Óleos essenciais: composição química, atividade antimicrobiana e desenvolvimento de um composto de inclusão com ciclodextrina

Abstract

Essential oils (EO) are complex mixtures of volatile substances, liquids, odorous and arising from secondary metabolism of plants with applications in personal care products, cosmetics, perfumes, pesticides, food, medicine, among others. They have been long exploited for its antiseptic capacity. However, an inherent difficulty of working with EO is its high volatility. The use of a volatile compound as a finished product requires caution related to its stability and developing methods such as encapsulation. In this work, microencapsulation was studied using cyclodextrin as the encapsulating substance. The aim of this study was to evaluate and compare the antibacterial and antifungal activities of fifteen essential oils and promote microencapsulation of the oil which would produce the best result using β-cyclodextrin as the encapsulating substance. The selected essential oils were: Melaleuca alternifolia, Cupressus nootkatensis, Syzygium aromaticum, Origanum vulgare, Cinnamomum cassia, Pelargonium graveolens, Pterodoron emarginatus, Xylopia brasiliensis, Cyperus scariosus, Cymbopogon citratus, Rosmarinus officinalis, Schinus therenbinthifolius, Protium heptaphyllum, Cupressus lusitanica and Boswellia carteri. The microorganisms used were Staphylococcus aureus ATCC29212, Staphylococcus epidermidis ATCC12228, Pseudomonas aeruginosa ATCC27853, Escherichia coli ATCC25922, Salmonella typhi ATCC 14028 and Candida albicans ATCC18804. The essential oils of Origanum vulgare and Syzygium aromaticum showed inhibition capacity of more than 90% at all tested microorganisms, similar result of standard antibiotics. All other oils showed good results in inhibition of at least one sort of micro-organism. The essential oil of Syzygium aromaticum, by having the best result, was microencapsulated in β-cyclodextrin by kneading technique. The chemical composition of each essential oil was also determined, including the formed inclusion complex, being characterized by gas chromatography with flame ionization detector (GC-FID). The thermogravimetric analysis was also used in the characterization of the inclusion complex. The results corroborated the high antibacterial and antifungal potential of essential oil and suggests the formation of the inclusion complex Syzygium aromaticum / β-cyclodextrin (OECβCD).