Lactoferricin of Bovine Origin is More Active than Lactoferricins of Human, Murine and Caprine Origin

The antimicrobial peptide lactoferricin is generated by gastric pepsin cleavage of lactoferrin. We have examined the antimicrobial activity of lactoferricins derived from lactoferrin of human, murine, caprine and bovine origin with minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) against E. coli ATCC 25922 and S. aureus ATCC 25923. We found that lactoferricin of bovine origin (Lf-cin B) was the most efficacious of the lactoferricins tested. By comparing the linear and cyclic Lf-cin B we found the cyclic peptide to be the most active. Lactoferricin B was moderately active against E. coli ATCC 25922 and S. aureus ATCC 25923, but had no activity against P. mirabilis or Y. enterocolitica. Lf-cin B showed good activity against C. albicans, C. tropicalis and C. neoformans.