Evaluation of the Antimicrobial and Cytotoxic Activity of Nerolidol Encapsulated in a Nanoliposome System

Nicolo Mezzasalma¹Costanza Spadini^1*Federico Righi¹Marica Simoni¹Gaetano Lamberti²Anna Angela Barba²Dante Greco³Alessia Merelli³Lorenzo Bosio³Alessandro Cupola¹Emiliana Schiano¹Simone Taddei¹Clotilde Silvia Cabassi¹

• ¹Department of Veterinary Science, University of Parma, Italy, Parma, Italy
• ²Department of Industrial Engineering, University of Salerno, Italy, Fisciano (SA), Italy
• ³Farmer SpA R&D Department, Italy, Mantova, Italy

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 freenerolidol (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, E. faecium, and L. acidophilus at all time points, at concentrations ≥ 62.5, ≥ 15.63 and ≥ 1000 µg/mL, respectively, but was ineffective against Gram-negative bacteria Conversely, LN and UN were effective against all bacteria, showing the best activity at 2500 µg/mL. LN showed the greatest activity against MRSA up to 6 h while UN on E. faecium up to 4 h (P < 0.05). No difference between LN and UN on S. Typhimurium up to 24 h and on E. coli up to 6 h at this concentration (P > 0.05) was observed. For L. acidophilus, 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 ≤ 1250 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.