Levodopa (l-dopa) is an amino acid precursor of catecholamines dopamine, norepinephrine, and epinephrine, which can be used in the treatment of Parkinson’s disease. Levodopa is present in several vegetable sources, such as Mucuna pruriens seeds. However, the extraction of levodopa from vegetable matrices is usually carried out with volatile organic solvents (methanol, hexane, and chloroform). In this work, we demonstrate that aqueous solutions of eutectic solvents (ES) can be used as alternative solvents for the extraction of levodopa. ES based on carboxylic acids or polyols combined with cholinium chloride ([Ch]­Cl) were studied. Experimental conditions such as the temperature, solid–liquid (solvent/biomass) ratio, and ES concentration in aqueous solutions were optimized by a response surface methodology, with the aim of maximizing the levodopa extraction yield. Extraction yields of up to 9.9 ± 1.0 wt % (levodopa per dry weight of M. pruriens seeds) were obtained at a temperature of 56 °C, a solid–liquid ratio of 1:7, and an ES concentration close to 35 wt %. The recovery of levodopa from the ES aqueous solutions was achieved by a subsequent solid-phase extraction step, allowing the recovery of 87% of the extracted levodopa with high purity. This step further allowed solvent recovery and reuse, demonstrating that the solvent can be reused at least three times without compromising the extraction yield of levodopa. This work shows the remarkable capacity of ES aqueous solutions to extract the value-added compound levodopa from biomass and the possibility of applying reusable solvents, paving the way for their use as alternative solvents to extract bioactive compounds from natural sources.

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Caracterização físico-química da amêndoa e do óleo de baru submetido à extração sólido-líquido com solventes alternativos Physicochemical characterization of almond and baru oil submitted to solid-liquid extraction with alternative solvents

The baru oil has a high degree of unsaturation and relevant amount of oleic and linoleic acids content, which favors its use for food and pharmaceutical industries. Hexane is the most widely used solvent for oil extraction. However, its flammability, cost, and polluting potential justify the study of alternatives solvents such as ethanol and isopropanol that are less toxic and flammable and efficient in the extraction of other oils, as already reported in literature. This work represents the extraction of baru almond oil with the solvents hexane, ethanol, isopropanol, and isopropanol: ethanol (1:1) to compare their extraction yields. The parameters solid: solvent ratio, temperature and time were optimized using a central composite design. The higher yields were found in lower solid: solvent ratios and higher temperatures (ethanol - 29.12 %, isopropanol - 39.66 %, isopropanol: ethanol - 41.13 % and hexane - 36.59 %). Isopropanol and isopropanol: ethanol (1:1) mixture presented satisfactory results when compared to hexane, becoming alternatives for its replacement. In the extractions which the time was significant, the adjustment of the kinetic models indicated that the extraction is described by a second order model. The solvents researched showed to be promising for hexane replacement in the oil extraction from baru almond.

Brasil apresenta diversos biomas que são conhecidos pela elevada biodiversidade e, dentre eles, destaca-se o Cerrado. O barueiro (Dipteryx alata Vog.), pertencente à família Fabaceae, é uma das espécies nativas de grande importância do Cerrado. Esta planta tem como fruto o baru, fonte de carboidratos, lipídios e minerais. A sua semente (amêndoa) possui um alto conteúdo de lipídios, proteínas e fatores de extrema relevância para prevenção de carência nutricional. Dela é possível extrair um óleo com alto grau de insaturação, rico em ácido oleico e linoleico. O presente estudo teve como objetivo a extração do óleo da amêndoa de baru em batelada agitada com os solventes hexano, etanol, isopropanol, e isopropanol:etanol (1:1) a fim de comparar os rendimentos de extração. A extração foi realizada com um delineamento composto central 2³ em que os parâmetros razão sólido:solvente, temperatura e tempo foram otimizados. Os maiores valores de rendimento foram encontrados em menores razões sólido:solvente e elevadas temperaturas. As extrações com melhores rendimentos foram: etanol 29,12 %, isopropanol 39,66 % e mistura isopropanol:etanol 41,13 %, enquanto para o hexano foi de 36,59 %. O emprego da mistura isopropanol:etanol (1:1) como solvente gerou um resultado satisfatório, sendo comparável ao hexano e, portanto, a melhor alternativa para sua substituição. Os solventes investigados são promissores para a substituição do hexano na extração do óleo de baru.