MELALEUCA OIL PICKERING EMULSIONS STABILISED WITH NANOCELLULOSE WITH ANTIVIRAL PROPERTIES

MELALEUCA OIL PICKERING EMULSIONS STABILISED WITH NANOCELLULOSE WITH ANTIVIRAL PROPERTIES

• Autor
• Greiciele Da Silva Ferreira
• Co-autores
• Daniel José da Silva , Derval dos Santos Rosa
• Resumo

• The Essential oil of melaleuca alternifolia (MaEO) is extracted from the tea tree, a plant from Australia, by steam distillation of leaves and terminal branches. It has in its composition several functional groups of terpenes and terpenoids, among them, terpinenol-4-ol, ?-terpinene, ?-terpinene, cymene, and ?-terpineol that contribute synergistically to antimicrobial activity leading to inhibition of cellular respiration processes, rupture of the bacterial membrane inducing leakage of metabolites from microorganisms, consequently causing cell lysis or death.

  Cellulose nanofibrils (CNFs) are fibrous nanostructures with a diameter on the nanometer scale (less than 100 nm) that allow high surface area without high production energy and financial costs. In this contribution, we evaluated various process parameters on the stability of Pickering emulsions of (O/W) using the designer of experiments (DoE) design of experiments. The instability phenomena (creaming, sedimentation), instability index, and droplet size were analyzed and controlled over time. In addition, the antiviral activity of MaEO and the emulsions were investigated against SARS-CoV-2. From the DoE point of view, parameters on the preparation and stability of Pickering emulsions stabilized with CNF were revealed. The Pickering O/W emulsion inactivates the COVID-19 coronavirus, showing great potential for use in rapid sanitizing products and food packaging formulations capable of protecting food against SARS-CoV-2.

  The stability of Pickering emulsions is related to the emulsifier's (CNF) content and the preparation process's parameters, such as (rotation time, CNF concentration, rotation in rpm, and oil and water concentration). According to the Design of Experiments tool, the stability index values are affected according to the process parameters. The emulsion stability index (ESI) increases with the amount of CNF due to the 3D network formations caused by the high interactions of CNF.

  MaOE concentrations negatively affect the stability of the emulsions. The rotation and homogenization time contribute to the system's strength over the storage time. An increase in the average diameter of MaEO droplets is observed with increasing oil concentration. Increasing the CNF content and mixing time prevents the coalescence of the oil droplets due to the Ostwald ripening mechanism. As can be observed in droplet morphologies, homogenization rotation, and CNF content have synergistic significative effects on droplet stability.

  Pickering emulsions 30EO/5T/0.5CNF/15RPM and 20EO/5T/0.5CNF/12RPM are the most stable emulsions concerning the most petite droplet sizes and ESI values, including the most minor variations of these parameters over the 30-day storage period. These Pickering emulsions were subjected to antiviral testing against SARS-CoV-2.

  The MaEO inactivated the viral load of SARS-CoV-2 in the viral inoculum medium at the same instant after contact with the essential oil. MaEO inactivated all SARS-CoV-2 virions in the viral inoculum medium immediately after contact with it. The 30EO/5T/0.5CNF/15RPM emulsion could inactivate all SARS-CoV-2 virions within 15 minutes after direct contact, as all viral S proteins were damaged in the inoculum sample.

   

  Therefore, the Pickering emulsion of MaEO stabilized with CNF shows antiviral performance against SARS-CoV-2. Melaleuca Alternifolia essential oil (MaEO) inactivates SARS-CoV-2 particles immediately by damaging its S proteins through capsid destruction, but its emulsions needed more time to inactivate, but it was possible to verify that Pickering emulsions have antiviral character.

• Palavras-chave
• MELALEUCA , OIL, PICKERING EMULSIONS, NANOCELLULOSE
• Modalidade
• Pôster
• Área Temática
• Nanociência e Nanotecnologia