Aqueous Solutions of Surface-Active Ionic Liquids: Remarkable Alternative Solvents To Improve the Solubility of Triterpenic Acids and Their Extraction from Biomass

Abstract

Triterpenic acids (TTAs) are well known for their relevant biological properties and have been facing an increasing interest for nutraceutical and pharmaceutical applications. To overcome the concerns associated to the commonly used volatile organic solvents for their extraction from biomass, here we investigate the potential of aqueous solutions of ionic liquids (ILs) as alternative solvents. The solubility of ursolic acid (UA) was firstly determined in several aqueous solutions of ILs (hydrotropes or surface-active) at 30°C to appraise the dissolution phenomenon. Conventional surfactants were also investigated for comparison purposes. The collected data reveal a remarkable enhancement in the solubility of UA (8 orders of magnitude) in surface-active ILs aqueous solutions when compared to pure water. Afterwards, the potential of these ILs aqueous solutions was confirmed by their use in the extraction of TTAs from apple peels. Total extractions yield of TTAs of 2.62 wt.% were obtained using aqueous solutions of surface-active ILs at moderate conditions, overwhelming the extraction yields of 2.48 wt.% obtained with chloroform and 1.37 wt.% with acetone using similar conditions.

Extraction of High Value Triterpenic Acids from Eucalyptus globulus Biomass Using Hydrophobic Deep Eutectic Solvents

“…For example, Domingues et al [11] have optimized the extraction of TTAs from E. globulus outer bark using supercritical CO 2 , under 200 bar, 40 • C and 5% ethanol, but with extraction yields 20% lower than those obtained with dichloromethane [12]. Ionic liquids have also been recently studied for the extraction of TTAs, achieving higher extraction yields when compared to conventional solvents [29]. This last study opened new perspectives to study alternative and tunable solvents for the extraction of TTAs from E. globulus outer bark, as ionic liquids but also deep eutectic solvents (DES) [30].…”

“…The mobile phase consisted of 87% (v/v) methanol, and 13% (v/v) of an aqueous solution of 0.1% (v/v) TFA. Separations were conducted in isocratic mode, at a flow rate of 1 mL min −1 and with an injection volume of 10 µL [29]. The wavelength was set at 210 nm.…”

Deep Eutectic Solvents as Efficient Media for the Extraction and Recovery of Cynaropicrin from Cynara cardunculus L. Leaves

“…Furthermore, it was recently demonstrated that they can also be used in the dissolution of more complex biomacromolecules, such as lignin [ 10 ]. Also worth noting, and similarly to ionic liquids [ 11 , 12 , 13 ], it was demonstrated that aqueous solutions of DES can perform better than the pure solvents [ 14 ], with inherent economic and process benefits. Finally, if benign or natural-based DES (the so called NADES) are used, these may be kept in the final formulations, in some cases also contributing to the improvement of the extracts biological properties [ 15 , 16 ], again with a close similarity to ILs [ 12 ].…”

Synthesis and Self‐Assembly Properties of New Surface‐Active 1‐Alkylimidazolium Ionic Liquids in Aqueous Media

“…Both cationic and anionic SAIL have been designed and investigated for their self‐assembly by changing the alkyl chain length, charged head group structure, functional groups, and counterions (Anouti et al, ; Baker et al, ; Blesic et al, , ; Galgano and El Seoud, ; García et al, ; Pillai et al, ; Rao et al, ; Šarac et al, ; Singh et al, ; Wang et al, ; Wang and Wang, ). The high tunability of IL opens up a broad range of applications for SAIL such as in micellar catalysis (Adam et al, ; Bica et al, ; Cognini et al, ) and in analytical chemistry and separation science (de Faria et al, ; Pino et al, ; Ressman et al, ). It was also demonstrated that some SAIL can be effective alternatives to the surfactants commonly used in enhanced oil recovery (EOR) processes with important advantages over the traditional surfactants and polymer‐flooding methods (Bera and Belhaj, ; Lago et al, ; Zhou et al, ).…”

“…* Claudia G. Adam cadam@conicet.gov.ar * Graciela G. Fortunato gfortuna@fiq.unl.edu.ar 2014; Šarac et al, 2017;Singh et al, 2016;Wang et al, 2008;Wang and Wang, 2014). The high tunability of IL opens up a broad range of applications for SAIL such as in micellar catalysis (Adam et al, 2017;Bica et al, 2012;Cognini et al, 2016) and in analytical chemistry and separation science (de Faria et al, 2017;Pino et al, 2012;Ressman et al, 2013). It was also demonstrated that some SAIL can be effective alternatives to the surfactants commonly used in enhanced oil recovery (EOR) processes with important advantages over the traditional surfactants and polymer-flooding methods (Bera and Belhaj, 2016;Lago et al, 2012;Zhou et al, 2016).…”