Synthesis and Anti-Cancer Activity in Vitro of Synephrine Derivatives

Glucocorticoids (GC) are widely used in the treatment of hematological malignancies; however, the long-term treatment lead to atrophic and metabolic adverse effects. Selective glucocorticoid receptor agonists (SEGRA) with reduced side effects could be the better GC alternative. More than 30 SEGRA were described but none of them reached clinical trials as anticancer treatment. In the present work, we proposed the novel approach to broaden the list of potential SEGRA by synthesis of derivatives of synephrine, the molecule of natural origin. We synthesized 26 compounds from the class of synephrine derivatives, and studied their anticancer effect in vitro in leukemia and lymphoma cells with MTT assay as well as their potential affinity to glucocorticoid receptor (GR) in silico using molecular docking approach. Novel derivative 1-[4-(benzyloxy)phenyl]-2-(hexylamino)ethanol (10S-E2) with the highest GR affinity in silico revealed the micromolar range cytotoxicity in lymphoma and leukemia cells after 24 h of treatment. The other compound, 2-(hexylamino)-1-(4-nitrophenyl)ethanol (13S-G2) with high GR affinity demonstrated cytotoxicity in the range of 50-70 µM. Overall, our results provide the rationale for the development and further investigation of synephrine derivatives as SEGRA with anticancer activity.