Potencial antifúngico de nanoemulsões de óleo essencial de Cravo-da-Índia (Syzygium aromaticum)

Abstract

Essential oils are extracts derived from plants, defined as secondary metabolites compounds, being an important defense mechanism of plants. The antimicrobial activity of the oils is mainly due to their hydrophobic nature, and it is believed that this activity against bacteria and fungi is directly related to the major compounds present in the essential oil. Clove (Syzygium aromaticum) is a plant native to Indonesia, with an extensive literature record of the activity of clove essential oil against bacteria and fungi. Phytopathogenic fungi that attack crops after harvest are responsible for the loss of tons of crops worldwide. In tropical regions, Penicillium spp. and Rhizopus stolonifer have a high incidence, and cause diseases known as “Green Rot” and “Black Rot”, respectively. The use and application of essential oils in their pure form has some limitations, such as their volatility, high reactivity and hydrophobicity, making their direct incorporation into foods difficult. In order to maintain their biological properties and reduce the impact of their application on food, the oils were incorporated into emulsions and nanoemulsions to later be encapsulated. Materials and methods: The production and characterization of nanoemulsions with Clove EO was carried out, after the determination of the Hydrophilic-Lipophilic Balance (HLB), from the mixture between aqueous and organic phase, consisting of the EO and a mix of surfactant composed by Tween 80 and Span 80. After characterization, a comparison was made between the antifungal activity of the pure essential oil, emulsion and nanoemulsion against postharvest fungi Penicillium spp. and Rhizopus stolonifer. Results: After the determination of the BHL, a nanoemulsion with a particle size of 50 d.nm was produced. From the antifungal activity tests, it is concluded that the nanoemulsion did not increase the essential oil activity against the tested fungi, being the oil in its pure form more efficient than the emulsion and nanoemulsion.