Essential Oils: Recent Advances on Their Dual Role as Food Preservatives and Nutraceuticals against the Metabolic Syndrome

Abstract

Essential oils (EO) are compounds synthesized by plants as secondary products and are a complex mixture of volatile molecules. Studies have demonstrated their pharmacological activity in the prevention and treatment of metabolic syndrome (MetS). Moreover, they have been used as antimicrobial and antioxidant food additives. The first part of this review discusses the role of EO as nutraceuticals to prevent metabolic syndrome-related disorders (i.e., obesity, diabetes, and neurodegenerative diseases), showing results from in vitro and in vivo studies. Likewise, the second part describes the bioavailability and mechanisms of action of EO in preventing chronic diseases. The third part presents the application of EO as food additives, pointing out their antimicrobial and antioxidant activity in food formulations. Finally, the last part explains the stability and methods for encapsulating EO. In conclusion, EO dual role as nutraceuticals and food additives makes them excellent candidates to formulate dietary supplements and functional foods. However, further investigation is needed to understand EO interaction mechanisms with human metabolic pathways and to develop novel technological approaches to enhance EO stability in food systems to scale up these processes and, in this way, to overcome current health problems.

Keywords: antimicrobial; antioxidant; diabetes; essential oils; metabolic syndrome; nanoencapsulation; neuroprotection; obesity.

Figure 1

Essential oils (EO) absorption mechanisms. (A) Olfactory administration. Odor compounds bind to cilia in olfactory receptor cells, which activates G protein-coupled receptors to depolarize cell membranes and promote signal transduction to the limbic system and cerebral cortex. (B) Dermal administration. EO can penetrate the stratum corneum and reach the bloodstream through transcellular or intercellular permeation. (C) Oral administration. Due to their lipophilic character, terpenoids and steroids can be easily absorbed in the small intestine through lipid metabolism. Saccharide-conjugated molecules must be hydrolyzed and then metabolized in the small intestine.

Figure 2

Mechanisms of action of antimicrobial and antioxidant properties of EO.

Figure 3

Schematic representation of encapsulation process and common shell materials used in food systems.