The discovery and biological activity evaluation of a novel peptide, QUB-3229, from the defensive skin secretion of the Chinese piebald odorous frog, Odorrana schmackeri

Then the synthetic peptide was identified by high performance liquid chromatography (HPLC) and Matrix-assisted laser desorption/ionisation Time-of-flight (MALDI-TOF) mass spectrometry (MS). Subsequently, the antimicrobial activity of QUB-3229 was evaluated against the Gram-positive bacterium, Staphylococcus aureus (S. aureus), the Gram-negative bacterium, Escherichia coli (E. coli) and the fungi, Candida albicans (C. albicans).

The minimal inhibitory concentration (MIC) values were 16, 8 and 32 μM, respectively. The peptide showed bactericidal activities against the bacteria, but not against the fungi even at the highest tested concentration. The 10% haemolytic concentration (HC10) of QUB-3229 was 15.3 μM, which demonstrated that the effective concentration against E. coli was in the safety margin.

The peptide did not display inhibitory ability in cancer cells.<br><br>Though the antimicrobial potency of QUB-3229 is not strong enough, it is expected that the discovery and obtained results of QUB-3229 may inspire the development of new drugs against common pathogens.