Design and characterization of liquid nanocapsules of rosemary oil (Rosmarinus officinalis L.)

Abstract

Currently, plants are important to produce medicines and functional foods, as they are a source of bioactive compounds. One of the plants that have been investigated since ancient times is rosemary (Rosmarinus Officinalis L.). The essential oil of rosemary is a complex mixture of volatile compounds used in the food industry since it contains phenols, flavonoids, and terpenes. These molecules have antimicrobial, neuroprotective, antioxidant, and anti-inflammatory, as well as anti-tumor properties. Therefore, it is necessary to enhance the benefits that these bioactive compounds can provide through the production of nanoemulsions, which would increase the bioavailability and absorption of these. The main objective of the present work was to prepare and characterize oil/water (O/W) nanoemulsions of rosemary aqueous extract and essential oil elaborated by ultrasound. To achieve the nanoemulsions, the aqueous phase was to prepare by a liquid-solid extraction method (ratio 1:6), whereas 0.3% of essential oil as lipidic phase, using Tween 40 and Span 20 as surfactants. Nanoemulsions loaded with rosemary extracts were fabricated using surfactants blend with a hydrophilic-lipophilic balance (HLB), ranging from 10 to 14 with a high-power ultrasound. The analysis of the appropriate parameters was performed out by evaluating the particle size, zeta-potential and polydispersion index. The mean diameters (Z-average) of the dispersed particles containing rosemary extracts ranged from 50 to 437 nm and negative value of Z-potential. The results showed that the nanoemulsions with better characteristics are those of 12 HLB value and 1:1.5 oil: surfactant ratio. These results provide useful information for the design of delivery systems to encapsulate and stabilize lipophilic molecules.