Background: Thanatin is the smallest member of Beta-hairpin class of cationic peptide
derived from insects with vast activities against various pathogens.
Objective: In this study, the antimicrobial activity of this peptide against some species of human
bacterial pathogens as well as its toxicity on NIH cells were evaluated.
Methods: Thanatin DNA sequence was cloned into pcDNA3.1+ vector and transformed into a
DH5α bacterial strain. Then the recombinant plasmids were transfected into HEK-293 cells by
calcium phosphate co-precipitation. After applying antibiotic treatment, the supernatant medium
containing thanatin was collected. The peptide quantity was estimated by SDS-PAGE and
GelQuant software. The antimicrobial activity of this peptide was performed with Minimum
Inhibitory Concentration (MIC) method. In addition, its toxicity on NIH cells were evaluated by
Results: The peptide quantity was estimated approximately 164.21 µmolL-1. The antibacterial
activity of thanatin was estimated between 0.99 and 31.58 µmolL-1 using MIC method. The result
of cytotoxicity test on NIH cell line showed that the peptide toxicity up to the concentration of
394.10 µmolL-1 and for 48 hours, was not statistically significant from negative control cells
(P>0.05). The antimicrobial assay demonstrated that thanatin had an antibacterial effect on some
tested microorganisms. The results obtained in this study also showed that thanatin had no toxicity
on mammalian cell lines including HEK293 and NIH.
Conclusion: Antimicrobial peptides such as thanatin are considered to be appropriate alternatives
to conventional antibiotics in treating various human pathological diseases bacteria.