The extraction processes for medicinal plants, particularly the distillation of aromatic plants, generate significant quantities of by-products, consisting of fibrous biomass and hydrosols. These by-products pose challenges for disposal and recovery. Consequently, it is imperative to make the entire, highly energy-intensive process more sustainable by valorizing all derivatives.
This study aims to recover bioactive compounds, particularly polyphenols, from these biomasses. Polyphenols represent a large class of compounds known for their biological activities. Artemisia dracunculus, Echinacea purpurea, Helichrysum italicum (from the Asteraceae family), and Lavandula angustifolia, Lavandula x intermedia, Melissa officinalis, Salvia officinalis, Salvia sclarea, and Salvia rosmarinus (from the Lamiaceae family) were subjected to steam distillation. The essential oils obtained were characterized using gas chromatography, and the residual biomasses were processed with innovative extraction methods.
The study investigated the use of natural deep eutectic solvents (NADES) for extracting polyphenols from the residual biomasses. Comparisons were made between the extracts obtained using NADES and those obtained using ethanol, a traditional solvent commonly employed for such purposes. The chemical characterization of the extracted compounds was performed using advanced analytical techniques, including HPLC-DAD and UHPLC-HRMS.
The application of NADES demonstrated superior extraction efficiency for biomasses from both the Asteraceae and Lamiaceae families. Additionally, NADES exhibited several environmentally friendly characteristics, enhancing their sustainability profile. For these reasons, NADES present a viable alternative system for the recovery of bioactive compounds and could be used to formulate new products for the food, pharmaceutical, and cosmetic industries.