Beyond natural aromas: The bioactive and technological potential of monoterpenes

Monoterpenes are natural aroma compounds that can be found in plants and processed foods, being used as flavoring agents in cosmetic, pharmaceutical and food industry. Essential oils are liquid mixtures of volatile and semi-volatile compounds, mainly monoterpenes and sesquiterpenes, from plant secondary metabolism and have showed great diversity in terms of chemical composition. Several in vitro and in vivo biological properties have been reported to these compounds demonstrating that may be useful, not only as aroma compounds, but also as bioactive molecules due to different biological activities such as antimicrobial and antioxidant. In this sense, these compounds have been employed for functional and technological purposes, including in diet supplementation, as animal feed additives, bioactive food packing development, and bioinsecticides. In this review are highlighted the main concepts regarding monoterpenes and monoterpene-rich essential oils (MREO) as well as their biological activities and applications. A critical approach based on the analysis and discussion of the most relevant studies on these substances is used. In this sense, the influence of chemical features in the biological activities are analyzed as well as the safety and toxicological concerns are discussed. Additionally, the functional and technological applications of monoterpenes and MREO are highlighted and discussed. The profile of biological activities is relevant to guide the use of monoterpenes and MREO for health or technological purposes. The knowledge of the physicochemical properties, through in silico drug-likeness study, and the correlation with the structural characteristics can be considered as important tools to understand the biological activities these compounds and consequently their applications. Thus, monoterpenes or MREO have been employed as additives in animal feed, in the manufacture of bioactive food packaging, as nutraceutical in diet supplementation, and as biocontrol agent for agri-food purpose demonstrating their versatility of application in food industry and related sectors.