Currently Applied Extraction Processes for Secondary Metabolites from <i>Lippia turbinata</i> and <i>Turnera diffusa</i> and Future Perspectives

• Main Authors: Guillermo C. G. Martínez-Ávila, Pedro Aguilar-Zarate, Romeo Rojas
• Format: Article
• Language: English
• Published: MDPI AG 2021-09-01
• Series: Separations
• Subjects: <i>Lippia turbinata</i>; <i>Turnera diffusa</i>; essential oils; polyphenols; monoterpenes
• Online Access: https://www.mdpi.com/2297-8739/8/9/158

The poleo (<i>Lippia turbinata</i> Griseb.) and damiana (<i>Turnera diffusa</i> Wild) are two of the most valued species in the Mexican semidesert due to their medicinal uses. The conventional essential oil extraction process is hydrodistillation, and for the extraction of antioxidants, the use of organic solvents. However, these techniques are time-consuming and degrade thermolabile molecules, and the efficiency of the process is dependent on the affinity of the solvent for bioactive compounds. Likewise, they generate solvent residues such as methanol, hexane, petroleum ether, toluene, chloroform, etc. Therefore, in recent years, ecofriendly alternatives such as ohmic heating, microwaves, ultrasound, and supercritical fluids have been studied. These methodologies allow reducing the environmental impact and processing times, in addition to increasing yields at a lower cost. Currently, there is no up-to-date information that provides a description of the ecofriendly trends for the recovery process of essential oils and antioxidants from <i>Lippia turbinata</i> and <i>Turnera diffusa</i>. This review includes relevant information on the most recent advancements in these processes, including conditions and methodological foundation.