language	English
Awarding Institution	Queen's University Belfast
Supervisor	Mei Zhou (Supervisor), Lei Wang (Supervisor) & Tianbao Chen (Supervisor)