Unveil the anticancer potential of limomene based therapeutic deep eutectic solvents

Deep eutectic solvents have been recently reported as an interesting alternative to improve the therapeutic efficacy of conventional drugs, hence called therapeutic deep eutectic solvents (THEDES). The main objective of this work was to evaluate the potential of limonene (LIM) based THEDES as new possible systems for cancer treatment. LIM is known to have antitumor activity, however it is highly toxic and cell viability is often compromised, thus this compound is not selective towards cancer cells. Different THEDES based on LIM were developed to unravel the anticancer potential of such systems. THEDES were prepared by gently mixing saturated fatty acids menthol or ibuprofen (IBU) with LIM. Successful THEDES were obtained for Menthol:LIM (1:1), CA:LIM (1:1), IBU:LIM (1:4) and IBU:LIM(1:8). The results indicate that all the THEDES present antiproliferative properties, but IBU:LIM (1:4) was the only formulation able to inhibit HT29 proliferation without comprising cell viability. Therefore, IBU:LIM (1:4) was the formulation selected for further assessment of anticancer properties. The results suggest that the mechanism of action of LIM:IBU (1:4) is different from isolated IBU and LIM, which suggest the synergetic effect of DES. In this work, we unravel a methodology to tune the selectivity of LIM towards HT29 cell line without compromising cell viability of healthy cells. We demonstrate furthermore that coupling LIM with IBU leads also to an enhancement of the anti-inflammatory activity of IBU, which may be important in anti-cancer therapies. Tis work was supported by the Associate Laboratory for Green Chemistry- LAQV which is fnanced by national funds from FCT/MCTES (UID/QUI/50006/2019). Funding from the European Union Horizon 2020 program has also been granted through the project Des.solve (ERC consolidator), ERC-2016-COG 725034. J.M.Silva would also like to acknowledge the fnancial support by the Portuguese Foundation for Science and Technology (FCT) through the post-doctoral grant with reference number SFRH/BPD/116779/2016 and L. Rodrigues acknowledges her doctoral grant SFRH/BD/116002/2016. A. Matias acknowledges the fnancial support received from the Portuguese Fundação para a Ciência e Tecnologia (FCT) through the PEst-OE/EQB/LA0004/2011 grant and by iNOVA4Health - UID/Multi/04462/2013. A. Matias also thanks to FCT, her IF Starting Grant – GRAPHYT (IF/00723/2014).