Evaluation of the antimicrobial and cytotoxic activity of nerolidol encapsulated in a nanoliposome system

Plant-derived compounds have emerged as potential alternatives to traditional antimicrobials in livestock; however, their application may be limited by degradation in the gastrointestinal tract. Nanoliposome encapsulation offers a strategy to overcome these limitations. In this study, we investigated the effects of nerolidol encapsulation, by evaluating the antimicrobial activity of free-nerolidol (NER), nerolidol-loaded nanoliposomes (LN), and unloaded nanoliposomes (UN) (Lipobox™) using a Time-Kill assay. The cytotoxicity of these formulations was assessed through MTT assay on swine and bovine cell lines. NER was effective against MRSA, <i>Enterococcus faecium</i>, and <i>Lactobacillus acidophilus</i> at all time points, at concentrations ≥62.5, ≥15.63 and ≥1,000 μg/ml, respectively, but was ineffective against Gram-negative bacteria Conversely, LN and UN were effective against all bacteria, showing the best activity at 2,500 μg/ml. LN showed the greatest activity against MRSA up to 6 h while UN on <i>E. faecium</i> up to 4 h (<i>P</i> < 0.05). No difference between LN and UN on <i>Salmonella Typhimurium</i> up to 24 h and on <i>E. coli</i> up to 6 h at this concentration (<i>P</i> > 0.05) was observed. For <i>L. acidophilus</i>, both LN and UN were effective up to 6 h even at the lowest concentration (9.77 μg/ml). NER showed high cytotoxicity on MDBK and IPEC-J2 cells at all doses; while LN and UN were low-toxic at concentrations ≤ 1,250 μg/ml or ≤ 625 μg/ml, respectively. These results suggest that nanoliposomes themselves exhibit dose-dependent antimicrobial and cytotoxicity activity; however, when NER is encapsulated its spectrum of activity its enhanced.