Characterization and antibiofilm activity of lipid nanovesicles containing essential oil of Thymus vulgaris

ANA PAULA PEREZ; PEREZ, NOELIA; CARLOS MAURICIO SULIGOY; MARIA JULIA ALTUBE; DE FARIAS, MARCELO ALEXANDRE; PORTUGAL, RODRIGO VILLARES; BUZZOLA, FERNANDA; EDER L ROMERO

Congreso; Reunion conjunta SAIC.SAI.SAFIS 2018; 2018

The clinical relevance of biofilms (matrix-enclosed communities of bacteria that are adherent to surfaces) is related to their wide occurrence together with their ability to cause relapsing infections characterized by chronic inflammation, tissue damage and the significant difficulties in their eradication. The antibiotic tolerance shown by bacteria in the biofilm has been attributed mainly to the matrix, that restricts the access of antibiotics by binding them to their components or inactivating them by enzymes. In that way, lipid nanovesicles containing antimicrobial agents (AMA) could penetrate the biofilm matrix and remain there releasing AMA in high doses. We have recently shown that the presence of total polar archaeolipids of Halorubrum tebequichense (TPA) in lipid nanovesicles increased their chemical and colloidal stability. We hypothesized that the encapsulation of essential oil of Thymus vulgaris (AETv - a potent AMA that has low solubility in water and rapid decomposition) in archaeolipid nanovesicles would allow to obtain a stable aqueous suspension of AETv with efficient antibacterial and antibiofilm activity. Archaeolipid nanovesicles (soy phosphatidylcholine: TPA: Tween 80 1:1:1.6 w:w) of 129 ± 23 nm, Z potential -7 ± 1.5 mV and nanospherical structure, containing 41.6 ± 14.6 mg/ml of AETv (Arc-AETv) were obtained by the lipid film hydration method. The encapsulation of AETv in Arc-AETv increased the solubility of AETv 20.8 times with regards to an aqueous suspension. After 150 days of storage, Arc-AETv maintained the concentration of AETv and was stable colloidally. Finally, Arc-AETv presented antibacterial activity on both planktonic S. aureus and biofilm at lower concentrations than Tween 80 1% v/v suspension of AETv and AETv in lipid nanovesicles lacking TPA (Lipo-AETv). In conclusion, the incorporation of AETv in archeolipid nanovesicles favored obtaining a stable formulation with effective antibiofilm activity.