Β-Sitosterol-imidazolium ionic liquid conjugates: synthesis, computational evaluation, and anticancer activity...

Colorectal cancer (CRC) remains a leading cause of cancer-related mortality worldwide, and current treatments are limited by low efficacy, toxicity, and resistance. Among phytosterol compounds, β-sitosterol (BST) was identified in abundance in plants and showed potential anticancer activity, as evidenced by several in vitro and in vivo studies. But the poor solubility of BST limits its efficacy toward anti-cancer therapeutics. Research showed that imidazolium-based ionic liquids (ILs) were found to be very effective for increasing the solubility as well as enhancing the bioavailability of anti-cancer drugs. To develop novel phytosterol-based drug candidates with improved anticancer potential, BST was chemically modified through the conjugation with imidazolium-based ionic liquid moieties to generate a series of BST ionic liquid derivatives (BST-ILs). The synthesized derivatives were characterized, and their physicochemical and pharmacokinetic properties were evaluated through in silico ADMET and density functional theory analyses. Notably, the ionic liquid derivatives displayed improved membrane permeability. The biological activities of BST and its BST-ILs derivatives were assessed in the human colorectal cancer (HCT116) cell line. The results demonstrated a concentration-dependent reduction in cell viability, with the ionic liquid conjugates exhibiting significantly enhanced cytotoxicity compared to the parent compound. Furthermore, the derivatives effectively inhibited cell migration and induced apoptosis, as confirmed by wound healing assay and gene expression analyses, including upregulated expression of apoptosis marker genes Bax and Caspase-3 and downregulation of Ki67 and Cyclin D1. Flow cytometric analysis in this study further demonstrated increased apoptotic cell populations following treatment with the derivatives. In addition, western blot analysis revealed altered pro-Caspase-3 protein expression, further supporting the modulation of apoptosis-associated signaling. Molecular docking and molecular dynamics simulations were performed to investigate interactions with key enzymes of the mevalonate pathway, namely farnesyl diphosphate synthase (FDFT1) and squalene synthase (SQS). These findings highlight BST-ILs conjugates as promising steroid-based candidates with the potential to target sterol biosynthesis pathways in colorectal cancer with significant anti-proliferative activities, highlighting the importance of these BST-ILs for further investigation for anti-cancer drug development.