Ultrasound-Pretreatment Combined With Hydrodistillation of Essential Oils and Extracts From Peruvian Plants, muña (Minthostachys mollis) and Huacatay (Tagetes minuta): Mathematical Modeling and Biological Activity

Essential oils (EO) are valuable substances due to their multiple properties and applications in various fields of industry. Thus, developing techniques that allow them to be isolated efficiently is essential. This research aimed to investigate the effect of ultrasound pretreatment (UP) on the extraction kinetics, chemical composition, antioxidant activity, and antibacterial activity of EO from the leaves of two Peruvian plants, muña (Minthostachys mollis) (MEO) and huacatay (Tagetes minuta) (HEO) obtained by hydrodistillation (HD). The effect of power (50% and 75%) and time (2 and 4 min) was evaluated in the UP. Compared with conventional HD, the UP application accelerated the extraction process but did not notably increase the EO yield. The antibacterial activity of the EO obtained by applying UP for 2 min and 50% power was evaluated against gram-positive strains (Staphylococcus aureus) and gram-negative strains (Escherichia coli and Pseudomonas aeruginosa). The extracts after the UP application were also studied, and the tails and hydrolates remained at the end of HD, which would help revalue these byproducts. The MEO and HEO showed important total phenolic compounds in their composition and a significant inhibitory activity that provides the basis for further applications.