Natural Macromolecules as Carriers for Essential Oils: From Extraction to Biomedical Application

Abstract

Essential oils (EOs) and their main constituents, the terpenes, are widely studied, mostly relating to their antioxidant ability and bioactivity, such as antimicrobial, anticancer, anti-inflammatory, and range of other actions in the living systems. However, there is limited information on their bioavailability, especially upon clinical studies. Having in mind both strong biological effects and health benefits of EOs and their specific physicochemical properties (volatility, lipophilic character, low water solubility or insolubility, viscosity, expressed odor, concentration-dependent toxicity, etc.), there is a need for their encapsulation for target delivery. Encapsulation of EOs and their constituents is the prerequisite for enhancing their oxidative stability, thermostability, photostability, shelf life, and biological activity. We considered various carrier types such a (1) monophase and polyphase polysaccharide hydrogel carriers, (2) polysaccharide-protein carriers, and (3) lipid carriers in the context of physicochemical and engineering factors. Physicochemical factors are encapsulation efficiency, chemical stability under gastric conditions, mechanical stability, and thermal stability of carrier matrices. Choice of carrier material also determines the encapsulation technique. Consequently, the engineering factors are related to the advantage and disadvantage of various encapsulation techniques frequently used in the literature. In addition, it was intended to address the interactions between (1) main carrier components, such as polysaccharides, proteins, and lipids themselves (in order to form chemically and mechanically stable structure); (2) main carrier components with pepsin under gastric conditions (in order to form resistant material under gastric conditions); and (3) main carrier components with EOs (in order to enhance encapsulation efficiency), as a necessary precondition for whole process optimization. Finally, different sources for obtaining natural carrier macromolecules are surveyed, especially the agro-waste materials and agricultural and food by-products. This review article highlights the bioavailability aspects of encapsulated EOs and physicochemical and engineering factors concerning natural macromolecule carriers for their target delivery and application.

Chitosan-Coating Effect on the Characteristics of Liposomes: A Focus on Bioactive Compounds and Essential Oils: A Review

“…In the last decades, a growing interest in using plant-based antimicrobials has been known a rise, and special attention was given to EOs. EOs are products obtained from aromatic plants by physical processes of distillation or pressing [92]. They contain volatile compounds stored in plant's specialized structures to offer protection against various insults, including pathogen (bacteria, fungi, viruses) attacks [93].…”

“…In addition, their low water solubility and bioavailability hamper the clinical use of EOs. Therefore, encapsulation has been widely used to overcome such limitations but also to ensure targeted delivery and to boost the antimicrobial efficacy of EOs [92,107,110,111].…”

Effects of Essential Oils and Selected Compounds from Lamiaceae Family as Adjutants on the Treatment of Subjects with Periodontitis and Cardiovascular Risk

“…In traditional medicine, EOs have been used for the treatment of inflammatory processes [65], as they possess many beneficial properties due to the presence of several antioxidant and anti-inflammation compounds such as terpenes, the main class of compounds, and especially monoterpenes [61]. They are also present in numerous pharmaceutical products [66]. In recent studies, Citrus bergamia Risso and Poiteau juice (known as Bergamot) on cardiometabolic risk in dyslipidemic subjects was shown to significantly reduce plasma lipids and improve the atherogenic lipoproteins and subclinical atherosclerosis [67].…”

Lipid-Based Nanostructures for the Delivery of Natural Antimicrobials

“…Conventionally, encapsulation of EOs has represented a viable approach to ensure the physical stability of EOs, including their protection from evaporation, and to enable their controlled release. In the last years, different encapsulation systems for EOs have been exhaustively reviewed [100][101][102][103]. In particular, the recent literature reports many different formulations of EO nanoemulsions as natural food preservatives.…”