Mucuna cinerea Seeds: Levodopa Extraction Using Deep Eutectic Solvent and Its Mammalian Cell Activity

A new class of deep eutectic solvents (DES) was used in the extraction of levodopa (L-dopa) present in Mucuna cinerea, which has been termed "green" or "designer" solvents, with notable productive and economic/environmental benefits. The seeds of Mucuna cinerea were prepared and submitted to extraction with heating and agitation in a solvent mixture of DES with citric acid, urea, or glycerol. The extracts were analyzed by high performance liquid chromatography (HPLC) which confirmed the efficiency of DES in extracting L-dopa. These extractions were carried out to determine the L-dopa extracts in DES with regard to the induction of cellular response activity, demonstrating the synergy between L-dopa and DES. The DES-glycerol extract exhibited a higher proliferative activity than commercial L-dopa after 24 h of treatment. The human glandular kallikrein-1 gene (hGK3) demonstrated higher expression in the treatment with the DES-urea, while the G protein-coupled receptor kinase-6 gene (GRK6) showed higher expression for all extracts compared to commercial L-dopa, with a higher value obtained for DES-glycerol, followed by DES-urea extract. The DES extraction method is therefore promising and unprecedented, confirming its possible use in the replacement of expensive solvents, supporting the use of ecologically viable DES in the extractions of other plant species.