Bioactivity and functional study of a peptide, temporin-GHb, from the skin secretion of the frog, Hylarana guentheri

Antimicrobial peptides are mainly derived from the skin secretions of frogs and have good antibacterial and anticancer activities. In the study, temporin-GHb, a peptide of the Temporin family, was extracted from the dorsal secretion of the southern Chinese marsh frog, Hylarana guentheri and focused to explore its therapeutic potentials.

Poly-A mRNA was isolated from the skin secretion, and a cDNA library was constructed which was searched using the 'shotgun' cloning method to obtain clones encoding a mature peptide sequence. The peptide was purified by the reverse-phase high-performance liquid chromatography. In the antimicrobial assays, temporin-GHb showed no effect against Staphylococcus aureus (Gram-positive bacterium), antibacterial activity against Escherichia coli (Gram-negative bacterium) at a concentration of 16 µM and Candida albicans (yeast) at a concentration of 32 µM. In the haemolysis assays, temporin-GHb showed a low haemolysis activity of no more than 10% at a concentration of 256 µM. In the anticancer cell assays, temporin-GHb showed some inhibitory activity against the human lung cancer cell line, NCI-H838, at a concentration of 200 µM with an IC50 value of 191.1 µM. Although the antibacterial activity against the Gram-positive bacterium in this experiment was low, its low haemolysis with antibacterial activity and anticancer activity, proved that temporin-GHb had research value and development potentia.<br><br><i>Thesis is embargoed until 31 December 2027</i>.