In vitro cholinesterase, lipoxygenase inhibition evaluation of rosemary and coriander essential oil nanoemulsion and characterisation

Abstract

IntroductionThe low water solubility, high volatility, and instability of essential oils limit the application of various formulations, which can be managed by essential oils nanoemulsions. In this present study, in vitro anti-inflammatory and anticholinesterase activities were evaluated by designing nanoemulsions of rosemary and coriander essential oils with their combinations. MethodsThe chemistry of Rosmarinus officinalis L. (Rosemary, Lamiaceae) and Coriandrum sativum L. (Coriander, Apiaceae) essential oils was confirmed by GC-FID and GC/MS methods. Oil-in-Water (O/W) emulsions of essential oils and their 1:1 (w:w) combination were prepared by water titration. The essential oil/tween 20 ratio of the emulsions were 1:9, 2:8, and 3:7 (w:w) respectively. Characterisation studies were performed by measuring the droplet size, polydispersity index (PDI), zeta potential, and viscosity of the emulsions. Also, resistance to centrifugation, freezing, and heating was determined as part of the stability tests. Anti-inflammatory effects of the essential oils and emulsions were determined by in vitro 5-Lipoxygenase (LOX) inhibition. In addition, in vitro Acetylcholinesterase and Butyrylcholinesterase (AChE and BuChE) effects were evaluated. ResultsThe rosemary (1,8-cineole; 44.1%), coriander (linalool; 74.9%) essential oils, and their nanoemulsion formulations prepared were observed as stable. The anti-inflammatory activity of coriander essential oil was relatively increased by nanoemulsion preparations. However, there was no significant difference in the cholinesterase inhibition effects, when compared. To the best of our knowledge this is the first combination study of bioactivity evaluation of rosemary and coriander nanoemulsion preparations. ConclusionRosemary and coriander essential oil nano emulsifications is a promising application for increasing stability and biological activity as well.