Millipedes vs. pathogens: Defensive secretions of some julids (Diplopoda: Julida) as potential antimicrobial agents

In the light of growing interest in discovering new sources of natural antimicrobial agents, we extracted and tested the efficiency of julid defensive secretions in comparison with commercially used antibiotic and antimycotics. This work involved chemical characterization of the defensive secretions of Cylindroiulus boleti (C. L. Koch, 1847), Megaphyllum bosniense (Verhoeff, 1897) and M.unilineatum (C. L. Koch, 1838), as well as in vitro evaluation of their antimicrobial activity against 11 bacteria, one yeast and eight filamentous fungi. Compounds of the analysed defensive secretions included p-benzoquinones, alkyl esters of fatty acids and ketones. Ketones were recorded for the first time in the order Julida, and they were detected in secretions of both Megaphyllum species. All three analysed defensive secretions showed antibacterial and antifungal potential against all of the tested pathogens. Staphylococcus aureus proved to be the most sensitive bacterial strain to all analysed sec...